Possible TPS issue

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wb292

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So I’ve read other TPS threads and I don’t see an issue like this one.
I picked up a 1995 GMC K2500 Suburban with a 454 and 4L80E. It’s real great for the last 500 miles or so. But now I’m having a bad stumbling issue. Along with surging idle. I removed the air filter and when opening the throttle by hand with the engine running the injectors will shut off until the throttle goes WOT then intermittently come on and go off causing the engine to stall and race. Could this be a TPS issue?
 

wb292

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Ok so I went into town and picked up a Innova 5512 Scanner. It was the only one that said OBD 1 and live data. Well after plugging it in and the short set up it said live data is not supported in OBD 1. Hopefully this post keeps someone else from buying on of these.
It did however display no stored codes. Witch I knew anyway.
So with no other option I fired the parts cannon. I checked the fuel pressure at the inlet of the TB and I’m getting 15PSI dropping to 13 when opening the throttle. Until the injectors cut out. Then it stumbles and tries to die. When checking timing I noticed it was erratic jumping from 12 to about 16 deg at 900rpm. I pulled the dust cap and the pickup coil looked like it got hot. So I swapped out the whole dist with a known good one from my 454SS. I unplugged the timing wire and set it at 4deg. Then plugged the wire back in and although the timing appears to be stable now, It ran the same no change. So I then replaced the TPS,MAP, and O2 with new ones I have on the shelf. No change. Since live data eludes me for the time being does anyone have any ideas?
 

grampadirt

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Because we have basically the same burb I'll tell you what I found re:the TPS,check the wires as they go under or near the EGR valve.I found on my burb two wires had melted together because of how hot it got.As soon as I seperated those wires things got back to normal.Wish I could connect my laptop & Tuner Pro RT to your burb,I'll bet we could find a lot of not so good readings.If you ever come to SoCal hit me up,maybe we could meet somewhere.
 

grampadirt

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Here's a little video I made a few years ago...just gives you an idea of what Tuner Pro can do.I don't have as much info as the old guy(PlayingWithTBI)does but it's kind of fun to watch.Watch the TPS sensor...I like to use percentage rather than voltage.When the percentage goes up on the TPS notice the speed of my burb increases.Think it's about a five minute video.

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