No Start - Smoke From TBI

[OzarkRunner]

Hi all, I have a problem I hope you can help me with. 1990 V1500, 350 TBI - all stock.
Had what felt like hesitation at low RPM, so replaced the plug wires, distributor cap, and rotor yesterday. While doing so, noticed a vacuum line that was in pretty rough shape that comes from a T on the firewall down to the intake on the back side of the throttle body (marked as 6 in the attached pic). Once I got the wires / cap / rotor done, i fired it up and it was running well. Got in to head to the parts store to get a vacuum line to replace the rotted one I saw. Got on it a little bit leaving the neighborhood; she died and wouldn't turn back over. Pulled the air cleaner off and pushed the throttle open, and some white smoke came out.
1. What is that vacuum line going to on the intake manifold (marked as 6 in the attached pic)?
2. Could that be the source of my problem?
3. She ran great after the wire / cap / rotor replacement until I romped on it a little. I think I got that done correctly, but anything I should check?
4. Any other ideas?

Thanks!

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[1987 GMC Jimmy]

1. Number six is the vacuum source for the HVAC mode control and cruise servo. It’s supposed to split off using a one way check valve, and the cruise side tees off to a vacuum storage canister and the servo itself.
2. No.
3. Check for spark because it sounds like that’s what you lost. If you don’t have spark, take your ignition control module out and have it tested at the parts store. I’m willing to bet that’s the culprit. If you don’t have spark but the module tests good after several attempts, it’s probably the pickup coil. If the inside of the distributor is really rusty, I’d just get a new one. Also, if you buy a new module, get an AC Delco. I’d be open minded to a Delphi module, but otherwise you’re wasting time and money on modules that’ll crap out later, and it’s possible what’s happening now anyway. If you have spark but no injector pulse, it’s still the module. A noid light test kit, available for borrowing at the parts store, will tell you whether or not you’re getting power to the injectors.
4. Is your MAP sensor fastened down to the carrier thingy? That vacuum line is awfully close to the EGR valve, and when it melts, crappy is not the word for how it’ll run till you can fix it. That happened to me once so I try to be careful with that particular vacuum line.

 

[OzarkRunner]

Awesome; thanks so much! That vacuum hose is probably why my HVAC never felt quite right...
It was pretty rusty under the distributor cap, so I'll try to start with the ignition control module and / or the pickup coil. I'll also check the MAP vacuum line to be sure, but I believe it was OK.

 

[4WDKC]

Awesome; thanks so much! That vacuum hose is probably why my HVAC never felt quite right...
It was pretty rusty under the distributor cap, so I'll try to start with the ignition control module and / or the pickup coil. I'll also check the MAP vacuum line to be sure, but I believe it was OK.

Just buy a new distributor then, the cost of pick coil, icm, cap, rotor, puts you about $20 from a new dist.. the new dist has new bushings in the shaft unlike the old and you have to remove the dist to replace the pickup coil anyway. Plus you can make th eld dist into an oil pump priming tool.

 

[Daveo91Burb]

X2 in replacing or rebuilding the distributor. TBI dists are notorious for corrosion problems. Mine was running fine one minute and went to no run at all the next. When I took it apart the pickup coil just crumbled apart.

 

[OzarkRunner]

Thanks for the advice! I'll try to let you guys know how it turns out.

 

[Jppr26]

I had a similar issue with my 87 changed all sorts of parts starting with the cheapest, 200 bucks later, spent another 120 for a alternator and it runs like a top. I had replaced my pickup coil first it was around 10 bucks, but I think it was the magnet on the shaft because the old shaft woumd spin freely like a top, the new one was like changing the channel on a old dial tv