Chillin014

Hey everyone! new here. The forum looked nice and well organized so I thought I'd join and get some help.

The vehicle is a 2001 Express van. It served as my dad's work van and has countless hours of idle time but the mileage is around 180k. I have, within the last year, tuned the car up with the basic stuff.

Now onto the problem. Out of the blue, the van would not start one morning. You could sit there and crank it until the battery went dead. I could hear the fuel pump pressurizing and checked for spark as well, all was fine. I found an exposed crank position sensor wire, replaced the harness and the sensor and the car started right up. Unfortunately I believe this was only coincidence seeing as how the problem was back the next day I went to start the vehicle.

The only trends I have noticed are that,
-once the vehicle DOES start it USUALLY runs relatively normal. It is as if it either starts and runs fine, or just doesnt start at all.
-Once it has been started once, it starts fine on 2nd and 3rd attempts, etc. This behavior lead me to believe that it was the passlock system restricting the injectors. BUT the security light doesn't come on so I decided not to go ahead with the bypass.

ALSO, contradictory to my "noticed trends" I actually coaxed the van into a rough start after a bunch of cranking and pressing the pedal and it stumbled to life but it WOULD NOT hold its own idle, it would die the second I let off the gas. It never did that before. It revs completely fine however.

So as you can imagine I am very confused as to what the problem is. I am thinking either some faulty sensor or the fuel pump. The fuel pump is a 3rd or 4th replacement.

any help is greatly appreciated!!

where is the easiest location to check for fuel pressure?

suzuki-guy

There should be a shraeder valve somewhere on the fuel rail.

Chillin014

I will try to locate it, thank you. I guess I can get a fuel pressure gauge to check it out in that case then without too much of a hassle.

stewdogg

Is the check engine light on? Do you have a scanner to check some real time data?

To check the fuel pressure:
1-Remove the Engine cover (dog house)
2-Locate the fuel rail that jumps between the injector rails
3-Hook up your pressure tester to the shraeder valve... should be towards the left/passenger side injector rail.
4-Check pressure in preignition (when pump is priming) and while truck is running.

Chillin014

tomorrow I am going to get a pressure tester and check everything out. Unfortunately there are no engine codes so I am blind here. I also unfortunately don't have equipment to monitor anything real-time or otherwise. I assume the van is obd-2?

Chillin014

Alright, that was surprisingly easy to check. Unfortunately the van felt like performing flawlessly today and everything checked out completely normal. It started right up on the first try and all.
Fuel Pressure with car off - pressurized right to 60psi and slowly depressurized a couple psi.
At idle- steady around 55 psi, very quick to respond with opening of the throttle.

Anyone ever heard of an intermittent fuel pump problem? Maybe a faulty regulator? I dont know

Chillin014

I really don't know what to say. The van has been acting flawlessly these past few days so I decided to take it out for a drive. It was a 20 mile trip and I had no issues.

For the longest time the oil pressure gauge always gave very inconsistent readings, the needle would flop all over the place, didn't notice anything weird today, but it never seemed to effect performance before anyway. It got me thinking though, does anyone think this could possibly be a oil pressure switch problem? Or would that cut fuel to the fuel pump?

Also, as far as the MAF goes (this is a common problem in my nissan) if I unplug the sensor will the van run in some sort of safe-mode? I unplugged it while the van was running and it did not shut off. No check engine lights appeared.

stewdogg

Sounds like it could be a short somewhere. I would check the fuel pump wiring/adapters on top of the fuel tank. I have known those to wear through before.
As for the MAF
How long is the vehicle running before you unplug the MAF and how long do you leave it unpluged? The van should idle a little rough when you unplug the MAF.

Chillin014

A short, that sounds like fun. The thing is though, the fuel pump ALWAYS pressurizes completely normal when I go out there to start it, so I'm almost ruling that out as a possibility. But once I drive most of the gas out of it I may drop the tank to take a look because I heard the ground wire was a common issue.

I unplugged the MAF for maybe a minute tops, the car was running before that for about 10 minutes. The engine seemed to stutter right as i unplugged it but then it caught itself and seemed okay. I just wanted to see if the car would run with it unplugged as my other vehicle will and it has saved me from being stranded before.

I wish I had an FSM so I could see the importance of the sensors such as the TPS, and MAP, oil pressure switch etc. Can anyone confirm if the security light would turn on whenever the passlock is engaged?

stewdogg

The security light does come on when the passlock is engaged. I can't remember if it stays solid or flashes though.