FJ62 Stumble (1 Viewer)

[Ocho77]

3FE stumbles when warm...and often dies. Starts right back up. Engine is de-smogged and has about 10k miles on a rebuild. In the video, I am not touching the gas pedal...it's doing it all on it's own:



So far I've replaced the following:
New fuel filter
New fuel pulsation dampener

Where do I head next? Fuel pressure regulator? Vaccuum leak? If I pull the hand throttle it will idle but smells of fuel.

Open to ideas/thoughts on where to go from here.

 

[Bleu62]

I've been chasing this issue as well. Have you pinned the diagnostic port?

 

[Ocho77]

I have, but not successfully. It’s gummed up. Have sprayed with cleaner and pinned it but still won’t read a code.

Have you?

 

[toy_tek]

I’d check for intake leaks, check and clean throttle body and TPS for starters.

 

[jesus888]

I had a very similar issue with mine... replaced the AFM with a junkyard part and boom/fixed.

Builds - Where it all began... an FJ62 story

So I gotta say something about @cruisermatt … I haven’t met the dude in person… but I trust him. He says what he’s gonna do and he does it. He’s always lookin out for his customers’ best interests, he is always communicative, he sends a bunch of progress pictures along the way… I’m saying… if he...

forum.ih8mud.com

 

[diesellibrarian]

Don't guess! Test!

Do you have a copy of the Factory Service Manual? Here are the systems you need to investigate:

If you don't have the FSM, I think there's a downloadable version in the "Resources" section of this forum. It'll walk you through the diagnosis and repair.

 

[Ocho77]

I had a very similar issue with mine... replaced the AFM with a junkyard part and boom/fixed.

Builds - Where it all began... an FJ62 story

So I gotta say something about @cruisermatt … I haven’t met the dude in person… but I trust him. He says what he’s gonna do and he does it. He’s always lookin out for his customers’ best interests, he is always communicative, he sends a bunch of progress pictures along the way… I’m saying… if he...

forum.ih8mud.com

I did swap it out for another AFM I had here in my barn but the issue persists.

I believe there is a vacuum leak somewhere...just have to find it.

 

[Ocho77]

Don't guess! Test!

Do you have a copy of the Factory Service Manual? Here are the systems you need to investigate:

View attachment 3582415

If you don't have the FSM, I think there's a downloadable version in the "Resources" section of this forum. It'll walk you through the diagnosis and repair.

I do have a downloaded copy. Thank you!

 

[diesellibrarian]

I did swap it out for another AFM I had here in my barn but the issue persists.

I believe there is a vacuum leak somewhere...just have to find it.

I always think vacuum leak when an EFI system is hunting for idle, but it also sounds like there's a hard miss, which suggests ignition? Or both! Good luck!

 

[HemiAlex]

I would set the TPS first. It’s free.

 

[Ocho77]

I would set the TPS first. It’s free.

Do those get out of whack? It was running fine since I put the rebuilt engine in 3 years ago. That was my first instinct, but figured since it happened somewhat suddenly it wouldn't be the TPS.

 

[red66toy]

TPS can definitely get out of whack .
I had some erratic rpms on my FJ62 when my coolant EFI sensor started to die. Computer didn't know what temp the engine was at anymore.
If it's not the TPS or any of the sensors (from checking with the ohm meter), sometimes looking for a bad connection by jiggling the harness or looking for corroded connectors may be a good place to check.

 

[Bleu62]

Does it miss regardless of being in gear or not? Has anything changed since the last post?

 

[Ocho77]

Doesn't miss at all when on the gas and drives fine. Only problem is at idle, whether it's in gear or not.

 

[89BIGBLUE]

Check the coolant temp sensor on the thermostat housing. Ohms test it.
Mine wet bad a while ago, and caused misbehavior at idle and random funny starts.