I'm still having idle trouble with my 88 -------2.8 Camaro.

Apart from changing the injectors and calling in a witch doctor , I stumpped.

The car still has a stumble to it idlewise. Plus the exhaust still smells rich.

So far I have replaced or rebuilt the following:

EGR valve

MAF sensor

IAC valve

Oxygen sensor

Fuel pressure regulator

TPS sensor---------adjusted to .54 volts

New wires, cap, rotor , plugs, coil.......

Rebuilt distributor.

Adjusted timing to 12* btdc

CTS sensor.......ad nauseam.............................

I did check the fuel pressure. It was around 42 lbs. However, it did bleed down to 0 after 20 minutes.
Since the fuel injectors and the ECM are about the only things that I haven't changed, I'm starting to think that I might have a leaking injector or one that isn't atomizing correctly.
The only trouble code that I have is a code 32 which I don't think is related to the idle problem since I changed the EGR valve.

Could a leaking or dirty injector cause this motor to stumble at idle? Also, this is not the original motor in the car. I was wondering if the injectors from this motor are causing a conflict with the ECM. Or are all the injectors the same for all 2.8's?

 

2.8's are to have their own injectors (minus fieros)
3.1's have their own
3.4's have their own

That fast of a bleed down, you do have a flaw somewhere. It could be injectors, it could be CTS, it could be in the tank.

In the manual, it tells a way how to check, heres what I rember "quick n dirty style"....

Pull upper intake, pull rail out, but leave lines and everything attached. Hang it from the hood somehow (wire, string, whatever) somewhat low close to engine.

Place paper towels/shop rags below it, , turn key on enough to gain fuel pressure, let it run the pump. Turn key off. Watch the tip of the injectors, if one leaks, it will drip onto the towels.

 

BTW, still have cat on the car?

do you have digital EGR, or ufo style? If you have ufo style, they have a vacume control module that you should look into.

 

or you could block the damn egr off and be done with it.
Then live with the egr code FOREVER as i do.

 

The EGR valve is new. The solenoid is more than likely defective. It's a vacuume style EGR not a digital. I still have a cat hooked up. My idle problem couldn't possibly be EGR related. It has to be an injector acting up. The car is running way too rich judging by the smell of the exhaust and that lovely eye-burning effect that comes with it.

 

Only thing you can do is pull the upper plenum off and test the injectors. There are 4 things you can do, but you need a fuel pressure gauge and an injector tester tool for a couple of them.

1- Injector balance test
2- Injector coil load test
3- Injector coil ohm check
4- Injector leak test: You can pull the fuel rail up out of the intake and then turn the key to ON and see if any injectors are leaking.

FYI, the TPI motors are NOTORIOUS for injectors shorting internally. It's not as common on the V6's but it happens.

This tester is sweet but too expensive: http://handsontools.com/store/show_p...roduct_id=1912

This one is cheaper but you can't do coil load tests with it: http://handsontools.com/store/show_p...roduct_id=5339

We have both of these at work and I use them ALL the time on GenII and GenIII 3100's. ALL THE FRIKKIN TIME.

 

i had a similar problem. i noticed a bit of a stumble occasionally and it always smelled rich. i also had the problem of it cranking for a long time before it would start if it sat for more than 20 min. it ended up being leaky injectors. when i put in the 3.4 w/ those injectors, problem solved, fires right up, no rich running, no stumble. just my .02 fo ya.

 

Here's TomP's favourite test tool sight. Real cheap injector tester.

http://www.sunpro.com/cgi-bin/web_st...d=3610534_5399