twoface262

Hi guys,

I have a small problem that has me worried with my 1989 Firebird Formula 305 TBI.

When I put my car in reverse, it acts fine, until I try to make a sharp turn while reversing. Once I release my gas pedal, and have the wheels still turned sharply the car will slowly bog down and die.

I think the power steering pump is causing the engine to lock up in reverse. I don't get the same problem in any other gear though, which makes me fear it might be a tranny problem as well. The transmission fluid still looks brand new, and doesn't smell funny so the gears aren't grinding.

Can I get some help troubleshooting this please. It's not throwing an error code when it stalls either.

Thanks guys, if this is in the wrong section I apologize. Thanks!

Dougy89

Hey twoface262, i have exactly the same issue here in Australia! Mine is also an 89 305 TBI base Bird. Seems no-one else has had this issue as no other replies?

I am stumped as to what is causing it as TH700R box has been checked, serviced and is perfectly fine. It has a new P/S pump and box fitted now also, so what else could cause this?

Very frustrating issue....

88Camiroc

i have not had this issue but i might be able to help i hope. Have you ever noticed if it does it going forward? Or is it only in reverse

twoface262

It only does it in reverse when the car is on a cold start (Approx. 10 min idling before I put it in gear). Once the car has warmed up (Fully, like after a drive) it doesn't have a problem.

Dougy89

Yeah mine is more prone to it when cold, but if on hard lock in reverse will still do it when warm too..... its the weirdest thing....But no issues in forward gears

88Camiroc

And there is no check engine light???

88Camiroc

as weird as it may sounds have you check your fuel pressure? How long has it been doing it?

twoface262

Yeah my fuel pressure is fine. I just put a new fuel pump in it and its had this problem since I bought it. All fluids are good and trans fluid is a nice clear red. No check engine light and the only code I get is 44 every now and then due to my O2 sensor being worn.

88Camiroc

Is your car or both of your cars are they manual or automatic.

twoface262

Auto 700r4

Dougy89

Yeah mine is TH700R also. I get no codes at all, and no other warning symptoms. It is simply in reverse on steering lock, otherwise motor runs strong as an ox. There is no rational answer from what I can determine so far...

greggbruce

iTrader: (1)

possibly that since in reverse, trans pressure is way higher than in any forward gears (until WOT), there is a little more drag on the engine, especially when cold (trans fluid thicker), plus add the power steering drag, and the idle control is lazy -- this could be the cause, but you would not want to change it by doing anything to the trans, new idle control motor might help, but can't be sure. Also make sure the throttle body is clean behind the throttle plates, if there's too much carbon build up there, sometimes the IAC can't compensate fast enough.

Nutti

Same problem here in Finland with my camaro -89 305tbi. I have swapped fuel pump, fuel filter, iac valve, spark plugs and wires, 13×3" air filter, fuel pressure regulator and cleaned the tbi unit and rebuilt it with a kit. Still the same problem and I have only driven the car for about 100 miles after changing all the parts. The only difference is that mine stalls when putting in reverse with engine warm after driving it instead of cold engine like you guys have. Mine also idles a little rough when hot, not mutch but you notice it.

Dougy89

Well it seems to be a mystery we can't resolve for now.... Once i figure out who ships to Australia without ripping us off I will get TBI overhaul kit and new flow matched injectors, as well as full service kit including fuel filter, cap, rotor, leads etc etc. Hopefully when all that stuff is done I can then start to eliminate things that are more complex to fix...

Thanks to all who responded!

fireburdluvr85

I'm gonna throw 2 ideas out, one for cold and one for the hot.
Egr system partially open during cold will bog it down when under a load cold. This could be a bad solenoid( personally dealt with) or a bad valve/ports.

Fuel vapor solenoid not holding back vapors and bogging down a hot engine. Again I've dealt with this. For some reason reverse would stall randomly til I repaired these issues. Worth a check because either of these issues can cause strange idling/ running conditions.

Dougy89

Thanks fireburdluvr85, appreciate the idea,s very much as had very little before this! being in Australia we have next to no access to knowledge apart from forums in the US and same goes with parts and interchangeability etc. I am new to 3rd gens, so really flying blind! Apologies to all in advance if I start to pop up around the traps with dumb a$$ questions etc too....
Thanks again!

fireburdluvr85

No problem man. I hope its nothing major. I had this random stalling for some time and reverse was impossible. Then I was reading some thread and a guy had similar issues as you state so I checked mine when it was stock. The vent solenoid wasn't holding back vapors and enrichening the system all the time. Easiest way to check for that is during rough running conditions, open the gas cap. It will either clear up or get worse. If it stays the same then its fine. The egr is a bit more in depth but these threads are full of knowledge. Hopefully this helps. Good luck!