ignatz

Hi All,

I bought my first Toyota Truck last Friday. It's a 1992 with the 22RE engine. I drove the truck home (~200 miles) with no problem. The next time I drove the truck, I noticed the CEL lit so I connected the diagnostic jumper and got code 25. I'm going through the FSM troubleshooting section for this code and have a couple of questions I'm hoping you can help me with:

1. When I turn the key to the on position, the fuel pump starts running immediately and doesn't stop. I do not have the diagnostic jumper in place. Is this normal? I couldn't find a section in the FSM for constantly running fuel pump and my searches were fruitless.

2. I've done the basic tests the FSM advises and am trying to test the fuel pressure. The FSM describes the use of a special Toyota part SST 09268–45012. Is there another way to test the fuel pressure or should I look for this part?

Thanks in advance!
~I

ignatz

It looks like the related thread feature did a better job searching than I did on my own. I followed the advice in this thread and tested my AMF (the FSM calls it a VOLUME AIR FLOW (VAF) METER). I got the following:

E2 - Vs - 185
E2 - Vc - 164
E2 - Vb - 278
E2 - THA - 2.36K
E1 - Fc - Open

which all seem within the specification. I should also mention that the truck starts right up and runs (the idle seems high to me but I'm new to Toyota).

abecedarian

The fuel pump should only run when cranking the engine and once the engine has started. Possible causes are ignition switch, wiring, circuit opening relay or AFM. You've ruled out the AFM: E1/FC should be open with the engine not running.

Code 25 is an O2 sensor lean signal. The high idle may indicate a vacuum leak somewhere which could lead to this code. Additionally, the heater circuit on the O2 sensor may not be working properly.

Stuwy123

iTrader: (1)

Look for a jumper in your diagnostic box between Fp and B+.

scope103

Do you care? You betcha! Your truck will run fine even though the pump runs whenever the key is on, but if you ever get in an accident that breaks a fuel line, you'll be glad the pump shuts off when the air flow to the engine dies.

Abecedarian identifies the usual culprits; you may have to work backwards. I'd start with looking for voltage on the FP terminal of the diagnostic socket.

ignatz

Thanks very much for the replies! Following advice, I tested the COR and Heated O2 sensor and both failed their resistance tests. I spent yesterday trying to find a local source for the COR but found out it's tougher than it sounds. I know the dealership has the part for ~$95 but I'm cheap and have found it online for $16 - $50 shipped. I tried the local upull junkyard but there was little Toyota inventory to choose from (1 '89 4runner, no trucks) which was promising and frustrating at the same time. Anyone local to Central Florida know of a good source for used parts?

ignatz

Just wanted to post a conclusion in case this is found in a search. The CEL is off. The fuel pump does not run when the key is in the on position. Replacing the O2 sensor was a real pain since the nuts were seized. Thanks to this thread I didn't cut the studs and used stainless replacement hardware. (8mm 1.25) I found a small local source for used Toyota Truck/4runner (only) parts in Central Florida. If you're interested check this link for the advert or PM me once it's expired.