TBI stalling, distributor pics

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Levman74

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So that begs this question, how can you tell if the spring is weak? I read that it doesn't usually go bad and are rarely replaced unless it has an obvious break but that doesn't mean never.
 

Jimmy D

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I had stalling issue with my 83,000 mile 91. After replacing a few underhood parts mainly due to old age and peace of mind, I did the plugs, wires, new distributor, new injectors and TBI rebuild, CTS, etc, etc, I found a minimum idle speed adjustment. There are a couple of procedures for it, one in the repair manual and ones on the net.
The IAC controls idle speed "most" of the time just fine. The "minimum idle speed" is set at the factory to a bare minimum but just like a carburetor, it may need adjusting. It's a screw stop for the throttle linkage just like a carb. Mine was so out of adjustment the throttle blades were sticking in the bore and I had to push hard on the pedal to take off from a stop which made the truck lurch somewhat. Sometimes the IAC will lower the idle speed a bit too much causing a stall. A new replacement IAC for the new IAC did not help mine. That min idle speed adjustment fixed my stalling issue.
Your scanner pic shows 662 rpm and that's good but it doesn't stay at that. Mine idled normal "most of the time" but dropped lower as I sat in gear with foot on brake for a few minutes until it finally stalled. My throttle body is tight as in no vaccum leaks, fuel pressure is 11 psi, on an all stock
91 350 truck. A few full turns of the idle speed screw solved my stalling issue. I did those turns a 1/4 to 1/2 turn at a time to ease up to that just right spot. Also the throttle blades no longer stick in the bore at idle. Maybe that helps you.
 

Levman74

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Jim- I appreciate the insight. I'll definitely take a look, it's similar to the condition I have. Time for a closer look. Thx
 

Levman74

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Alright, swapped computers, no change. I pulled the pump once more, cleaned up the sock and reinstalled the stock style pump. Now it runs and doesn't die for the most part though it is sluggish to recover. Seems I changed too many parts at once which sent me off course. I appreciate everyone's help.

I drove it down the road a couple times, it gets up to about 50 mostly no problem but throttle response is garbage. I try to floor it and it bogs down and won't accelerate until I ease up.

Thinking the exhaust it clogged up with God-knows-what after sitting for 3 years. Unless poor condition plugs and wires would do the same? Fuel counts are going up, maybe to compensate to keep it running with excessive back pressure? I'm a little rusty on my drivability skills.
 

Levman74

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Alright, thought I would finally close this out. I had pulled the o2 as well, no change. I cannot remember if I had mentioned there was rust in the fuel tank, but after exhausting all other avenues I replaced the tank and the sock as it was full of crud. Now I can run it down the road at 70+, even used it to haul goats to the vet yesterday. So after all the fun, and replacing a bunch of aged parts it came down to a corroded fuel tank that was blocking up the pump. Thanks for everyone's help. Now I am off to finish up my '84 diesel project. I will be back to deal with the other '91 4x4 project I picked up for some reason.
 
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