Ecu misfire?

[TTO5]

Another observation when pulling the vacuum hose off the vacuum switching valve on top of the intake manifold the engine barely slows down. We expected a bigger drop even maybe stall.

 

[rexington14]

Have you done a compression test on the engine when hot?

 

[TTO5]

Have you done a compression test on the engine when hot?

Yes. It's fine

 

[TeCKis300]

Have you tried moving around the injectors?

 

[TTO5]

Have you tried moving around the injectors?

That's next. Just strange how it takes about 7 minutes of run time from a cold engine start to have it happen

 

[liv2bike]

Do you have a warranty on the donor?

 

[TTO5]

Do you have a warranty on the donor?

Already expired. Only 30 days. Thing runs mint until it goes into it's fit. My mechanic doesn't think it's anything internal to the engine

 

[TTO5]

Mechanic did a compression test. 220 in cylinder 4, 190 in 7.

 

[Ali FJ80]

Leak down test may be a good idea with that much variation.

 

[rexington14]

I'd want to rule out a blown head gasket on your donor. Run compression test on hot and cold engine, leak down test, combustion gas block tester, pressure test radiator borescope cylinders, etc. Send oil to blackstone for analysis if you have any decent amount of miles on it (even a couple hundred or so). And I'd be on the phone with the donor supplier letting them know of the situation.

 

[TTO5]

Leak down test may be a good idea with that much variation.

Leak down done passed no problem. He saw a fair amount of carbon on the piston and valves. Maybe that's heating up and breaking apart? But why only 2 cylinders?

 

[Boston Mangler]

Leak down done passed no problem. He saw a fair amount of carbon on the piston and valves. Maybe that's heating up and breaking apart? But why only 2 cylinders?

If the 2 low cylinders are next to each other, it’s a head gasket , if not fully blown, at least leaking

 

[TTO5]

If the 2 low cylinders are next to each other, it’s a head gasket , if not fully blown, at least leaking

Opposite sides

 

[Boston Mangler]

Opposite sides

That’s a good sign

 

[Ali FJ80]

Leak down done passed no problem. He saw a fair amount of carbon on the piston and valves. Maybe that's heating up and breaking apart? But why only 2 cylinders?

If buildup is bad only on 2 cylinders, would guess fueling or spark issue. Injectors were swapped/checked?

 

[TTO5]

If buildup is bad only on 2 cylinders, would guess fueling or spark issue. Injectors were swapped/checked?

Yes

 

[TTO5]

This sucks. I'm 12k in the hole here and still have a truck I can't drive .

 

[TTO5]

This sucks. I'm 12k in the hole here and still have a truck I can't drive .

I see a service on ebay that can repair ecu. Maybe they can tell me if something is wrong with it?

 

[Ali FJ80]

Yes

Shot in the dark but would start following the wires from those two coils back down into the harness and check for possible damage. Engine swaps aren’t easy on old brittle harnesses.

 

[TTO5]

Shot in the dark but would start following the wires from those two coils back down into the harness and check for possible damage. Engine swaps aren’t easy on old brittle harnesses.

That's been done. Thanks everyone for all this help by the way.
The shop I had do the install is letting me try a ecu from another lx570 but they don't have the system to reinitialize the immobilizer. Anyone know if the paper clip into 2 ports on the obd connector trick works, and if so the exact way to do that please