Hey every one just after some advice of where to go next. 1991 Z28 350 tpi. When its cold it runs ok. Please forgive my explination if i get it wrong. When the choke/ cold start turns off she runs like a sack of sh*t impossible to drive, revs up and down no more than 1200 rpm at a peak and drops to a stall then it stalls and wont start then runs bad. until its stone cold again then its all good. Have done distribuator/ rota arm/ filters/ fuel filter/ plugs/ leads vacume hoses all the hoses i can see anyway. it seems to run lean as if its being flooded with air and starved of fuel but fuel pressur seems ok. Any help or advice or just say have you tried this your obvious might not be mine. many thanks guys.PS: its not throwing out any codes

 

i would also try the c02 sensor, and mass air flow sensor, if the MAF is dirty that can also may it run like your describing. wouldnt help to buy some cleaner and clean it. if you need help with location let me know.

but the c02 can also cause it to run crappy, would try both of those, the c02 sensor is only like $18 plus the cleaner for the MAF is $7

 

Hi as far as im awear my car has no MAF but thats according to some guys on here and the fact i carnt find the dam thing. c02 sensors are a bit more expensive in the uk but thanks i will give it a go

 

the maf is expensive in the US for mine was $189
its located here in the pic. but the c02 is cheap i paid $18 for it.

 

Nope def not got one my intake starts as a Y shape then straight into the throttle body but thanks anyway

 

Check the fuel injectors, common problem with TPI. There are a bunch of threads with similar symptoms. I myself had the same symptoms that killed a whole summer for me. Over half a dozen flatbed trips, hundreds of dollars in replacing good parts while trying to troubleshoot, and multiple trips to multiple mechanics who took the intake manifold off more than once because they could swear that is what the problem was. Finally a GM dealer hooked a node light up to the injectors and knew right away what the problem was. A note though, (2) of my fuel injectors were bad, the car had well over 100,000 miles on it. Might as well change all (8) injectors, going OE will be expensive at $80 per injector... Look at aftermarket sets, MUCH cheaper. Do have the injectors checked before replacing though, one bad injector can effect the rest.

 

Hi, Just checked the injectots six are at 17.5 ohms and one at 4.3 and the last is 3.4 but this means nothing to me.

 

As I said, it's a very common TPI problem, looks like you found it!

I do not know the specifics of it, but as I said, there are a ton of posts on this issue on here. For specifics, do a search for "TPI injector ohm", a number of posts will come up regarding your issue. Again, this is the same exact thing I've run into, as well as many others. One post I ran into with the above search seemed to be full of usefull info with more specifics:

https://www.thirdgen.org/forums/tech...falls-off.html

Again, I wouldn't just replace the (2) bad injectors, I'd get an aftermarket set, you'd be looking at maybe a $300-$400 DIFFERENCE in aftermarket and OE injectors.

 

Will i have to strip the intake down to the fuel rails to get the injectors out?

 

I'm going by memory a few years back here, but I believe you have to take the upper plenum and intake runners off, which really aren't bad, then you have to undo the fuel lines by the thermostat to disconnect the fuel rail. There is a vacuum line that needs to be disconnected at the FP regulator, then (4) bolts hold the fuel rail to the lower intake manifold. I believe once the fuel rail bolts were out, the fuel rail just lifts up, injectors and all. There are little "C" shaped locking clips that hold each injector to the fuel rail, a little screw driver or scribe help with the clips, they need to be swung one way or the other. When putting things back together just be very careful when attaching the fuel rail/injector assembly back to the manafold, make sure the injectors line up into their ports just right, if they are off and you torque down the rail, the injectors will crack and/or break.

You MAY want to get new O-rings for the fuel lines, and you may also want to get new runner gaskets when you put things back together.

The job really isn't too bad. I had mine done by the dealer when they found the problem, don't remember how much they charged. I have done this recently though as well when I re-did the motor.

 

Thanks man i will pull it apart tomorrow and let you know how it goes

 

There are two bolts that go from the inside out to hold the runners to the lower intake. They can be hard to spot, but they aren't too bad to remove.

 

thanks for the advice. do you know where the vacum hose from the underside of the throttle body goes?

 

I have yet to finish running all my vacuum lines, so I am unsure, but the following post may point you in the right direction.

https://www.thirdgen.org/forums/faq-...-diagrams.html

The links at the top of the post are dead, but at the bottom of the thread, it mentions you just have to register for free to see the diagrams.

 

Well after waiting for the parts to come from Rockauto the Camaro is back on the road again and running sweet. It was worth the wait though as there nearly $200 each in the uk. Thanks for all the advice......

 

$200 each?!?! Owch, fuel injectors would be worth more than the car...

Well, glad you found an alternative, and glad you are up and running again!!