2003 4runner v8 dies at warm start

M

mazyland

New member
Hey everyone,

This is my very first post. I have an issue wih my 2003 v8 limited 4runner. I couldn't find any info anywhere on the web and decided to post it here. Maybe someone else had this issue before.

So, the cold start is ok for about 10 minutes or so, and then engine dies. Stepping on gas pedal doesn't help. At warm start engine starts up ok, but dies right after. Had replaced the fuel pump so far. First I suspected the ECU, since the battery had been disconnected for over 2 months. But this issue started happening after I drove it for about 200 miles. Then made a stop for 2 hours and this started happening. I have taken to a local shop and they haven't been able to figure it out.
I would appreciate any help. Thanks folks.
 
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-Have you tried leaving the battery disconnected for 10~15 minutes, then restarting the vehicle and letting it idle with NO loads (i.e. no headlights, no HVAC, ect.) for at least 5-10 minutes?

-How many miles are on your vehicle?

-Does it sort of sputter/misfire/stall out or does the engine just cut-off cleanly?

-Do you have an MIL (Malfunction Indicator Lamp, aka "CEL") on?

-Do you have a code reader/scantool capable of reading Data Lists?
 
Thank you for your quick response BlackWorksInc.
I have tried disconnecting the battery for 20-30 mins before. It did not fix the issue.
I just hit 200K miles on it. Most of the times engine cuts-off cleanly, and only sometimes it jerks off while on the go. No misfire, no sputtering or stalling noticed. And after it's off pretty much all the lights come up, VCS OFF, Check engine, TRAC. I believe CEL also did come up. I left it at the shop where they were reading all the codes and checking the wiring according to the codes (not exactly sure if they are doing the right thing). But there is a handful off code printouts they were looking at. I will try to get the code readings after work today.
But, if CEL is on, what would that mean?

Thanks for your help.
 
If the engine is starting but then stops immediately, some things to consider checking on might include ...

1. Loose or damaged wire harness connections in the ignition system or at the alternator.

2. Intake manifold vacuum leaks.

3. Insufficient fuel flow to fuel injectors.
 
Bossman said:
If the engine is starting but then stops immediately, some things to consider checking on might include ...

1. Loose or damaged wire harness connections in the ignition system or at the alternator.

2. Intake manifold vacuum leaks.

3. Insufficient fuel flow to fuel injectors.
Click to expand...

Yeah, that's what the guys at the shop doing right now, checking the wiring all around. I considered the fuel flow issue and replaced the fuel pump, it did not fix the problem. And it runs for around 10 minutes on cold start.
The issue persists only when the engine is warm.
Intake manifold vacuum leak could be one of the options, I will have it checked.
Thank you for your input Bossman.
 
I'd say you're alternator may be the culprit.

The alternator may be trickle charging the battery just enough to get the car started but after the car starts, the entire electrical system runs off the alternator. If your alternator is shot, then the car will continue to run off of battery power alone until the battery dies.

Since everything on a vehicle now is computer controlled (ie fuel pump, fuel injectors, ignition, etc) large fluctuations in electrical system voltage can wreak havoc on a vehicle.
 
check for your crank position sensor. it may be starting to fail.

mazyland said:
Hey everyone,

This is my very first post. I have an issue wih my 2003 v8 limited 4runner. I couldn't find any info anywhere on the web and decided to post it here. Maybe someone else had this issue before.

So, the cold start is ok for about 10 minutes or so, and then engine dies. Stepping on gas pedal doesn't help. At warm start engine starts up ok, but dies right after. Had replaced the fuel pump so far. First I suspected the ECU, since the battery had been disconnected for over 2 months. But this issue started happening after I drove it for about 200 miles. Then made a stop for 2 hours and this started happening. I have taken to a local shop and they haven't been able to figure it out.
I would appreciate any help. Thanks folks.
Click to expand...
 
scw1991 said:
I'd say you're alternator may be the culprit.

The alternator may be trickle charging the battery just enough to get the car started but after the car starts, the entire electrical system runs off the alternator. If your alternator is shot, then the car will continue to run off of battery power alone until the battery dies.

Since everything on a vehicle now is computer controlled (ie fuel pump, fuel injectors, ignition, etc) large fluctuations in electrical system voltage can wreak havoc on a vehicle.
Click to expand...

Thanks. That was one of the possibilities that we also considered. But since the truck starts up fine after a cut-off that suspicion was eliminated. The battery is still fine.
 
Seems like it could be an ECU/ECM issue. Does anyone know if there is a difference between a V6 and V8 ECU unit, are they interchangeable (Or even an ECM from Tundra/Sequoia etc.)? I just found a local guy selling one for a 2003 4runner V6. Not sure though if it fits V8.
 
Last edited:
Fuel pressure regulator? Failing in a position where fuel pump cannot overcome the built-up pressure?

Maybe a vacuum leak large enough that the computer cannot compensate with enough fuel?
 
mazyland said:
Seems like it could be an ECU/ECM issue. Does anyone know if there is a difference between a V6 and V8 ECU unit, are they interchangeable (Or even an ECM from Tundra/Sequoia etc.)? I just found a local guy selling one for a 2003 4runner V6. Not sure though if it fits V8.
Click to expand...

You need an ECM from a 2003~2004 4Runner with a 2UZ-FE (4.7L V8, No VVTi) engine; the ECMs are not going to be compatible. I don't believe the Tundra/Sequoia ECMs will be compatible either as there are minor differences in the coding that may cause problems if used in the wrong application.
 
Thanks everyone. The issue was found and appeared to be the ECM. There were a few wires open and caused a short circuit damaging the ECM. But did not kill it completely. All the wiring around the engins compartment was replaced.
ECM was just reprogrammed and my baby runs like new again.
 
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