1997 Chrysler Smart, 3.5L V6
I'm David Gorth and that i lately experienced an electric train engine misfire problem which might of great interest to a few of the AutoTap customers. To create a lengthy story short, the PCM on my small 1997 Chrysler Smart, 3.5L V6, reported a P0301 code with the AutoTap, which indicated a cylinder # 1 misfire. The troubleshooting process I experienced to finally repair was extensive. I've referred to it at length below however, should you only desire to be aware of exact cause in advance, it had been a gasket failure between your intake manifold and also the cylinder mind. Vacuum pressure leak, to become more precise, caused the my frustration.
Around mid The month of january 2003, my problems started using the characteristic of " constant rough idle" using the transmission in drive and neutral/park. It was also supported through the Malfunction Indicator Light (MIL) or Check Engine light code of 43. When I own the Chrysler Service Manual for that vehicle, I could retrieve the code in the vehicle simply by counting the amount of "Check Engine" light flashes. I understood I had been in danger at this time because the manual defined code 43 like a multiple engine misfire, a misfire in any of the 6 cylinders, or perhaps a malfunction of any kind of, or all three of the primary ignition coils. At this time I didn't own the AutoTap 123 which may make existence much simpler.
I made the decision to begin with the "easy to check" products first. This meant altering the spark plugs, checking the resistance of all of the spark plug wires and lastly, checking the ignition coil primary and secondary circuits by having an ohmmeter. Each one of these components were discovered to be serviceable. I additionally aesthetically verified that the spark plugs were firing making certain no original spark plugs were fouled or discoloured. All of them made an appearance normal having a brown tint around the insulator. I believe, I'd virtually eliminated the ignition system as the reason for the misfire however i wasn't completely convinced.
After checking the ignition components, I had been now quite certain the MIL code 43 indicated a misfire instead of an ignition coil failure. The following area I made the decision to check on was the fuel delivery system. A fast verification from the fuel pressure in the fuel rail established that the fuel system, up to the stage from the fuel injectors, was working correctly. I possibly could therefore eliminate the fuel filter, pump, regulator and closes as the reason for the misfire.
It had been at this time that the new MIL code turned up. Code 24 (I still didn't possess the AutoTap) established that the Throttle Position Sensor (TPS) signal current was either excessive or lacking and/or even the TPS signal didn't correlate towards the Manifold Absolute Pressure (MAP) sensor signal. Now I had been believing that it either needed to function as the TPS or even the MAP sensor which was leading to my misfire. I checked the TPS input current along with the idle and available throttle current output having a digital voltmeter. The TPS signals were within specs. At idle, I discovered the MAP sensor output current to become .2 volts below specs. I figured I'd found the issue! I transformed the MAP sensor (about $125 Cdn) and also the vehicle did run a little better, for a short period. To increase the confusion, following a MAP sensor alternative, I discovered that the idle speed had elevated from 700 revoltions per minute to roughly 850 revoltions per minute using the transmission in drive and as much as 1300 revoltions per minute in park/neutral.
Round the finish of The month of january, I received my AutoTap 123. It was timely because after altering the MAP sensor and clearing the MIL codes (disconnected battery), code 43 came back within 2 excursions using the vehicle. The AutoTap reported Diagnostic Trouble Codes (DTC's) of P0300 (engine misfire) and P0301 (misfire detected in cylinder #1). Which was the code I had been searching for! I possibly could now focus attention on finding the reason for the #1 misfire.
I understood the problem needed to be triggered through the ignition system, the fuel delivery system or something like that mechanical. I began having a make sure from the ignition system. Because the ignition coils for cylinders #1 and #4 fire simultaneously, I swapped ignition wires and coil towers from cylinder #1 to #4. No improvement. That's, cylinder #4 ongoing to fireplace normally while cylinder #1 didn't. I merely disconnected the spark plug wire boot from each one of the spark plugs consequently. Engine revoltions per minute wasn't affected when cylinder #1 was disconnected. Conclusion, the ignition system was fine.
