Erratic Vacuum Gauge Reading

Sometimes it cracks and leaks. A low reading could indicate a vacuum leak or possibly a leaking EGR valve. The issue is that I took the vacuum reading and the reading jumps from 5-10 in of Hg. This FAQ pertains to short sweep, electric gauges, that use a single-terminal sender. (in a smooth or jerky manner, erratic, etc. Gauge reference models read zero with the gauge port open. 5x has developed a worsening erratic idle once eng is warm. It also could be as simple as a loose or broken coil wire, dirty throttle plate, pcv valve or cracked vac line. The gas gauge has been flaky the last three weeks. The Sport III Tachometers deliver style and performance while featuring our highest accuracy with fast needle response for complete scale. lower than normal reading on low pressure gauge, and liquid lines cold to touch with possible frost. If your meter reads less than 2300, that is fine. I've had a number of suggestions on how to fix it and nothings seems to work. Any other suggestions about why the vacuum readings are erratic? I just got my carb back from SMI and needed to use the vacuum gauge to adjust the idle mixture screws. Erratic AFR's, running rich Ok, so after I had the CPE downpipe taken off and had the stock cats put back on, I started to notice the car jerking, It was subtle at first but has progressively gotten worse. I've been reading through the factory service manual, and theres more information in there on how to diagnose a squeaking serpentine belt than an issue like this. The most common cause of all vacuum gauge failures is contamination of the sensor. Voltage from plug to guage reads 5. how do you do a compression test. This is done by disconnecting the vacuum tube from the vacuum source (engine) and attaching it to the tester. If the vacuum reading fluctuates within the normal range, it is likely to be as a result of broken ring or leaking valves. Never mistake your Mustang for overheating again, it could just be your gauges. If something is wrong with the engine, it can mean a greater problem than. A vacuum gauge will fluctuate or give erratic readings while handling air during operation. Connect a vacuum gauge to the intake manifold vacuum take-off; many carb spacers have one, if you don't have one on yours, it's nice to have. It runs like a champ. As soon as I raise the rpms just a little bit, I get a steady 20. (has run twice tho) comes up with p0335 rpm noise. This filter would be helpful if you have interference on the tachometer’s signal which is causing erratic behavior on your tachometer. ISC (Idle Speed Control) Troubleshooting, Replacement, Repair. NOTE #3: Code P0460 specifically refers to issues in the fuel level sender unit input circuit, even though incorrect or erratic fuel gauge readings can also be caused by short circuits and other problems between the sender unit and the fuel gauge. This leads to a very erratic idle and poor off-idle throttle response. ABOUT AIR LEAKS - The engine you save could be your own. what can be the reasons for this erratic reading in the vapor line. It depends on what type of rings were installed and the bore finish to determine how long they take to break in. Some vehicles have a resistor wire running from the ignition switch to the coil’s + terminal. A vacuum leak can produce a misfire as well. I showed up several hours late and took it to the pumps, it took 20 Gallons of Gas. MG MGB Technical vacuum gauge readings BBS discussion. Analyzing Ignition Misfires Download PDF. vacuum readings are becoming more common due to changes in engine design. If you want to do your own burner service, read on. ABN Carburetor Synchronizer and Adjustment Tool Kit - Vacuum Gauge Set Gs Kz 550 650 750 Get accurate readings and synchronize the values of 4 carburetors as well adjust them at the same time with the ABN Carburetor Synchronizer and Adjustment Tool Kit - Vacuum Gauge Set Gs Kz 550 650 750. I don't believe there is a leak, I tested with a vacuum gauge and the vacuum holds steady. Kepping in mind that this is a cheap-o Harbor Freight tool, it probably is not what one would consider a precision instrument. gyroSuction3-200-12. If the vacuum is not dumped we will need to check for a pinched vacuum hose or a faulty or out of adjustment brake vacuum-control switch. However, you'll have to plug the vacuum line to prevent a vacuum leak to the intake manifold. Not by just a vacuum reading. Erratic Readings Erratic Readings can be caused by a poor connection, moisture in the unit, or a damaged transmitter. From Crankshaft Coalition Wiki. Slowly depress the throttle pedal to wide open. When driving the fuel gauge drops rapidly and there seems to be excessive vacuum in the fuel tank. Input Output V ~ Load