1986 Chevy c10 stalls in gear until warm (even on hot mornings)

[Ricko1966]

Just went and checked again fires right up and drives away with no hesitation. It took lots of time and patience to get to that point,modifying ignition curves,playing with fuel pressure. I had my fuel pressure too high, I didn't check it the other day after I worked on the truck,then forgot about it.

 

[Davidj]

I’m sure my fuel pressure is fine. My front float sunk last week and it spouted about 2-3 inches out the bowl vent. Did a full rebuild but still grumpy until hot.

 

[Ricko1966]

The vacuum flap on the exhaust is suppose to close when cold to force exhaust through a passage in the intake manifold to keep the fuel suspended in cold weather.

 

[Ricko1966]

How long have you had this truck? Has it always run this way?

 

[Ricko1966]

You know I was making some assumptions at first that I shouldn't have. Do you have any thermo vacuum switches on this engine. 1 should have manifold vacuum to the efe(exhaust flap) if it is connected to manifold but not the vacuum servo you will have a vacuum leak until the vacuum switch closes. Another possibility if the hoses are m8srouted the egr could be getting vacuum during warmup

 

[Davidj]

I can’t say I’ve seen this switch. I’ll take a look and a few pictures when I get home from work. As well as testing the vacuum advance with manifold vacuum. Thanks for all the input. I really appreciate it. I got it last year around this time. At first it started fine and I don’t recall ever having to wait for warmup. At some point about three months in, something melted in the distributor and so we had that replaced. About a week later we had more issues and the mechanic we brought it to said the secondary on the carb was bad. Something about the rod that goes from the first to second to actuate (at the time, mechanical secondary) this is when we first noticed the starting issue but I don’t know if it was directly after the distributor replacement or the carb. And Ofcourse there’s no telling what else he did in there. Ever since I’ve been trying to work out the bugs on my own.

 

[Ricko1966]

Did he replace the carburetor?

 

[Davidj]

Yeah, sorry. He did replace it. So the distributor and carb were replaced within a week or two from each other. Every since we’ve had this cold start issue. I’ve done too much since then to recall everything but mostly just went through distributor timing and the carb adjustments/rebuild and made sure every vacuum hose coming off the carb was holding vacuum.

 

[Davidj]

You also mentioned the egr valve. I assumed this later model just didn’t have one but it seems someone did a delete on it before I’m the truck was in my hands. Should I add one if so?

 

[Ricko1966]

Ohh, this is going to be fun. Okay make sure vacuum and centifical advance are working. Do you know what distributor he put in?One thing at a time. First we make sure distributor is working. and timed as it should be.

 

[Davidj]

I’m still at work so I can’t check the actual model but it looks like this one and the rotor on the inside is a red brick of plastic. Not the kind with the two metal “crab claw” centrifugal weights.

 

[Davidj]

This type of rotor

 

[Davidj]

About to try the vacuum advance to full manifold.

 

[Davidj]

Yes, vacuum advance to full manifold increases idle significantly. I’d say probably 200 rpm increase. Here’s a better pic of the full deal.

 

[Rusty Nail]

He's a tooth off maybe.
Distributor installed incorrectly.