94 Yukon 350 Idle issues and Loss of power.

[AllStrobedUp]

Where are you at in Orlando?

St. Cloud.

 

[AllStrobedUp]

Wild Guess: the IAC passage is "leaking" because the IAC is fully-open due to the engine running poorly. When the engine runs right, the IAC will close-up to achieve proper idle speed, and it won't sound so loud.

In other words...it's probably normal. I bet something else is wrong, the noise from the IAC passage is a symptom, not the actual problem.


Doesn't mean that stuff is STILL functioning properly.


I bet the timing light is available from a local parts-store "Loaner tool" program, along with a fuel pressure tester.

A REAL scan tool is now an "essential" item. Either buy, or borrow one. You need access to a decent tool.

I've requested to be added to the list for the forum scanner.

 

[scott2093]

I'm in East Orlando... I have an (old) taskmaster scanner and a timing light that you can borrow...
You can message me...

 

[AllStrobedUp]

I'm in East Orlando... I have an (old) taskmaster scanner and a timing light that you can borrow...
You can message me...

That would be awesome! I'd really appreciate it.

 

[AllStrobedUp]

I don't think the knock sensor is supposed to look like that. Not sure if it's part of the problem, but definitely not part of the solution.

You must be registered for see images attach

 

[MBski]

If you are able to get a scan tool that reads live data, monitor the temperature the computer reads to see if it matches the dash. I had a fueling/flooding problem once due to it bouncing between -40 and 300+ once. Note: The temp sensor for dash does not feed engine computer, it has its own.

 

[scott2093]

helping out now and his iac counts were 150...

then truck died... can't get it started... no fuel from injectors...no noise from pump but it was already running before...
so maybe it won't prime???

blm cell was 6 when it was running....
didn't have time to look at more before it died

ok...pump primes and fuel is pushing to throttle body after loosening the line at throttle body to check ,but no injector fuel coming out when trying to start.....

 

[AllStrobedUp]

helping out now and his iac counts were 150...

then truck died... can't get it started... no fuel from injectors...no noise from pump but it was already running before...
so maybe it won't prime???

blm cell was 6 when it was running....
didn't have time to look at more before it died

ok...pump primes and fuel is pushing to throttle body after loosening the line at throttle body to check ,but no injector fuel coming out when trying to start.....

This guy is amazing. Came to my house and dove right in, he even suggested we pull parts off of his truck to troubleshoot! Absolute life saver.

As stated, we didn't get much info before it shut off. Injectors are not firing, we changed fuel filter and ensured we had fuel at the TB. Need to order a rebuild kit for the injector housing.

 

[scott2093]

If you are able to get a scan tool that reads live data, monitor the temperature the computer reads to see if it matches the dash

It was not running long enough to get up to temp but it was at 58*c iirc and climbing before it shut off...
Spark advance was lingering around 22*
Fuel pump voltage was good..

same codes as listed earlier were present but no codes returned after clearing them for the time it ran or when trying to get it running again.

 

[AllStrobedUp]

Alright so at it again today. First day without constant rain. My injector and TB gasket kits showed up, got it all put back together. Truck started and ran until the scanner booted and shut off. I sprayed the TB with starting fluid and it didn't even try. Had my amazing and flexible wife replace the ICM for me. She noticed the screws on the cap only got finger tight and nothing more, just free spinning but cap was tight and not moving so we resumed. Same crank no start, but fuel pump relay code came up, I just so happened to have one and swapped it. No change. I am still at a loss.