Cell. Disconnect the exhaust ventilation equipment. Going off the EBC's reading of -0. This brings up an accurate reading of the gas gauge. Manual reparacion Jeep Compass - Patriot Limited 2007-2009_ Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. It is important to judge engine performance by the general location and action of the needle on a vacuum gauge, rather than by a single reading. while this is happening the fuel gauge goes to zero and back then back to zero and so forth until. anyone fitted a vacuum guage? some time ago I fitte a new pair of DIY ported SD1 heads to a P6 block, new timing gear, new 3. An automotive air conditioner has a high and low side, divided by a metering device and the A/C compressor. Return with readings and inspections done. Valve partially closed. Check vacuum advance operation (where equipped) as follows: a. It's simply a matter of statistics. If you can’t reach this level of vacuum, you may have a leak or an overflow hose needs to be clamped off. 331 erratic bouncing vacuum gauge readings while at idle. Note the vacuum reading. I have the total vacuum set at 16 degrees (about 2 notches less than the maximum limit), and my vacuum advance starts at about 5 inches of vacuum and is all in by 15 inches, which I checked with a vacuum gauge. Erratic fuel gauge readings? 1 following. Gauge readings that may be found are as follows: Normal Engine Operation At idling speed, an engine at sea level should show a steady vacuum reading between 17" and 21" HG. General Motors vehicles have had a tremendous problem with dash gauge malfunctions. If your micron gauge is acting erratic, for instance, vacuum readings at atmosphere, readings rising and falling during a steady pull down or holding vacuum, cleaning the sensor may be necessary. Page 1 of 2 - Erratic fuel pressure at idle and dropping pressure on load - posted in R35 GT-R: Got the car back, and fuel pressure was initially not dropping though sometimes reading erratic. I've checked all plugs on all sensors and jiggled wire harness and vacuum hoses while at idle and heard no change to the. So your oil pressure gauge fluctuates while driving? People instinctively don't believe dash gauges. Relief valve set too high. The VDO sender has a higher resistance rating than the old one, so I figure the gauge is reading high because of that, no that the pressure is too high. If you have some pressure build up in the in the tank when you open the fuel cap, it would indicate that the carbon canister is plugged. these cars had a lot of problems with the fuel level sensor (in the tank). Cranking Vacuum Test: 1. The o2 sensor can go bad if it’s getting too hot. NOW SHIPPING! - MTX Analog series gauges feature a microprocessor driven industrial grade, high torque 270 stepper motor with superior holding force needle for the most extreme applications. Connect a vacuum gauge to the intake manifold vacuum take-off; many carb spacers have one, if you don't have one on yours, it's nice to have. What parts allow the fuel consumption gauge to work? Hey guys, my gauge goes from zero to max, and back and forth during normal driving. Once the connection is sealed, crank the engine over for 20 seconds. Record gauge reading here _____" HG for use later. This is "1955 Ford Fairlane 292 Y block Erratic Vacuum Gauge Reading" by Daniel Jessup on Vimeo, the home for high quality videos and the people who love…. leaking valves. I have a 2012 F150 which is giving erratic fuel readings. Note the vacuum readings, and any fluctuations, at each speed. I haven't measured it, but would assume at idle the vacuum reading will be very steady because this is the greatest amount of vacuum. It also could be as simple as a loose or broken coil wire, dirty throttle plate, pcv valve or cracked vac line. readings taken from the two types of gauges at three different pressures. High reading would indicate a. of increase in altitude, 1 "hg is subtracted from the vacuum reading. This vacuum gauge reading indicates: A. Changing the fuel pressure on an EFI System is an effective method of affecting engine performance and making more power. Fuel, oil pressure and temperature gauges also can read erratically and stick. Just this weekend, i noticed that the temperature gauge will go up to 91 deg. 0 mm refer to Fig. See MKS Instruments vacuum gauges or Granville Phillips ion gauges (now owned by Helix Technology). If the voltmeter response is sluggish or the voltage. Let's say you were in high gear, at 2800 RPM, going up a medium hill, and your dash mounted 3 inch vacuum gauge was reading 8 inches of vacuum. I had a very similar vacuum guage in 1967 that I used on my '55 Chevy. Vacuum Gauge Reading - 308 a couple of things that can cause the erratic