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Discussion Starter · #1 · (Edited)
This is an odd one... 1995 gmc 1500 low mileage truck working great a few months ago. Now when started as soon as I put into R or D the engine immediately cuts off. If i move the shifter quickly to 1 or 2 it runs and drives.
I don't know if it was always like this but I don't have to step on brake to shift from P to any gear.
I did some google searches and people in other forums thought this was a torque converter issue but it seems if that was the case it would not run or drive in the low gears. When the shifter is moved the engine does not sputter or rough idle, it just immediately cuts off.

Any thoughts as to a cause/repair would be greatly appreciated. Thanks in advance

Quick note - the engine does not stall, it cuts off the same way as if you had just turned the key off
 

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93 Silverado 350 XE268H Performabuilt 4l60e Heavy Hauler US Shift Quick 4 (FiTech<----yuck)
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This is an odd one... 1995 gmc 1500 low mileage truck working great a few months ago. Now when started as soon as I put into R or D the engine immediately cuts off. If i move the shifter quickly to 1 or 2 it runs and drives.
I don't know if it was always like this but I don't have to step on brake to shift from P to any gear.
I did some google searches and people in other forums thought this was a torque converter issue but it seems if that was the case it would not run or drive in the low gears. When the shifter is moved the engine does not sputter or rough idle, it just immediately cuts off.

Any thoughts as to a cause/repair would be greatly appreciated. Thanks in advance
Does it allow you to go back in drive after taking off? If so would it die at a stop light if you didn't down shift?

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93 Silverado 350 XE268H Performabuilt 4l60e Heavy Hauler US Shift Quick 4 (FiTech<----yuck)
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Only problem I would see with a torque converter is staying locked up..
Good luck starting your vehicle locked up.. its almost like starting a manual in gear. well except you wont have high pump pressure..I dont know, never rhough about TC like rhat... I'm not saying you don't have valve body problems and your tcc valve is locking fluid in, but I'd forget torque converter for now...

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It sounds like an idle problem, not enough speed, or maybe not enough air..what the idle speed when in Neutral?
 

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93 Silverado 350 XE268H Performabuilt 4l60e Heavy Hauler US Shift Quick 4 (FiTech<----yuck)
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It sounds like an idle problem, not enough speed, or maybe not enough air..what the idle speed when in Neutral?
I initially thought IAC may be the issue, but I'd suspect the same in any gear not moving(butterflies open).. Could be poor fueling good ol pressure test wouldn't kill ya to try.

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I don't know if this will add anything, but I'm wondering if it could be an electrical issue -- something shorting to ground when the computer sends certain signal to the transmission.

My '98 had a kind of sort of similar issue for a few months years ago, the first winter after replacing a speed sensor connector on the transmission. It would idle beautifully, but, as soon as I put it in gear (even did this with the truck on jack stands so there was no resistance to the tires spinning) and the wheels started spinning, it would run really rough and stall. I believe, (though it "fixed" itself, so I haven't been able to confirm) that water got into that replaced connector and caused a short whenever the speed sensor sent a signal. After a time for the connector to dry out, then it ran just fine and has never got enough water up there again.

Seems like a long shot, but I wonder what electronically is different in L1 or L2 from D/OD that might cause a short that would cause a stall condition.
 

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Discussion Starter · #8 ·
I don't know if this will add anything, but I'm wondering if it could be an electrical issue -- something shorting to ground when the computer sends certain signal to the transmission.

My '98 had a kind of sort of similar issue for a few months years ago, the first winter after replacing a speed sensor connector on the transmission. It would idle beautifully, but, as soon as I put it in gear (even did this with the truck on jack stands so there was no resistance to the tires spinning) and the wheels started spinning, it would run really rough and stall. I believe, (though it "fixed" itself, so I haven't been able to confirm) that water got into that replaced connector and caused a short whenever the speed sensor sent a signal. After a time for the connector to dry out, then it ran just fine and has never got enough water up there again.

