Hi everybody, I'm having trouble with my 85 Iroc. It started about two months ago with the car getting hard to start when the engine was cold. About two weeks ago, it developed a skip at idle and a nasty skip under load. I've replaced the plugs, wires, coil, and fuel filter. The timing is still where I set it, but seems to be unsteady when I reconnect the wiring harness to the distributor. I'm out of ideas. Any suggestions?

 

Hey

I would set all the timing and stuff to stock specs. I would also go and get a compression test done on ur engine. Something might be wrong there. Does ur check engine light come on or not. If the check engine light comes on tell us.

Http://camaroz28.cardomain.com/id/56424

 

The check engine light isn't on. I was hoping it was something simple that I may have overlooked. The engine only has about 35,000 miles on it. I forgot to mention that since I replaced the coil, it started backfiring. I don't know if that means anything other than I'm screwed.

 

I would check the condition of all your plug wires. Make sure there are no cracks. Even though they're knew may not be enough, I know I've burnt a couple wires after replacing them.
Do you have a cat?

 

The wires are good, it was a pain trying to route them away from the headers. I've gone through and double checked for any grounded wires and also for the proper order to make sure that the right wires were in the right cylinders. Yes, I do have a cat, but it's only about two years old. Could the cat be causing a problem? If so, how would I check it?

 

Have u ever done the 1/4 mile in ur 1985 IROC Z.

 

Nope, I've never taken it to the track. But, I do have alot of fun humiliating the sport compact guys. Well, not right now since my car is sick.

 

Usuall if the cat is clogged, it might glow or the car will tend to run warmer than normal.

 

The car still runs at it's normal temp. This thing just has me stumped.

 

Have you checked the fuel pressure? How about the EGR? Is there any time when it runs smooth?

 

I haven't checked the fuel pressure or the EGR. It has a lumpy cam in it, so it has never really run smoothly. But, it runs normal cruising down the highway until I give it some gas, then it starts skipping causing the whole car to shake. It also skips really bad when I take off from a dead stop. Basically if I accelerate, it skips. I hope it's not the fuel pressure, because I hear that pulling the fuel pump is a nightmare.

 

Replacing the fuel pump is a pain, but no worse than most other jobs on Camaros. I've done it twice in 9 years.

Get a fuel pressure guage and put it on that puppy. It should read about 40 psi at idle and rise to ~45 when you hit the throttle. If the pressure drops its probably a bad pump.

 

Have you checked the fuel pressure regulator to see if it is leaking? Hard to say if that could be it, but if it was hard starting it might be....

 

There's also the cold start valve. I figure mine needs to be replaced. Way too many revolutions before the motor fires.

 

I've checked around the fuel pressure regulator, and everything appears O.K., but I will be checking the fuel pressure this weekend. I've wondered about the cold start valve, but I don't know how to check it. To start the car, it's like starting a carbureted car with an inoperative choke. Would that cause it to run rough under load too?

 

I believe the only function of the cold start valve is to "prime" the engine since only one bank of injectors fire half the fuel necessary at a time. Of course I'm no expert, but I think that's how it works.

Let us know what you find.