Hi gents (sorry, and girls),

I need some serious advice from hopefully someone who knows about Neons. I am an army mechanic in the UK and need some advice on a fault on my Neon. I have nearly exhausted all my fault finding options and am very close to paying a local Chrysler Dealer (in this country its Chrysler not Dodge) for their assistance. Something i really dont want to do as it will cost me a fortune and they probably wont find the fault, so here goes:

Chrysler Neon on a 1996 2.0l SOHC, 60 K miles

The engine can be heard quietly popping back through the exhaust throughout the whole rev range (most noticable when revving the car gently on the drive and on over-run). It stumbles on acceleration, and feels like it is supplying more fuel on over-run and surging on slightly. It lacks acceleration and flatspots alot. Generally you dont notice this fault as it seems quite slight but as it is my daily driver it is really beginning to p*iss me off. The tick over when warm is also slightly lumpy. This is a fault that is apparent at all engine temperatures and ambient temperatures and is there from start up. There are no fault codes showing and 5 - 5 appears when I access them with the key.

This is what i have done so far:

Cam shaft sensor replaced (it was cracked and leaking oil), Plugs, leads, coil pack. coolant temp sensor replaced. Throttle pot changed and MAP sensor replaced. Throttle body removed and cleaned along with ISCV. Usual oil and air filter change. All items apart from oil / air filter & plugs etc have been sourced second hand and have not made any difference. Fuel injection cleaner used. All vacuum pipes etc checked for cracks / splits.

It drives sometimes as if the timing is slightly retarded but i have eliminated this as the fault doesnt seem severe enough as if it had slipped a tooth on the belt etc. Both Lamdas were changed before i bought the car and i wonder if this was because of this fault. it was done by a dealer and i think diagnosed incorrectly.

As you guys would appear to be the experts on this vehicle i would appreciate some decent technical advice. Is this a common fault on this car? Any assistance is appreciated. If anyone can get me access to a wiring diagram that shows the ECU pins i would be grateful.

I feel that having been in the Army as a vehicle technician for nearly 18 years working on Challenger Tanks I have a damn good understanding of mechanics and vehicle diagnostics, but this one is really bugging me!!

Cheers

Mick

 

your cam position could be off or their gas over there sux...backfiring can be caused by an overage of fuel...also check your catalytic converter, if it goes bad it can cause problems as well especially if is plugged up...Im sure there is more stuff that can cause some of your poor running conditions but you prolly need to go through those first. It might be cheaper in the long run to take it to the service center. If you have multi cylinder misfires /bad plugs wires it can cause power loss...try that too...

 

thanks for that mate. As we pay nearly £1 a litre over here for unleaded I have a feeling our fuel quality is top rate, bloody better be at that price so i dont think it is a quality problem. the car had its annual testing a few weeks ago, (M O T in this country) and the emmisions were not found to be faulty otherwise it would have failed. I forget to mention that the plug leads have also been changed as well. Not looking too good at the mo is it? any more suggestions????

 

Definitely sounds like a fuel proportioning problem. If the O2 sensors (lambdas) were replaced by the dealer with dealer parts, there shouldn't be a problem. If they were replaced with someting other than the NGK's that the dealer uses (like Bosch), you may have found the problem (mine makes the car run a tad rich I've noticed). I don't recall offhand if there are identifying markings on either... A failing cat could also be causing problems, but the downstream sensor should throw a code for cat efficiency, eventually... mine made it 180k miles or so before needing replacement. The injectors themselves could also be beyond what little the injector cleaner does for them, and those are pricey... Although it probably wouldn't hurt to pull them off and check the condition of the o-rings and whatnot. If your '96 has the externally mounted fuel filter (forward of the right rear wheel), that's supposed to be replaced every 35k miles. Exhaust leaks close enough to the upstream O2 sensor could also cause the car to run rich.

If you replaced the plugs with platinum, definitely switch back to copper.

Best of luck!

Edit: sorry, posted the wrong year PCM...

 

Mate, thanks for that advice, probably the best i have recieved since this fault started. i am pleased you think it is fuel related as that is where my thoughts are centered!!! I intend to remove the injector rail and have a close inspection, however, i dont feel confident that i will notice anything wrong with the injectors themselves unless it is quite obvious. Is it worth turning on the ignition and see if one is leaking, is this common? The wiring diagrams are fantastic and will certainly help me to do some tracing, so again thanks for that. I'll keep ya informed. Cheers!!

One other question, is it normally really difficult to remove the bottom pulley when trying to change the cam belt? i have bent two puller centre bolts so far trying to shift the little blighter[:@], Is it always necessary to use a bit of heat for its first removal??

 

its not a pulley its like a harmonic dampener and requires a special tool, the tool puts a rod into the hole you take the bolt out of and then the "pulley" will come off very easily and no heat is needed, your oil pump is behind and slightly below the "pulley"

 

oh christ, thanks. i was getting very near to throwing a bit of heat at it. i suppose the special tool is only available from the dealer then. is it one that can be manufactured????

 

nope you can buy them at parts stores like auto zone or carquest, i dont know what stores you have where you are but i can buy the tool for about 35 canadian, so it is a cheap but very necessary tool.

 

Thanks for that, spoke with the dealer yesterday before I read your reply and he told me exactly the same. got a mate with a lathe so hopefully he can knock me one up. I assume it just has to be the length of the internal hole in the crankshaft where the bolt would go so that it butts up inside then this takes the load of the pulley???

 

i think the rod is 6 to 8 inches long, and if you have a three jaw gear puller i would just drill out a hole in the center of the threaded rod.