needle at idle, not saying your number 2 is missing, lol. Furthermore, the unit has a long hose for an easy each and is also flexible to easily go round curves. It is very important to correctly size and select the vacuum pump as it is to lay down the right specifications. It must also be remembered that vacuum leaks and/or poor compression can result in a low vacuum. The boost gauge jiggle got worse and the car began to idle like crap. The most common cause of all vacuum gauge failures is contamination of the sensor. Reading many posts stating the gauge doesn't actually measure vacuum but only receives an electronic signal from a device, and that reading is shown on the gauge?. How to obtain a VACUUM GAUGE reading: The Vacuum Gauge (5120) indicates the amount of vacuum, in inches of mercury (Hg). these vacuum gauge fluctuation may be caused by: A. The pressure of the media to be measured is compared against a reference pressure of absolute zero (absolute vacuum) in a sealed reference chamber. At times my overdrive light flashes and the transmission shifts very hard, what could cause this? I have a 91' F-150 with a straight 6, E4OD trany. Is this common? 460 ford with erratic vacuum part 2?. In the rotary oil-sealed pump a. Coolant if low alone would make gauge reading erratic and heater(s) run warm, hot or stone cold even while. If the reading is what was expected, then the transducer is operational. As mentioned if one or more cylinders produce less vacuum than the others the needle of the tester will fluctuate. Vacuum comes from the vacuum pump; located on the driver's side of the head. The tachometer gauge may read erratic or not at all. Decided to put the vacuum gauge on the wrx, results don't look good. This brings up an accurate reading of the gas gauge. If the gauge is reading funny, check the main earth strap from the coil pack of the sixes to near the air filter box. Vacuum Tests A. Just this weekend, i noticed that the temperature gauge will go up to 91 deg. 3 Dashpod Self-Diagnosis. To each their own. Test #4 tests the wide open throttle (WOT) setting. , dry gas meter with 2 percent accuracy, and re- lated equipment, or equivalent, as required to maintain an isoklnetic sampling rate and to determine sample volume. Anyway the actuator - see photo checks out electrically with purge valve working. He put in new ignition wires, rotor cap and said this should correct the problem. Symptoms of a compression problem can include hard starting, erratic idling, loss of power under load and hard starting when the engine is hot. Step 5: You're now ready for sassafras! Go up and continue reading from the top. Manual reparacion Jeep Compass - Patriot Limited 2007-2009_ Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Categories: Baghouse Gauges , Pneumatic Gauges. Do you have a fuel pump/vacuum test gauge you could compare it with. will a weak valve spring cause a steady low reading on a vacuum gauge? will a weak valve spring cause a steady low reading on a vacuum gauge? Follow. I filled it back up and the gauge worked correctly. Corvette Speedometer & Tachometer Repair Installation. CONTINUED AIRWORTHINESS 3-15. Last edited by 74 Thing on Mon Jun 03, 2019 12:35 pm; edited 1 time in total. Temperature gauge or engine mounted gauge sensor defective or shorted. I have a Ford F series Pickup equipped with the E4OD. Make sure that it is one for a gauge not a temp light. Verify that the correct temp sender has been installed--the pastic portion of the sender and the harness connector should be gray, not black. Next, race the motor for a moment and again observe the pressure reading on the gauge. This is because the car cannot combust on carbon dioxide from the tailpipe — it needs atmospheric oxygen. Erratic idle + falling out of sync « on: September 19, 2019, 09:59:50 AM » I've got the 700sc running really well, i was having some issues last week, so i decided to re-sync the carbs. The goal is to run enough timing advance that you obtain the highest manifold vacuum level at the lowest engine speed possible. Gauge readings that may be found are as follows: Normal Engine Operation At idling speed, an engine at sea level should show a steady vacuum reading between 17" and 21" HG. The vacuum reading sounds about right for the cam and cubic inches but it should not flutter. 