2008 Yukon dying.

[rdezs]

Are we talking about the Buick 231 odd fire V6? OMG, I squeezed one into a triumph spitfire with a turbo 350 transmission. Everybody wanted it, and in less than 6 weeks I sold it for a price I couldn't refuse. Damn I wish I still had that!

 

[jfoj]

Are we talking about the Buick 231 odd fire V6? OMG, I squeezed one into a triumph spitfire with a turbo 350 transmission. Everybody wanted it, and in less than 6 weeks I sold it for a price I couldn't refuse. Damn I wish I still had that!

I knew someone who did the same thing with a Triumph Spitfire around 1980/81 but I think it was not an odd fire and I think it had a 2 speed Powerglide. Poor man's AC Cobra

 

[rdezs]

It was a blast. One of the first conversions I did. Power to weight ratio made it quite fun.

 

[Tonyrodz]

b 0 ng? Thats a bad word?

Edit: @Tonyrodz I need an adult!

Lol, none here.

 

[Marky Dissod]

Are we talking about the Buick 231 odd fire V6?

Was referring to the Buick-designed longitudinally mounted 231 c.i. V6 based on the one
GM redesigned in '77 to be even-firing by using off-center bore spacing,
which GM referred to as LC2 by adding an intercooler to a sequentially injected LD5.
Think GM called it a 3.8L, but NOT a 3800; 3800 dropped the turbo and put it into fwd cars in '88.

 

[Tonyrodz]

Was referring to the Buick-designed longitudinally mounted 231 c.i. V6 based on the one
GM redesigned in '77 to be even-firing by using off-center bore spacing,
which GM referred to as LC2 by adding an intercooler to a sequentially injected LD5.
Think GM called it a 3.8L, but NOT a 3800; 3800 dropped the turbo and put it into fwd cars in '88.

Good motor withouta turbo. 3800--Excellent motor.

 

[Tahoe_Denali]

Acknowledge that tge MAS was cleaned, but when it will not start try disconnecting it and try to start. If it fires you need a new MAS.

 

[SpareParts]

OK you wandering fkr's back on track.

Here are the fuel trims before the intake gaskets were changed.

And after the gaskets were changed. Drove it about 15 miles and this is idling in driveway after drive. During the drive, they did not very much that i saw. So success!

After removing intake.

Ready to install intake

And finally,

the old gaskets.

 

[SpareParts]

I could not find a used MAS at the wrecking yard to try so i took the MAS off my car and installed on the friend's Yukon and mine read exactly the same as his.
So i have to assume they both are good. Leads me to believe his MAS is not a problem.
His Yukon is running GREAT now, but i don't know if this has cured the randomly dying problem.
Could have been a totally different issue, meaning he originally had two separate issues.
I have not experienced the dying issue but will drive it some more today and tomorrow.

 

[donjetman]

OK you wandering fkr's back on track.

Here are the fuel trims before the intake gaskets were changed.
View attachment 464277

And after the gaskets were changed. Drove it about 15 miles and this is idling in driveway after drive. During the drive, they did not very much that i saw. So success!
View attachment 464278

After removing intake.
View attachment 464280

Ready to install intake

View attachment 464281

And finally,View attachment 464282 the old gaskets.

Intake gasket does look messed up.
But the ECU was subtracting fuel (-25) because it was getting too much fuel, not enough air.

 

[SpareParts]

I don't really understand the whole way it works, but unmetered air will cause negative fuel trims. Seems backward, i know, but the proof is in the readings.
The ECU was subtracting -14 and -16. The 25 you see is not the reading

 

[89Suburban]

Good job dude.

 

[SpareParts]

I have driven it about 35 miles today after the gasket change and trims are holding steady.
See how a cold start does tomorrow morning.
Still has not died on me.

 

[alpha_omega]

I was working in Michigan when the GNX came out. Saw GNX #001 in the Buick HQ garage. The Buick GM was driving it to work for a while. This was the first GNX I saw possibly before they even ended up on the dealers hands. Looks like GM kept #001 for itself, but I did get to see it actually daily driven to work for a short time.

Your story makes my heart smile and gave @Tonyrodz a salute to his under regions.
I saw one for sale a year or two (probably more than that by now aye Tony?) and it only had like 33 original miles. F*¢&ing incredible shape. Bought, parked, covered and forgotten about.

Acknowledge that tge MAS was cleaned, but when it will not start try disconnecting it and try to start. If it fires you need a new MAS.

MAF

Say it with me. MAF.

Mass
Air
Flow [sensor]

You are going to give someone an aneurysm or continue confusing the old guys with your hipster abbreviations like the words this new generation is using. Haha!
I was told I was looking “clutch” the other day. I thought to myself: “I sure hope that I don’t smell clutch or sound like one being burnt up”.

And after the gaskets were changed. Drove itabout 15 miles and this is idling in driveway after drive. During the drive, they did not very much that i saw. So success!


After removing intake.
View attachment 464280

That’s bad. Like damn.

 

[alpha_omega]

Did you say whether or not you’ve recently pulled the plugs out and checked/replaced them?

 

[SpareParts]

Ok, MAF it is.

Looked kinda like the rear foam dam was all melted and disintegrated. It all cleaned up good enough, but i was not trying to get it sparkling clean.

 

[SpareParts]

The plugs and wires were changed about 2 months ago.

 

[Fless]

I don't really understand the whole way it works, but unmetered air will cause negative fuel trims. Seems backward, i know, but the proof is in the readings.
The ECU was subtracting -14 and -16. The 25 you see is not the reading

Unmetered air causes a lean condition, and the ECU ADDS fuel (positive fuel trims) to compensate. Negative fuel trims means the ECU is taking away fuel, which is a rich condition.

Fuel Trim: What the numbers mean

Discover how fuel trim affects your vehicle's air-fuel mixture and how understanding it can help diagnose engine issues.

ricksfreeautorepairadvice.com

EDIT: I can't remember if disconnecting the battery will reset the LT fuel trims on these engines, but that could also be. Obviously they'll constantly recalculate over time.

 

[SpareParts]

Right.
But as you can see above the fuel trims were -14 and -16 in the pic earlier. After changing the obviously bad intake gaskets, the trims are near 0.
The fuel trims were reset both STFT and LTFT before firing it up and have driven it around 30 miles or so, it will stay near what the trims are now im sure.
Is what i think was happening was because of the intake gaskets leaking it was causing the MAF to underreport. Reading was 4.7 g/s(ish) at hot idle. Too low causing the ECU to take away fuel.
After gasket change, MAF is reporting 5.3 g/s(ish)More accurate and about what it should be at hot idle.

 

[OBSandaNNBS]

View attachment 464280

Whoa! Nasty!