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Carbed to TBI - help!

DavidB

DavidB

1/2 ton status
Joined
Oct 8, 2001
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Location
El Centro, CA
My buddy bought a rock buggy with a TBI engine, blew a headgasket, ordered a (1986= carbed) crate engine from Summit, along with a manifold and bigger (2" bore) throttle body for it. Went to put it together, the 4 center bolts in the intake manifold have a different angle, roughly 18* vs 36*. What gives? I didn't think anything changed carb or TBI until VORTEC.

:mad:
 
OK, figured it out, got a carb crate engine with TBI parts to go on it. How/can we make it fit?
 
The 4 center bolts changed angle starting in 1987. You can modify the manifold to work and the dizzy will work no problem.
 
Thanks!

So that should be about it right? We have a hole for the knock sensor. Anything else?
 
I am going to be doing the same exact thing. Pre 87 crate engine in a 88 1-ton. Bought the 88 1-ton with everything minus the engine. I am going to run the crate engine I bought in '04 out of my '75 with the TH350 and 203 behind it. I dod have the manifold out of the '88 but it doesn't sound like it will bolt up.

Could I run my existing manifold? Just get a throttle body adapter?

How well is the enging going to run? Will it run at all?
Thanks
 
I have done the same thing i had a brand new crate 350 for a 78 and my suburban 87, I took the stock TBI manifold and had a shop redirect the holes at the right angle to match the 78 moter the holes are a little bigger but i have not ever had any leaks and i did the switch 2 years ago also if the moter is motified you have to have the computer reprogramed to match, I found out the hard way
 
The engine is a stock crate engine from Summit, not a hi perf or anything. Think the cam might cause issues?
 
I'm still working on my project and can't get it to run right. I bought a chip from tbichips.com and still can't get it to run right, I think there was a miscommunication between him and I though.

On others that have done this, did you have to get a custom chip burned?
 
Not running right leaves a lot of open questions...are you SURE everything is physically right? Plug wire order, no vac leaks, timed right, injectors ok, etc.?

If everything else is in order, what are the motor specs, specifically engine displacement and cam specs?

If Brian worked with you, it must be possible to get to run right, but if you think there was some miscommunication, really need to work with him to make sure what he gave you is right.
 
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Mine would run somewhat ok with the stock computer, but gave me ECM errors for the missing equipment (EGR, etc) that I didn't have. It did have a big stumble and misfire until I got the new chip.
 
Well, I have new coil, wires, firing order correct, timing set to zero ESC unplugged and good fuel pressure. I have 15" vaccum to the MAP sensor. Also I am not getting a Check Engine light.

My big issue now is a big flat spot just off idle when I am getting into the throttle. Also there are a few other flat spots throughout the rpm range.

According to Brian @ tbichips I don't have enough vaccum at idle to make it run right.

Obviously there are other folks that have done what I have done.

bp71K5 - where did you get your chip at?
 
I got my chip from brian as well. It sounds like a vacuum leak issue if your cam is ok. I used a TBI specific cam.

I can say mine ran very similar before I connected the o2 sensor. I also had flat spots right off idle that were timing problems. I could see the timing mark drop to 10 degrees atdc right when the stumble happened. Brians chip fixed that part though.

You plugged the timing wire back before testing right?
 
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