Lexus082

I have a 94Sc400 and I was driving on the highway for about ten minutes going to work at 70mph and the engine cut off and I had to drift to the shoulder. After sitting for ten minutes I was able to start the engine and continue on the highway for another 2 miles and then it stalled out again. I let it sit for a few minutes and I was able to continue driving and parked it before it had a chance to stall out again.

It seems that after about 10 or 15 min. of driving the engine stalls out. The engine will start up but it immediately stalls out after about a second each time. I searched quite a bit looking for a similar stalling issue and it seems the main difference between my problem and others is that I can not keep the engine running by giving it gas. Even if I try to give it gas it doesn't help and the engine still stalls out.

The last time I drove it, it stalled out and I wasn't able to keep it running and had to have it towed.

I think the problem lies within the ignition system and when the car gets to a certain temperature that is when the component fails (whatever it is). When the engine is cold it starts up and drives just like it should. It idles smoothly and I haven't had the check engine light come on at any time. I thought it was the fuel pump at first and I replaced it, but it didn't fix anything. I'm not sure if it could be a bad fuel pump ecu or not. I'll try that if I can re-create the stalling issue. I just don't want to drive it and get stranded.

I'm about to inspect the ignition system and try and take a closer look at the ignition coils.

GS4_Fiend

iTrader: (22)

Try the 12V bypass for fuel ecu. There is a thread about this

ihiryu

iTrader: (7)

Have you tried jumping the FP and B+ in the diagnostic box? Once you do that, it'll bypass the fuel pump ecu.

I would think it's the coils, or the crank position sensor, since they are known for getting ripped out

Lexus082

Thanks for the quick responses. I will try to bypass the fuel pump ecu first before I start tearing into the engine. I was trying to search for the correct pins to bypass it, so you just saved me a bunch of time. Meant to write them down earlier.

I started the car up and i'm waiting for it to stall out so I can start diagnosing and bypass the fuel pump ecu to see if that fixes the problem. Just dont know how long its gonna take for it to start acting up.

There car's been running for about 30 minutes and i"ve been reving up the engine on and off waiting for it to stall out and it hasn't yet. I know if i went for a drive the damn thing would stall out. Guess i'll keep it running for an hour to see if it stalls. Otherwise I may not have a choice and may have to drive up and down the street a hundred times for it to stall and then push it back. So much fun.

GS4_Fiend

iTrader: (22)

Just do the bypass first its not gonna do any harm and just drive it

Lexus082

Yeah i may have to. Would have been nice to have it act up then do the bypass real quick and then know right off the bat if the bypass worked without taking the chance of being stuck somewhere. But I guess i'll just have to deal with it if it happens.

After letting the engine idle for an hour and reving it up two dozen times holding it at different rpms I was unable to re-create the stalling issue. And without my friend here as back-up I'm not gonna take a chance driving it.

Haven't had a chance to work on the car, but this morning I'm headed to the closest junk yard to collect everything I can think of that would/could cause this stalling issue. Hopefully I get lucky and its a bad fuel pump ecu, one of the ignition coils, etc.

Is it possible maybe one of the igniters is going bad. Intermittent problems suck. My car has been sitting for a week today.

Lexus082

Has anyone had a similar problem with a bad maf, I don't have any codes stored. I think it possible the maf could be causing these issues.

GS4_Fiend

iTrader: (22)

Disconnect the MAF if it runs better. Chances are that MAF is defective

xspsi6

iTrader: (31)

Really sounds like the fuel pump ecu.

Lexus082

I was in the process of doing a tune-up and I noticed that on the camshaft position sensor wire harness there seems to be a ground wire that comes off of it. This is a bare silver wire that is part of the wire harness which makes a total of three wire 1 bare wire and two colored wires. I see a small metal (male) tab mounted on the front of the engine where probably at one time there was a female connector on the end of that bare wire. I just don't remember seeing this and was wondering if someone can confirm this. But I do believe this wire should be grounded. I'm just wondering if this would be enough to cause any problems. I'm pretty sure its not causing the engine to stall or I would think it would be all the time and not after ten minutes of driving.

Lexus082

I still need to change out a few more things before I go for a test drive. I'm in the process of having that finished by tonight. But I haven't done the fuel pump bypass yet, because I would still like to have the car stall out on me and then bypass the fuel pump while I am experiencing the problem. Over the last two weeks I've been trying to think and research what could cause the stalling issues.

From what I have gathered one source states when the vehicle stalls unexpectedly while driving it is often ignition related. The underlying cause is often a bad crankshaft position sensor, or sometimes a failing ignition coil (if the engine has only one coil). A faulty ignition switch that loses contact intermittently may also cause the engine to suddenly die for no reason.

One update I want to give you guys is after not driving the car for a few days, I started it up that one day trying to recreate the stalling issue and it started right up and I let it idle for an hour and from time to time I would give it some gas and hold it at 2000-2500 rpms. So recently I started to work on the car and discovered my battery was dead and it only had approx 10.5 volts. So I took the battery to have advance test and charge it, i just figured it just needed a charge, but they told me the battery came back defective. I guess it wouldn't hold a charge.

So I'm trying to figure out if the battery had a bad cell to begin with and was going bad which caused the engine to stall or was the battery depleted and damaged by my thirty attempts to restart the engine the last time I drove the vehicle. That night I was trying to finish driving home and got stuck so I would start the engine and it would immediately stall out. So I would try again and again and probably started the car 30 different times all resulting in it stalling out each time. All those cranking amps needed to start the engine. I think that most likely caused the damaged to the battery. Do you guys agree?

GS4_Fiend

iTrader: (22)

Get a new battery and try again.

Lexus082

Got a new battery, the other one was only 8 months old and still under warranty. With the limited time I have had to work on the car I have replaced the following parts. Battery, Spark Plugs, Distributor Caps & Rotors, Both Ignition Coils, and both Igniters (Ignition Control Modules). I still plan to swap out the crankshaft position sensor, a few relays, the fuel filter (b/c its over due) and eventually bypass the fuel pump ecu. I removed the battery and haven't had a chance to start the engine to check the results.

g4ebguy90

If the battery was that bad, it wouldn't restart,,,

ScDoinIt

iTrader: (2)

I hope replacing all those parts fix it! having it stall out and stuck and having to pull over is no fun. plus being worried the whole time that it going to stall again is not cool feeling. when do u plan on putting battery back in and checking results? i am in the same boat as u, we have similar problem not exactly the same but both our engines stalling out and we stuck on side of road. i too order the part i need and on monday after installing it will see the results. hope all that fixes the problem. good luck, i think u replaced about every part that could be causing those symptoms. nice.