Diagnosing Rough Idle Hell

[Schurkey]

I usually use pb blaster,or brake kleen flammable brake parts cleaner because that's what I have on hand,

I get scared when folks talk about using brake cleaner to check for vacuum leaks. Some kinds of brake cleaner aren't flammable, they'll make no difference when sucked into the intake stream. Other kinds create phosgene gas when burned, which is very poisonous.

I use aerosol carburetor cleaner.

if this turns out to be a 305 tbi not off a 350 then the regulator spring is probably wrong pressure as well

TBI 305 and TBI 350 use essentially the same fuel pressure. The injectors have higher flow on the 350 vs. 305.

 

[1993GMCC2500SLX]

I get scared when folks talk about using brake cleaner to check for vacuum leaks. Some kinds of brake cleaner aren't flammable, they'll make no difference when sucked into the intake stream. Other kinds create phosgene gas when burned, which is very poisonous.

I use aerosol carburetor cleaner.


TBI 305 and TBI 350 use essentially the same fuel pressure. The injectors have higher flow on the 350 vs. 305.

Ok I figured maybe the pressure springs were different??

 

[Schurkey]

Ok I figured maybe the pressure springs were different??

There's several designs of pressure regulators, which look the same from the outside.

Some have a stamped-sheetmetal platform that the spring sits on. Some have a small casting of aluminum or zinc or something that the spring sits on.

You must be registered for see images attach

So it's not impossible that the springs are also different. However, it wouldn't be because the pressures are different, or because one was 305 and the other was 350. It might be because of model-year changes; or California vs. Federal emissions regulations, or some other reason.

Point being, if you keep all the parts together, the fuel pressure for 305 and 350 are the same, so the pressure regulator including the spring is interchangeable as an assembly.

The "important" difference is in the injector capacity.

 

[1993GMCC2500SLX]

There's several designs of pressure regulators, which look the same from the outside.

Some have a stamped-sheetmetal platform that the spring sits on. Some have a small casting of aluminum or zinc or something that the spring sits on.

You must be registered for see images attach

So it's not impossible that the springs are also different. However, it wouldn't be because the pressures are different, or because one was 305 and the other was 350. It might be because of model-year changes; or California vs. Federal emissions regulations, or some other reason.

Point being, if you keep all the parts together, the fuel pressure for 305 and 350 are the same, so the pressure regulator including the spring is interchangeable as an assembly.

The "important" difference is in the injector capacity.

This is what I know truck is a early 94 Chevy Silverado Z71 extended cab short bed and the motor is a 1987 Chevy p30 350 tbi tbi I'm not sure about especially after the other things I have had to fix.. I'd guess it is similar to the 87 and whatever they needed to make it work for the 94 truck, but as I've said the ect sensor wires, and ground wires at the thermostat housing were cut and twisted back together, TPS sensor was the same way, the iac connector tubes were broken, and then I realized that the three prong TPS sensor plug they were using is green that would mean it is actually for the map sensor, and then there's the throttle shaft bushings are worn, and the two different injectors so I'm just changing the whole damn thing,I am keeping my new ac delco iac valve and maybe the fuel pressure regulator I rebuilt after I cleaned up the bowl and the spring and put a new Walker Rochester 220 350tbi diaphragm in it and torqued the torx bolts/screws back down.

 

[1993GMCC2500SLX]

This is what I know truck is a early 94 Chevy Silverado Z71 extended cab short bed and the motor is a 1987 Chevy p30 350 tbi tbi I'm not sure about especially after the other things I have had to fix.. I'd guess it is similar to the 87 and whatever they needed to make it work for the 94 truck, but as I've said the ect sensor wires, and ground wires at the thermostat housing were cut and twisted back together, TPS sensor was the same way, the iac connector tubes were broken, and then I realized that the three prong TPS sensor plug they were using is green that would mean it is actually for the map sensor, and then there's the throttle shaft bushings are worn, and the two different injectors so I'm just changing the whole damn thing,I am keeping my new ac delco iac valve and maybe the fuel pressure regulator I rebuilt after I cleaned up the bowl and the spring and put a new Walker Rochester 220 350tbi diaphragm in it and torqued the torx bolts/screws back down.

Motor is supposed to be 0.40 over with speedpro Pistons that I can't say for sure as I have not had the heads off yet.. I replaced the fuel sending unit assembly because it had a b which looked absolutely nasty when I pulled the sending unit out of the tank,I replaced the rusty distributor and cracked distributor cap it had a small crack on the screw boss to hold the cap down on the distributor.ad fuel pump in it,

 

[1993GMCC2500SLX]

Motor is supposed to be 0.40 over with speedpro Pistons that I can't say for sure as I have not had the heads off yet.. I replaced the fuel sending unit assembly because it had a b which looked absolutely nasty when I pulled the sending unit out of the tank,I replaced the rusty distributor and cracked distributor cap it had a small crack on the screw boss to hold the cap down on the distributor.ad fuel pump in it,

It moved my words around..^

 

[1993GMCC2500SLX]

I ordered a set of dorman ground straps for replacement for the important one missing from the firewall to the back of the passenger cylinder head.

 

[1993GMCC2500SLX]

Don't know if it matters but the tbi on my 350 in the early 94 Chevy Silverado Z71 that is on the 87 motor is 17087101.