Stop Stalling

[begregor]

Ok so my latest issue with my ls. this is a 2000 v8 130000miles. A few weeks ago i was hit in a side collision and the police officer would not find the dipshit at fault. So when i went home to get an estimate i was at a standstill but not parked and the engine just shut off but the radio and lights were still on. No prewarning. Then this morning I prepare to leave home for school start up fine, i always wait for the car to idle down before i move it and just as i put it in reverse and then give it some gas it begins to go backwards then engine goes off again. Radio still on and air still going. WTF. I have seen some other posts relating to this but none of them were showing that the issue was resolved. I get the rattles and other minor stuff but frankly thats not important I just need to get down the road without this thing turning off.

[shorod]

Sounds similar to what my wife's 2002 LS V6 would do. She'd put it in reverse to back out of the garage and it would stall. No codes, no misfires, engine idled smootly. I checked fuel pressure, air filter, cleaned the MAF, nothing seemed to help. Next I replaced the PCV elbow (not fun on the V6, I don't think the V8 has a PCV), no luck. Finally I replaced the battery and there's been no further occurance in over a year.

I see from your other post though that you've replaced the battery, so I'm not sure what to suggest for you next. Are there any stored diagnostic codes?

-Rod

[begregor]

where would i find diagnostic codes. also could this possibly be that spark plugs may need replacing. i didnt have them replaced after the valve cover gasket was put on and i thought i read that oil could have leaked on the plugs. could oily plugs cause it to stall. oh and the last time the spark plugs were replaced was only about a year ago. but i let the valve cover gasket problem go on for about a year so idk.

[shorod]

The generic powertrain codes can be read for free by most of the auto parts stores. However, if codes are stored, you'll want to get the exact code, not their interpretation of the code. It should be in the form of P0123 where "0123" will be some sequence of numbers.

If the car seems to start fine, it just stalls and you are not experiencing a rough idle, then I don't think spark plugs would be the issue. The oil wouldn't leak onto the firing area of the spark plugs due to the leaky valve cover gasket/plug well seals unless the spark plugs were horrendously loose.

-Rod

[lumberjak1984]

I have a lincoln ls v8 2001 and everything runs pretty good but on occasion when i come to a stop the rpm'sdrop around 400-500 then jumps back up again and everythings fine. 1 time it actually stalled at a light. What could be the cause??? Another minor thing that i noticed is that the car idles at 700-800 rpm. its a smooth idle, just a little high. i don't know if this is normal for the v8?

[shorod]

I'm actually experiencing this on my wife's V6 currently. The idle speed isn't high, but when coming to a stop, the engine speed will momentarily drop and lights will briefly dim (if they're on). Fortunately she doesn't have the stalling.

I've only made it as far as checking the fuel pressure at the fuel rail and found that the pressure is low at KOEO, but if I turn the key off for 5 seconds, then back on, the pressure gets up to around 34 psi. Spec for the V6 is 30-65 psi. KOER at idle is around 32 psi, and the KOER spec is the same. However, if I speed the engine up to around 2000 rpm with the transmission in Park and hold it, the pressure jumps around, and when I let off the throttle, the pressure will briefly drop below 20 psi corresponding to the low idle.

A month or so ago I replaced the fuel filter, so I don't suspect that's the case. I watched the pressure after shutting the engine off and it didn't drop, so I don't think it's a leaky injector or other leak somewhere. I haven't looked to see what controls the pressure regulator or what else is in the fuel system to consider. Other than the initial KOEO pressure reading, it doesn't seem like a pump issue (I don't think the pump would cause erratic pressure readings when KOER).

The car has about 50k miles on it and the plugs are fine, the valve covers/plug well seals are not leaking into the plug wells, I have a new battery, and new PCV elbow. I've used fuel injector cleaner regularly and a borescope down one of the spark plug holes shows the piston tops are clean. I've also verified there are no codes or misfire counts on any of the cylinders. I've also pulled the EGR valve, cleaned it and verified with a vacuum pump that it works and holds vacuum fine. I cleaned the IAC and passages, as well as the throttle body and cleaned the MAF sensor. Last year I performed a cylinder decarb on it which livened the engine up, but I wasn't looking for an idle problem at the time. Since the borescope doesn't show carbon build up on the pistons, I don't think a decarb would help right now.

