89 305 tpi runs rough after warm up
 

Hello..I have a 305 tpi that runs rough after it warms up
engine sees to shake like a miss fire and looses some power like it hesitates
thing I have done so far...
new temp coolant sensor
new idle air control valve
fuel filter
cap/rotor/wires/plugs/
car seems to vibrate and acts like its no getting enough gas/spark but it runs fine the first few minutes ....this car di sit for a bit..
bad fuel pump?? bad MAF??..Injectors??
thank anyone..new to this

Re: 89 305 tpi runs rough after warm up
 

Check the fuel pressure when its acting up.

Re: 89 305 tpi runs rough after warm up
 

https://www.thirdgen.org/forums/tech...formation.html




1st thing with any problems is to pull the engine fault codes and see if anything showing

https://www.thirdgen.org/forums/tech...s-dumbies.html

The fact your problem is when warm points towards a faulty O2 sensor that the computer uses to control the fuel when the engine goes into closed loop operation (warm )

Re: 89 305 tpi runs rough after warm up
 

thank you for the heads up will do that today

Re: 89 305 tpi runs rough after warm up
 

wow not easy getting that out ...any special tool for that ??
thanks for the info

Re: 89 305 tpi runs rough after warm up
 

For what ?

Re: 89 305 tpi runs rough after warm up
 

oxygen sensor but I see autozone has it ..thank man

Re: 89 305 tpi runs rough after warm up
 

Check everything that has been suggested, and if all that pans out I would place money that it is an injector issue-especially if they are original, or replacements of the Multech design.
My '91 starts like a champ and runs great for a few minutes until the injectors get hot.
Then I get down to about 4 injectors that are actually working right/pass the ohm test.

Re: 89 305 tpi runs rough after warm up
 

:doh:

I didn't say to replace it ;I showed you in post # 3 how to check the codes to see if it is showing as faulty.

Checking the codes is the FIRST thing you do when you have a engine problem

It may be a O2 wiring ( or something else ) problem and you are just wasting time and $$$ putting in new parts in the hope of fixing something

Re: 89 305 tpi runs rough after warm up
 

I had the exact same problem with my 89 IROC-Z 305 TPI. Would run good when it was cold but as soon as I would get it on the road and get it up to good operating temp it would start shaking and hesitating when I would give it gas it would eventually die. I would start it back up and it would still shake and as soon as I would give it some gas it would die. Would have to wait until the engine cooled and it would run fine again until it got up to normal temp. I took it to a auto shop and they replaced the O2 sensor, MAF, ECM, spark plugs, wires, etc. and within the hour of me always getting the car back from the shop it would start sputtering again so I decided to just troubleshoot myself and I checked the injectors. I had three that were bad. They read a 3, 7 and 5 Ohms. Replaced them and never had another problem. I don't know if this is the exact same type of problem you are having but never hurts to check the injectors. Would have saved myself a lot of money.

Re: 89 305 tpi runs rough after warm up
 

I totally agree with Vassago. Do yourself a favor and check the resitstance...The stock injectors are notorious for failing coils when they are hot.

Re: 89 305 tpi runs rough after warm up
 

Smooth at idle and shakes like a grizzly bear when hi idle drops out -

OHM out the injectors (search youtube) very simple, I had the same exact problem, replaced everything you mentioned above ... found 3 bad injectors ....

Put all new 19 LB bosch IIIs in camaro and it is as smooth as a caddy now.

Re: 89 305 tpi runs rough after warm up
 

thank you all for you're help will check injectors today....
if I do need them anyone know where to find them for a good price (bosch IIIs 19lbs)

Re: 89 305 tpi runs rough after warm up
 

My car was doing that rough idle at lights and wanting to stall. Took to a 2nd mechanic and got an engine inspection. Here is what they said" verified abnormal idle and poor engine performance. Engine overheats, excessive pressure build up in cooling system, cooling fans do not come on. MAP sensor is not reading proper voltage, possible electrical failure in MAP sensor circuit. Performed chemical test of cooling system and found combustion gases in coolant. head gaskets have failed, possible warped heads. Recommend replacement of engine". Car runs great otherwise and only has 105,000 on the engine. Should I get a second opinion,

Re: 89 305 tpi runs rough after warm up
 

Did you look at post # 11 ?

South Bay is a sponsor here and they stand behind their work, I hear great things about them. They reman and test the sets. While you have the TPI torn down for a few more bucks replace the fuel regulator, you did everything else. They usually come with new oring kits for the fuel rail.