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350 tbi dies/stalls at idle/ shifting into reverse

AugustDiesel

AugustDiesel

Rusty Cedar & Co.
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Posted this in my build thread but thought I’d lost here as well.


So my wife’s burb has this issue where it will stall out when at very low RPMs - doesn’t happen all the time, but mostly when shifting into reverse gear. This morning it happened as she was pulling into a parking space at the store. Cranks right back up.

Has anyone ever heard of or encountered this with a 350 gasser before? Tbi


Thanks in advance.
Andy
 
AugustDiesel said:
Posted this in my build thread but thought I’d lost here as well.


So my wife’s burb has this issue where it will stall out when at very low RPMs - doesn’t happen all the time, but mostly when shifting into reverse gear. This morning it happened as she was pulling into a parking space at the store. Cranks right back up.

Has anyone ever heard of or encountered this with a 350 gasser before? Tbi


Thanks in advance.
Andy
Click to expand...


I’m thinking vacuum lines. Found this cracked one. I don’t have any extra so I’ll get some tomorrow and see what happens

65E807FD-58DC-4F93-BA0C-ABF8A6C6A99C.jpeg8544C856-39BE-4E49-9F35-475374F795AC.jpeg
 
yup, vac can definitely do that.. you can check with a bit of starting fluid sprayed in the suspected area, if it revs up some, you found it... if it hasn't thrown a code, that's a good bet...
 
ryoken said:
yup, vac can definitely do that.. you can check with a bit of starting fluid sprayed in the suspected area, if it revs up some, you found it... if it hasn't thrown a code, that's a good bet...
Click to expand...

I do happen to have some starter fluid. I’ll give it a shot. No codes thrown yet.
 
ryoken said:
yup, vac can definitely do that.. you can check with a bit of starting fluid sprayed in the suspected area, if it revs up some, you found it... if it hasn't thrown a code, that's a good bet...
Click to expand...

shot some starter fluid at it but no change in rpm. I’ll change out the lines tomorrow anyways.
 
Can anyone tell me what part this canister is? What is it called? I figure while I’m replacing the vacuum lines I’d go ahead and replace this as well.

D004507B-B530-4559-8D50-336222118904.jpeg
 
just to carry this on a bit further.. being it hasn't thrown a code like an EGR or IAC... on that note, I'll assume that system is functioning properly and light comes on at start up... if verifying a good vac system, I'd be looking at fuel... pressure, pattern, etc... I've seen lots of stock TBI set ups limping around on like 6, maybe 7 psi... they run great at 13! ;)
 
AugustDiesel said:
thanks guys. Is there a part number for these boots, or just pull one and take it to the parts store to match?
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I just buy the assorted vacuum plugs and slide one on that fits. I still need to find a small enough clamp, maybe that will help them not to crack so quickly.
 
70jimmy said:
I just buy the assorted vacuum plugs and slide one on that fits. I still need to find a small enough clamp, maybe that will help them not to crack so quickly.
Click to expand...
I ordered some silicone plugs from summit (I think). Those have been doing fine.
 
Perhaps I got lucky and it was those vacuum hoses. Haven’t had any issues yet on this trip, though I have been very cautious shifting in and out of reverse. Still, the truck is definitely showing it’s age.
 
Spoke too soon. Truck died on us while sitting at a red light. Cranked right up though and kept going.
 
I don't have repair experience with factory TBI so most of my thoughts are coming from an aftermarket efi perspective.

I've had trouble with my C10 dying when it's shifted into gear from park. I've gotten that to stop by increasing the idle speed/RPM. I don't know if that's an option with the factory TBI.

I wonder if there's some chance the IAC is getting tired but hasn't completey failed so it's slow to respond.

My other thought would be the ignition system. Maybe one or all components are getting weak. Might be time for new plugs, wires, coil, cap, and rotor.

I'd also double check the timing. Remember there's a plug near the brake booster that needs to be disconnected to "lock in" the distributor so that the computer stops controlling timing. Then set timing at 0.

The TBI350 originally in my crew cab was set incorrectly by the previous owner. He apparently tried to zero the timing with the computer still controlling timing. When I disconnected the wire the timing was set so far AFTER top dead center (TDC) it was off the timing tab. Normally you'd like to see it at 10 to 30 before TDC. The truck ran like that, but not great.
 
mrk5 said:
I don't have repair experience with factory TBI so most of my thoughts are coming from an aftermarket efi perspective.

I've had trouble with my C10 dying when it's shifted into gear from park. I've gotten that to stop by increasing the idle speed/RPM. I don't know if that's an option with the factory TBI.

I wonder if there's some chance the IAC is getting tired but hasn't completey failed so it's slow to respond.

My other thought would be the ignition system. Maybe one or all components are getting weak. Might be time for new plugs, wires, coil, cap, and rotor.

I'd also double check the timing. Remember there's a plug near the brake booster that needs to be disconnected to "lock in" the distributor so that the computer stops controlling timing. Then set timing at 0.

The TBI350 originally in my crew cab was set incorrectly by the previous owner. He apparently tried to zero the timing with the computer still controlling timing. When I disconnected the wire the timing was set so far AFTER top dead center (TDC) it was off the timing tab. Normally you'd like to see it at 10 to 30 before TDC. The truck ran like that, but not great.
Click to expand...
Thanks. I did the plugs, wires, cap, and rotor a couple weeks ago, so those are good.

I’ll get a timing light and see where I’m at and adjust.


Topp_rolmc said:
Egr can cause this too. Replace it and clean out the passage. Always one of the first things I do on tbi trucks
Click to expand...

Will also check this.

Good news it didn’t give us any trouble the rest of the trip and got us home.
 
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