1989 Chevrolet K2500 Flooding when Hot?

[Deadkid9110]

1989 Chevrolet K2500, 350 TBI

Ok, so I was driving home from Burger King (My Guilty Pleasure) and my truck randomly died. I went to accelerate and nothing happened. The RPM's just slowly lowered, everything was still running (such as lights, CD Player, Etc) but the engine pretty much just stalled out.

I pulled off into a parking lot and put my truck in Park. Started up the truck, no problem starting it. I put it in drive and started driving off, and when it got to about 1300 RPM, it cut out, backfired really loud, and then kept driving. I pretty much idled home (which was luckily only 1 block away) and let the truck sit for a while.

I went to drive it the other day and it did the same thing. It cut out, backfired, then kept driving unless I drove it to about 1300 RPM in 3rd gear.

Does anyone know what might be causing this?

Background information that I don't have time to organize, so I'm just throwing it into one catagory:
- It doesn't do this when it's just starting up. Only when the temp hits ideal operating temperature (about ~170, give or take).
- It's done this before. I usually drive my truck in Overdrive, so I don't have to worry about RPM's being too high. It does this once I drive it, not in over drive, at about 2000 RPM's in Second gear for too long. That's why when it does it in Overdrive (Low RPM's in 3rd gear instead of High RPM's in Second gear), I'm kind of surprised.
- I have no O2 sensors, or Catalytic Converter. I think that might mess up the Fuel Ratio?
- I added Valvoline Fuel Injector + Intake Valve Cleaner to this full tank of gas. I had to use two bottles to treat all 34 gallons of gas I added. (I dont know if this is related or not, but it's worth throwing out there).
- Spark plugs look fine. They show a little wear, but not too much for being drove for about 5 - 7k miles that I've put on the truck since I bought it.

any other needed information can be provided. Thank you!

 

[Deadkid9110]

Ok, so after a little bit of Research I've come to the conclusion that it's one of Four things:
1. Distributor Cap
2. Distributor Rotor
3. Ignition Module
4. Ignition Coil

I have a hard time believing it's 1,2 or 4. It runs just fine when it's cold, but when it gets hot, then we start to have trouble. Anyone have something to add to this? Any help is appreciated.

 

[Deadkid9110]

I think I figured out that it's the Ignition Control Module. Apparently it will run fine until the engine reaches a certain operating temperature, and then fault. It's a $45 part, so that's not so bad. I wasn't really looking forward to replacing it, since I was hopefully selling my pickup in a week or so. Oh well.

 

[84bluebronco2]

Sounds like you tackled this pretty quick! Always helpful to hear more about any trucks be it chebby ford or dodge. Knowledge is power!

 

[Deadkid9110]

Of course!
Whenever I find a problem with my pickup, I like to tackle the problem very quickly. I don't like driving around with a messed up pickup.

Even if I can't replace it, I surely like to know what's wrong with it so I don't have to troubleshoot it when It's time to fix 'er up.

 

[Deadkid9110]

Just a follow up, it was the ICM. I replaced it, to find out that it has corroded. My distributor had corrosion all on the inside of it. The ICM Tabs were Corroded, every spark plug terminal was corroded, etc. I replaced the Cap and Rotor while I had the distributor top off.

Runs like a charm now!

 

[RustedRanger]

Since you have a TBI you need to have an O2 sensor or it will run from the fuel map in the ECM....so if it runs decent now it will run better with an O2 sensor.