1999 olds silhouette fluctuating heater gauge. Probably the first thing you'll notice is the oil pressure gauge or the warning light reading very low or coming on when the car is fully warmed and idling like at a traffic light. I've sprayed solvent throughout vacuum and gasket connections around intake and throttle body, but no idle change. We've all been there. The 2000 Chevrolet Silverado 3500 has 28 NHTSA complaints for the fuel system, other:storage:fuel gauge system at 42,482 miles average. Loss of vacuum can occur when the tank lid gasket is missing or cut. Find helpful customer reviews and review ratings for Supco VG60 Electronic Vacuum Gauge, 50 to 5,000 micron, LED Display at Amazon. Draft volume specifies the cubic feet of gas that a chimney can handle in a given time. This low reading is normal. The engine idles perfectly. what can be the reasons for this erratic reading in the vapor line. It's simply a matter of statistics. Mechanics can read a trouble code to trace it to a leak in the evaporative. Ported vacuum should be connected to the canister. This tells us the vacuum pump is working properly. This company is not yet accredited. properly inspect gauge ground. I disconnected the vacuum line to the distributor and the timing is like it should be. The speedometer has similar symptoms: The needle fluctuates, sticks in one position, will not return to zero, will not register past a certain speed, reads slow or fast, the odometer does not register or it also just does not work. Diagnosing car engines with a vacuum gauge. when gutted locked out hei dizzy pick up is wired to msd 6al and blue wire is hooked up and set to tach setting engine runs fine. Welcome To V6Mustang. From Crankshaft Coalition Wiki. If outside. It also could be as simple as a loose or broken coil wire, dirty throttle plate, pcv valve or cracked vac line. Furthermore, the unit has a long hose for an easy each and is also flexible to easily go round curves. The PD of flash zone and the ejector system matches with the design value. There will also be a very noticeable valve train noise when the valve spring is broken badly. Ford 460 engine problems: Sam Mckee: 11-21-04 : I have a 1997 Ford 460 with about 100,000 miles on it. If full manifold vacuum is not present at the outlet fitting, but was present at the inlet fitting, replace the valve. This is called a running vacuum test. The electric and mechanical gauges feature various temperature scales and designs to match the setup of your vehicle. Noisy or erratic readings and total gauge failures are all possible indications of gauge contamination. The gauge should start climbing. The needle on the gauge fluctuates between 15 "hg and 20 "hg vacuum at idle. Pressure gauges indicate if a system or component in a process is operating correctly or not. when the 2 pick up wires are connected to fitech and black wire is hooked up to white wire on msd 6al and setting is set to vr+coil and key cycled. CASE 2: Your multimeter DID NOT display a decreasing voltage signal as you pumped up the vacuum gauge. Erratic AFR's, running rich Ok, so after I had the CPE downpipe taken off and had the stock cats put back on, I started to notice the car jerking, It was subtle at first but has progressively gotten worse. pressure line, thumping noise in. The goal is to run enough timing advance that you obtain the highest manifold vacuum level at the lowest engine speed possible. when gutted locked out hei dizzy pick up is wired to msd 6al and blue wire is hooked up and set to tach setting engine runs fine. Disconnect the exhaust ventilation equipment. The readings should not become erratic, should remain reasonably stable and return to original zero readings. A vacuum gauge will fluctuate or give erratic readings while handling air during operation. Switching off the engine for about 5 minutes everything goes back to normal. Once you've connected the gauge you should see a STEADY reading at idle with the throttle closed. If a fuel level sensor DTC sets, the fuel gauge will default to always showing low fuel. Make sure that blood’s flowing to all the right places with an Oil Pressure Gauge. The High Vacuum Gauge might be erratic. This eliminates erratic vacuum gauge readings due to lean. You could be sure of the problem if there is an accompanying banging sound. Part of the job a throttle position sensor does is give the computer the exact position the throttle is in. The fact that these readings are normal indicates the low suction pressure is not caused by low refrigerant, but insufficient heat getting to the evaporator. How to Adjust Timing. Categories: Baghouse Gauges , Pneumatic Gauges. This FAQ pertains to short sweep, electric gauges, that use a single-terminal sender. If vacuum doesn't increase at least a couple of inches when you release the throttle, you may be looking at worn rings, cylinders or valves. HoneyComb MAF Mass Air Meter Airflow Straightener. Once you’re engine is up to operating temperature, you can begin reading your vacuum gauge. Furthermore, the unit has a long hose for an easy each and is also flexible to easily go round curves. Only after I start to drive does the gauge move to the full position and stay there. Switching off the engine for about 5 minutes everything goes back to normal. the vacuum gauge at the vacuum actuator with a “tee” connection will determine the integrity of the vacuum supply (compare values to the attachment). If the vacuum pump gauge's needle does not hold steady, but starts to go down to 0 (zero) in. A Bourdon tube vacuum gauge should go down to near its lower limit (e. Sometimes it cracks and leaks. 