quote Originally posted by buddycraigg: Stop buying stuff. We need to diagnose the problem. I cannot help anymore until you tell me what happened when you tried to make it idle with using your finger over the hole when you took the IACM out.

Ok here's chapter 12. As you asked: With the IAC removed the car starts and runs 3000 RPMS for about 8 seconds and dies. With the IAC hole PLUGGED car starts and runs but dies after 3 seconds. Car will run if you keep feeding gas with the throttle, as soon as you let go of the throttle car dies.

[This message has been edited by 72and86 (edited 10-11-2021).]

quote Originally posted by 72and86: See a pic from a few days ago when we took the plenum off. We checked, double-checked and triple checked for leaks or cracks. Everything around the engine looks real good. Wheres this cold start tube?

Pretty sure this is it.


also its not a cold start tube its the tube that feeds the engine so that it can idle while the throttle is closed.

quote Originally posted by 72and86: With the IAC removed the car starts and runs 1000 RPMS for about 8 seconds and dies.

There is a problem with that. It should have had a very high idle. Probably higher than 3000.

There are 2 fuses for the injectors on the V6. Each row has its own fuse. Check both of the fuses. If one of them is blown, then only one bank will spray.
I'm also curious to see what your fuel pressure is when it is trying to run after you get your gauge.

[This message has been edited by buddycraigg (edited 10-10-2021).]

As I understood, the tube I indicated supplies air to the cold start injector, so if it leaked a lean condition would happen. But maybe that was incorrect?

quote Originally posted by Rexgirl: As I understood, the tube I indicated supplies air to the cold start injector, so if it leaked a lean condition would happen. But maybe that was incorrect?

I've never heard it described as being there for that particular purpose.

As I understand it, air entering the indicated IAC port below is metered by the IAC valve and then passed through the tube at the back of the TB and into the intake plenum.

quote Originally posted by Patrick: "Cold start tube"? Doesn't that tube supply air that's been controlled/regulated by the IAC valve?

[This message has been edited by Patrick (edited 10-10-2021).]

quote Originally posted by buddycraigg: There is a problem with that. It should have had a very high idle. Probably higher than 3000. There are 2 fuses for the injectors on the V6. Each row has its own fuse. Check both of the fuses. If one of them is blown, then only one bank will spray. I'm also curious to see what your fuel pressure is when it is trying to run after you get your gauge.

Yeah it was probably closer to 3000 RPM, not 1000. I will check those fuses if I can find them.

quote Originally posted by 72and86: Yeah it was probably closer to 3000 RPM, not 1000. I will check those fuses if I can find them.

Well then you gave me bad information the first time.
So did it really idle around 3000 with the IAC removed?

I think you said you have a fuel pressure gauge on order.
The next thing I want to see is how the fuel pressure responds while it is running/stalling.

quote Originally posted by buddycraigg: Well then you gave me bad information the first time. So did it really idle around 3000 with the IAC removed? I think you said you have a fuel pressure gauge on order. The next thing I want to see is how the fuel pressure responds while it is running/stalling.

Well its hard to remember all the combinations we tried to get this car running, must be 50 or more things we tried.

Its important to understand it doesn't idle, it SURGES to an RPM, in this case roughly 3000 then dies. Run time is only a few seconds. BUT If i keep pumping the gas pedal it will continue to run but very choppy and Im really "on the pedal". I let off, it dies.

Also this car was purchased last year as not running. We got it running by new distributor/coil parts, but idle was always choppy and high. It only has been yard driven cause I dont trust it. It has never seen under 1300RPM at idle when it ran. I thought it was the inherant problem with the TACH computer board. But even then when I drove it around the block it had a bad low end dead spot, no power.

Yup Fuel Gauge on order.

Just so you know, I wasn't bashing you.
I was letting you know that we need accurate answers when we ask question, or it could throw us off with what we think is going on.
Waiting to hear what your pressure is when you get your gauge.

quote Originally posted by buddycraigg: Just so you know, I wasn't bashing you. I was letting you know that we need accurate answers when we ask question, or it could throw us off with what we think is going on. Waiting to hear what your pressure is when you get your gauge.

Ok well the gauge arrived and we tested it. This is the V6 engine.
Key on position : 5 psi,
Key starts car and constantly pumping the gas to keep it going; 15 psi. Obviously very low. We know gauge is reading right cause we put the line into a bottle and turned the key on and had a very low stream.

