Engine surges then stalls

[hecZ26]

Little history...original z26 quad4 powered car, engine kept messing up so i swapped in a 3500 and kept it 5 spd and did obd2 swap at the same time.


So my car surges then stalls, im thinking it has to do with vac lines. If i leave one vac port on the throttle body unplugged itll idle and not stall.

Need help routing vacuum lines to the fpr, map and the purge solenoids at the bottom of the coil pack assembly. Also since i have a 3500 upper intake manifold and lx5 throttle body....there is some vac ports on the throttle body that if i leave unplugged the car will idle 900-1000rpms with small surges but will not stall. I took it out for a spin with the small port on the side of the throttle body unplugged and usually stays above 2krpm while driving, will only idle at 1k at a complete stop. Did not stall.Any help/tips appreciated!

Edit: running stock 96 ecm with stock 3100 tune. Only difference im running 3.4DOHC injectors.

[TGP37]

Probably running too rich. The added un-metered air brings it back to a better AFR.

Any wideband readings available? What about narrowband logs?

[carbon]

Un-metered air to combat un-metered fuel? FPR leaking into vacuum line?

[pocket-rocket]

Well no matter what you do, that PCM needs recalibrated (tuned) so it knows the size of the injectors at least, then tuned for the engine instead of trying to compensate with larger injectors and hoping it will run right.

Don't take this post the wrong way, I'm not trying to bust your chops, but rigging it instead of setting the computer up the right way will never be as effective of a solution, which you are experiencing.

Sent from my HTC One X using Tapatalk 2

[hecZ26]

Thank you everyone for the tips. I'm getting ready to ship my ecm so it can be reflashed. That should take care of my issue and make my engine run better.

Thanks again.

[pocket-rocket]

Good deal. I hope that fixes your problem. It would kill me to put all of that work in a swap like that just to have it unable to drive correctly.

[TGP37]

Also be sure to keep the intake air tight, especially after the MAF.

Did you reuse the injector o-rings? They can leak air if reused cause they don't seal right at times.