[dlsmith1979]

I have an 89 chevy TBI that is giving me fits and Im pulling my hair out with it. I took a 327 block and put my 350 heads on it so I could run the tbi on it. got it to running yesterday and it is popping back in the tbi and once it gets warmed up it will not idle and has not power cause when I mash on the gas it starts popping and cracking really bad, The 327 block was built for racing and I am having to run a 2000 stall in it, and suggestions on how to get the popping out and get it to idle wiuld be very much appreciated

 

[DoubleVision]

Set up for race meaning? What are the mods done? cam size? compression ratio? If the 327 has high compression, a sizeable cam and other mods you can`t just bolt a stock TBI to it and expect it to run correctly. The TBI system can learn to compensate for some performance changes but that band is very narrow. By the way it runs it sounds like you have some plug wires mixed, that or the fuel mixture is so lean it`s forcing it to pop.

 

[dlsmith1979]

How can I adjust the fuel on it to make it run better cause I have checked the wiring timing and sensors a dozen times and changed everything

 

[DoubleVision]

The only way you can adjust it is to install a adjustable fuel regulator with vacuum compensator. You didn`t answer my question so I`ll ask again, what mods are done to the 327? what`s the compression ratio? what`s the cam size? what heads?

 

[dlsmith1979]

Another friend of mine built the 327 and he put it in his garage then he gave it to me it is a standard bore and he told me the cam was a green line came but i put a stall in anyhow even though with a green line it is right on the boarder for a stall as far as the ratio I dont know I do not have any off my tools no longer to check that but the compression is 175 ponds on all cylinders and the heads are stock 350 heads that I had to put on it to be able to run the tbi but I am starting to think I will be better off to put the 327 heads back on the engne and pull the fule pump out of the tank and run a carb

 

[curtis73]

Almost any change to a TBI motor will require a custom chip to be burned. Certainly reducing cubes to 327 and a race cam are way beyond what a stock TBI can compensate for.

Small engine, big cam, massively different VE parameters, tiny head ports, small TBI flow... its a mismatch to say the least. I'm actually surprised it runs at all.

 

[dlsmith1979]

Would it change any if I was to pull the cam out and put a stock cam back in it and get rid of the greenline

 

[curtis73]

Yes. You'd still have to burn a new chip, and you'd go from the stock 180 hp of the 350 down to about 140 because of the reduced compression and displacement.

 

[dlsmith1979]

ok what i am thinking bout doing is taking and putting the 327 heads back on and intake and rumming a card with a vaccum advance dist and running all manual guages and taking the pump out of the tank and putting a manual pump on the motor

 

[curtis73]

Ok... you might find that the motor doesn't have the hole drilled for a mechanical pump. If that's the case just buy a regulator to step down the pressure and use the factory electric pump.

 

[price]

Put a length of pipe where the the pump is now.It has to be the same length as the pump. Make up a screen out of some mesh like on a coffee filter. It doesn,t have to be fancy. Rubber gas line will get you from the braided (existing) line to the mechanical pump. You can get a pump with a return line and use the existing braided line or not.If you plug the return line you may have to drill a small hole in the gas cap.
Clint

 

[Jim Rockford]

Did you use the 350 tbi heads? If so you wasted your time, they are only good for door stops, If you have a good set of 327 heads with assy holes , you are better off reinstalling them and getting a custom burned from a place like TBIchips.com he has good experience dealing with strange TBI setups.

 

[chevythmpr]

I don't know a whole lot about this stuff but you might want to double check your valve timing. I had my valves way off on my tbi and it ran similar to what you're discribing.