I have a modified TPI camaro. Its basically an 87 TPI engine with a T-5 on a 92' Body. Lately its been acting up. TPS is new and adjusted to specs so thats out of the question. The problem remains as follows:

Only when cold or car hasnt been running longer than 30 min. in first gear it will jerk and jerk until you get to second. Once engine is heated up problem with go away with first gear jerking motion. Second, If performance driving as soon as i hit 3rd gear and its at WOT power is there, but as the RPM start climbing, the car starts to JERK really bad as if it were hesitating and i could feel and hear the drivetrain as if were gonna tear apart. It actually broke a passenger side bolt on the crossmember and left 2 remaining bolts holding the transmission. Luckily no other mounts broke. If the jerking motion happens i shift to 4th and the problem persists, but not as bad as 3rd and will go away when in 5th. While the car is warmed up, 1st and 2nd gear is fine, but until i hit 3rd and as soon as the RPM starts climbing the jerking comes to play. Could this possibly be due to clutch slippage or grabbing? If so why dosent it slip in 1st or 2nd? I've recently installed an AFPR(holley) and increased fuel pressure to 45psi since the engine has been running lean for some reason. I've got not codes that read whether its a sensor such as a O2,intake temp. coolant temp. I did a 3 wire O2 sensor conversion and im thinking the 02 could possibly be bad. The clutch has about 1500 miles on it and i'll admit i drive like a dick. Plus its a Cumberland clutch from autozone so its a cheapo. Another thing i'll have to admit is that i possibly messed up my timing. So could this possibly be an issue with either problems stated above. I cant seem to figure how to adjust timing on a computer controlled car lol. I understand the logistics about timing, such as mark distributor and make sure #1 piston is at TDC then adjust the distributor manually while timing gun is hitting 8 degrees from tab. But do i disconnect the TCS(timing control switch) before or after adjusting? *** help lol

 

It sounds like possibly a problem with the fuel or the spark suddenly cutting out and coming back again. Does the engine sound like it misses or momentarily cuts out when this occures?

As for the timing, looka bove the hater box in the engine compartment and in the loom there youll find the single wire bypass connector. Witht he engine running, disconnect it and set the base timing to either whats called for on the label on the underside of the hood or whatever else you think may work. Reconnect the connector and tuck it back into the loom when done.

 

sounds like ignition to me, check your spark plugs, coil and wire, more likely coil, loose the clutch in favor for a centerforce d/f i had that autozone clutch and it slipped, but it wont jerk the car, the engine will rev and the car will feel like its not going anywhere

 

i see the bypass connector but when the engine is running and i disconnect it the engine dies. And yes its the correct connector. This issue only happens in 3rd and 4th. While in 3rd gear is driven normally it'll run decent, but when the throttle starts and the RPM's start rising it starts JERKING to the point where you'd feel the drivetrain about to explode. Its really a jerking motion.

 

Well, would get the timing set as stated above first and then look for other problems The timing may just be far enough off that it dies when you disconnect that connector. I would have someone sit inside and try to keep it running while you disconnect the connector until you get it close enough it will keep running. You should have the car warmed up to operating temp when setting the timing also.

Ben

 

I would say it could also be how you are driving it. I live in a windy park where the roads are short, split in forks and sweep all over the place. When my car is cold I can only creep through in 2nd gear, and I must keep a stedy pedal pressure or I get the tranny buck. If I tried 3rd it would look like a rodeo ride. But once warmed it will do 10mph in 3rd n creep like a MF.

If ya ever drive a real big truck you will find it can be done any time. Its how you used the pedal most times. I think its called torque buck and is just strange.

It helps to just sit there a few mins and let the tranny warm up it seams. leave it in netural n get your foot off the clutch so things just spin inside.
Matt

 

Gumby brings up a good point. There could be so much play in the drivetrain that it begins to ocillate. With my old rear when i put the auto in first i could really get the car to jerk forward and back. The pinion would bounce off the driven side of the teeth on the ring gear, then off of the coast side, and back rapidly and cause some pretty violent motions. Too much backlash. Also whined real bad b/c of this as well.

 

I know what you guys are talking about as far as the extra play, but I dont think that this is what he is talking about. It simply be your timing. Timing can make a huge difference. If you get that set then I would see if you are still having problems. You might check for vacuum leaks also. I had a car that had a pcv valve gromet go bad and it caused the car to shake when I drove it. It didnt do it when I first started it and woudl stop after completely warmed up, but it would buck when in the middle. I imagine that the pcv was just causing a huge vacuum leak.