8 Erratic/high-idle Issue I will fine-tune it with a vacuum gauge at some point, but I'm confident that it is set very close to where it needs to be for now. This can be accomplished by using a reference gauge tube which has a known vacuum pressure in it, or using a vacuum system capable of generating pressures better than 10-4 Torr. Sign up if you have a question, answer or to meet like minded individuals. Convection Enhanced Pirani Vacuum Gauge. ) Did you check vacuum with a gauge? (Hint: Gauge should drop a few inches of merc when ign is turned off, if an injector is…. vacuum line to the fuel pressure regulator. Tighten it securely and run only the pump (burner not running). i would assume if it actually slipped out of gear while giving it gas the engine would rev as if i was in neutral. GM: THERE ARE SEAT BELT PROBLEMS: DIFFICULTY LATCHING AND DURAMAX DIESEL INJECTOR DRIVER CODES WITH 6. Seeing the Light: An Overview of Visible and UV-VIS Spectroscopy. Voltage from plug to guage reads 5. Many times with an early winter frost the gauge bourdon tube can become distended and distorted by water inside freezing. 1000 psi and higher sensors are a sealed reference type. Well,I swapped vacuum line to another full vacuum source and compared readings still the same,then hooked up vacuum gauge to see if port was plugged which wasn't the case getting same reading every where i connect to full vacuum source and sprayed some carb/throttle spray into the port where Map Sensor goes rechecked vacuum reading same. If not, see if the readings resemble any of these problems: A low vacuum gauge reading. See MKS Instruments vacuum gauges or Granville Phillips ion gauges (now owned by Helix Technology). Thyracont offers many models of self-contained vacuum measurement instruments that are proving their worth in hundreds of unique applications around the world. A mechanical-pump drive hardly ever fails — though signs of wear may appear on the cam and operating lever, linkages and pins. This is called a running vacuum test. This creates a slightly erratic idle because when the engine vacuum drops below the max advance point, this slightly retards the timing. This reading could be as low as 5". There is so much mystery surrounding the CIS (continuous injection system) fuel system Bosch has dubbed K Jetronic, I wanted to try and make some sense of it for all Porsche owners. Gauge reading 20 randomly or all of the time? Check the connections to the o2 sensor. Re: 99 Silverado w/ erratic fuel gauge 09-30-04 01:20 PM - Post# 521180 In response to Snaught Not knowing what 450 and 451 are, you should probably have them read the codes again to find out what they are. I bought a 2004 ford explorer about 2 months ago and I have already had it in twice for different things. We've put together this quick-guide to reading your vacuum gauge to help you identify potential mechanical or tuning issues more quickly. Pressure transducers are the components most vulnerable to damage from pressure spikes. If gauge reading fails to return to 16 inches, diaphragm assembly is leaking and should be replaced. The gauge should start climbing. A MAP sensor continually compares atmospheric absolute pressure to the intake manifold vacuum and sends the appropriate voltage signal to the vehicle's computer. They are all controlled by the computer you can tell that when it sends them all to 100 percent during initial startup. Once the connection is sealed, crank the engine over for 20 seconds. How to use gauge in a sentence. Now what? Misfire diagnosis in this kind of situation should be fairly easy. Sealed-gauge pressure-measurement is similar in concept to an absolute pressure gauge, except that the pressure of the media to be measured is compared to standard atmospheric pressure (at sea level). Vacuum gauge readings will be erratic when the valve spring is broken badly. My problem lay with the Lambda sensor on the exhaust sorry I didn't update There could be a lot of items to check first before you go down the road of taking the manifold off and cleaning the ICV, check for any air leeks caused by splits from the vacuum pipe going into the throttle body, a faulty oxygen sensor/lambda and also the MAF sensor could be faulty try and get the fault codes read. NOTE #3: Code P0460 specifically refers to issues in the fuel level sender unit input circuit, even though incorrect or erratic fuel gauge readings can also be caused by short circuits and other problems between the sender unit and the fuel gauge. The first step is to determine whether the problem is with the gauge or the sending unit. If it feeds the wrong data to the computer such as telling it the throttle is all the way to its highest end even though the vehicle is only running at normal speed, the computer may shut down the engine to protect it from over-revving. Disconnect the exhaust ventilation equipment. these cars had a lot of problems with the fuel level sensor (in the tank). Noisy or erratic readings, the inability to set zero or atmosphere, and total gauge failure, are all possible indications of gauge contamination. Diagnosing RPM Idle Issues in a MINI Cooper Posted on May 6, 2016 by Insourcelife Back in 2012 I bought a 2009 MINI Cooper hatchback to replace the aging 2004 BMW 330i ZHP that was rapidly approaching the point where a bunch of expensive work would be needed on a regular basis. Temp gauge moving up and down. Sometimes, fine metal shavings or or a paste like film from normal transmission wear can cover the end of the sensor. Or possibly, the heater will run fine with the top cover removed but when the cover is replaced the heater shuts down. Not left door but probably bellows faulty. Vacuum Gauge Pressure Readings (January 14, 2000). Verify that the correct temp sender has been installed--the pastic portion of the sender and the harness connector should be gray, not black. 16 initial with a 12 degree distributor gives 28 degrees of timing - good enough for now at 3500 all-in slope, just not as economical for gas mileage with a properly set vacuum advance. If this vacuum falls off after shut down, atmospheric pressure is entering the suction pipe causing the pump to lose its static lift. Find many great new & used options and get the best deals for docooler Turbo Boost Vacuum Press Gauge Meter for Auto Car 2" 52mm 0~30in. readings taken from the two types of gauges at three different pressures. All of the Gauges are drive by wire. Valve partially closed. It seems like the vacuum gauge method would come closer to matching a particular engine rather than being a generic method. Low Reading. False readings can make a bad pump seem okay. a spark leak can cause a. After a brief history, the design, use, and accuracy of ionization gauges will be described in this article. The gauge reading will be low, at idle speed the gauge reading should be erratic. I thought this was interesting: Was flying my dad's 182 about a month ago on a trip. I was not so concerned with the actual numbers, just wanted to see if one cylinder was lower than others. Also, its a good idea to check your air filter before moving on to another step, a plugged filter can cause intake vacuum value to skyrocket so replace as necessary. very last gauge shows something like what i see. Erratic fuel gauge readings? 1 following. Once I did this the vacuum did begin to move but it was erratic and would sometimes stop and refuse to budge. I still think the carb/lean is the key. properly inspect gauge ground. You could be sure of the problem if there is an accompanying banging sound. In this example, 088-100A-KIT fits a Land Cruiser built between 1963 and 9/73. Thus a vacuum of 26 inHg gauge is equivalent to an absolute pressure of 30 inHg (typical atmospheric pressure) − 26 inHg = 4 inHg. 6 ENGINE (VIN 2 - RPO OR ERRATIC OIL PRESSURE GAUGE READING SETTING DIAGNOSTIC. Initial Setup of Liquid-Filled Gauge. Were you running the same cam when you seen the higher readings? I feel that you probably do not have a vacuum leak if these are the only symptoms you are having I would consider it normal and gauge variation, you may try a liquid filled gauge for a more stable needle. Might be a failing Harley speed sensor. Probably the first thing you'll notice is the oil pressure gauge or the warning light reading very low or coming on when the car is fully warmed and idling like at a traffic light. Reading many posts stating the gauge doesn't actually measure vacuum but only receives an electronic signal from a device, and that reading is shown on the gauge?. 3 Dashpod Self-Diagnosis. Erratic idle + falling out of sync « on: September 19, 2019, 09:59:50 AM » I've got the 700sc running really well, i was having some issues last week, so i decided to re-sync the carbs. Compound ranges read vacuum in inches of Mercury, pressure in psig, and zero with the gauge port open. The codes were reading misfire on numerous cylinders. This is "1955 Ford Fairlane 292 Y block Erratic Vacuum Gauge Reading" by Daniel Jessup on Vimeo, the home for high quality videos and the people who love…. The sending unit reads right going by ohmmeter and gauge (when it works right) 113 ohms, i figured around 250deg. At shut down, the suction gauge reading will display the vertical distance from the gauge tap to the product level. 