I have a 1988 Camaro IROC convert. w/ 305cid 5 spd., completely stock.
I am having problems with the car running, after the car warms up, the car begins to runs rough and the engine starts to misfire. The problem began a week ago as I was driving to work in a Cleveland torrential down pour. I limped the car to work, feathering the gas pedal and using the clutch to keep the RPMs up. I get to work shut the car off, start making plans to get it home. I go out at lunchtime the car starts right up. I drive it down the block, no issues. I think maybe the ignition system got wet. I start my drive home, about 15mins into my drive; the car starts to run rough again. I limp the car home. I start at the ignition system. I find the pickup coil connection corroded, I find cracks in the stator of the distributor. I find no sense in wasting my time repairing a broken distributor, I buy an aftermarket distributor (complete with a control module and new pickup coil), and I also purchase a new coil. I put everything in; set the timing figure I am good to go. Well….. I figured wrong, the misfire comes back when the engine gets warm.
Everything in the ignition system has been replaced, unless I am missing something. New: cap, rotor, coil, distributor, control module, wires, plugs.
I tested the fuel pressure at the rails, never drops below 40psi.
Can you give me some ideas on what to do next? ECM? PROM? Any ideas or tests I can check next?
I don't have any error codes from OBD1 connector
I sprayed starting fluid around the intake and vacuum hoses looking for any leaks, I couldn't find anything.
Thank you in advance for your help.

 

Does your SES light come on? Any codes? https://www.thirdgen.org/open-loop-closed-loop

 

is your car a TPI? if so look at your MAF and its associated relays and wiring. sometimes you don't get a SES light when the relays are going south.

 

Check your compression. The only reason i say that it could be possible that there is a blown head gasket in between the cylinders but not leaking antifreeze. When the car warms up it causes the engine to expand so when everything heats up and expands maybe its just enough for a compression leak. and when it cools down it will contract and potentially seal the gap. I know its far fetched but the one thing that i have learned about when working on cars is don't ever immediately rule something out.

 

Thank you gentlemen for the replies.
The car is a TPI 305.
There are no error codes. I have used the paperclip method and the sears scanner I have shows nothing.
Any other suggestions?

 

Hi--- I have pretty much the same thing-- except I am pumping out black exhaust --- still NO Codes. I currently have a "board posting". Looking for answers. Have you CHECKED your Grounds??? The center coil ground strap must be connected when you clip everything back. Also check the Block to firewall ground strap--- use sandpaper and cleaner to make sure its clean metal to clean metal. Wirebrush. The Block is hard to reach Soooooo make a second connection from that firewall strap and run it to the back of the cylinder head- there should be a tapped hole <feel for it> and run a bolt to connect it TIGHT. Keep in touch- good luck - for both of us. John from Long Island.

 

where is the center coil ground strap? I am not sure what you are speaking of. I an going to make another ground for the dash, I'll make another for the engine if you think that would work.
black smoke? from running rich? or is this oil smoke (dark blue?) where is your posting?
Thanks for the idea. I am going to try something later tonight and I will let you know what happens. Thanks

 

I believe what he means is the center cowl ground strap at the rear of the engine. It attaches to the rear of the RH cylinder head and then to the firewall, below the cowl. I have seen alot of heat related injector issues. If you have access to a compatible scan tool(GM OBDI 12 pin ALDL), use it to monitor fuel trims as the engine warms up and the problem begins to occur. Fuel trims on the OBDI GM are Block learn(long term) and Integrator(short term). If you see the fuel trims start to go high, indicating additional fuel compensating for a lean condition, suspect injectors. MAF was also mentioned and can be checked by looking for a general drop in MAF voltage, when the problem is present, as compared to when the engine runs normal. You can test the injectors for resistance by accessing the terminals. They should 12-15 ohms higher when warm. Test them cold and again hot. If any go down in resistance and/or if any read below 12 ohms, replace them as a set.

If you still have the original injectors in the car, they are Multec pieces and it's actually surprising they have lasted this long. Look up Southbay injectors. He is a supporting sponsor of TGO and offers a discount to members.

 

I have a 1984 trans am 305 and the square coil pack is affixed directly on top of the distributor cap. On the right side of that cap is where the clips for tach and battery are attached along with the longer black clip. In the center of that rectangler area a "center" metal sleeve accepts the black clip and this is where the coil gets grounded even though there is a 3rd wire coming out of the coil that also gets screwed into place. All of this means "nothing" if you have a separate single coil and wire leading to the Top of your Distributor Cap.

 

Of course, I didn't even think of the "coil ground strap" in the large body, internal coil, HEI. I've had issues on these when the screw hole in the plastic cap, for the screw that goes through the strap and tensions it to the coil frame, was stripped. The strap ends up corroded from poor contact with the coil frame. The 88, if stock, would have the external coil HEI. I don't think GM used the internal coil after, the 87 carbureted applications.

 

right, the coil in cap went away after 86.

 

I wasn't sure if it was 86 or 87. They did still do the CCC carb in 87 on a few V8 units, even though they were big on saying that the carb had gone away after 86 in favor of EFI. I haven't seen a factory carb application V8 yet with an external coil HEI, but then I haven't seen everything.

 

I have two error codes, 14 coolant temp sensor, code 33 mass airflow sensor. I tried replacing the coolant temp sensor hoping to get rid of both codes but that's not the kind of luck I have. I will be spending $150.00 buying a mass airflow sensor today. I will let everyone know what happens.

 

I think I would try looking for vacuum leaks and the MAF relay first.

 

In my first post:
I sprayed starting fluid around the intake and vacuum hoses looking for any leaks, I couldn't find anything.
I also can put my palm over the mass air flow sensor inlet and choke the car out immediately. If the car would stumble or continue to run, I would suspect a vacuum leak.
The MAF relay might be a good advice.
Thank you for your help.

 

I just thought i would throw the vacuum leak issue out there again. I had a code 33 i couldn't track down, I changed the MAF sensor and all the relays. It turned out to be a leaky throttle body shaft, and a loose runner bolt on the bottom inside of the intake manifold. Spray wouldn't find it either. I just thought that maybe just be thorough before you spend $150.

 

at $150 you wont be buying a NEW MAF sensor. and believe me , a re man MAF is just pissin away good money.