1987 Chevrolet 350 tbi high idle

[iamtherealJayy]

Truck took a few seconds to start today and stayed around 1000 for a while and eventually dropped to 650ish, although running rough and stalled a couple times. Could this be the timing still needing slightly adjusted?

 

[gmbellew]

Truck took a few seconds to start today and stayed around 1000 for a while and eventually dropped to 650ish, although running rough and stalled a couple times. Could this be the timing still needing slightly adjusted?

could be. did you ever check it with engine fully warmed up now that you have fixed the vac leak? that would be step 1.

 

[iamtherealJayy]

Negative. Timing light quit on me, reckon it only had one use left in it. I haven’t went and gotten another one yet, but the truck runs better now for the most part. It takes a while to idle down and when it does idle down it stumbles a little. When it warms up it idles at 650 fine. But the thermostat still seems to be falling behind on opening.

 

[Rusty Nail]

Yep.
Up to 40 key starts is as real as it can be.

Carb cleaner is excellent bug spray also, but it'll eat the varnish off furniture in a new york minute. Mother f- don henley too.

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650 is too low now.. If you can let it idle to temp, I would do that AND THEN set the timing. (takes a long time correctly remember?) That is why you has backfire, it's building up unburnt gas.
I suggest a setting it to stock spec, sorting other issues first , AND THEN advancing it if necessary or desired.

Why is that timing tab all Rusty? I dont see any damned BLUE PAINT.

Must be the right tree to bark at huh?

 

[iamtherealJayy]

@Rusty Nail blue paint line is on the harmonic balancer, the timing tab was completely covered in oil but I got it cleaned up enough to read it. The engine by no means is clean, the timing chain cover leaks just enough to get on your nerves but not enough to leave drops of oil on the ground.

 

[iamtherealJayy]

Just took the truck on about a five minute drive doing 55 most of the way on highway and thermostat opened first time fine but after it closed and the temperature started going up again it got the whole way to 260 before I pulled over and shut it off. Started it back and the temp gauge had dropped. It didn’t appear to leak coolant out of the thermostat housing this time, although it didn’t get ran long.
Edit: no obvious boiling sound, no steaming, not stranded luckily my destination was where I pulled over. The aldl cable should be in tomorrow and I’ll monitor live data and see what it’s actually running and I also need to purchase a new ir thermometer

 

[AuroraGirl]

Just took the truck on about a five minute drive doing 55 most of the way on highway and thermostat opened first time fine but after it closed and the temperature started going up again it got the whole way to 260 before I pulled over and shut it off. Started it back and the temp gauge had dropped. It didn’t appear to leak coolant out of the thermostat housing this time, although it didn’t get ran long.
Edit: no obvious boiling sound, no steaming, not stranded luckily my destination was where I pulled over. The aldl cable should be in tomorrow and I’ll monitor live data and see what it’s actually running and I also need to purchase a new ir thermometer

Air pocket

 

[iamtherealJayy]

How would I go about getting an air pocket out of the system? Where would it be? Near the sensor or near the thermostat?

 

[gmbellew]

How would I go about getting an air pocket out of the system? Where would it be? Near the sensor or near the thermostat?

or in the water pump.....

 

[iamtherealJayy]

What should I do to remove it? Am I gonna have to drain a bunch of coolant again…

 

[AuroraGirl]

What should I do to remove it? Am I gonna have to drain a bunch of coolant again…

Bleed your system like you do normally .just again, and you need to do it long enough to get the thermostat to open, and for coolant to cycle through it, probably once or twice. That will help with air. revving it while your t stat is opening may help. running your heater too to get flow ot heater core

 

[iamtherealJayy]

Alright, I’ll pick up another gallon of coolant tomorrow and let the thermostat cycle a few times while adding coolant

 

[AuroraGirl]

Alright, I’ll pick up another gallon of coolant tomorrow and let the thermostat cycle a few times while adding coolant

i mean, its one of those things where air can only go so far, if you have your idle kicked up, heat on high, and your cap open, and it starts plunging down, you add coolant to keep it good, but maybe squeeze your hoses to burb any air too, that may be the case.if you really need help you can find a 3800 thermostat housing and steal the bleeder out of it and install it in an sbc one and try that

 

[iamtherealJayy]

By bleeder do you mean the thermostat housings that have the bolt you can remove on top? Also just took the truck back down the same route so I could get home and the temperature gauge didn’t even drop this time, it got to around 240 and I just shut the truck off and coasted in neutral waiting on the gauge to drop then started the truck back and kept going until it got warm again and then coasted again. Still don’t hear any boiling or steam. I really need to verify the accuracy of the gauge. I have an aftermarket thermostat housing and I believe it has a bolt on top(grub screw is what I’d actually call it) I bought it when mine kept leaking but I didn’t like the angle the neck went up and the hose angle.

 

[Rusty Nail]

Why dont you change the water pump first, ? they're really cheap.