L28ET Problems, need solutions please help!!!

[ArchetypeDatsun]

Hello guys, I got a 1981 280zx non turbo I did a L28ET swap to and been having some real stressful problems with the motor here's a brief story:

 

So I purchased a 83 280zx Turbo as a donor car in California, the car had upgrades like 87 Z31 ECU & MAF T3/T04E Turbo 3 inch exhaust & Koyo aluminum radiator. Ever since I got my 81 280zx back after the motor swap it's been having major studdering issues even when I put my foot down all the way on accelerator there's no go. I'm running stock boost anything before hitting 5 pounds of boost is all good but past 5 pounds the car seems weak and kinda slows down, also running really rich there's always that gassy smell. I did my research on the Z31 ECU & MAF swap & the commen problems behind it and did all the corrections and still have the same problems. The Z31 ECU & MAF were already installed and if I try to go back to stock I would need to replace the MAF connector which I don't have since it's been switch to the Z31. So my question is what am I doing wrong here, am I forgetting something???

Edited June 1, 2010 by 280zx@541

[Brad-ManQ45]

Hello guys, I got a 1981 280zx non turbo I did a L28ET swap to and been having some real stressful problems with the motor here's a brief story:

 

So I purchased a 83 280zx Turbo as a donor car in California, the car had upgrades like 87 Z31 ECU & MAF T3/T04E Turbo 3 inch exhaust & Koyo aluminum radiator. Ever since I got my 81 280zx back after the motor swap it's been having major studdering issues even when I put my foot down all the way on accelerator there's no go. I'm running stock boost anything before hitting 5 pounds of boost is all good but past 5 pounds the car seems weak and kinda slows down, also running really rich there's always that gassy smell. I did my research on the Z31 ECU & MAF swap & the commen problems behind it and did all the corrections and still have the same problems. The Z31 ECU & MAF were already installed and if I try to go back to stock I would need to replace the MAF connector which I don't have since it's been switch to the Z31. So my question is what am I doing wrong here, am I forgetting something???

 

Did you take the stock Pop Off Valve off the intake manifold and plug the hole? If you didn't then once you build more than ~7 psi you WILL run rich.

 

I believe you would be better off buying a MegaSquirt or other aftermarket ECU and using the settings that others have already set up for their cars (with the same basic setup ie: turbo size and injectors) as a base point.

[ArchetypeDatsun]

Did you take the stock Pop Off Valve off the intake manifold and plug the hole? If you didn't then once you build more than ~7 psi you WILL run rich.

 

I believe you would be better off buying a MegaSquirt or other aftermarket ECU and using the settings that others have already set up for their cars (with the same basic setup ie: turbo size and injectors) as a base point.

 

You know I have not tried that I will do that, I was thinking of running Nistune for the Z31 ecu I have installed already. But I still have a stock ecu for the 83 turbo so I guess I do that too thanks you very much for the help.

[KnightoftheRound]

Here are some things I would ask myself in regards to the Z31 swap:

 

Run ECU diagnostics?

Wiring correct?

CAS disk in upside down?

CHTS good?

All sensors test good and/or adjusted correctly? Especially MAF.

Correct o2 sensor (87Tturbo uses Titania type IIRC.)

Correct injectors?

Fuel Pressure good? My car ran like crap under load, with good fuel pressure, but the pump I guess couldn't keep up, found that my power wire loop connector at the pump was hanging on by like 2-3 threads!

Grounds good?

Connections to all sensors and ECU good?

Air leaks?

If the pin 9/start signal wire gets constant 12v, your car will run like s***, this is the WHOLE CAUSE that my Z31 swap ran like crap, and I found it out AFTER I swapped everything back stock. If this wire gets constant 12v, you will have injectors sticking open longer than they should, and the timing advance won't work, you will get a CAS code that will never go away, and run rich enough to blow clouds of smoke if you rev it.

 

So check some of that stuff out, get an FSM, and go at it. Or convert back stock like me. I learned enough about my car with the Z31 swap that I was able to make my stock ECCS run damned perfect.

[ArchetypeDatsun]

I never even thought about half the stuff you mentioned, that's a huge help thank you very much I appeciate the help I will check it and there was that chance I would go back to stock because it never runs right no matter what I do only when it hasn't warm up enough it's kinda ok I'd say like 45-50% good but thank. For the help again.