First, a little background:

I have an 88 GTU N/A with a rebuilt 13B that has a light streetport.

A few years ago, when the engine was out of the car being rebuilt, I sent in the fuel injectors to be cleaned and balanced. It turned out that two of the fuel injectors had the wrong impedance (the secondary injectors). The shop told me that having the wrong impedance value injectors would damage the ECU, so I soldered in some 10ohm resistors in line with the ECU harness. The engine ran fine.

After adding in an ignition box, cold air intake, high-flow cat and RB header, I started having a hesitation problem; and this has been mentioned on the forum before, but there has been no clear cause.

When I floor it, as it runs to red-line, the engine will hesitate, then briefly act like it has more power and continue to run up to the redline. I've bypassed the ignition box to see if it was the cause, but the hesitation is still there. Plugs and wires are new--I redid the ignition coil assemblies with new wiring, connectors, and heat sink compound--engine timing is correct, and the AFM and TPS sensors check out. There is an Aeromotive fuel pressure regulator and Walbro 255gph fuel pump; so fuel pressure could be the problem, but adjusting the regulator didn't seem to make any difference. I'm currently running it on the low side to keep the engine from running rich.

My question is: if the secondary injectors have the wrong impedance (the primaries are low and these are high) and someone already corrected it by putting 10Ohm resistors in line (not in the harness; I completely tore that down when I rewrapped and terminated it), could increasing the impedance value cause the secondary injectors to not function or function erratically?

 

seems to me that you have the same secondary transition issues everyone else has... usually due to crap floating around in the injector filter. I suggest taking the injectors out and replace or clean the little filter in the top of the injector