Re: Full engine Power light & Check Engine light
 

I think rather than beginning the process by thowing parts at the problem (ie: arbitrarily replacing the fuel pumps), I'd get a copy of the factory service manual and run the tests and other diagnostic procedures for those two codes.

Why do I suggest that?

Well, 1) because it's how service techs go about solving problems and 2) you've got a strange situation with DTC 55 and 65 setting together. DTC55 is for lean exhaust when the secondaries are commanded open. DTC65 is for rich exhaust on the right bank.

Let's think for a minute. To set DTC55 the system has to be in closed loop and PE, the secondary pump has to be commanded on and either the right or left O2S has to indicate a lean exhaust for at least 2-sec.

But...DTC65 sets when the system is in closed loop, the throttle is less then 2.7% or more than 20% TPS for 30 seconds or more and the right bank runs rich for 30 seconds or more.

Seems strange to have the engine lean and rich at the same time.

Indeed, this could be a pump problem, but it also could be something else. Before I'd spend the bucks on a pump assembly and go to the trouble to change them, I'd run some tests out of the FSM to verify that the secondary pump is the problem.

Re: Full engine Power light
 

Hib, thanks for the insight. I don't have the FSM yet since I just got my car. I know the injectors need to be done so will go ahead and do those, and the pumps were cheap enough to just do them at the same time.

The DTC 55 code has me puzzled if that only happens when the secondaries are commanded open, since when my power key is in full power the light does not stay on. I am 99% sure my car has the stock chip, but maybe the original owner put in a chip that keeps the secondaries open all the time? If a chip is put in to keep them on, does the light stay on all the time on the dash though?

Re: Full engine Power light
 

Here is the chip in my car, have no way knowing if it is stock or from someone else though.

Re: Full engine Power light
 

the power light is a result of a bad switch, same problem I had for a bit before I took it apart

Re: Full engine Power light
 

So is the car going to full power with the switch in full power mode even without the full power light coming on?

Re: Full engine Power light
 

Ok, Paul W. sent me a PM with some info. I had not tried clearing out the codes, so disconnected the battery for about half an hour. Just drove the car, still no full power with the switch. However, when I manually hold it against the stops and the light illuminates, I am getting full power when I punch it. Drove it for a while and came home, checked the codes and none appeared except the code 12. So, going to hold off on the fuel system for now. So, in the end it was the switch. I am getting a Hailbeck chip so may just have him fix it in there instead of pulling the switch out for now.

Re: Full engine Power light
 

Steve, that AUAH is the stock original chip. Marc H will be able to get you the upgraded GM chip which I believe is AYBK3 and he adds his goodies to it as well. Go to his site which is "ZR1 specialist" and check out the new chip advantages over the stock one. I have the upgraded chip from Marc and it works great.

Re: Full engine Power light
 

on a 90 the chip won't fix the switch. on the 91+ cars the car defaults to off when you start the car, on the 90 the car will start with what ever position the key is on.

Re: Full engine Power light
 

Ah, OK. Looks like I am pulling the switch out today then.

Re: Full engine Power light
 

I found that I left the switch in FULL POWER all the time anyway (on my 90). And, as I said the REAL reason for it in the first place had to do with sound abatement - that "valet key" was a smoke screen that came out of the marketing department (specifically detailed in Young's book "HEART OF THE BEAST")

Of course, if you delete the Secondary Port Throttles* (SPT), then on a 90 it is recommended that you assure the switch is ALWAYS turned to FULL POWER mode or else one of the injectors will be cut off and resulting in a dangerously LEAN condition, should the switch not be in FULL POWER either by accidentally turning it off, OR if the switch itself becomes intermittent.[-X (For engine safety sake, I soldered a jumper wire across the switch so that intermittent connection would never happen. It's easy to install the jumper, and can easily be reversed if desired.)

* This is causing your thread to veer off the path, but just FYI for now, unless your car already has been modded for secondary delete. (That is doubtful, or you'd be having a lot of trouble getting it to run anywhere close to 5000 rpm on half the fuel - as the fueling is split between both injectors in FULL POWER mode.)