Then i returned towards the fuel delivery system. I checked the interior resistance of all of the injectors along with the current signal from the PCM to spread out the injectors. The #1 cylinder injector resistance and also the signal current in the PCM were within specs and discovered to be much like the rest of the injectors. The audible "click" all the injectors seemed to be present. I reasoned when I didn't look for a mechanical reason for the misfire, the issue would definitely be triggered with a dirty or blocked injector.
I them carried out a compression test around the engine. The outcomes established that cylinder #1 was sealing in addition to all of the others. I went so far as setting cylinder #1 at Top Dead Center (TDC) and putting about 30 pounds of air pressure in to the combustion chamber utilizing a spark plug adapter. The concept ended up being to listen for air getting away in the tail pipe (exhaust valve), the throttle physiques (intake valve) or even the oil filler cap (rings). A tiny bit of air might be heard from the oil filler however, exactly the same noise level was apparent all other cylinders too. Conclusion, the combustion chamber was sealing fine. The only real other mechanical problems I possibly could think about that will make the misfire were whether worn camshaft lobe (unlikely - 130,000 kilometers) or perhaps a mis-timed camshaft sprocket. I verified the timing belt was set correctly.
Since I Have had eliminated the ignition system and understood it's highly unlikely which i were built with a worn camshaft lobe, I made the decision to alter the #1 cylinder injector. It was a period consuming job and parts were costly. I changed all of the fuel rail O-rings and gaskets and washed the two throttle physiques making sure all vacuum hoses and electrical fittings were who is fit. I believed I'd the issue beat this time around! I had been wrong. Actually, not just did I have the cylinder #1misfire, however i also acquired a replacement, MIL 25 or P1294 that is Target Idle Not Arrived at meaning the particular idle speed doesn't satisfy the target idle speed. The idle speed was now as much as roughly 950 revoltions per minute from 850 revoltions per minute using the transmission in drive and as much as 1600 revoltions per minute from 1300 revoltions per minute in park/neutral.
Now i thought which i had caused vacuum pressure leak somewhere after i removed the intake plenum. I had been correct this time around. The Exhaust Gas Recirculation (EGR) tube, that is basically a "Y" pipe from the EGR valve (situated around the right side cylinder mind) and hooking up to each side from the intake plenum, was seeping in the EGR valve. This permitted extra air to become attracted in to the intake plenum. Being unsure of it had been just the gasket between your EGR valve and also the Y pipe which was disturbed, I transformed the entire EGR unit. Another $130 Cdn contributing to 3 hrs to accomplish the job. The idle speed returned lower towards the 850 revoltions per minute and 1300 revoltions per minute amounts that was better however, I still had the cylinder #1 misfire!
At this time I had been from methods. I ingested my pride and required the automobile towards the Chrysler garage. For $95 they connected the PCM for their diagnostic oral appliance determined which i were built with a cylinder #1 misfire which all of the electronic components were operating within set parameters. Additionally they determined that my Smart was without the most recent form of software from Chrysler set up in the PCM. For the next $95, they up-to-date the program (ie. the trip wasn't an overall total loss). The following little bit of news required me unexpectedly, they found vacuum pressure leak in the intake manifold gasket around cylinder #1. They used the “propane” test to locate it. Which means that they opened up the valve on the simple shop gas torch, directed the gas toward the gasket area under suspicion and also the idle revoltions per minute acquired substantially. Naturally the gas torch continued to be "unlit" through the test.
In the end that, for an additional $90 I bought the gaskets I desired and resealed the intake manifold towards the heads. This task seemed to be extensive but this time around, the reward was worthwhile. The engine has smoothed out (it's never run very well), forget about codes company, it idles at approximately 700 revoltions per minute.
- A person article led by David Gorth, Canada - Feb 21, 2003
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