1989 chevy 350 tbi transplant

[62burbdream]

Hello everybody, I'm a newbie on here. I'm on here to learn more about the tbi system. Mainly how to get my 62 suburban driving down the road reliably. Heres the story in short. I bought a 1962 gmc suburban took out the 305 6cyl manual tranny. For a 1989 chevy 350tbi that I got from a guy that owned a shop. I was told the tranny was a 700r4 which in later I found out was a th400. Which is fine I guess. It had no computer or wiring harness so I got a ecm from a wrecking yard its a # 1228747. Which I think would work for it. (I'm a beginner on this stuff) I bought and wired up a painless tbi harness.

So my truck idles pretty good sounds great. Having problems getting it to drive great. When put in gear and try to actually drive the thing its sluggish and backfires which sounds like in the engine compartment. I've set timing by first unplugging that cigar shaped plug by the ecm and set to 0 let run turned off and plugged back in. First time I did this I drove it and it ran great around the neighborhood. I was excited! Next day I got in and it was back to wjere it was. Looked at timing with my timing light. It was back to where it was before I timed it. Which made it run crappy.
What I'm I doing wrong? Any advice would help out a lot. One more thing is my motor at least the gauge says it running hot it gets to 240 than I turn it off. I have a new 190 degrre thermo in it. The heater blows warm-hot air. Clogged radiator? I purged the system as well thinking it could of been a air bubble.
Basically any help with any knowledgable advice would be hugely appreciated!! Thanks a lot for reading this long intro.

[62burbdream]

One more thing about the radiator is the water is cool when temp gauge says hot. Clogged radiator? It is 50+years old and from the big 6 cylinder .

[EagleMark]

It could be the radiator plugged after all this time who knows the condition, or sticky thermastat? With only warm air from heater is it clogged to or is dash gauge off?

With a transplant and conversion harness there could be lots of issues? Have you checked for codes yet? Also could be a fuel pressure issue, lot of fuel flowing now all the time cleans out all the debree from old tanks as well, hope you have a pre pump filter? If you left the sock in the tank it will collect all the debree there and restrict fuel flow. Way to test all this is fuel pressure at idle and when reved up.

[62burbdream]

I have checked for codes and it showed 12. Which is nothing wrong apparently. As for the radiator its probably clogged. I can easily fix that, its the other issues I'm having.
My fuel pressure should be good I have a new pump rated @20psi and a gauge that says 8- 11 it jumps around allover the place. I think the gauge might be bad. This is my 2nd pump. Its an in-line pump from carter. I forget the model# All new gas lines I have a prefilter and have taken the gas tank out a couple times so its clean.I have also changed-rebuilt the tbi spring and regulater as well. new IAc as well. The issue is the timing I think. I set it to 0 with cst unplugged turn off plug it back in Still runs like crap. I'm thinking about taking it to a mechanic to diagnose it, which I really would hate to do. I've only used a mechanic a couple times in my life.

[EagleMark]

Carter is a good in-line pump I have used many times. Fuel pressure gauges are known to be off, if not liquid filled Known to shake but 8 to 11 PSI is not enough. Specs from GM say 9 to 13 but unless it's 13 it's never as good as can be so I don't know where the lower pressures come from.

Sounds like you set timing correctly, can always unplug wire and recheck. Will be around 20 warmed up wire connected. But you did not mention code 42 which usually sets when doing this? Have to clear codes after re attaching wire. Now it drove good then next day back to bad... I wonder if you hooked the ECM power wire to IGN on power? There should be 2 power wires, one is power always goes to like battery and one is power Key On which usually comes from old point wire with no resister! This would explain why it was driving better with time then worse in morning and no code 43. The ECM has a BLM learn until you kill power it looses it.

Another big issue on conversions is grounds and charging system. You have a complete TBI motor so I am assuming it has the alternator which is WAY better then a 62 Suburban. Hows the battery? What kind of volts is it getting when running?

Back to filters, I usually run a clear filter before pump so I can look and see, but after pump a metal can EFI filter is still needed as they clean fuel to much lower micron level.

Where is MAP sensor located and vacuum line run to?

Better yet we have fixed a bunch of conversions with pictures! We'd all like to see the cool ride anyway but if you can get a bunch of pictures of the conversion, wiring, fuel pump and lines under hood etc... lots of times we can see mechanical issue possibilities right off.

HTH!

[62burbdream]

Thanks for the reply. I checked codes this morning and got 42, and 43 so whatever that means. Its really running crappy now. Frustrating. I have pics need to figure out how to get them on here. Is 43 a bad throttle position sensor? With these codes What do I need to do now?
The vacuum lines I have I tried to get pics of. There is a few vacuum lined blocked off and not really well. I don't have a clue to what they would go to. Since this is the way it was when I got it.
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