Ben

 

Someone mentioned about too much play before i posted this so it does sound like a possibility. As for timing thats a possibility, althouh since i do have a air/fuel mixture gauge its constantly on the lean side and even on WOT its right around there as well.
Doubt theres a vacuum leak since at idle its perfectly fine and wont die. There are times when the problem dosent happen but its very rare.

 

I have had a couple serious vacuum leaks and the car would still idle fine, including the one I was telling you about. A lean mixture will cause a stumble on its own. This is often called a lean stumble. Imagine that. Timing being to retarted will also cause this. If your base timing is to retarted it will also cause the car to die without the advance connecter plugged in. I always believe that the best bet is to fix problems that you know you have and go from there. I would start with the timing, and then try to figure out why you are running lean since both of these things can cause a stumble. It can cause a real bad one if it they are bad enough. BTW a vacuum leak can cause a lean condition.

Ben

 

Thanks Momar, you've been really helpfull. I did get a code which i believe is 33 MAF reading too high. The MAF is a Wells. I have to say that 4 months ago i had a coolant problem where as it leaked into the MAF cause i do see residue on the inside. Sorry for neglecting to mention it.

 

Found something new, If the cars been sitting a while and i start it up and drive it letting it warm up maybe 30 sec. the problem isnt there so much, but when it warms up starts to happen. Even if i drive it a while and shut the car off and go on it, it'll run fine sometimes. Something is leading me to believe its the O2 sensor. I did do a 3 wire conversion about 9 months ago hmmm.

 

well, start with the simple stuff, check you fuel psi and if you have a long hosed guage tape it to you windsheild and drive it see if the psi stays steady while it bucks, you can read lean and really be dumping fuel too which can cause the same thing. have you checked the plugs?

 

how quick does it begin to have the problem after it starts? The computer wont read the o2 sensor when it first starts. If you have a heated it should start reading off of it within about 30-45 seconds I believe. Checking the fp is a good idea, because if you loose fuel pressure, there is no way that the computer will be able to give you enough fuel.

Did you at least check to make sure that the pcv valve doesnt feel real loose in the grommet? I know it sounds kind of stupid, but I had a problem that sounds about exactly like it when I had a leak around my pcv valve because of a worn out grommet. Like I mentioned before a vacuum leak will cause surging because it causes a lean condition, and timing that is to retarded will cause surging also.

Oh, I just read the MAF sensor thing. That could definately throw off your fuel mixture as that is what the engine uses to judge how much air is coming in. I dont know how you would really clean the inside of one though because they are rather delicate as well as expensive. Like I stated before, I would look at the stuff you know you need to fix first though. So you know that you have a maf code. You need to figure it out, and then I would set the timing. After that if you still have a problem go from there.

Ben

 

i would have to say it is your clutch

 

Why would you say that? A clutch can slip or even engage a bit rough but it souldnt cause the car to jerk that violently.

 

Check for a vacuum leak at the intake gasket. Had about the same problem and it was a B------ to find. Also it did not throw any codes. All the Sensors from the Maf to the ECM were replaced. Once the vacuum leak at the intake gasket was found and replaced, this corrected the problem.

 

a clutch can and will do that, especially a cheap clutch and a flywheel that wasn't resurfaced properly

 

A cheap clutch can have problems when engaging, but wont do that when fully engaged. What he is describing does not sound transmission related. It is the same effect I had when I had a vacuum leak from my pcv valve, and can also be caused by timing being to retarded.

Ben

 

Could it be a clogged or malfunctionning egr system? Or quite possibly low fuel pressure or a clogged fuel filter will cause the problems you have described. My daughters car would do the symptoms you described, replaced the fuel filter tested the fuel pressure seemed to solve the problem

 

Yup, we've already told him to check the fp too. It souds like he either has a lean condition or the timing is to retarded. He needs to check out those areas. Fuel pressure, or vacuum leaks can cause the lean condition, and the timing is pretty obvious.

Ben

 

my moms 82 firebird did the same thing as his car is doing. the only thing that cured it was a new clutch. it went threw 3 clutches by the time it had 32,000 miles on it. it had the 2.8 and the 4 speed. even after all that, the car would still buck and surge from a stand still and slipping the hell out of the clutch to get it going. it also did it in third gear. the only time it didn't do it was when you would dump the clutch and light the one tire.