91 SC Motor Swap problems, and code 26

[PeterSR20]

Hi,

1st off, I desperately need an FSM for the 91 SC, any ideas where I can get it?

Secondly, the mods:

From a stock '91 DOHC L4-116 1.9, to ...

10.5:1 Compression pistons, total seal rings, head work, forged rods/pistons,
235/235 duration, .400/.340 intake/exhaust lift Gude Cams, ported throttle
body/intake manifold, 75-shot nitrous.

Motor was recently done, have about 700 miles on it.

Thirdly, the Symptoms:

Running hugely rich, starts out with the A/F gauge in the first ideal LED,
then hunts it's way consecutively richer, finally going into way too rich. ECU gives code
26, which refers to a faulty quad control module, called the dealer, they claim no such
thing exists, and the Haynes manual information is completely bogus.

The engine stalls under braking, and idles very poorly. Code 32 has also come up, pointing to a faulty EGR valve, the valve feels like it doesn't move very easy, and probably needs to be replaced.

The vacuum connection between the EGR solenoid and the EGR valve seemed bad,
replaced it, symptoms didn't go away.

The O2 sensor was fouled, the spark plugs were fouled, replaced those. Replaced the coil pack
to spark plug wires as well.

What's making the ECU richen? How do I quickly figure out what's wrong? Could some sensor
just be unplugged somewhere?


BTW - This is my neighbor's car, not mine, but I'm trying like a banshee to help him figure it out :P

Thanks guys,

As well, if you can't help, can you tell me who can?

[Carguy393]

First of all that sounds like a nice car.

Secondly, It sounds like a piggyback computer would be able to fix the problem. If you get a fuel controller then you will be able to fix the problem with fuel system.

[billyturbonitrosl2]

sounds like the idle air control valve (IAC)