So its hard to believe we replaced a weak pump with a NEW weak pump. Needless to say we dropped the tank and I ordered a new fuel pump. Also checked the fuel filter, it was fine. Is there a way to accurately test the pumps before installing them. I know I can get it to run but...?

That sounds like you got a L4 pump not a v6 pump

I have to agree that you have very low fuel pressure. I think the V6 is supposed to be about 35.
Could be the wrong pump.
Could be a bad fuel pressure regulator. (I don't think I have ever seen one go bad)

[This message has been edited by buddycraigg (edited 10-17-2021).]

quote Originally posted by buddycraigg: I don't like this statement. both the 4 and 6 pumps move a lot of volume. it has nothing to do with pressure. We might be fighting a restriction somewhere. I'm not thinking that right now, but want to keep it in the back of our minds.

We will see. I definitely got the wrong pump. Hopefully I get the pump Monday, install Tuesday...

Ok. So here's whats happened.
We installed a new "correct" fuel pump. Neg battery was disconnected. After install, I hooked up battery and the car started but idled at a crazy high RPM like 3200, The idle also surged way up and down!
At least it didnt die which was our initial problem. And the SES light came on with the high idle. Code 22 ; TPS.

We changed out the "new" TPS for the old and same result. Crazy, High idle.
We changed out the "new" IVC for the old and same result. Crazy, High idle.
I disconnected the battery to clear the code. Reconnected.

With old ICV and TPS in, I tried to start the car and 3 or 4 attempts it wouldn't start. Crank, no start. Wouldn't turn over...! Argggh.
We waited a few minutes and tried and IT STARTED! Idle was little high but was smooth! After a few moments the idle came down to what sounded like 900-1000. The tach read 1500, which we know is wrong.
(I know my tach is off due to common problem in calibration as Ive found out through research...)
I think we finally solved this but I haven't road tested it yet cause its on jack stands for the gas tank extraction.

So through all this nightmare it appeared I had a failing fuel pump and we unknowingly replaced it with a "wrong fuel pump". Im keeping my fingers crossed we fixed it.

[This message has been edited by 72and86 (edited 10-21-2021).]

Sorry I am late back to the party.
It has been 2 days.
How is it going now?

quote Originally posted by buddycraigg: Sorry I am late back to the party. It has been 2 days. How is it going now?

Have you read my post above yours? Thats where Im at. I haven't taken it off jack stands because its at a nice height for buffing paint.

[This message has been edited by 72and86 (edited 10-24-2021).]

yes, your post was 2 days before mine.
I wondered if there had been any new news.

quote Originally posted by buddycraigg: yes, your post was 2 days before mine. I wondered if there had been any new news.

Well, the car is still on jack stands for reason mentioned. I do have 2 issues;
1- When the car starts it idles pretty high but seems to tame when it warms up. I forget if this is normal for a V6? I know my tach is waaaay off. It sounds like it settles to about 900 after about 3 minutes.
2- All of a sudden I lost the highest fan speed on everything climate controlled. Just gone. Nothing.
Thats where at. A big mega storm aimed at us for a couple days so I cant work on it.
Steve

Ok so Update:
Its been 2 weeks about since the new fuel pump has been installed. Car has been started several times and reaches a high idle in the very 2000s RPMS. After about 3 minutes it seems to settle at 1000. (Thats my guess as the tach calibration is off).

Well now since the weather is colder (40sF) its taking 3-4 attempts to start the car. Today the car started on 4th attempt, ran to high idle, faltered to a unstable lower idle and died. Four tries yeilded the same result. Starts, high idle, erratic idle and dies in all of about 20 seconds.

WTF?

Im back to the beginning!!!!

Have someone watch the pressure guage when you start it and try to keep it running.

Update Nov. 11th.
We've replaced the fuel PUMP AGAIN with an AC DELCO. Car starts right up and idles lower and smoother. Drove it little and seems to finally run well. I hope this is the winner. Tired of dropping the tank. Thanks to all that helped.
Steve

[This message has been edited by 72and86 (edited 11-12-2021).]

So my car had the exact same symptoms after I installed new/cleaned injectors.
The issue was I had forgot to connect the vacuum tubes to the MAP sensor. One is directly under the MAP sensor and the other goes into the side of the upper intake plenum so check them.

quote Originally posted by Forrest: So my car had the exact same symptoms after I installed new/cleaned injectors. The issue was I had forgot to connect the vacuum tubes to the MAP sensor. One is directly under the MAP sensor and the other goes into the side of the upper intake plenum so check them.

Third fuel pump fixed the problem. Thanks.