TBI stalling, distributor pics

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Levman74

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hello all, posting from phone, so don't mind the errors. Been all over this site and others and want to get a second opinion on the condition of this distributor. It's in a 93 c2500 5.7, stalls out randomly at low speed. Fixed multiple problems from it sitting for 3 years including TBI kit, fuel sender and pump. The outer housing is loose, not sure if that's normal, but the magnet looks mighty crumbly. Thoughts? Thanks
 

Levman74

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Going to document the problem without replies. Replaced distributor, no change to stall condition.

When it stalls, the SES does NOT illuminate. It passes all tests with the tech 2. Think I may have stumbled upon the problem.
 

Schurkey

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That magnet is apparently cracked in at least one place--through the lower-left rivet. But "crumbly" is a good description. I'd be amazed if it was working properly.

Does the SES light-up when the key is turned to "Run" before you crank the engine? It should. It should also light up when the engine stalls (key on, engine not running.)

The "outer housing" of the magnet/reluctor is a sheetmetal stamping. Yes, that has some rotational play. Totally normal.

Does the pickup coil have proper resistance, and isn't grounded? Mind you, pickup coils and ignition coils can be confirmed to be "bad" by an ohmmeter, but they cannot be confirmed "good" by an ohmmeter.
 

Levman74

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Thanks for chiming in.
Yes, the SES does light up initially as it should. I just noticed it doesn't come on after stalling, which is odd. I tapped the ECM while running with no result. No codes and everything seems to be in normal specs.
I checked the coil, it was out of spec on the primary side, so I swapped with a new one but had no change in it's manners. Truck still has inconsistent throttle response and doesn't like to rev well.
In particular, the truck stalls out just sitting in the driveway, I was able to drive it around a couple times up to about 40mph before but I don't trust it to even back it out now. Oil pressure is showing low, so maybe the OPS is shutting it down? Going to swap the fuel filter again to make sure it flows enough as well.
 

Erik the Awful

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That magnet is apparently cracked in at least one place--through the lower-left rivet.
Schurkey mentioned that first for a reason. It's not going to run right until you replace that magnet, and the only realistic way to replace the magnet is to replace the distributor housing.
 

AuroraGirl

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does the distributor have defined magnetic poles when rotating it by hand? if its weak or not there then its not gonna work lol. the previous people have covered a lot too that i wont repeat but if it were in the engine and the engine could idle, a timing light could tell you a lot about how that things working. under a certain rpm when the jumper(Its a jumper right?) is pulled the timing should be fixed but under a certain rpm it wont , ideally, have any advance curve just stays static. but over a certain rpm im pretty sure its supposed to have a generically applied advancem, but a bad magnetic part will just simply either be eratic or be all over almost no matter what you do, esp when its fixed. but im using a early 90s B body information for this... so could be different. but the magnetic part i assume is the same concept either way.
 

Levman74

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Thanks, but I have already replaced the distributor from post #2 the other day after inspecting the original dizzy. I timed it and it's good to go on that aspect. As I said though, no change in it's habits. It starts right up and it will seemingly idle all day, but put it into drive and it's unpredictable.

PS-Oddly enough the timing was dead on with the original and the mag poles were there, I could feel the resistance in the shaft. I'm pretty experienced working with older systems but this one is throwing me a curve ball. Like I said, I have replaced the fuel sender and pump, replaced the dist, rebuilt the TBI, cleaned up the IAC and reset it using tech 2, replaced the ECT as well. I appreciate the insight that anyone can provide.
 
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PWC Repair

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When you rebuilt the TBI did you check the FPR spring? They have a tendancy to break into several pieces and cause issues like this.
 

Levman74

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It was in serviceable condition, it was pretty strong so I cleaned it up and replaced the diaphragm.

Question, would any of these symptoms exhibited be indicative of a stuck TCC?

It'll rev all day long in park/neutral but can't seem to stay running in gear especially when it's in reverse, it does sputter down until it dies, no amount of additional throttle will keep it running. It'll fire right up after it stalls, every time. Injectors were ohmed out to 1.8 and 1.7 and I just replaced the fuel filter again, thinking it could have filled back up with crud after the last filter change two weeks ago, but no change. I have a OPS that I can swap, just unplugged the connector with no change until I can get a proper socket on it. TPS shows smooth readings from .5 to 5V on tech 2, goes into closed loop no problem.

Replaced: TBI gasket kit, fuel sender, filter and pump, distributor, ECT

Disconnected vac booster, still dies.
 
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