3) Snap throttle to WOT and release, while watching the gauge. FIAT Forum Useful Links: Erratic/ Bouncing RPM at idle ( 900-3500!) my car had the same problem and ever since i installed my vacuum gauge and replaced the. 08V on theTechtom) and ~1. What is the MOST likely cause? A. The gauge now read 3/4 of a tank. If you don't have a vacuum gauge, use a low-speed tachometer. Device and method for checking and calibrating vacuum and low pressure pneumatic gauges and differential pressure switches by utilizing a helix of tubing partially filled with a liquid and then rotated about its axis to a new position as a readily adjustable, highly accurate, constant source of vacuum or low pressure. 34 Applications For applications with high dynamic pressure pulsations or Suitable for corrosive environments and gaseous or liquid media that will not obstruct the pressure system. If it seems like it running rough, you may have switched push rod positions by accident, that will cause the car to die out or run rough. The tachometer gauge may read erratic or not at all. This vacuum gauge reading indicates: A. Many times the adjustment is simply the position of a ball valve based on the pressure reading on a gauge. My scan tool showed that everything looked normal, except for the ignition timing, which was bouncing around between 10 BTDC and -2 BTDC (I assumed this was the reason for the erratic idle). • Erratic idle. We have digital gauges We have digital gauges with alarms, DC loop-powered gauges, commercial-grade type C gauges, differential pressure gauges, and many others. The only area I can't get to is the rear of the manifold, behind the dizzy. They are all controlled by the computer you can tell that when it sends them all to 100 percent during initial startup. Make sure each vacuum hose is properly connected. That reading should be between 17 and 22 inches of Mg (mercury). which if contaminated, can result in faulty readings Make sure that the sensors are cleaned with rubbing alcohol (Isopropyl) if readings seem erratic or as part of a regular maintenance regiment DV-22N will display a “1” if vacuum reading is above 9,000 microns The DV-40/DV-41 will display “00000000” when the vacuum. It is also possible to run a self-diagnostic check with the dashpod. AllClaveParts. Erratic fuel gauge readings? 1 following. There is a port on the rigid vacuum line to which a smaller vacuum line attaches. try cleaning the electrical contact on the gauge it should be on the fuel tank. The MAP sensor senses intake vacuum, which the PCM uses to estimate load so it can adjust the air/fuel mixture accordingly. How to Adjust Timing. It will constantly do this while driving. Many times, gauge failure can be attributed to misapplication, but all too often, extreme or stressful conditions may cause gauges to fail. The most common cause of all vacuum gauge failures is contamination of the sensor. Make sure to install it at least 3 feet away from the motor. There are no other codes and the engine has a steady miss. Loss of vacuum can occur when the tank lid gasket is missing or cut. I am thinking that I should be closer to 18 or 20mpg. Symptoms of a compression problem can include hard starting, erratic idling, loss of power under load and hard starting when the engine is hot. The fuel gauge is driven from a float located in the tube inside the tank. Idle drops then picks up in speed. You could be sure of the problem if there is an accompanying banging sound. Now I just got it back last week and my gas gauge went out(it only reads 1/3 of a full tank), and also I am getting a loud pitch whistling noise at 2200 RPM from the engine. For example, if the reading on the vacuum gauge fluctuates between 9 and 19. If the check engine light is on, get the code. I had to block off the door lock vacuum lines at the firewall and coincidentally, the temp gauge became steady over a period of 3 days. The fuel gauge indicator sometimes rose above the empty mark after driving over 100 miles. 2000 Cummins N14 525hp. A second gauge group consists of voltmeters and ammeters, and they work a bit differently. If the vacuum reading increases—say, from 14 inches to 14-½ inches. From Crankshaft Coalition Wiki. : the contact stated the fuel gauge indicator malfunctioned. you are not working the engine too hard, but after 5 seconds or so, you start to hear some detonation. Read the pressure on the digital readout and compare it to the gauge pressures.