copyfixr

iTrader: (3)

Ok guys, I need some help. My son's car. 88 Camaro 2.8 with an automatic. had it for a couple years and we have been fixing the years of neglect. It still had the original injectors in it and a fuel pressure gauge confirmed we had some leaking injectors. Idled a little rough and had a hesitation. When we pulled it out of storage this year we went to work. Ordered some injectors from Southbay, got a gasket kit and a few other parts. We replaced the injectors, throttle body gasket upper plenum and middle intake gasket. Put a new o-ring on the dizzy since it was leaking and replaced the PCV valve. Since doing this work we have a surging idle issue. I have had a friend who is also a mechanic look at it and we are stumped. checked and re checked the timing, TPS voltage, tried a different know good MAF. It we pull a vacuum line and feed it a little propane its fine or if we pinch the fuel return and bring the pressure up to around 85psi its fine. We have prayed carb cleaner and propane on all the vacuum lines. Sorry for the long post, just want to get as much info out as possible. Any help would be much appreciated. Its My 16 year old son's first car. He bought it with his own money and I feel bad I can't get it running good enough for it to be his daily driver.

project89

iTrader: (1)

pull the ecm fuse and let the ecm reset, sinc eu have new properly spraying injectors the ecm will need to relearn the fuel trims for the new injectors


also check the o2 sensor make sure the voltage is swinging rapidly back and forth and not just staying in one spot once the engine is upto operating temps


only other thing i can think of is to remove the iac valve and clean it very well and reinstall it

copyfixr

iTrader: (3)

Thanks for the reply. I replaced the O2 a couple days ago and have let it sit for quite a while with the battery disconected. When it started doing this I pulled the IAC and carefully cleaned it and the butterfly and passages in the throttle body. My mechanic has had it hooked up to a scanner and says all the readings look good. I will double check anyway.

I had not checked the timing before we removed the dizzy to replace the o-ring. Is it possible the timing was set to compensate for another issue? I haven't messed with the timing yet, thats the next step..

project89

iTrader: (1)

as long a su had the est bypass wire disconected when u set the timming u cant really mess it up.

how long in total has the car run since u had the battery unhooked and the new injectors in ?

and does it idle better once the car is upto normal operating temp?

Six_Shooter

iTrader: (2)

I agree with project89, the first thing to do is check timing.

Timing can have varied affects on the way an engine runs.

copyfixr

iTrader: (3)

We did have the EST wire disconnected when we set the timing. I am wondering if the balancer maybe slipped. I have had a couple cars where that has happened. Had to time them by ear.

The car has run quite a bit. Drove it about 80 miles from my dad's where it was stored. We did the work there. Seemed to run ok at first. I have disconnected the battery since we have had it back and let it sit for a long time then fired it up and let it idle for 20 min. It usually runs nice when first started, for a min or 2, then gets stupid. The CTS was replaced last fall before we put it into storage. Thanks again guys.

project89

iTrader: (1)

can u take a video of it running and surging? sometimes its easier to help when u can actually hear whats going on vs somone trying to explain it

copyfixr

iTrader: (3)

I can't get a video right now. I have the plenum off waiting for another set of injectors. I called Southbay to ask some questions and they are shipping me another set of injectors to try just to make sure they aren't the problem. That's great customer service!

copyfixr

iTrader: (3)

I got the new injectors but haven't been able to install them yet. Son had prom yesterday and Mother's day today. Hope to get after it tomorrow.

I have had a little time to do some research. When I look on line most places show two different injectors based on the original part number. When I called Southbay they didn't ask. It ran ok when we fired it up at my dad's so I tossed the old injectors and my son headed home. Is it possible I have the wrong injectors? This car is killing me!!!!

project89

iTrader: (1)

i just noticed u said u cleaned the iac passages in the throttle body, there really shouldnt be any passages except the air inlet infront of the tb.

on a 2.8 the aidle air motor takes its air in from the front of the throttle body and then it travels down a hose to the rear of the lower intake from there there are 6 passages one goes to each cyl


the reason for this is the 2.8 has a cold start injector in the back of the intake, so it helps with the cold start fuel


if u dont have this type of setup that means somone either changed out the original throttle body for one off a 3.1 , which has a totally different ( normal style iac/ takes air infront of tb blade and lets it pass around the blade into the intake) if this is the case that is ur problem


if its all original u may want to check the cold start injector this will cause idle surging with the motor cold and could cause idle hunting when the motor is warm if the cold start injector is leaking

copyfixr

iTrader: (3)

Thanks. Maybe i'm not describing it correctly. I removed the throttle body and the IAC and cleaned the IAC, the area that the IAC goes into, the entire throttle body and the blade. How would I check the cold start injector? The thing I can't get over it that it runs worse now than before I replaced the injectors.

copyfixr

iTrader: (3)

Success!!! Problem solved! After great frustation we have a smooth running Camaro. Tried the extra fuel injectors that Southbay sent but they didn't fix it. On a hunch, or mayby desperation, we removed the O2 sensor and started it with it out so exhaust could come out of the bung. It ran pretty nice. unbolted the cat from the Y pipe and it ran really nice. Took it to an exhaust shop and had a new cat and muffler put on. Runs like a CHAMP!!! A little fine tuning now that everything is about right and we should be golden. Thanks to all that offered help and advice. Hats off to Southbay Fuel Injectors. They sent me a second set of injectors at no charge just to try! Thats customer service.