I'll let you know as I check into more things. The issue doesn't bother my wife, so she's not pushing me to spend time on it.

-Rod

[lumberjak1984]

Originally Posted by shorod

I'm actually experiencing this on my wife's V6 currently. The idle speed isn't high, but when coming to a stop, the engine speed will momentarily drop and lights will briefly dim (if they're on). Fortunately she doesn't have the stalling.

I've only made it as far as checking the fuel pressure at the fuel rail and found that the pressure is low at KOEO, but if I turn the key off for 5 seconds, then back on, the pressure gets up to around 34 psi. Spec for the V6 is 30-65 psi. KOER at idle is around 32 psi, and the KOER spec is the same. However, if I speed the engine up to around 2000 rpm with the transmission in Park and hold it, the pressure jumps around, and when I let off the throttle, the pressure will briefly drop below 20 psi corresponding to the low idle.

A month or so ago I replaced the fuel filter, so I don't suspect that's the case. I watched the pressure after shutting the engine off and it didn't drop, so I don't think it's a leaky injector or other leak somewhere. I haven't looked to see what controls the pressure regulator or what else is in the fuel system to consider. Other than the initial KOEO pressure reading, it doesn't seem like a pump issue (I don't think the pump would cause erratic pressure readings when KOER).

The car has about 50k miles on it and the plugs are fine, the valve covers/plug well seals are not leaking into the plug wells, I have a new battery, and new PCV elbow. I've used fuel injector cleaner regularly and a borescope down one of the spark plug holes shows the piston tops are clean. I've also verified there are no codes or misfire counts on any of the cylinders. I've also pulled the EGR valve, cleaned it and verified with a vacuum pump that it works and holds vacuum fine. I cleaned the IAC and passages, as well as the throttle body and cleaned the MAF sensor. Last year I performed a cylinder decarb on it which livened the engine up, but I wasn't looking for an idle problem at the time. Since the borescope doesn't show carbon build up on the pistons, I don't think a decarb would help right now.

I'll let you know as I check into more things. The issue doesn't bother my wife, so she's not pushing me to spend time on it.

-Rod

i received info from some 1 on another forum on here and he said it might be the iac valve which i believe is located on top of the throttle body. im checking it tom. hopefully this helps you... by the way where exactly is the egr valve and the pcv valve if there is 1. i have the v8.

[shorod]

Thanks for the info. I cleaned the IAC valve and passages and verified that the IAC does function by turning on the A/C and turning the steering all the way to lock, but didn't consider it may just be slow to respond....

The V8 doesn't have a PCV valve. My service manual for 2002 shows the location for the V6, but just says "3.9L is similar." On the V6, the EGR valve is mounted on the throttle body near the throttle plate. I don't remember where it was on my V8, but I had a 2004 so it may have been a bit different then as well.

Your V8 EGR is probably vacuum actuated, the valve will have a round, somewhat flat diaphragm housing about 3 inches in diameter with a vacuum line going to the top of it and a hard steel line threaded into the valve portion of it. The valve portion will be mounted to probably the intake manifold with 2 bolts.

-Rod

[lumberjak1984]

Originally Posted by shorod

Thanks for the info. I cleaned the IAC valve and passages and verified that the IAC does function by turning on the A/C and turning the steering all the way to lock, but didn't consider it may just be slow to respond....

The V8 doesn't have a PCV valve. My service manual for 2002 shows the location for the V6, but just says "3.9L is similar." On the V6, the EGR valve is mounted on the throttle body near the throttle plate. I don't remember where it was on my V8, but I had a 2004 so it may have been a bit different then as well.

Your V8 EGR is probably vacuum actuated, the valve will have a round, somewhat flat diaphragm housing about 3 inches in diameter with a vacuum line going to the top of it and a hard steel line threaded into the valve portion of it. The valve portion will be mounted to probably the intake manifold with 2 bolts.

-Rod

thanks for info

[begregor]

i finally replaced the fuel filter and it hasn't stalled since. there are other problems now but its been six months so its about time.

[shorod]

Thanks for the update.

-Rod