Cascade Crew

[Formulareed]

I'm about to give up and take my camaro to a shop. I have been fighting it for the past few months and I'm getting really tired of it. Any one have a recommendation for a shop that knows the TPI system and is not going to rip me off too bad?

Thanks in advance,

Reed

[Twilightoptics]

There is a wealth of advise on here if you want to take another shot at it?

For older GM, no idea in the Seattle area. Most of the guys I know work on newer cars or imports.

[Formulareed]

I'm willing to give it another try. Here's the story:

1992 z28, 305 TPI, auto trans. 92k miles.

I bought the car about a year ago. It's in nice shape, but had been sitting for a year or so. It ran ok, but never ran great. It always felt a little sluggish. After a month or so it started running worse. Poor throttle response, very bad gas mileage (6-8 city) and it was hard to start when it was warm. It also had a high idle.

I figured that it was related to the car sitting and when i checked the codes, the o2 sensor was showing to be at fault. I replaced the o2 sensor, and the IAC valve. After I did that, I tried to reset the idle, but I could not get it to idle low at all, it would just die. I checked the fuel pressure at the rail and it was fine. Only thing was after I checked it, the valve broke and when I turned the car back on, it shot gas everywhere." It was a little better, but still felt sluggish and the hard warm start had not been fixed.

Next, it started throwing the egr code. So I replaced the egr valve and while I was in there I did the file pressure regulator and replace the vacuums lines. Again, I had a similar result. A slight improvement but not quite right.

Next, I ohm tested the injectors and 3 were found to be bad. I got a set from southbay, cleaned the intake and runners (it was quite dirty with oil) and replaced the gaskets on the intake and runners. I also did the plugs. Again, it ran better, but not great. Still sluggish, poor hot start.

Next I did the fuel filter. No change.

It still ran, and it was better than when I bought it, but not a night and day improvement.

About a week later, I was driving home on the freeway and it overheated. Temp shot up on the freeway and I pulled over. Sure enough, coolant was boiling in the overflow. I had it towed home. I checked the oil and water and found no intermix. When I tried to start it, it fired right up. I was told to check the cat pipe and found that it had come apart and was twisted and blocking the exhaust. I replaced the cat and it was way better. Still not great, but much better.

However, the next day the water pump started leaking and it was running hot again. It sat for 2 weeks while I waited for a good day to replace the pump. I replaced the water pump today.

Now it's got a new problem. After I got the pump on, it fired right up, but once it got to operating temp, it start stalling out and died. It restarted fine, but would cough and die. If you give it some gas, you can keep it running, but even than, it's trying to die. I reset the iac valve and this time it did let me set low idle, but kept dieing. This is where I am right now. It's not showing any codes. It's low on gas, but the gauge is still showing about 1/8 of a tank.

If anyone has an idea of what to do next, it would be much appreciated.

Edit: I also replaced the coolant temp sensor for the gauge and the fuel injection system.

Reed

[aaron_sK]

Do you have a scan tool or some ability to datalog from the ECM (i.e. a Moates cable)?

Does the speedometer work and if so, it is accurate?

[MrMike98]

I would do a min. idle air flow adjustment(tweak the TB blade opening).
if you can scan then check the Idle counts -when warmed up the counts should be 20-50.
if it wont idle open blades until it will then check counts etc. and adjust as needed.

check to make sure you have no trouble codes first.

GL
Mike

[Formulareed]

I don't have a scan tool or any way to datalog. The speedometer in the car is broken, I was using a gps for speed.

I have already tried to set the idle air flow, but I don't have a scanner so I don't think I can check the counts.

Reed

[aaron_sK]

A lack of VSS signal from the speedo to the ECM will cause a stalling condition and overall rough running. Has it been broken since you bought the car?

This cable plus TunerPro software on any laptop is probably going to be your best bet for an economical scan setup:

http://www.moates.net/aldu1-and-cabl1-p-127.html?cPath=64

[Formulareed]

The speedo was broken when I got the car. I think that it's still getting VSS signal because the cruise control works.

Short of the scanner, is there another way to test the vss?

[Formulareed]

New development: I added 5 gallons of gas to the car and when I did a major rush of vacuum came out. The car ran the same. I took the gas cap off and an even larger vacuum rush came out. I tried starting the car with the cap off and it would not start. I put the cap back on and it started but still ran like garbage. A few times it will start and run good, but when I give it gas, it revs and dies when it's trying to come back to idle.

I also noticed that when its stalling, it's not sending out black smoke. It missing pretty bad, and I would think that if it was getting fuel, it would be sending out black smoke and would smell like gas. There's no smoke and no gas smell.

Do I have bad timing and and the fuel pump died right after I replace the water pump? I'm going to get a pressure tester tomorrow and see if it's got decent pressure.

[Twilightoptics]

Gauge on fuel rail to verify pressure. Also need to verify timing before setting tps and min air.

[aaron_sK]

You can rent an EFI fuel pressure gauge from Autozone or O'Reillys for a refundable deposit if you don't already have one.

No way to condemn or vindicate a potential weak fuel pump without a gauge, as Paul said.

[Formulareed]

First off, thanks for the help so far. It's been a big help and made me try another stab at fixing the car.

I rented a fuel pressure tester this morning and I think I need a pump. At prime, I have 9 psi. When the car will run, it creeps up to 28-30. I tested it a few times and got the same results.

I have replaced the fuel pressure regulator, so it sounds like the pump failed right after I replaced the water pump.

Before I replace the pump, anyone have another thing I should check?

Thanks again!

[Twilightoptics]

I want you to get pair of hose liars to pinch off the rubber return fuel line. Then key on. That gauge should spike 60+ at prime. If it does, your regulator, even new, is bad.

If it doesn't that means your pump is bad, OR the soft line from the pump itself to the sending unit hard line is split. Seen it a dozen times. People replace the pump and have the same symptom because that rubber line is failed. Either way if you pull the tank and pump, replace that line with the people high pressure fuel rated hose.

[Formulareed]

Good tip, and good timing. I was about to return the tester.

With the line pinched, it still has the same reading. I'm assuming that you mean the soft line that's in the engine bay. Are there any other soft lines to check?

[Twilightoptics]

Pinching just the soft line in the engine bay. Cycle th key a few times just in case. If same reading then the tank has to come out.


The soft line to inspect is in the tank and attaches to the pump itself.

[aaron_sK]

Just replace that bit of rubber line when you've got the tank out IMO.

Most fuel pumps I see now come with a new piece of line in the package anyway, as well as new clamps and gaskets and whatnot.

[Twilightoptics]

[Twilightoptics]

http://cascadecrew.org/phpBB2/viewtopic.php?t=2631&highlight=pump

[aaron_sK]

It's reading comprehension for me!

[Twilightoptics]

And my auto correct wants him to replace it with people so.... we both suck at life lol.