EJ swap in GL10, rough running

[Turbone]

I did a EJ22 (complete engine rebuild) swap on a friends 87 GL10 and the things been giving us grief. Its running real rich and dumping fuel and fouling the plugs. I've checked fuel pressure, its good. Comp on all cylinders is over 200 (rings have extra gap for NA/T in the near future. Its also hard to start and runs rough for several seconds, then smooths out. Has a little bit of a surge too. Non EGR and have replaced the fuel reg. Looking for a little guidance on where to look next, should I start going thru the wiring harness next?

[Numbchux]

What year engine/wiring/ECU? What transmission does the ECU think it has (I assume it's a manual now)?

Correct MAF sensor, IAC, TPS etc.?

DTCs?

 

I'm having the thought that hoses might have been switched and excess fuel is ending up in a vacuum line. But if it's getting pressure and running at all, I can't think how. Maybe return line right off the rail to a vacuum source? I'm just thinking out loud at this point.

Or maybe temp sensor reading super cold? I know on our 04 EZ30 Outback, when the wires to that got chewed, it defaulted to 40*F. But it was about 10 below that day, so it would not fire. But maybe a short might make it read crazy cold? 

[Turbone]

Just replaced the temp sensor, no change. Everything is from a 92 Legacy with original parts, with a stock 5spd D/R trans I might take another look at the return line

[Turbone]

Another bit of info. We used custom made headgaskets from Cometic. Cant remember the exact thickness, but they were made thicker for future NA/T application.

[Numbchux]

9 hours ago, Turbone said:

Another bit of info. We used custom made headgaskets from Cometic. Cant remember the exact thickness, but they were made thicker for future NA/T application.

And it still makes 200psi? Wow. I'm impressed.

 

I'm pretty stumped by this.

All 4 cylinders? I was thinking stuck injector, but it would be strange to be all 4.

 

I know you know this, but I'm brainstorming. The injectors are pretty simple. One wire is constant power from the ignition relay. I can't think of a likely failure mode on either side of that that would cause more fueling. But also would require some seriously bunk input information for the ECU to actually command that much fuel. And even then, I would think it would throw a DTC and override to open loop "limp mode".

I guess you could unplug the MAF, then you would know it's open loop, and see what that does.

 

But it seems far more likely that it's something mechanical. A leaky or stuck injector, a hose connected incorrectly.

[Turbone]

Turns out the IAC needed adjusting. Part of my problem (in my shop) is having too many parts laying around. This GL10 was a rebuild from the ground up and I had parts from my RX laying around also. Which means multiple IAC's to choose from (and not keeping stuff separated). So I grabbed the best looking one and cleaned it, then installed it on the GL. Only messed with it once, after getting the engine running, but knew too much fiddling is a bad idea. I got the car back to my shop last week and after going thru everything (again), I tried a little adjustment on the IAC. It worked like a charm, no more surging and fuel dump is almost gone. No more smoke after startup. It went home last night and the owner took it to work. He txt'd me and said it stumbles, shakes and farts at first, then runs better when its warmed up. I have the 2 10in fans on a switch now, the engine struggles to get to Op Temp but manages after several miles. Big reason is the radiator is a BIG 2 row aluminum rad (In prep for NA/T), so we may find a smaller rad to run temporarily. Now he needs to find another 5spd D/R trans as the current one is almost gone