Engine stalls when at idle?

Good morning,

If you 2 foot it, will it stay running?

https://www.2carpros.com/articles/stall-at-idle

Roy

Yes, if you 2 foot it while driving it will stay running. But that depends on if we can get it to start. And it idles just fine and stays running while in neutral.

Okay, was this the issue prior to your repairs?

Did you check for vacuum leaks?

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Did you check the fuel pressure?

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

I am wondering to about the distributor. Did you verify the cam retard with the engine running?

Roy

No this was not an issue prior to the repairs. And yes we did a vacuum check after reinstalling the intake manifold. Haven't done a fuel pressure check yet. And did not verify cam retard. What is the cam retard?

The distributor is actually a cam sensor. Timing is set through the ECM. The cam retard is alignment of the crank sensor to the cam sensor. They have to aligned with 2 degrees of each other.

Are there any codes set?

Roy

Don't have a code reader and can't get it to start and run long enough to take it somewhere.

Start with checking the fuel pressure.

Let us make sure it is not fuel delivery related.

Roy

Okay.

Keep me updated.

Roy

Okay. So I got the truck started. I didn't do a fuel pressure check yet. But when it's idling in neutral the rpm's are around 500. And when I held the brake and put it into drive i had the gas pedal all the way to the floor and the rpm's were only around 2000.

Is the check engine light on?

Roy

Yes.

Okay, it sounds like you have the distributor in incorrect.

I attached the procedure for installing it.

Roy

IMPORTANT: The engine front cover has 2 alignment tabs and the crankshaft balancer has 2 alignment marks (spaced 90 degrees apart) which are used for positioning number 1 piston at top dead center (TDC). With the piston on the compression stroke and at top dead center, the crankshaft balancer alignment mark (1) must align with the engine front cover tab (2) and the crankshaft balancer alignment mark (4) must align with the engine front cover tab (3).


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1. Rotate the crankshaft balancer clockwise until the alignment marks on the crankshaft balancer are aligned with the tabs on the engine front cover and the number 1 piston is at top dead center of the compression stroke.


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2. Remove the distributor cap bolts and discard.
3. Remove the distributor cap.


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4. Install a NEW distributor gasket onto the distributor.
5. Align the indent hole on the driven gear with the paint mark on the distributor housing.


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6. Ensure that the distributor rotor segment points to the cap hold area.
7. Align the slotted tang in the oil pump driveshaft with the distributor driveshaft.
Rotate the oil pump driveshaft with a screwdriver if necessary.


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8. Install the distributor and distributor clamp.
The flat in the distributor housing must point toward the front of the engine.


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9. Once the distributor is fully seated, align the distributor rotor segment with the number 6 pointer (1) that is cast into the distributor base.
If the distributor rotor segment does not come within a few degrees of the number 6 pointer (1), the gear mesh between the distributor and camshaft may be off a tooth or more. Repeat the procedure again in order to achieve proper alignment.


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10. Install the distributor clamp bolt.
Tighten the distributor clamp bolt to 25 Nm (18 ft. lbs.).

Okay, I will give that a try and let you know what happens. Thank you

You are welcome.

keep us updated.

Roy

will idle when cold but will not when hot and you can smell gas form exhaust.

check fuel pressure with a gauge first auto parts rent gauge should be 41-47 psi key on only. if that is okay scan for codes. see link.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Blazer with 4.3l Vortec. I have a recurring intermittent issue where my truck will stall out when I put it in gear--park to reverse, park to drive, reverse-neutral-drive, etc. Pretty much only happens in parking lots within a minute of starting the engine.

This doesn't happen every time, and has happened with a warm and cold engine, and in moderate and ridiculously cold ambient temperatures. (Range from +45 to -25 f, haven't owned the truck during warmer months yet).

I just recently replaced the fuel pump/screen and fuel filter. I also replaced the spark plugs just because the plugs that were in there looked pretty old.

This is not an emergency or anything, I can keep the truck from stalling by giving it a little gas as I put it in gear. I am just wondering what could be causing this issue, and how to fix it.

Good evening,

Are there any codes set in the system?

I would start by cleaning the throttle body of all carbon.

https://www.2carpros.com/articles/stall-at-idle

https://www.2carpros.com/articles/throttle-actuator-service

This could also be an idle air control motor. I attached a picture and procedure.


