GX 470 2008 Stalls randomly in traffic.

[DFuller]

Engine stalls in traffic sometimes turning a corner sometimes pulling up to a stoplight. Always restarts and runs just fine. No check engine light no stored codes. Has 39 pounds of fuel pressure.

 

[Rednexus]

For something like this you'll need to livestream sensor data to figure it out. I've had that problem a few times in my rig and it was the wiring to the MAF sensor, I only figured it out due to running Torque Pro and having a live plot of MAF data vs. time. The MAF would randomly under-report air due to the wiring issues, which would then cause the computer to cut fuel and kill the engine. No codes. I'd plot MAF sensor data, commanded air-fuel data, and actual air-fuel data. Then you can see if the MAF is acting funny or if it is something else causing it to randomly go lean. Or, if you have an ignition/electrical issue causing the problem.

 

[Gxunit201]

Engine stalls in traffic sometimes turning a corner sometimes pulling up to a stoplight. Always restarts and runs just fine. No check engine light no stored codes. Has 39 pounds of fuel pressure.

I agree with Rednexus above. I had a stalling issue that was due to a dirty gummed up throttle body and MAF. You can buy a $15 kit at Walmart that includes spray for MAF and throttle body. Only use MAF cleaner on the MAF! These are very sensitive. Use an old tooth brush for the throttle body. You need to do a throttle relearn procedure once cleaned. Completely fixed my problem

 

[DFuller]

I agree with Rednexus above. I had a stalling issue that was due to a dirty gummed up throttle body and MAF. You can buy a $15 kit at Walmart that includes spray for MAF and throttle body. Only use MAF cleaner on the MAF! These are very sensitive. Use an old tooth brush for the throttle body. You need to do a throttle relearn procedure once cleaned. Completely fixed my problem

I cleaned the throttle body last night. Did it last summer as well. Was not terrible. I also cleaned the Mass Airflow Sensor. I have a Hewitt SAIS bypass installed but I’ve had that for a few yrs now.

I noticed today some bronze/brass shavings around the ID on my PS drive pulley. Both inside and out like a brass bushing is wearing out. Steering is a little noisy and hard I noticed today. Maybe locking up and stalling???

 

[Gxunit201]

I cleaned the throttle body last night. Did it last summer as well. Was not terrible. I also cleaned the Mass Airflow Sensor. I have a Hewitt SAIS bypass installed but I’ve had that for a few yrs now.

I noticed today some bronze/brass shavings around the ID on my PS drive pulley. Both inside and out like a brass bushing is wearing out. Steering is a little noisy and hard I noticed today. Maybe locking up and stalling???

How often are you getting the stalling? I think that a failing PS pulley would eventually cause the serpentine belt to fail, but not stall the engine. I'd still get live data like @Rednexus suggested.

 

[GrandpaGold]

Reach out to Hewitt about this. I had the same, and it turns out for a few years they had intermittent issues with wiring harnesses. Have you noticed whether this primarily happens when the car is cold started?

Originally i thought mine was a transmission issue. Cleaned the maf. Repalced the maf. Cleaned the throttle body. Cleaned sparks. Replaced air filter. Only thing that fixed it was replacing the SAIS system with OEM parts.

 

[DFuller]

Reach out to Hewitt about this. I had the same, and it turns out for a few years they had intermittent issues with wiring harnesses. Have you noticed whether this primarily happens when the car is cold started?

Originally i thought mine was a transmission issue. Cleaned the maf. Repalced the maf. Cleaned the throttle body. Cleaned sparks. Replaced air filter. Only thing that fixed it was replacing the SAIS system with OEM parts.

I reached out to Paul today. He suggested I unplug it and return to stock. I have the block off plates installed so not sure about that.

It is not at cold starts, after being driven and warmed up primarily. It’s always re-started with no issues. It’s always been very reliable so it’s odd.

 

[DFuller]

Reach out to Hewitt about this. I had the same, and it turns out for a few years they had intermittent issues with wiring harnesses. Have you noticed whether this primarily happens when the car is cold started?

Originally i thought mine was a transmission issue. Cleaned the maf. Repalced the maf. Cleaned the throttle body. Cleaned sparks. Replaced air filter. Only thing that fixed it was replacing the SAIS system with OEM parts.

Did you do the work yourself restoring the original SAIS?

 

[Rednexus]

Did you do the work yourself restoring the original SAIS?

Have you checked the MAF readings while the engine is running? Otherwise, it's premature to think about replacing SAIS parts. A number of us have had similar problems on here due to a bad MAF connector, which is $16 on Amazon. Without checking the connection, you run the risk of replacing parts that aren't bad and having the same problems.

 

[GrandpaGold]

Have you checked the MAF readings while the engine is running? Otherwise, it's premature to think about replacing SAIS parts. A number of us have had similar problems on here due to a bad MAF connector, which is $16 on Amazon. Without checking the connection, you run the risk of replacing parts that aren't bad and having the same problems.

I checked the MAF readings on mine, and have had the new SAIS kit with no stalls for a year on mine- not sure if you were asking me or him. Agreed- def check MAF numbers first

 

[DFuller]

I checked the MAF readings on mine, and have had the new SAIS kit with no stalls for a year on mine- not sure if you were asking me or him. Agreed- def check MAF numbers first

I need to check those readings. Thx for the advice.