car shut off while driving

[ray]

hello there im new to this forum please forgive me if i posted this in the wrong section or anything but my car ( 2001 lexus is300 – 135k) is cuting off while driving basically first time the car shut off on me was when it was overheating about 3 months ago replace radiator ,water pump , thermo , timing belt. Didn’t think that the car cutting off on me was a problem at the time though it was a failsafe or something since it was overheating . then 3 weeks ago in one day the car shut off 4 times while driving. went to autozone they tested the alternatnor said it was over chargeing . then i replaced the alternator with a high output one (150 -160 amps) it didnt shut off till today . my thoughts are it cant be the battery cause it goes into acc and starts right back up with no problem ,i did sand down the wire terminals on the alt and battery when i replaced it . isnt throwing any codes checked, fuel pump and relays .also check all the connectors in the engine bay i could reach. when the car shuts off it starts right back up on the first try no problem . please i would be greatfull for all help .

Topic

[mikeyb]

I think you might have an issue with your battery. I had an experience with a ’99 Yukon that would do this exact same thing, but when I replaced the alternator and crappy OEM battery with a better one, it solved the problem. If a battery doesn’t solve your issue, i would look into replacing your ECM, as sometimes faulty ones can cause this problem.

[Steve]

I’m having issues right now with similar things. You checked the fuel pump; did you test the pressure? Also check the fuel pressure regulator (FPR). Mine shut off several times a few days ago while driving and i unhooked the vacuum hose off the FPR and it allows me to get back and forth to the store and whatnot until I can figure it out and fix it proper. My check engine light is never on either. AND, I had an overheating issue couple weeks ago; replaced the thermostat but rough running and stalling is still something I’m troubleshooting.

[dan]

might be a crank sensor….

[ray]

i really hope it isnt the ecm thats going to be a pretyy penny.i will look into the fuel pressure regulator and crank sesnor but im able to drive the car .its driveable the car just cuts off on me randomly when i least expect it too .

[dan]

with the 3800s at least i know they will randomly quit just cruising down the road if the crank sensor fails as it is responsible for telling the PCM what position the crank is in along with the cam sensor it is essential in determining things like the firing order of the spark plugs and fuel injectors…

[MARK FELDSTEIN]

First off, welcome to the party !
Got any codes from your car’s computer? If you don’t have a scanner, you can take it to a local parts store and ask them if they would check your engine codes. Always a good place to start. While you’ve already gotten some good suggestions here, if it’s throwing some diagnostic codes that get you onto the fast track a bit sooner and easier. It’s also a good way to help figure out if your ECM has gone Kaputsky and in the interim, might help you sleep better at night. 🙂
Sparks

[college man]

sounds like crank sensor is failing.

[ray]

well the car doest throw any codes i do have a scanner & i checked . its driveable i even tested my car with my friends we both have the same car are cars have 14.4 volts on idle and 13.0 volts when the car is off .so that takes the battery and alternator out . the car idle does drop when i come to a stop in traffic it goes to the first stroke before zero . you guys really think it could be a cam sensor cause it starts up with no problem and drives but it just cuts off when it feels like it also when i start up the car on a cold start up it idle above 1100 rpm . also the car is burning more gas than it should thats something i also noticed. today i did replace a few hoses in the car but it didnt help . might replace a few more but im sure i dont have a vaccum leak

[MARK FELDSTEIN]

I’m inclined to think a sensor failing as well, but I’m wondering why that wouldn’t generate any trouble codes.

Nonetheless, here’s one on how to test a crank sensor with a meter.

OTOH, while you mentioned it starts back up again after it quits on you and you checked the fuel system, did you test the relay, check the fuse and the pump itself? Here’s something you might find useful to help you out.

Here’s one by a buddy of Eric’s. It covers how to test an electric fuel pump in a no start situation although it might also help in intermittent failures as well

How to check for fuel pressure.

Sparks

[ray]

well i checked all these things and they all turn out to seem fine not sure whats left to check

[ytram]

Time to start doing wiggle tests with connectors going to sensors while engine is running.

[ray]

I done a test like this already I took a screwdriver and I went around and I hit relays and major connectors but I got nothing. today I did replace my ground wire on my battery, chassis and engine block to make sure there a good connection.

[Author]

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