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98 NEON 2.0 DOHC Ruff Idle After Timing Belt Change

06-08-2010, 06:13 PM

My gf had her timing belt and head replaced on her 98 neon dohc. After geting it back from mechanic it idles very ruff almost dying. Pulled the Codes and said it was 1 tooth off on the timing belt. Took it back he returned it and its still idling ruff almost dying but runs fine after raising the rpm. I verified it was in time and ran ran codes again. No codes. Compression test results were basically 180, 180, 150, 180. Cyl 3 is 16% lower than the rest and the car also has oil smoke and the car never smoked before the belt broke.

Any ideas? is one cylinder just 16% lower than the rest anough to make it idle that ruff? bad exhaust valve from used head?

06-09-2010, 08:39 AM
Why was the timing belt replaced? Did it snap? If so, you may have a bent valve or two. Ideally, you would like the compression to be within 10% of one another.

06-09-2010, 11:11 AM
As stated in the first post, both the timing belt and the head were replaced. That was due to a timing belt failure. The mechanic which we now know to be very incompitent, said it was just easier to get another head. He purchaced a head from a running vechical and said it was guaranteed. When he braught it to us the first time the belt wasnt very tight and had slipped at least 1 tooth on the crank. Second time i went to him and the belt was still loose. his excuse was that he was leaving it loose till he was sure the timing was right. DUMBASS@@@

I want to get the pos back from him so i can run a leakdown test on cyl 3 to see if it might have bent a valve when it slipped or the head had a bent valve in the first place. I asked him if he had the head pressure tested and he sayed "no, it came off a running car" DUMBASS@@@@

I did not choose this mechanic... her mom did, he was friend of family who did their car work. Theres alot more to this story to so his ignorance but it would take alot of typing.

06-09-2010, 11:23 AM
Sorry, I didn't read thru the whole 1st post. I am try to help while I am at work.

Leakdown test would help definitely. The timing on the DOHC can be tricky. I know people who will swear up and down there timing is dead on, but after going back and redoing it, it fires up or idles much smoother.

06-09-2010, 11:49 AM
I do apreciate your help. The issue is that its not in my hands, its in a mechanics hands and i cant touch it till he desides he is done with it. I am hoping that just having the belt so loose was causing the timing to go off and cause the miss. I went to his shop and ran a compression test, timing belt tention, and checked the timing myself. Off the bat the belt was almost loose. He stated that he left it like that unpurpose to make sure it was in time first, but he had allready completely assembled the car and had been driving it! I ran a compression test on it which the results are on the first post. After that i used a long screw driver and got cyl 1 to top dead center and the cam gear marks matched up but the belt was still way loose. I explained to him the proper procedure for adjusting the tension on the belt and installing the hydrolic tensioner and he seemed intrigued. He didnt believe me and took it to a friend at a mopar dealer and that friend is post to be helping him finish it up. It was post to be finsihed this weekend but now its wed and he still dont have it together. By the way all this time he has been blaiming the o2 sensor on all the idle problems. DUMBASS@@@ i cant stand him! he makes me mad! im a computer technician and i know what he is doing is WRONG@

Oh yea this has been going on for 2 months now. when he braught it back the first time he did not change the oil and left a note for me to do that as well as put in power steering fluid which was empty.

Labor $250
Head $250
Timing belt / Idler / Water pump $150.00
Hydrolic Tensioner $70.00
Gasket Set $110.00
Sparkplugs $8.00 (done myself)
Oil Change $15.00 (done myself)
Passenger Motor Mount $35.00 (he left the insert out - done myself)

06-10-2010, 11:37 PM

The mechanic now says that he thinks its the coil causing all the issues sense the spark plug has a orange spark instead of a blue spark. he is going to the junk yard to get another coil. He has almost replaced every sensor on the car without any codes to warant it. he is just shooting in the dark. I checked the ignition with a timing light to make sure they were all firing smooth. I didnt have a reason to test resistance on the coils but i asked him if he had and he hadnt but he is replaceing it anyways.... arrg!

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