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Topic
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1996 Doge Neon
287,??? miles
DOHC 4 cyl
5 spd manualLooking for SECOND opinions as to what should be the first step to take.
Wife has been complaining that when going at slow speeds only, and when putting the CLUTCH IN (not shifting to Neutral) to stop at a stop sign or traffic light, the idle goes low, almost to the point of the car stopping (engine not running stopping that is). This seems to have been happening for some time now and there has been no CEL. Yesterday on her way home the CEL came on and a P0172 code has been stored.
Trouble Code Conditions:
Engine running in closed loop, IAT (Intake Air Temperature) Sensor signal over 20ºF, altitude less than 8,000 feet, and the PCM (Power Control Module) detected too large an amount of Fuel Trim correction due to a rich A/F (Air/Fuel) condition.
Possible Causes:
Base engine fault (i.e., cam timing incorrect, oil level too high)
EVAP vapor recovery system failure (e.g., canister full of fuel)
Fuel control Sensor is out of calibration (e.g., ECT, IAT (Intake Air Temperature) or MAP (Manifold Absolute Pressure)
Fuel delivery component fault (injector leak, high fuel pressure)
O2 element is contaminated, deteriorated or it has failed
O2 heater is damaged or it has failedDidn’t get all the information last night from the scanner but will try to get it tonight when wife gets home (if the CEL is still on and the code is still stored) I did not reset the code. I believe it will extinguish the light if it does not detect the problem again within ? cycles.
Cam Timing ? If sensor says yes should it be OK
Oil level if anything was a little low was just changed 5 days ago.———————————————————————————-
With engine running at idle in neutral Parking Brake on.
Using Snap On MT2500 scanner.*EVAP – Don’t know, I think I can purge it with the scanner. Will update
IAC (Idle Air Control)- Could easily move the idle up to 2000 RPMS + and back down smoothly and without problems.
CAM Sensor – Yes Crank Sensor – Yes
*ETC – ? What is it?
*IAT/MAP (Intake Air Temperature / Manifold Absolute Pressure) – TBD (To Be Determined) I think I saw +5V there with the scanner last night will check and verify tonight).STFT (Short Term Fuel Trim)- varied from +2 to -2 (mostly between +1 and -1
*LTFT(Long Term Fuel Trim) – will update (but think it was around 12 don’t know whether + or –
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Fuel injectors did not seem to be leaking.
Fuel Pressure – will check tonight if possibleO2 element – has never been replaced since I’ve owned the vehicle (from 130,000 to 287,??? miles).
O2 heater – has never been replaced since I’ve owned the vehicle (from 130,000 to 287,???miles).Will update this thread as I find the missing info to post here.
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She isn’t home yet so don’t know if the same code came back or whether it’s a different one will check tonight.
Don’t know whether to continue this thread or start a new one. Put the MT2500 on the Neon tonight when the wife got home from work and I’m happy to report that it no longer has the P0172 code. However the CEL / MIL is on and I now have a P0304 code and the low idle with an almost stalling at slow speed (with clutch in) coming to a stop, is still there. For now I reset the code and we’ll see what comes up tomorrow.
Changed my icon from the yellow traffic light to a frown face because one of the original problems seems to have gone (P0172) but a new one has come up (P0304)
p0304-cylinder #4 misfire. start with that cylinder.
check the plug.check the spark to that cylinder.when
was the last tune up. try doing a power balance test.
do it both ways electrical and fuel.For sure look into the misfire but you might also want to check the fuel pressure also just in case.
Couldn’t do much tonight but I was able to do some testing with the Snap On MT2500. I used it to test the fuel injectors with the car running. For each injector I toggled it between On and Disabled and found that for injectors 1, 2 and 3 the engine rpm decreased slightly when I disabled it with the scanner. For injector 4 there was for the most part no change. I went through this process a few times just to make sure I got it right. I’d never done this test before with the scanner and thought it was kinda cool to be able to do testing like that with it. Who knows what other things can be done that I haven’t had the opportunity to do with it yet. I had reset the P0304 code yesterday and she drove it to work with no problems. The code came back though when she came home tonight and also had a P0300 for multiple misfire. Won’t be able to do much with it though till the weekend, but I did reset the codes and will probably see them again tomorrow night when she gets home.
Keep us posted and i know you have the skills to get this one fixed.
I would do some very basics troubleshooting steps such as checking for spark with a adjustable ignition tester so you can stress test the system, checking the integrity of the injector wiring using a noid light (or sometimes a long screw driver to hear the injector clicking may work) and +1 on checking for fuel pressure.
Keep us posted.
Saw something on another site that mentioned about oil in the spark plug tube causing a misfire. Will check it out and update. Probably this weekend. If there is oil I’ll just replace the valve cover gasket and the spark plug tube seal rings.
[quote=”johnbkobb” post=33541]Saw something on another site that mentioned about oil in the spark plug tube causing a misfire. Will check it out and update. Probably this weekend. If there is oil I’ll just replace the valve cover gasket and the spark plug tube seal rings.[/quote]
No oil in the spark plug tube. Removed the plug and put in another. Will see what happens tomorrow. Reset the P0304 code (no P0300 code tonight)
Replacing plug #4 made the problem worse. Instead of a rough low idle now the vehicle is actually stalling when slowing down and coming to a stop with the clutch in.
old plug which was replaced
That’s an interesting white crusty color on your spark plugs. This is what I read regarding that color:
Ash (Lead) Deposits
APPEARANCE: Ash deposits are characterized by light brown or white colored deposits crusted on the side or center electrodes. In some cases it may give the plug a rusty appearance.CAUSE: Ash deposits are normally derived from oil or fuel additives burned during normal combustion. Normally they are harmless, though excessive amounts can cause misfiring. If deposits are excessive in short mileage, the valve guides may be worn.
RECOMMENDATION: Ash-fouled plugs can be cleaned, gapped and reinstalled.
How was your fuel pressure?. And did you check your distributor/rotor, etc. for any problems?
Ya, I ran a bottle of cleaner through the tank about 3 or 4 weeks ago just before an oil change. That’s what that ash is I would imagine. I’ve already cleaned the plug and the gap was about .042 SWpec calls for 0.033 to 0.038 so re gaped it and saved it. Tonight and this weekend I’ll try to do some more testing. Got the fuel pressure tester, spark tester, spark plug R&R tools, new wires & plugs and am ready when it gets home tonight. It’s supposed to rain here this weekend so will try to get as much done as possible tonight. Checking pressure will be no problem and checking spark will be fun at night (fireworks show!)
[quote=”mckrishes” post=33636]How was your fuel pressure?. And did you check your distributor/rotor, etc. for any problems?[/quote]
No distributor, coil pack was new 6 months ago replaced old one which I think is still good because new one didn’t solve the problem I had. I was too lazy to put the old one back in, so just kept the new one on.
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