Code 23 and code 54 on '92 3.4dohc

[sspeedstreet]

I have a dead stock 3.4dohc in an '88 Fiero with a 9396 ECM and stock 5-speed chip. I keep getting a hard Code 54 (Low fuel pump voltage). I've replaced the fuel pump relay and the oil pressure sender with no luck. What else can I try?

The MAT code doesn't make any sense as a scan shows 85 degrees F. Suggestions?

This is a new install with a crate motor and a Fidenza flywheel. Man it does fly!

Any help would be appreciated.

Neil

[86FieroSEv6]

You would have to check the pinout for the ECM and make sure the fuel pump relay output to fuel pump has a wire going to the fuel pump relay confirmation pin. Sometimes labeled as fuel pump on in. The 85 value you are seeing for MAT may be a default value. Did you disconnect the MAT and check for an open circuit value? That would confirm the circuit and tell you if it is an internal test error related to programming.

[FerrariFan]

those are good points. Also check that the MAT is actually reading the air temp. It should get hotter as your engine heats up.

[sspeedstreet]

Thanks for the responses. The code 23 (as well as other odd codes I was getting) was a problem with the ECM "A" plug not completely seated. The random Code 54 lives on.

Today was my appointment with the smog referee to get the swap passed for registration. No codes the 40 miles to get there. When I restarted the car to pull it into the test bay, 'bing' there was the Code 54. An SES light is an automatic fail, but the tech continued with the test to help me with any other problems he might find. Everything on the visual passed except the PCV connections (a simple fix).

When he hooked the scanner to the ALDL he could not get a connection. My Tech 1 works fine on it, but his would not communicate. I'm still using the stock Fiero ALDL plug and didn't add any other wires to it. I need to look at that in my Lumina manual to see if I missed something.

86FieroSEv6, I did revisit the way I had the fuel pump relay wired and I had left it the way it was in the Fiero. The Lumina manual shows a five pin relay with a confirmation terminal where mine is a four terminal and the computer is getting its signal at the oil pressure sending unit. Could this be my problem?

Again, thanks for the help!

Neil