vanderwiel

Hey guys, still struggling with what has turned into a nightmare ever since I bought it...

1994 4runner, 3vze, 5 speed manual.

I recently had a head gasket job done along with timing belt. When I got it back from the mechanic, it ran great. I put about 100 miles on it before deciding it was reliable enough to take up to the mountain to go snowboarding. After about 2.5 hours of continous driving, I reached the mountain, which in order to get to requires a good 5 minutes of driving up a steep incline, so obviously it created a tremendous load for the motor. About 3/4 of the way up it started to lose power and really struggled to reach the top.

It began running very poorly, when I would get on the gas it would stumble and hesitate, but if I managed to get it above 3k rpm, it seemed to be running ok.

After this I brought it back to the guy that did the head job.

Since then I've had replaced:

Fuel filter (new)
Catalytic converter (old one apparently was plugged)
vafm from my parts truck
fuel pressure regulator from my parts truck..
new plugs and wires - plugs are getting burnt up the way it is running now - because too rich?

It is throwing code 31, which is for the vafm..

I unplugged the 02 sensor before the cat and it runs the exact same..

one thing I noticed is if I pinch off the line on the fuel pressure regulator, It runs quite a bit better, I was actually able to get it to 70 mph like this.. whereas earlier I had a hard time getting to 50 mph let alone 30 if i had to deal with a hill at all...

SO I am led to believe something is telling the motor it needs more fuel then it does?

guy at the garage who ran it on the computer said it is running too rich..

02 sensor? perhaps the vafm I swapped is bad as well?

I have limited knowledge, though I have a copy of the fsm on my computer.. just wondering where I should go next.. i can try the 02 sensor from my other 4runner... perhaps that is it.. could the fact I had a plugged cat cause the 02 sensor to go bad? and would the consequently throw a code 31?

any help is much much appreciated...

worshipmentor

iTrader: (3)

Just a thought: the code could be old, have you reset the computersince making the above mentiioned changes?

oldblue

so when you pinch off the vacuum line to the fuel pressure regulator, it runs better? removing vacuum will cause an increase in fuel pressure resulting in a richer condition. if this helps during acceleration, it sounds like the truck is starving for fuel. i'd say hook up a fuel pressure test gauge (if you know someone that has a kit for this) and see what the pressures look like.

vanderwiel

I cleared the code, after running for a minute or so it threw code 31 again



I am pinching off the return line from the pressure regulator and it makes it run better.

vanderwiel

ipski