Thermostic air cleaner causing rich condition

The flap being closed makes the engine draw hot air from across the exhaust manifold, I suppose it might make the engine run a little bit rich. Wiring open the flap may make your engine warm up a little slower but that is it.

on my truck i have gibson custom headers so the thermostatic air cleaner is more or less in the landfill. but the part i still have is the filter housing. with this truck i ended up replacing the icm beacuse it had failed under heat loads, every time i checked the timing with the tan wire unpluged it would be off 7 degrees btdc, i would re adjust it back to 0 and drive it and after 20 mins the truck would start missing and backfiring under load. all the live data checks have told me that the distributor is out of time. do distributor just move on their own?

it wont throw a code for anything. the only code i have had was for the egr valve which i replaced. tonight i left from the house and when i gave it anything more than quarter throttle it would be bogged down and miss and backfire

I'm assuming ur talking about the tan wire on the passenger side. When its unplugged the idle changes but when you give it any throttle the truck misses sputters and back fires immediately. I ruled out the timing chain because the rotor moves the moment I move rotate the engine by hand. And it idles without a problem and its quiet and smooth. I'm thinking either fuel pump or the pickup coil is going out

I did notice that the distributor had rotational play and up and down play but nothing like videos show

I followed all that. Timing chain moves 2 degrees before the distributor rotates. I'm going to take it to the dealer and pay the big bucks. They have the equipment to do all the testing

I've used this dealership before for other services they only fix what actually is broken, all the local shops near me wont mess with it since Ive had them try to fix it, they just go to the timing is off and re adjust it, I do know the dealership has a service tech that only works on pre obd1 trucks

Yea the tech is 60+ but I have had the truck in before for a TCM replacement and they have a bay set up just for obd1 vehicles because a lot of people have classic cars that need tuned up or the guys with the off road trucks need their ecm flashed. So they keep a bay for that reason. But the service tech said not a little problem just give us two days and they will know exactly what's wrong. They said the same thing for my dads Chevy master deluxe and sure enough they found faulty wiring that would only cause a issue at operating temp

Got it back from the dealership and they couldnt pinpoint the exact problem but they said it had to do fuel delivery. So they suggested I drop the tank amd Clean it out beacuse it sounds like water is in the gas.. And while I'm there I'll replace the fuel pump because it only gives me 10 psi when I should have 12-13 psi, and I'll work my way back to the engine

Yea I've done the fuel filter and pump relay already...I'm thinking the pump is just tired, I hear the pump come on and run but I never hear the pump load up just the same running sound...but I'll drop the tank clean it and replace the fuel pump

I have a few laying around somewhere in the hangar. If not I'll just go to the local box store

I did the fuel pump replacement the old one was only putting out 11psi the new one puts out 20. Ru built the TBI again because I saw a fuel leak. Put it a new distributor because the gear looked pretty beat up and IAC because why not. I refined it back to 0-1 degree btdc idles great runs like crap when I give it fuel it hesitates and back fires when giving it gas and stays bogged down. Anybody know what would make this engine do this? Is it a bad injector at speed?

I did the exhaust back pressure test my self I have about .3 of back pressure before the cat. It also dosnt matter if I try to adjust the timing. I've tried factory 0 I've tried 4, 10, 13 ,17, all done by unplugging the est under the the dash. Right now its set for 14 advanced just so I can drive it around town. The only things I haven't changed is 02 and the injectors and the main ignition coil, all my test I've done leads me to ignition, or fuel. But it has never thrown any codes for it, even the dealer ship gave it back saying they don't know. A obd1 gm 350 only has so many parts. I'm going to buy a cigar and smoke test the intake to see if I'm leaking vaccum somewhere. I really only have the intake gasket that can be suspect

Solution : ignition coil had a bad internal ground after the engine warmed up. Replaced ignition coil and retimed engine, runs perfect

When they were testing the coil is was grounding properly..but when it was on the road it would fail Intermittently

No it looks exactly like the brand new one..he said if you do a resistance check on it and shake it, you can see it on the ohm meter and that he has never seen a coil fail like that with out giving a indication. It was bad

At least I managed to find other things wrong with the truck like the distributor and fuel pump. Plus got a chance to clean out the fuel tank. But it idles so smooth and quiet that I forget its running