Fuel Trouble please help

[TuRBoTaLooN]

I was driving home tonight and cruising at like 60mph and the car bucked once or twice similar to hitting fuel cut...just not as harsh. I slowed down and then accelerated without any more problems. The car drove fine for the next 5-10 minutes. Then I was driving on a side road going about 30mph in 3rd gear. All of a sudden the rpms drop as if my foot was off the gas pedal. I pushed it down farther with no results. The car eventually died and I pulled over the side of the road. I tried to start the car again and the start motor turned just fine, but there was no combustion. Not even a sputter. I opened the hood and took a look. Throttle cable was securely connected and working. Spark plugs looked fine. There was no fuel, oil, or coolant on the ground or leaking. Oil level was fine. Coolant level was fine. The car did not overheat. It seems like there is just no fuel being sent to the motor. I have a 190 fuel pump that has been re-wired (installed by previous owner) and RC 550's (previous owner). I don't know how many miles on either. Any suggestions? I just want an idea of what to look at tomorrow when I get back from work. Any help is appreciated guys. Thanks ahead of time!

 

[dsm-onster]

Since you have a rewired fuel pump, it might be the added relay used for such a rewire.

Likely, it is the MPI fuse.

 

[Street_Killer]

You could be having ignition problems, did you check to make sure they were getting spark?

 

[absolute_DSM]

Since you think it is fuel : Turn the key from off to on and listen for the pump kicking on.

Further Id check over the connections, make sure the relay the previous owner installed didnt crap out. Check the grounds. Apply 12V to the pump (check wiring diagrams for wire colors) and make sure the pump kicks on.

If it kicks on when you apply 12V, but not when you turn the key, expect the MPI/MFI relay to be bad. (Unless you can hear it click on under the radio)

Theres more you can check but for now stick with the basics. Make sure you have spark, fuel, air coming in, and good compression.

 

[92eagleTSI]

I would check the connections for the fuel pump and make sure they are clean and tightly connected. You can try testing the pump and see if it comes on. I found this in another thread.

My manual CD shows the connector to be in the middle of the fire wall near the top. If your looking under the hood it's just to the right of the battery in front of the passenger side comaprtment coming out of a wiring loom just above what appears to be the cruise control attached to the firewall, but I could be mistaken.

MFI <2.0L ENGINE (TURBO)
AND 2.4L ENGINE> - On-vehicle Service
.,
FUEL PUMP OPERATION CHECK' '-
*ii* ,!
' rn*
1. Check the operation of the fuel pump by connecting the scan
tool to force-drive the fuel pump.2. If the fuel pump will not operate, check by using the'
following procedure. If normal, check the fuel pump drive
circuit.
(1) Turn off the ignition switch.
(2) When the fuel,, pump drive'connector (black) is at-.
tached directly to the battery, *check if the sound of
the fuel pump operation can be heard.
NOTE
As the fuel pump is an in-tank type, the fuel pump
sound is hard to hear, so remove the fuel tank filler
tube cap and check from the tank inlet.
(3) Check the fuel pressure by pinching the fuel hose
with the fingertips.

Good luck!

Try that and make sure the pump is working.

 

[TuRBoTaLooN]

I will check the fuse first as it will be an easy fix. Someone else mentioned that it might be the CAS. Just to put it out there, my 1995 2g does not have a CAS so that eliminates the possibility. But yes I will check the wiring to the fuel pump as well. I didn't check for spark, but that's another thing to look at after work today.

Please let me know if you guys have any other thoughts. Thanks!

 

[dsm-onster]

Since you think it is fuel : Turn the key from off to on and listen for the pump kicking on.

The fuel pump doesnot come on if you simply turn the ignition on. The ECU senses engine turnover then activates the fuel pump. This provides a measure of safety.

And 92eagleTSI is correct in the only means to test the pump to see if it is operating. But also, the ecu may not be receiving the signal from the cas or the MPI relay is not energized during starting. This could be because the:

1. CAS is faulty
2. MPI relay is faulty
3. MPI fuse is faulty
4. Faulty connection from the ignition switch to MPI relay or from CAS to relay
5. Faulty connection from relay to ECU or relay to pump.
6. Faulty ground.

You do have a CAS. It is nonadjustable for ignition timing. But it is there and can fail.

PS . . .I am much more familiar w/ 1G circuitry so double check my info.

 

[TuRBoTaLooN]

well i couldn't check the spark because i didn't have anyone to help me. however, i was able to establish that the fuel pump was not turning on. the pump is re-wired so it has a power wire going from the harness directly to the positive terminal of the battery with a 20A fuse. The fuse is in tact. I used a tester on the power wire with the car in the "on" position and while trying to start the car and there was no power. if this wire goes directly to the battery, it should get power when the car is in the "on" position right?? i literally just checked the power wire itself from the positive terminal on the battery. i checked the whole wire and it's not torn or broken and looks to be in good shape. any suggestions?

