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lean on both banks...1999 C2500 Suburban

General engine tech -- Drag Racing to Circle Track

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travis
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Re: lean on both banks...1999 C2500 Suburban

Post by travis » Thu Jun 27, 2019 1:20 am

BigBro74 wrote:
Thu Jun 27, 2019 12:22 am
Have you checked the distributor gear? I put intake gaskets in ones of these, And it ran fine. Few months later it comes back acting similar to what you describe, and the gear on the distributor was all worn sharp. New one of those and all done (after much head banging trying to figure it out)😁
The distributor gear looks brand new.

I didn't mess with this thing today...I may fart with it some more tomorrow. Or I may make a big BBQ out of it

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Re: lean on both banks...1999 C2500 Suburban

Post by jake197000 » Fri Jun 28, 2019 1:22 am

if egr isnt right it should throw a code isnt hard to see if system is plugged

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Re: lean on both banks...1999 C2500 Suburban

Post by ijames » Fri Jun 28, 2019 1:33 am

Engine coolant or maybe intake air temperature sensor? You didn't mention them and probably looked at them with your scan tool, but just in case ...
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Re: lean on both banks...1999 C2500 Suburban

Post by jake197000 » Fri Jun 28, 2019 1:35 am

spay some carb spray around egr stem and watch your fuel trims

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Re: lean on both banks...1999 C2500 Suburban

Post by jake197000 » Fri Jun 28, 2019 1:38 am

could be bad pcm voltage drop test your powers and grounds under load.

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Re: lean on both banks...1999 C2500 Suburban

Post by jake197000 » Fri Jun 28, 2019 1:41 am

spray some carb spray around theegr stem and watch your fuel trims.bad or wrong pcv valve maybe too.

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Re: lean on both banks...1999 C2500 Suburban

Post by jake197000 » Fri Jun 28, 2019 1:47 am

timing chain would have to be pretty loose to cause an issue should be able to see timing chain with timing light.put a wrench on crank bolt to see how loose it is.

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Re: lean on both banks...1999 C2500 Suburban

Post by travis » Fri Sep 13, 2019 7:30 pm

This time it was the TPS. A $30 /)($&@!! TPS. I had tested it twice and it read perfect from closed to wide open throttle, no less!

The TPS is the only thing left I hadn’t replaced, but I noticed as I got other issues fixed it had a completely dead spot at very light throttle tip in from a dead stop. When I pulled the old TPS off, I noticed a lot of slop in it. Put the new one in, took it for a test drive, and there was no change at all initially...still had the light throttle surging but still ran ok at heavier throttle. After a couple miles, it threw a check engine light (I haven’t checked that out yet), then started running perfect.

Gawd...what a beating trying to figure this out

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Re: lean on both banks...1999 C2500 Suburban

Post by woody b » Fri Sep 13, 2019 8:35 pm

So far I have replaced the fuel pump, fuel filter, injector assembly, O2 sensors,
I'm correct to assume you had the problem before replacing all of these parts? It's been a minute or 2 since I've worked on one of these. IIRC there used to be a BUNCH of wrong fuel pumps out there. (This is an "R" motor isn't it? 8th vin digit = R) The injectors were problematic, but usually caused cold starting, or cold skipping/misfire problems.(It's the spider looking injector assembly under the intake isn't it?) If you unplug all the O2 sensors how does it run? Does in run like it needs more fuel, or does it run OK. (this forces open loop) Again if I'm remembering these models correctly I've seen PCV problems cause lean codes. Make sure there's a good connection from the valve cover to the air cleaner housing. Timing chain, or distributor gear problems usually cause low power or detonation. If the cam to crank angle is off enough it will set DTC's. You can see the cam to crank angle with a scanner, but I don't remember what's it's called. I've slotted the distributor hold down to get a few more miles out of ones with worn timing chains. I've had driveability problems caused by (what I call) tuliped intake valves. The cranking compression would be good for some reason. I don't specifically remember lead codes...but it's been a while. Connect a vacuum gauge and see if it dances around at idle.

I used to work on these pretty much every day a couple decades ago. I apologize for not remembering more, or if I'm remembering the wrong engine.
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Re: lean on both banks...1999 C2500 Suburban

Post by travis » Fri Sep 13, 2019 8:48 pm

There was actually a multitude of problems that seemed to occur all at once. That’s part of what made this thing so hard to troubleshoot. I think the initial problem was a distributor cap failure, which caused a misfire, which killed several plugs and one of the O2 sensors. Then the fuel pump crapped out while trying to figure out the initial problem. And apparently the TPS crapped out at some point in there too.

