Reinbag

Hey all,
I was having some idling/accelerating issues and getting a code 25 on my 94 pickup 22re engine (code 25 is lean fuel/air mix). Also getting horrible fuel economy and power. Found a fuel leak on the rail. Fixed it. Still get the code. Today I tested the Air flow sensor. Here's what I got:

Vs-E2 158 ohms range 20-400
V2-Ec 180 ohms range 100-300
E2-v8 281 ohms range 200-400
THA-v2 1.86k ohms at approx 66 degrees f haynes says it should be between 2k-3k at 68
E1-Fc infinity
no continuity between terminals and meter

So, as you can see my temp sensor is maybe off by a hair. Does this mean I have to replace the whole thing. Any tricks? It's an expensive part as we know. I was also planning on running some redline through my fuel system to clean it out, but hard to imagine burning a tank of gas with it driving like it is. Also fyi, I just rebuilt the engine on this with new head gasket, head resurfacing, timing chain, oil and water pump. I also replaced the tps, which was faulty.

wyoming9

iTrader: (1)

I think your close enough not to get to worried .

I am guessing you don`t have a Calibrated Meter

Give some numbers for Fuel mileage ?/

Running stock tires ??

What are you comparing this engine to for power ??

scope103

Code 25 is (often) a stored code. So reset it (pull the EFI fuse for 30 seconds) and drive it a bit to see if it comes back.

Even if your VAF thermo were bad, it's unlikely to be the cause of code 25. The O2 sensor will sense the mixture and the ECM will correct, even if the VAF is spouting nonsense. It's when the ECM pushes it all the way rich and can't get the right mixture does it throw 25.

A fuel leak (which reduces the pressure in the rail is a very easy cause of code 25. Another is a vacuum leak.

I agree with Wyoming9; those numbers are close enough. Even with a perfect meter, you can have trouble getting a perfect connection with the probes.

Reinbag

Gotcha. Well, the mpg is mainly city driving. about 14 mpg. With this code 25 i've been a little afraid to open it up on the highway, for fears of overheating. The multimeter is nothing fancy, so calibration could certainly be an issue. It is fairly new. Stock rims and tires.

In terms of driving, and accelerating, it's bad. I mean, if I'm in 2nd or 3rd gear and acc over 2000 rpms I start to get shuttering and jerking from the engine. So i can't really even accelerate with traffic. I've driven a few of these 22res and 22rs and this is noticeably worse than anything I've encountered. It did this before the TPS was replaced (which i had a mechanic calibrated the resistance for me) and it went away. That was before I rebuilt the engine. It idles bad when it's warmed up. I also tested the cold start injector, which seems to be fine.

Nice to know it aint definitely shot, cause it's crazy what people sell them for online.

Should i test fuel pressure?

wyoming9

iTrader: (1)

When you did all this engine work you did install a new fuel filter I might have missed it.

All the other tune up parts are new.??

I would not even know what tune up parts to use most all the aftermarket has gone down hill

Reinbag

Y'know I didn't change the fuel filter.

New gaskets, water pump, timing chain, guides, cover, adjusted valves (didn't replace any), remachined head (at a machine shop), new used oil pump.

I also redid a number of the vacuum lines. I can't find any vacuum leaks.

I've reset the code. It keeps coming back.

Reinbag

Well, got the fuel pressure tested today. Turns out it was the fuel pump all along. Looks like I got some more work to do. Any recommendations for pumps. Toyota factory vs oem?

Reinbag

Also I noticed there's a fuel leak from around the gasket, not for the sending unit but for the fuel level gauge, which strangely is separate in this truck. Could that bad gasket have anything to do with the fuel pump not working properly?

wyoming9

iTrader: (1)

If your going with a new pump make sure to change your fuel filter .

Might want to relocate it as well

If your any place that sees winter Chemicals getting the fuel pump bracket out and lines disconnected can be real interesting

New pump I would go with Denso

Only a leak in the pressure side of the pump would effect performance fuel leaks most often Invite the local fire company to make sure nothing else catches fire

Reinbag

by new fuel filter I assume you mean new sock filter at the pump? Luckily I'm in Arizona. Reason why these trucks are so expensive out here and impossible to find in junk yards.

wyoming9

iTrader: (1)

No the one bolted to the right side of the block above the starter.

Just where did you check fuel pressure ??

What pressure did you get??

Reinbag

Oh. Yeah. You're right. Might as well. I doubt it was ever changed. (I bought this truck off a lot. It had been sitting for 6-7 years undriven).

Um, I had to have a shop do the fuel pressure test cause I don't have the equipment (never done it myself). They told me the pump was running at like 15psi approx, which is really low if I'm not mistaken. They checked it on the line itself from the pump to the filter. The sending unit looks pretty beat--the bolts are pretty seized--so I ordered a whole unit from toyota direct (I needed to order this special fuel level sensor gasket from them anyway).

Where would I relocate it? Just zip tie it or something to the wheelwell? I have good wrenches, should be able to get the sucker out, although I've never had to on this model truck. Heard it can be a PITA.

Reinbag

Well, went to replace the fuel pump today. Gas tank is rusty as hell, but only on the inside (condensation?) Lots of rust particle in the gas. Guess that explains why the pump died. Erg. I'll need to wait til after the holidays to deal with this one. Guess I'm just going to replace the tank.

Terrys87

iTrader: (1)

14 mpg in city driving with stop and go probably isnt that bad. The 4x4 22re only gets about 19-21 on the highway. In city driving you are maybe getting into 3rd gear for short periods of time. Stop and go kills mileage. Sounds like you did/do have fuel issues but just did not want you thinking you were going to get outstanding mileage in city driving.