fuel problem...I think!!!

[jinxy666]

Hi chaps,

Not been on for a while ( kids and their new KTM's.....my car takes a back seat ). Anyway Our SC 3.0 will not start at all now, I cracked open No4 cyl fuel line and on cranking the car over no fuel at all was present ( this was at the connection before the injection nozzle ). So I had the pump off and checked the operation of the pump, all was fine. However I do not know how to check the relay....not sure on the pin operation for voltage in and out. But if the relay is ok, what else could stop fuel from getting to the fuel lines if these items are ok. My fuel gauge reads ok as we put a good few ££££'s in last weekend.

I am stumpped to what the problem may be.

cheers guys for any help.

[sammyg2]

Remove the air cleaner and filter. Turn ignition to the ON position. Reach in and lift the air flow sensor plate. You should hear the fuel pump and injectors spraying and feel a little bit of downward resistance on the plate. If that does not happen, turn the ignition to the off position and start checking fuses and if you don't find a bad fuse check the red relay in the front trunk.
Usually it's the connections so you can carefully spread the pins slightly to get them to make a better tight connection. Relays aren't very expensive, if in doubt replace it or temporarily swap it with another.

[sammyg2]

There is also a switch on the back of the fuel distributor that tells the fuel pump when the air sensor plate is lifted off it's resting place. That may be the problem but that would be rare. I'd check the other stuff first. I've found fuel pump fuses that look good but were cracked and didn't make a connection. Swapping it out with another of the same rating will rule that out or confirm.

[Craig]

+1 on everything sammyg2 said.
I had the same issue, lots of crank, no start.
On checking the fuses with a test light, when I touched the fuel pump fuse, I could hear the pump 'fire' up. Upon further investigation, it turned out the red wire that screws in at the top of the fuse was somewhat corroded. I unscrewed it and clipped it back 1/4 to 1/2 inch, stripped the wire clean and reconnected. Everything was fine after that.

Good Luck!
Craig

[jinxy666]

Just checked all the fuses and relays for the affending item and I have 12v. I can even hear the fuel pump relay clicking when the ignition is turned over but the pump is not. I still have the pump dissconected from the fuel line but have the power connected to it........I am now really at a loss. I do not seem to have power at the pump leads under the car but at the fuse box I have power.

cheers all

[dshepp806]

Did you SWAP the relay with another?


Best,

Doyle

[boyt911sc]

Originally Posted by jinxy666

Just checked all the fuses and relays for the affending item and I have 12v. I can even hear the fuel pump relay clicking when the ignition is turned over but the pump is not. I still have the pump dissconected from the fuel line but have the power connected to it........I am now really at a loss. I do not seem to have power at the pump leads under the car but at the fuse box I have power.

cheers all

jinxy,

Sammy and others gave you very sound advises. But if you want to diagnose your problem, I would suggest you start from the simple and basic investigational procedure. Pull out your fuel pump relay (FPR) and look closely at the backside. There are the five (5) pins or terminals in your FPR:

FPR socket:
terminal #87a ----------power souce to FPR and from the ignition switch @#15.
terminal #87 -----------power source to starter and from #50 (ign. switch).
terminal #86 ---------- bridged to #87a.
terminal #85 ---------- ground connection going to air sensor switch.
terminal #30 ---------- power source to FP, WUR, AAR, and TV.

But before doing all these tests, try to plug a known good working FPR if you have one available. If not, continue the investigation.

Turn the ignition switch to 'ON' position not START. Pull out the FPR.
1). Use a simple test light and check for power at #87a and #86. There should be power.
2). Check #85 for ground, there should be ground at this point. To confirm that the air plate sensor switch is working, try to lift the air plate and the test light will turn off.
3). Check for continuity between terminal #30 to (+) terminal of the FP. There is positive and negative markings on the FP. If the tests all say YES, your ready to test the FPR next.

Plug the FP relay in the FPR socket with a wire hooked up at pin#30 as shown below:





With the ignition switch turn to ON position, lift the air sensor plate:
If the test light will light up, the FPR is GOOD. This is to confirm that you are getting power at terminal #30. Contact me at atd911@hotmail.com if you have any question. Keep us posted.

Tony

[jinxy666]

Thanks for all that Tony. I have just woken up and I am ready for a fresh start with your advice.

I shall report all my findings



jinxy

[jinxy666]

Having just powered up the pump from the batt the car started, so I then put the relay back in and took the power away from the pump via the leads. The car stopped and would not start again whilst the relay was in. I have power at 87a and also power at 30 when the engine is running and then zero volts at 30 when I kill power to the pump......does this explain the fault.
I feel I am almost there as I have had the car running. Could I not make a dashboard fuel pump switch with an inline fuse from the battery + to the #30 pin hole or would this not be advisable or indeed could this harm the car in anyway.

Andy

[boyt911sc]

Andy,

Test results:
(1). You have 12 volts when IS (ignition switch) is ON.......that's normal.
(2). Have you tested #85 from ground? The're should be ground when the car is not running but you have to confirm this. If there is no 'ground @ #85' this is a problem. There is a simple procedure to verify this problem.
(3). Where did you connect the (+) line from the battery? To (+) pole of FP or via #30?

At this point, you are not getting power at #30 due to any of the following:
1). Defective FPR.
2). Defective FPR socket.
3). Defective air sensor switch.
4). Loose connection (ground wiring).

If you could verify the presence or absence of ground @ #85 (socket) is very critical in finding the culprit that causes the anomaly. Keep us posted.

Tony

[jinxy666]

Please give me a good test procedure for ground......is #85 using a continuity test to the neg on the battery a good test or am I in the wrong area......is earth the same as ground?...

[jinxy666]

Tony, I connected the + from the battery to the #30 on the relay holder and away it went!!.

How could I develop a relay holder problem? if this is indeed another fault check.

[jinxy666]

Problem solved...at last. On checking the relay again using pins #85 ( ground ) and #86 ( + ) the relay worked with a 12v feed that I rigged up. On looking further into the electrics I had an idea the immobilizer may be at fault.......and it was. After a bit of re-work the car starts from the relay as it should and all is well again, now I just need to get it off it's axle stands and back on the tarmac for some fun!!!yes.

Moral......never trust your after market ignition immobilizer ( in my case anyway )


Thanks for all your help guys on this fault ( it did make me look further into the world of car electrics........not easy!!! )

[boyt911sc]

Andy,

Nice to hear that you found the problem. Troubleshooting is not that difficult just need some logical analysis and you'll arrive to a better insight of the problem. The happiness and joy you experienced was priceless. Now, drive and enjoy your toy.

Tony

[jinxy666]

Will do Tony......cheers