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Re: lean on both banks...1999 C2500 Suburban

Post by midnightbluS10 » Sat Sep 14, 2019 12:56 am

travis wrote:
Fri Sep 13, 2019 7:30 pm
This time it was the TPS. A $30 /)($&@!! TPS. I had tested it twice and it read perfect from closed to wide open throttle, no less!

The TPS is the only thing left I hadn’t replaced, but I noticed as I got other issues fixed it had a completely dead spot at very light throttle tip in from a dead stop. When I pulled the old TPS off, I noticed a lot of slop in it. Put the new one in, took it for a test drive, and there was no change at all initially...still had the light throttle surging but still ran ok at heavier throttle. After a couple miles, it threw a check engine light (I haven’t checked that out yet), then started running perfect.

Gawd...what a beating trying to figure this out
Glad to hear you got it fixed. I thought I had recommended that in one of your previous threads but after looking through them, that wasn't the case. I had a bunch of issues in my 01 Vortec truck that all disappeared with a new TPS. But I was having issues with the TCC not unlocking and locking up consistently, as well as a few other minor things and nothing really similar to your issues. Glad you got it fixed.
JC -

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Re: lean on both banks...1999 C2500 Suburban

Post by GARY C » Sat Sep 14, 2019 2:30 am

travis wrote:
Fri Sep 13, 2019 7:30 pm
This time it was the TPS. A $30 /)($&@!! TPS. I had tested it twice and it read perfect from closed to wide open throttle, no less!

The TPS is the only thing left I hadn’t replaced, but I noticed as I got other issues fixed it had a completely dead spot at very light throttle tip in from a dead stop. When I pulled the old TPS off, I noticed a lot of slop in it. Put the new one in, took it for a test drive, and there was no change at all initially...still had the light throttle surging but still ran ok at heavier throttle. After a couple miles, it threw a check engine light (I haven’t checked that out yet), then started running perfect.

Gawd...what a beating trying to figure this out
So now we can put nitrous on it?
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THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!

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Re: lean on both banks...1999 C2500 Suburban

Post by midnightbluS10 » Sat Sep 14, 2019 3:37 am

GARY C wrote:
Sat Sep 14, 2019 2:30 am
travis wrote:
Fri Sep 13, 2019 7:30 pm
This time it was the TPS. A $30 /)($&@!! TPS. I had tested it twice and it read perfect from closed to wide open throttle, no less!

The TPS is the only thing left I hadn’t replaced, but I noticed as I got other issues fixed it had a completely dead spot at very light throttle tip in from a dead stop. When I pulled the old TPS off, I noticed a lot of slop in it. Put the new one in, took it for a test drive, and there was no change at all initially...still had the light throttle surging but still ran ok at heavier throttle. After a couple miles, it threw a check engine light (I haven’t checked that out yet), then started running perfect.

Gawd...what a beating trying to figure this out
So now we can put nitrous on it?
LOL I wouldn't without at least a marine intake manifold and 8 real injectors.
JC -

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Re: lean on both banks...1999 C2500 Suburban

Post by GARY C » Sat Sep 14, 2019 3:47 am

midnightbluS10 wrote:
Sat Sep 14, 2019 3:37 am
GARY C wrote:
Sat Sep 14, 2019 2:30 am
travis wrote:
Fri Sep 13, 2019 7:30 pm
This time it was the TPS. A $30 /)($&@!! TPS. I had tested it twice and it read perfect from closed to wide open throttle, no less!

The TPS is the only thing left I hadn’t replaced, but I noticed as I got other issues fixed it had a completely dead spot at very light throttle tip in from a dead stop. When I pulled the old TPS off, I noticed a lot of slop in it. Put the new one in, took it for a test drive, and there was no change at all initially...still had the light throttle surging but still ran ok at heavier throttle. After a couple miles, it threw a check engine light (I haven’t checked that out yet), then started running perfect.

Gawd...what a beating trying to figure this out
So now we can put nitrous on it?
LOL I wouldn't without at least a marine intake manifold and 8 real injectors.
I was thinking a 50 shot just to clean the plugs... :)
Please Note!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!

travis
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Re: lean on both banks...1999 C2500 Suburban

Post by travis » Sat Sep 14, 2019 6:37 am

GARY C wrote:
Sat Sep 14, 2019 3:47 am
midnightbluS10 wrote:
Sat Sep 14, 2019 3:37 am
GARY C wrote:
Sat Sep 14, 2019 2:30 am


So now we can put nitrous on it?
LOL I wouldn't without at least a marine intake manifold and 8 real injectors.
I was thinking a 50 shot just to clean the plugs... :)
It would probably take a 200 shot to put this thing into the 15’s!

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