 

[dsm-onster]

A rewire job consists of using a relay (not the MPI relay, a non-factory installed relay) to switch on the higher voltage from a thicker wire running to the fuel pump via the weaker voltage from a stock pump power wire. If your fuel pump was rewired properly, then it is probable that this additional "rewire relay" is just bad. Replace w/ a 30 amp relay.

 

[TuRBoTaLooN]

A rewire job consists of using a relay (not the MPI relay, a non-factory installed relay) to switch on the higher voltage from a thicker wire running to the fuel pump via the weaker voltage from a stock pump power wire. If your fuel pump was rewired properly, then it is probable that this additional "rewire relay" is just bad. Replace w/ a 30 amp relay.

so i picked up a new relay for the fuel pump. i wired it up according to vfaq. i connect the battery again and go to start the car. i put the key in the "on" position and the TT comes on as well as the wideband. so i push in the clutch and go to start the car. it goes completely dead. everything turns off and the starter motor does absolutely nothing. i turn the key to the off position and wait a minute or two. then i put it in the "on" position and the lights on the TT go on for like 1 second and the wideband does the same. i'm waiting on some jumper cables to try and jump it. any thoughts??

 

[TuRBoTaLooN]

battery was dead, so i jumped it. then....

no spark. no fuel. i need assistance.

 

[dsm-onster]

Have you double checked the leads off the relay to make sure you have the right wire going to the right terminal? I'd do away w/ the rewire for a while just to remove a variable here and see if it still starts.

Just to get my facts straight. . .

then i put it in the "on" position and the lights on the TT go on for like 1 second and the wideband does the same.

What' happening here? The turbo timer came one for a moment then went off even though the ignition is still on?

You have a short killing the battery. And you have no fuel flow when you DO have power. I'd start looking for ashort in the fuel pump circuitry. . .

 

[TuRBoTaLooN]

Have you double checked the leads off the relay to make sure you have the right wire going to the right terminal? I'd do away w/ the rewire for a while just to remove a variable here and see if it still starts.

Just to get my facts straight. . .
What' happening here? The turbo timer came one for a moment then went off even though the ignition is still on?

You have a short killing the battery. And you have no fuel flow when you DO have power. I'd start looking for ashort in the fuel pump circuitry. . .

yea, the TT comes on for a second and then goes off. would this short be caused by a bad ground? before i put the new relay in, i followed the ground wire. it ran parallel to the 12v fused power wire to the battery and (from what I could tell) the ground wire ran to the positive terminal of the battery as well with another fuse. ?? so when I wired the new relay I made the ground go to the chassis.

and as far as the spark goes....stupid question I'm sure. but, when I went to check the spark, i pulled out the plug from cylinder #4 and put the boot on. had someone try to start the car, i held the plug wire so it didn't fall and arc somewhere. i didn't see a spark, but i felt electricity going through the wire in my hand. any thoughts?

 

[dsm-onster]

yea, the TT comes on for a second and then goes off. would this short be caused by a bad ground? before i put the new relay in, i followed the ground wire. it ran parallel to the 12v fused power wire to the battery and (from what I could tell) the ground wire ran to the positive terminal of the battery as well with another fuse. ?? so when I wired the new relay I made the ground go to the chassis.

and as far as the spark goes....stupid question I'm sure. but, when I went to check the spark, i pulled out the plug from cylinder #4 and put the boot on. had someone try to start the car, i held the plug wire so it didn't fall and arc somewhere. i didn't see a spark, but i felt electricity going through the wire in my hand. any thoughts?

Are the wires oily? You should see an arc to an engine surface. This may be part of your problem. . .

 

[TuRBoTaLooN]

the wires are dirty, not so much oily. i was holding the plug in the air. should i just lay it down on the engine block to see this arc? i feel like this is a dumb question, but i'd rather know.

btw thanks for all the help dsm-onster, much appreciated.

 

[dsm-onster]

the wires are dirty, not so much oily. i was holding the plug in the air. should i just lay it down on the engine block to see this arc? i feel like this is a dumb question, but i'd rather know.

btw thanks for all the help dsm-onster, much appreciated.

if you're the only path to ground and your ignition system is functioning properly then feeling the spark should hurt. atleast scare enough to jump away. Yes, angle the end of the plug wire to the head or block. I pull back the boot to get a short air path to a ground and angle to the driverside motormount.

If you have weak enough spark then you will not start. . . If you do not have spark at all, then your CAS could be bad and you're fuel pump will not pump. Did you ground the fuel pump wire or the ignition timing wire when checking the fuel pump? There are TWO open wires there.