Roy

It is a 1994 S-10 TBI 4.3L.4x4. The engine will start and idle a couple seconds then immediately stalls. It will start right back up and idle for a few more seconds and stall again. After numerous attempts, it will start and stay running without stalling and I can drive on like normal with no problems and it might be normal for a few days then start acting up again. I replaced the ignition module but that didn't fix it. I tried spraying starting fluid into the throttle body just as it was about to stall and it appears to stay running until I stop spraying indicating a fueling issue. I swapped out the fuel pump relay and that didn't help either. Walking to and from work in the cold weather is starting to suck. Any help will be greatly appreciated as I am at a loss.

Check the fuel pump itself when the problem occurs. Key on, engine off, check fuel pressure. Check the injector relay also. One or the other is suffering an intermittent failure.

Clean out the idle air control valve and EGR valve to include checking the fuel pressure if its within specs

I visually inspected the EGR valve and didn't notice any faults. I need to check it with a vacuum tester I suppose. Not sure where the injector relay is located.

Should be in the underhood relay box just aft of the battery.

I do not have a relay box under the hood. There are 2 relays located on the firewall and a relay box that houses the fuel pump relay in the cabin below the center console. My manual doesn't show a injector relay. Any suggestions?

Check to see if the injector is pulsing. I have attached a schematic that shows where the injector receives its signal from. Upper right corner.

Thank you for the schematic. It is hard to view and it appears to be different than my vehicle wires. I noticed the schematic is for a VIN W. I have the TBI VIN Z.

VIN Z schematic. Slightly different. Click the thumbnail. Then right click the image and select "Save Image As". Then you can view it with any image viewing software you may have, or print it.

Ok guys. The abouve diagram was too blurry once printed, but thank you anyway. I spent the majority of Sunday messing with this thing with no success. Here it is Monday morning, and it starts right up and stays running. What the heck is going on? Brought it to work so no walking today. I'll see what happens around 5 when I go home. I might do some more checks at lunch time. Any more suggestions please? The IAC was removed and appears to be clean and not stcking. The PCM was removed and no visual problems noticed. There is a red pig tail under the hood to apply battery voltage to, to power up the fuel pump. I hear the pump running with battery voltage being applied to the pig tail. Is it safe to try that while the engine is running and apply the voltage just about when you can tell it's going to stall?

You were told to check fuel pressure 2x and I don't see you performing it-the fuel pressure is critical we need to know what it is before we can continue to help you-

The fuel pressure was about 13psi.

How did the EGR valve and ports looks when you open it up? the IACV is clean try replacing it and see what happens

EGR valve looked good and with vacuum applied the diaphram moves and holds steady so I assume it is good. I guess I can try a IAC valve but I don't like the idea of throwing parts on it like the ignition module which didn't fix it but I guess I don't have a choice at this point. Thanks for the info. I'll keep you posted. At lunch it started right up with no faults again. I bet it won't run when it's time to go home though.

Think! positively were trying our damnest to help you out-Did you clean out the IACV port? Were not here to tell people to throw parts at it till its fixed, if we do we don't belong here-Remember were not there with the vehicle-Good Luck

I understand. I thank you guys for the help and advice. Just gets very frustrating as you probably understand. Would an IAC valve cause these issues only at start up? Trying to understand what exactly is happening during start up and idle that would cause this mystery to occur. Never stalls when driving it. Reliable while it's actually running, just getting it to that point is difficult sometimes. Really weird how it acts up sometimes for a few starts, then somehow fixes itself, then will drive fine for 3 - 5 days with no problems then all of a sudden the next morning it won't start again. freaky???

Engine Performance problem
1994 Chevy S-10 6 cyl Four Wheel Drive Automatic

When I try to start my 1994 s-10 Blazer , 4.3 auto, it will only start when the gas pedal is held down a little bit , and when you release the gas pedal , it will not idle and dies. It will drive fine until you have to let up on the gas pedal and then it will die. I actually swapped out everything that had a wire running to the intake area with another running s-10 that I own and nothing seem to change the starting issue. All vacuum lines are hooked up. However when I pulled the off the map sensor and left it out by accident , it started right up and ran fine, Now what?

replace the map sensor and see how it does . That is more than likely the problem since you unhooked it and it ran fine.

That 13PSI fuel pressure reading concerns me. It should be much higher, like between 30 and 50PSI. Try checking the fuel pressure over a period of time. When it's acting up and when it's driving nicely. See if it varies and by how much.

[quote:ab8ad978d1="legitimate007"]replace the map sensor and see how it does . That is more than likely the problem since you unhooked it and it ran fine.[/quote:ab8ad978d1]I have already swapped out the map sensor off of another good running s10 that I own and it did'nt fix it.

Well, it wouldn't start yesterday after work. Does the same thing as before. Actually it does start but stalls about 5 - 10 seconds later. This is a TBI Z VIN engine. I think the pressure is suppose to be around 13psi.