Hey guys I have a 92 firebird formula with an 89 305 tpi in it. The car runs great at low speeds, and hesitates bad when you accelerate, I'm thinking fuel related? I am not sure what to check maybe fuel injectors are bad? It has a new fuel filter. Any help would be appreciated thanks.

 

https://www.thirdgen.org/forums/tpi/...tates-bad.html
Read suggestions on your first thread !
http://www.amazon.com/gp/aw/d/B000IZ...142190-8637133
http://www.southbayfuelinjectors.com...l-injectors-8/

 

Talked to the old owner turns out the original motor was a 305 all along so injectors fuel rail manifold etc are fine. Checked tps and is in spec. I will check fuel pressure and replace map and get back to you. Any other suggestions with the new information? thanks

 

A few common things, tune up items. Cap rotor, plugs, plug gap, initial timing . Checking fuel pressure under a load (power breaking).identifing the injectors are they a grayish color multec (post a pic). Then move onto using a aldl to USB cable data log using tuner pro rt. check to see if the cat is plugged.

 

It has a new distributor, cap, and rotor. Is timed, I'm going to check fuel pressure next.

 

Checked fuel pressure and key on engine off was 45 and slowly dropped to 38 because the car was not running and with the engine while running pressure held at 32. Is this too low or where it should be? Map sensor should read 1-2 volts key on engine off closed throttle and wot is 4-4.8 key on engine off. It read 4.9 closed throttle and 4.9 for wot.

 

Fuel pressure is fine and so is wide open throttle on the map but on a one bar map unless you live over 9-10k feet should be less.http://chevythunder.com/map_code_33.htm

 

Alright so good on the fuel pressure and my car did throw a low vacuum code on the map sensor and I live in olympia Washington so I don't think there's a high elevation here

 

not unless your doing drugs your not that high !

 

Lol I bought a map sensor and am going to put it in tomorrow and hope it fixes the hesitation

 

 

Just got back from driving and the map sensor fixed the hesitation! I'm going to put new fuel in it tomorrow because has old fuel in it. Have one funny ifle problem left it idles at 1k and bumps up to 1500 but you can kicked it down by hitting the gas peddle this could the extra spring I have on the throttle not being tight enough or could possibly be a colorant temp sensor failing giving a false code of being too cold requiring more fuel? Going to check out the spring and make sure it has tension. Thank you for helping me!

 

Is that idle issue just when it's cold or all the time ? If it's all the time it maybe a worn throttle shaft. Cold start it would be a iac adjustment .

 

Iac is new and it occurs all the time

 

When you installed it did you set the minimum idle speed ? or ic you have a scanner look at the warm idle iac counts ?

 

I did reset the iac when I installed it. And I did have a scan tool on it showing that it was working. The stock iac was had a short Pintle on it and the replacement part had a much longer pintle on it so I thought that the longer pintle was not the correct size so I found in my auto shop an iac to match the stock pintle length and used that one. Should I be using the replacement with the longer pintle or the one I found to match the shorter pintle?

 

The pintle length would very on the old vs the new depending on where the old one was parked when removed. To prevent damage new iac are parked out. If a iac pintle was to long and installed it could damage the iac. IIRC from the gasket surface to the tip should be 1 1/8 or less when installed. Take off the secondary throttle return spring, with the engine off open the throttle about 1/4 throttle move the throttle shaft back and forth not in and out. If there is much play the throttle body is shot. there are no bushing for the shaft to ride on the throttlebody housing has wear causing the throttle hang up as well as a small vacuum leak. summit has professional product throttlebodies for a decent price or you can look in the classifieds for a good used 89-92 tpi throttle body.

 

Okay thanks you I will look into it And check out new throttle bodies

 

http://www.jegs.com/i/Professional+P...69705/10002/-1

 

that throttle body is $$$. I know some people sell good used 52mm ported throttle bodies. Anybody know if there is a cheaper source?

 

Old post, I believe the linked tb use to be in the $200 range.
You missed the sale summit had for there rebranded bbk tb . You should call tpis I think they still do boring.