 

[TuRBoTaLooN]

Well I'm going to re-check the spark today. I'm confident there is SOME spark considering I felt a significant amount of electricity run to my hand. I'm also going to undo the fuel pump "re-wire" and just hook the OEM wires back up to make sure the wiring is correct. Then we'll see if she starts and if not, if any CEL codes come up. I will report back.

 

[TuRBoTaLooN]

Ok so it turned out to be a simple fix. It was either a bad wire or the re-wire relay was bad. I disconnected the relay and re-wired the fuel pump back to the OEM harness and the car started right up. As for the battery, the negative clamp was warped so I got a new one...and while I was at it, I just put in a new battery. She runs better than before. I'm still going to put the relay back in eventually. Thanks for all the help though!

Also, quick question if someone can clarify something. Since I plan on re-installing the relay, I'm not 100% sure about the ground wire. I know there is a ground wire in the stock harness. VFAQ says to create a ground to the chassis. Can anyone clarify how to connect these ground wires with the relay? I'm just not 100% on how it's supposed to wire up as vfaq is a little vague.

Again, thanks a lot to all your help!

 

[dsm-onster]

I've looked over the VFaq fuel pump rewire procedures and drew up a circuit diagram that applies to all years (1g, 2g).

You must be logged in to view this image or video.

Hope this helps. Glad to see your problem is solved. And you posted your solution so others can see when researching.

 

[TuRBoTaLooN]

excellent! that diagram is very helpful. but quick question about it. the original ground wire: is it just not used anymore? or do you connect that to the ground wire going to the relay with the chassis ground?

thanks a lot dsm-onster!

 

[dsm-onster]

It is not neccesary when setting up the rewire as in the configuration above. This is also what the 2G rewire VFaq mentions.

Have at it. Boost safely. Don't forget your logger .

 

[TuRBoTaLooN]

It is not neccesary when setting up the rewire as in the configuration above. This is also what the 2G rewire VFaq mentions.

Have at it. Boost safely. Don't forget your logger .

Thanks a lot dsm-onster. I will re-wire the pump this week.

Just to piggy back on this thread...I noticed the battery voltage seems a bit low. At idle/cruising, the voltage (according to my Apexi TT) is 13.0-13.2 volts. Under acceleration (or afterwards rather) the voltage usually drops to the 12.5-12.8 volt range. Which seems pretty low. Could this be due to a bad ground?

 

[dsm-onster]

Hmm, is your belt slipping and you just havn't noticed? The current drawn from an alternator may fluctuate widely. But as you increase your rpms, your alternator voltage should increase instead of decrease.

13.2 is OK at idle. 13.8-14.2 is what I see as I rev up. My alternator is brand new.

Our alternators are internally regulated. So all you can really do is swap alternators if one is acting up. It will probably suffice for now. It may kill a battery over time running the head lights consistantly. . .

 

[Talesin]

yea, the TT comes on for a second and then goes off. would this short be caused by a bad ground? before i put the new relay in, i followed the ground wire. it ran parallel to the 12v fused power wire to the battery and (from what I could tell) the ground wire ran to the positive terminal of the battery as well with another fuse. ?? so when I wired the new relay I made the ground go to the chassis.

and as far as the spark goes....stupid question I'm sure. but, when I went to check the spark, i pulled out the plug from cylinder #4 and put the boot on. had someone try to start the car, i held the plug wire so it didn't fall and arc somewhere. i didn't see a spark, but i felt electricity going through the wire in my hand. any thoughts?

Something is wrong with this line:

the ground wire ran to the positive terminal of the battery as well with another fuse.

Negative is ground. Was that a typo, or just a mis-eye of the wire? At this point I'd say a full re-rewire would be in order.

I'd really be uncomfortable with running a ground fuse, given that the power is coming into an area potentially surrounded by a liquid environment, and chassis ground pretty closeby. Might be paranoia, but I'd be a little nervous about the ground line fuse popping, and having power arc the insulator, and through the fuel.


PS- I've never had an alt that my Apex TT read as putting out more than 13.3v, except the one that failed and overvolted past 15. Isn't 13.7 when the battery starts to off-gas and overcharge/cook? Usually I read about 13v when I first start in the morning, and it'll dip to ~12.5 during normal cruise... sometimes all the way down to 11.8 in heavy traffic.

 

[TuRBoTaLooN]

No, I'm 99% sure the "ground" wire for the fuel pump re-wire ran to the positive terminal of the battery with a 20A fuse. Weird. But yes, I plan on completely re-wiring it. I will rip out the old wires the last owner put in and run a 10 gauge wire to the battery with a fuse and ground it to the chassis and put in a brand new relay.