#97790, "Car won't fire (fuel related...i think)" Apr-12-06 04:29 PM by xcasbonx
97 Related mods: AFX ECU, crower 2's, ported head.
Well about a week ago the car decided to barely want to start...cranked for awhile and then finally started up. I drove home and parked it for the night. The following day when I woke up to get ready to work the car would not start. It would just keep cranking and cranking.
I did notice however that the fuel pump was not priming when the key was turned to the 'ON' position. No hum/buzz sound whatsoever. Everything else in the car works fine. I checked for power at the pump, and was getting around 12v for about a second when I would turn the key to 'ON'. I checked the test port at the fuel rail and there was no pressure in the rail.
My conclusion at this point was that I had a fuel pump failure, so I picked up a Walbro 255lph since I was planning to turbo the car in the future. I installed that today and everything went smoothly...went to turn the key to 'ON' and once again no priming sound of the pump, no pressure at the fuel rail, and I'm still getting a 12v reading back at the fuel pump.
I'm really stumped on wtf is wrong. I assume all thats left is to check ASD relay, other than that a possibly bad ECU...which I really hope not, because its an AFX ECU. I've never had to check or replace the ASD relay...can someone enlighten me on that matter please? Also any other thoughts or opinion are welcomed. Thanks.
#98141, "RE: Car won't fire found NEW PROBLEM" In response to Reply # 1 Apr-24-06 05:12 AM by xcasbonx
Well I think I've found the culprit finally. It's looking like a faulty ignition key switch. After diagnosing everything related electrically to the fuel pump and relays; everything checking out okay, I decided to mess with the key turning it on and off for a bit.
To my surprise after several attempts the pump kicked on and the car started perfect and ran perfect! However, if you bumped the key from the position it was able to start from, the car would eventually lose fuel pressure and die.
The only thing I can think of it being is a loose wire/connection somewhere inside the steering column thats related with the ignition key switch. Has anyone else ever had this problem or atleast heard of it before? I've never had to take this area of the car apart before, and it would be great if I could get some advice and or some direction.
#98147, "RE: Car won't fire found NEW PROBLEM" In response to Reply # 3
Sounds liek a bad ignition. There isnt much as far as connections that can fail at the column. you can clean the plug that connects to the ignition switch but that prolly isnt it. Ignition switched failing is common with older vehicles. Ther switch can only take so much twisting.
The relays are on the way Cas, keep them for spares.
#98148, "RE: Car won't fire found NEW PROBLEM" In response to Reply # 4
Thanks Terry I appreciate the response. I've got the column apart right now but, I'm having trouble being able to reach in anywhere to take the ignition switch out. The screws that hold it I can't reach to without taking the steering wheel off, so I think thats my next step...and to also start looking for a ignition switch to buy. Man I hope I don't get raped on one of those.
#98337, "RE: problem strikes back" In response to Reply # 5
Well, I tried a new ignition switch and the pump is still not kicking on, no prime, no fuel pressure. Car cranks and cranks.
I jumper'd the fuel pump relay to the battery and the pump kicks on and runs perfect. So I suspect it is not relay. Also the power wire (black/blue stripe) that leads to the connection of the fuel is getting a steady voltage.
I've checked various grounds on the ECU and have an established ground. This is a 97 AF/X ECU, and I'm really hoping its not a bad ECU, however I do not have a spare 97 ECU to swap out and check.
Other than this, I'm stumbled. I was looking forward to driving it up to the Chicago 2GNT meet next weekend, but at this point it's looking like its not gonna make it. HELP!
#98338, "RE: problem strikes back" In response to Reply # 6
Just for the hell of it, replace the relay..i've seen relays go bad and show voltage, but there isnt enough current potential to drive the pump. Verify the ground at the fuel pump connector as well. When you "jumped" the relay and it worked, how did you jump it? Did you go arouund the relay, or did you turn on the relay by suppling ground to the relay coil? I would also verify the ground signal to the fuel pump relay that comes from the ECU. Remember, when you turn the key to on, the ground signal from the ECU only lasts a few seconds to prime the pump, then it shuts down.
13.5 @108 MPH-2.2 60ft(stupid FWD!) S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential fuel injection) My webpage: http://eclipsed4evr.home.comcast.net -1998 Mitsubishi Eclipse RS-T- "Toy" -1992 Plymouth Laser Turbo AWD(SOLD) -2000 Honda CR-V(daily)
#98345, "RE: problem strikes back" In response to Reply # 7
Originally posted by XtremeRS When you "jumped" the relay and it worked, how did you jump it? Did you go arouund the relay, or did you turn on the relay by suppling ground to the relay coil? I would also verify the ground signal to the fuel pump relay that comes from the ECU. Remember, when you turn the key to on, the ground signal from the ECU only lasts a few seconds to prime the pump, then it shuts down.
I pulled out the relay and ran a wire from terminals 2 and 8 off the relay to the battery. Based off the relay inspection picture in the posts above.
Terry has been giving me the same advice and this is what I've came up with so far.
AFAIK on a 97, the white wire/red stripe PIN 74 on the ecu plug harness is the ground signal wire to the fuel pump. With the relay plugged in, I put the + off my multimeter at battery, - to fp ground signal wire(white wire/red stripe) I get 12v on the meter with the key turned off.
With the relay unplugged, using the same connections as above I get no reading on the meter with the key off, or when it is switched to ON.
I don't know exactly what I'm doing, or where the grounds are that I need to be testings. It's quite confusing and I've been learning as I go trying to solve this problem, which is basically a disaster.
#98348, "RE: problem strikes back" In response to Reply # 8
Here are your wire colors and functions for the fuel pump relay:
black/white- switched ignition power 12volts(hot in start and run) white/red- ground signal from ECU to turn on relay
These 2 wires, the black/white and white/red are the relay wires that turn the relay on and off.
red/black - this is the 12volt power feed input to the relay black/blue - this is the power output wire to the fuel pump
The red/black and the black/blue are electrially connected together within the relay when the relay is switched on.
So now, you need to test the relay SOCKET with the relay unplugged.
Turn the key to ON, and put the meters ground on the battery, and the positive lead on the black/white wire. You should get 12 volts.
Also with the key on, meter ground on the battery ground, put the pos meter lead on the red/black wire. You should see 12 volts.
Now put the pos meter lead on battery positive, and the meter ground lead on the white/red. You should see 12 volts when the key is on for approx 2 seconds from key off, to key on, and also during "crank".
The black wire at the fuel pump harness, is the ground wire, and is grounded to the body. Put the meters pos lead on the battery pos, and the meters ground lead on the black wire at the fuel pump harness. You should see 12 volts all the time, regardless of key position.
Hopefully this helps a bit..
13.5 @108 MPH-2.2 60ft(stupid FWD!) S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential fuel injection) My webpage: http://eclipsed4evr.home.comcast.net -1998 Mitsubishi Eclipse RS-T- "Toy" -1992 Plymouth Laser Turbo AWD(SOLD) -2000 Honda CR-V(daily)
#98349, "RE: problem strikes back" In response to Reply # 9
Originally posted by XtremeRS The black wire at the fuel pump harness, is the ground wire, and is grounded to the body. Put the meters pos lead on the battery pos, and the meters ground lead on the black wire at the fuel pump harness. You should see 12 volts all the time, regardless of key position.
Thanks for the walkthru Matt. I will try all the above stated tomorrow after work...it is dark now.
I'm pretty sure my meter's pos lead will not reach all the way to the battery and the neg lead to reach the ground on the pump harness in the backseat.
