Tbi help!

[Schurkey]

I have a 93 chevy kodiak with the 366 gasser in it

I had no idea Chevy was still using the 366 in '93. I thought they retired the 366 long before then.

 

[DerekTheGreat]

I had no idea Chevy was still using the 366 in '93. I thought they retired the 366 long before then.

EFI on top of it! I thought all of those turds were carbureted.. Learn something new each day.

 

[1989GMCSIERRA]

Hi all, new to the forum, looking for any info that would be beneficial on these tbi systems.

I have a 93 chevy kodiak with the 366 gasser in it and I'm really having a hard time getting it to run right. I know this site is for the gmt 400s but I was hoping someone on here could just share any information.

The truck starts good, but seems like it runs really poorly to me, and as it warms up it seems like it gets worse. I run it up and down the road a couple times and it can't really even get out of it's own way. it seems like it has a miss that's inconsistent as well.
I've replaced: iac, map sensor, injectors, fuel pressure diaphragm, plugs, wires, cap (haven't been able to get a rotor yet), coil, coolant temp sender on the intake manifold, oxygen sensor.

Tested: fuel pressure 20 psi (my gauge works to 100psi if that matters)
Tps: .55v at idle, 4.44v at wot
Codes: only showed code 12

I had a friend look at it and he messed with the timing when it was running but that didn't help much, I tried spraying around the intake manifold with starting fluid to see if it had a leak but it didn't seem to, I checked the vac lines on the engine when I replaced the sensors and no leaks, I checked the egr and it works like it's supposed to, cold compression is between 135-150.

Any suggestions? I am really confused on this an I've already thrown a lot of parts at it.

when was the last time the fuel filter was changed? My buddy had a 454 suburban and same symptoms as yours. Idled fine but had no power. The PSI was fine as long as the engine wasn’t under load. As soon as you required more volume of fuel it fell on its face. I replaced the fuel filter and truck ran fine

fuel filters are really never changed because most people think it’s in the gas tank. lol under the frame rail. I bet it’s original GM

 

[Dak24]

when was the last time the fuel filter was changed? My buddy had a 454 suburban and same symptoms as yours. Idled fine but had no power. The PSI was fine as long as the engine wasn’t under load. As soon as you required more volume of fuel it fell on its face. I replaced the fuel filter and truck ran fine

fuel filters are really never changed because most people think it’s in the gas tank. lol under the frame rail. I bet it’s original GM

Actually I just replaced it, I had hoped it was the issue as well but it didn't change anything.

 

[Dak24]

Quick update:

I am currently in the process of replacing the intake manifold gasgets. I got looking and they were so cheap for this motor and because it's a truck there so easy to do I figured I would do them just to rule it out.

I didn't really see any signs of the old ones leaking though so I doubt they were the issue but I guess we shall see.

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[Dak24]

Well I got the gasgets in and re tested all my lines and cleaned my electric connectors when I reassembled it. I think it runs a little better but it still hesitates pretty bad, if you just floor it it almost dies and only really revs up if you let off the gas and then slowly try and accelerate. It also is pretty hard to downshift because if you try and rev it up fast it just bogs down. Any thoughts?

I think I've found someone near me who can look at the computer but is there anything else I can try?

 

[sntrym]

So I went back through the thread, and I couldn't find what caused the engine to not run correctly. Did you just buy this and try to get it running, or was it running ok then just started running rough? Any backstory would be good.

 

[Dak24]

So I went back through the thread, and I couldn't find what caused the engine to not run correctly. Did you just buy this and try to get it running, or was it running ok then just started running rough? Any backstory would be good.

Well to be honest I don't know the entire story on it either, but basically what happened is my father bought this truck maybe 10 years ago and was going to put a different bed on it to use it. That never happened so the truck mostly has just sat a lot of that time but we would run it periodically just to keep it from having issues (not that it's worked). Other than that I don't know much about it's previous life other than a crop seed company owned it. It also looks like it has had a jasper replacement engine in it, which I assume the previous company that owned it installed.

I don't really know how it drove when we first got it because I never run it so I can't really say if it already had issues then.

 

[sntrym]

Well to be honest I don't know the entire story on it either, but basically what happened is my father bought this truck maybe 10 years ago and was going to put a different bed on it to use it. That never happened so the truck mostly has just sat a lot of that time but we would run it periodically just to keep it from having issues (not that it's worked). Other than that I don't know much about it's previous life other than a crop seed company owned it. It also looks like it has had a jasper replacement engine in it, which I assume the previous company that owned it installed.

I don't really know how it drove when we first got it because I never run it so I can't really say if it already had issues then.

Are you sure it's still a 366? I saw the intake was but those intakes will fit other big blocks IIRC.

 

[Dak24]

Are you sure it's still a 366? I saw the intake was but those intakes will fit other big blocks IIRC.

Yeah unfortunately I am, i checked the casting number on the block when I first started working on it because I didn't trust the sticker on the air cleaner. I really wish it had the 427 instead because even if this motor runs well it's still going to be gutless with the amount of weight we will be putting on it.

The number off the block is 10114183, which when I used some websites came up as the 366.