The car is a 1995 Trans Am and here is a little background on the car. I did a heads/cam swap back in march along with a new FLP tranny with a 3600 converter and the car put down 380 rwhp at 6400. For a list of what I have done to my car go here http://www.smknta95.cz28.com/mods.html . Incase I dont get any responses here, I sent this to someone that is very reputable on this board.

Back in June, the car started floating the valves and I tore the motor apart to install new lifters. I installed some Comp R's and the valve float problem went away, but it had a knocking noise from the front of the engine. After we tore the motor down, we found out that the back teeth of the main timing gear that drives the water pump had been stripped and it put metal through the whole motor. This timing set was also the LT4 extreme timing set. Well anyway, we put ARP main studs back in, new ARP rod bolts, main and rod bearings, rings and a Rollmaster Billet timing chain set. We got the motor back in the car and running, and it ran great at first.

After about 200 miles, the car started stumbling and missing or what felt like a miss on several cylinders. I talked to the guy that built my motor and the car had at least 2 dead cylinders. So i changed the plugs and wires again and the problem went away for another 100 miles or so and then returned. At this point, I thought the problem was the opti so i went and used my warranty on the new opti that was installed in there and got a new one as of last week. I installed the new opti and new coil last week and guess what, the stumbling and dead cylinders were still there. I had been getting a Maf Failure code so I swapped in a friends MAF that worked on his car, but the problem was still there. I then swapped his coil and his ICM onto my car to see of the ICM was my problem. That didnt do it either.

After a few days, I decided to smell the vacuum line that goes to the fuel pressure regulator and it smelled like gas. I changed the regulator to an Adjustable CAS billet one. After we installed this, the car sort of ran better but it still was running way way rich and was poring lots of fuel in. The next day, I pulled the plugs out and they all smelled like raw fuel. there were 2 plugs that the insulator was still white and had no carbon buildup on them. These 2 cylinders were 3 and 5. I then put new plugs in the car and it ran ok when cold but when the motor warmed up at all, the problem gradually came back. I now changed my injectors today, and I drove the car for 2 miles and it was fine when cold, but when it heated up, the problem came back AGAIN. But, one thing I do know is that I accidently broke the center section of the knock sensor and its spins inside of the main housing when you try to remove it. Could this be my problem because it has so much knock retard?? At idle, it has anywhere from 3-9 degrees of knock retard. I dont know what it has for sure going down the road because I dont have datamaster on a laptop. We checked it originally when it started this problem and it was at 8 degrees of retard at 2500 I believe. I really could use some help with this problem, as I am getting very frustrated with the car.

Any help would be GREATLY appreciated.

Thanks,
Brian

 

well, you see, it sounds like ure car is just never going to run right, so you might as well sell it. your puny 380 rwhp isnt worth what you've put into the car, and it probably won't have that ever again anyway because all 8 cylinders aren't going to fire correctly. sorry, big guy, you're s.o.l.

 

Brian,

I believe the knock sensor could be your problem. You have replaced quite a bit of stumble releated parts already. Now your saying your running rich. How bad is your idle when your at operating temp? I would guess you should see if your EVAP system may be purging fuel vapor back into the motor when it's not supposed to be, check and clean your EGR valve and did you notice anything different about the spark plugs? Why I ask is because I had a blown head gasket and when the engine would start to heat up, coolant would be dumping into the cylinders making a very rough idle.

 

Dont listen to him , its gotta be something minor... Then agina if your thinking of selling it, Lemme no

Heres a TTT for ya

 

ok

 

The broken knock sensor might make it feel a little weaker than normal because of constant knock retard, but it won't cause only a couple of cylinders to be lame. I would do a compression and leakdown test to be sure you don't have some mechanical issues (suspect, IMO).

 

Dude, settle down, they know each other and I know both of them.

 

Nice LATE post J/K I didnt know they knew each other, i thought he was just being an ignorant a$$

 

Yea, I know I'm late. I don't check the board as often anymore. And he IS an ignorant ***, but since I know him, I figured I'd keep my mouth shut...at least for a lil bit.

 

1 More Late Post ... So at any rate, what the problem is ? What was it that caused it to run so anally in the first place?

 

Well i found out that a plug wire was burnt down to the metal core on #6 and once this was changed, the car ran fine. I couldnt see it at first because it was hidden behind one of my Taylor 1200 degree heat sleeves. After we pulled each injector wire off separately while the motor was running, we found that #6 was the only one that pulling the wire off didnt change anything. But all is good and I am planning on making some dyno runs this weekend with the new motor.

Brian