Seems like a long shot, but I wonder what electronically is different in L1 or L2 from D/OD that might cause a short that would cause a stall condition.
I think it is electrical as the engine does not stall, it just shuts off the same way as if you had turned the key off
 

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93 Silverado 350 XE268H Performabuilt 4l60e Heavy Hauler US Shift Quick 4 (FiTech<----yuck)
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Long shot..

Check your vacuum reading at idle

Clean the MAF too..

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Howdy and welcome, Mike.

Mech, ‘95’s didn’t have the MAF yet. Totally agree with checking fuel pressure, but there’s too much pointing at electrical.
I wonder about position of the shifter against wiring inside the column. Might be worth a look inside.
 

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93 Silverado 350 XE268H Performabuilt 4l60e Heavy Hauler US Shift Quick 4 (FiTech<----yuck)
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Howdy and welcome, Mike.

Mech, ‘95’s didn’t have the MAF yet. Totally agree with checking fuel pressure, but there’s too much pointing at electrical.
I wonder about position of the shifter against wiring inside the column. Might be worth a look inside.
I really do know this lol...
COMPLETELY read 1995 and thought 05. I will take the lashing on that one.

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‘Sall good! We’re here for each other. 😎
 

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This is an odd one... 1995 gmc 1500 low mileage truck working great a few months ago. Now when started as soon as I put into R or D the engine immediately cuts off. If i move the shifter quickly to 1 or 2 it runs and drives.
I don't know if it was always like this but I don't have to step on brake to shift from P to any gear.
I did some google searches and people in other forums thought this was a torque converter issue but it seems if that was the case it would not run or drive in the low gears. When the shifter is moved the engine does not sputter or rough idle, it just immediately cuts off.

Any thoughts as to a cause/repair would be greatly appreciated. Thanks in advance

Quick note - the engine does not stall, it cuts off the same way as if you had just turned the key off
I believe that this truck has a transmission position sensor that is possibly bad.
 

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Agree with everyone that says electrical. On my 1994 the wires that plug into the distributor were loose at the connector - it took me a long time to figure this out. When you plug it in, it is tight because there is that waterproof rubber around it. The problem was the females that go into the distributor had gotten loose. Every now and then out of the clear blue the truck would die. I'd reach back looking for something wrong and it would start back up. Eventually found the problem when swapping distributors didn't fix it because the new non A/C delco units had slightly thinner male connectors. I'm think that if you shift fast enough you are preventing the engine from rocking enough to knock it loose. Won't cost you anything to unplug that and tighten those females with a pair of pliers. Just don't crimp them too tight.
 

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93 Silverado 350 XE268H Performabuilt 4l60e Heavy Hauler US Shift Quick 4 (FiTech<----yuck)
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Agree with everyone that says electrical. On my 1994 the wires that plug into the distributor were loose at the connector - it took me a long time to figure this out. When you plug it in, it is tight because there is that waterproof rubber around it. The problem was the females that go into the distributor had gotten loose. Every now and then out of the clear blue the truck would die. I'd reach back looking for something wrong and it would start back up. Eventually found the problem when swapping distributors didn't fix it because the new non A/C delco units had slightly thinner male connectors. I'm think that if you shift fast enough you are preventing the engine from rocking enough to knock it loose. Won't cost you anything to unplug that and tighten those females with a pair of pliers. Just don't crimp them too tight.
Same here..temporarily used zip ties was a tricky one to find, but I was a novice mechanic back then.

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93 Silverado 350 XE268H Performabuilt 4l60e Heavy Hauler US Shift Quick 4 (FiTech<----yuck)
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TCC clutch solenoid could be shorted to ground. Does it lunge forward before dying? It should still die if you come to a stop in manual first or second though....Still confused with the issue.

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In reading the solutions I tend to think everytime you put the vehicle in gear you have to step on the brake.... Simple
If you have a bad vacuum brake booster it would be a vacuum leak stall...... Every time you brake to shift..
Take a vacuum guage on your intake manifold it should be 18 inches of vacuum at idle....
 

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Well you would notice a problem if you hit the brake in park or neutral if it was the booster right?

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But a better test would be to block off the booster and try...right?

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