Puma Won't Start - Fuel pump Electrical Problem [SOLVED]

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rigsby

New member
Joined
Dec 10, 2008
Messages
67
Guys, I could really do with some help please, I'm having problems getting my Puma started.

There is a weird problem with the fuse box. With the ignition on, if you touch the first relay (for the ECU) you hear the relay click and I think it then restarts the ECU, you hear a whirring sound by the engine (like a priming or resetting of something), it also causes the speedo clock etc to do their reset procedure, this happens anytime I touch this this relay, it even did it as I took the fuse box lid off - this can't be normal? I think there is a fault somewhere in this fuse box, maybe bad connections or damaged wire - I guess I'll have to remove and examine. Anyone with any ideas on this or had anything similar? Is it easy to remove the fuse box??

It started fine on the previous journey but on the way home the engine momentarily cut out for a second or two but came back to life and the rest of the journey was fine. The ignition comes on and I get all the normal lights on the dash, the immobiliser goes off (according to the red LED on the clock), the engine turns over fine (battery is fine) but it does not fire. I can hear the fuel pump prime and have fuel to the injector rail, there is a spark at the plugs. I have changed the TPS, MAF and ICV, I have checked the fuel inertial switch and its okay, I have checked all the fuses and they are fine, I have reseated the earth wires to the body near the front suspension top and by the inertial switch and check for any faulty wires by the transponder too. I have swapped the two relays from my lighting with the fuel pump and ecu positions, they all appear to be working.

I would be hugely grateful for some further ideas to try please.
 
Just an idea because i had a problem like this myself everything worked but the car didnt start for me was an aftermarket alarm i have put in the car and sometimes it didnt unlock properly and didnt let the engine start i hope this idea help if no sorry to bother you :grin:

Update: get the fuses out and tension the connection with a screwdrive CAREFULLY not to touch with its outher put and some WD-40 ! As for the fuse box i think this could help you

https://www.projectpuma.com/viewtopic.php?t=13577
 
Thanks AngelitoGt.

It is the fuse box in the engine bay. I am having a go are removing it and examining it, but not sure how to get it out. Undone the two connectors and removed the screw securing it to bulkhead but the wiring loom seems attached to it at the bottom and wing-side edge of the box. Can't see how to disconnect this. Maybe I don't need to remove it, just want to see if this relay connector is faulty and what I can do to fix it.
 
UPDATE: I was not so sure about my fuel pressure when I tested it further. There was fuel coming out of the pipe with white connector to fuel rail, with pipe disconnected and turning over engine some fuel come out. Also, when turn engine over there is a dribble of fuel out of the Schrader valve, when depressed, on the fuel rail, but not at any great pressure. This should spurt out under high pressure. I have double checked there is a spark, and on the last attempt, it did cough and try to fire on one turn but that was it. Does sound kind of like fuel. I took a plug out and apart from the oil in the plug hole (D'oh), it was dry.

I looked at this a bit further and fuel pump is definitely working. If I apply a direct connection to the inertial switch, it runs the pump. If I remove the relay and apply a direct current to the relay connector pin, it runs the pump. When the pump is running, I am getting pressure at the injector rail (spurts out all over the place from the Schrader valve when pressed). I have swapped out the relays with replacements. With everything back together, if I turn the ignition on, I hear the whirring at the front of the engine, but no pump noise from the rear when it should be priming and if I turn the engine over, there is no pressure at the Schrader valve. So, I had this idea. I removed the fuel pump relay, then while the wife was trying to start the engine, turning it over, I temporarily put a live feed to the relay connector and hey presto the engine started!. Obviously it died as soon as I took the live feed off, but for about 30 seconds, it was running! So, the fact that the engine will run has ruled out loads of things, and has to be to with the switching of power to the fuel pump. I have tried four different relays, so don't think its a faulty relay, and check the fuse. What the hell can it be and what can I test next?
 
Not going to be much help really but sounds as though the fault is between ignition switch and pump relay, but as I have no idea where the wiring goes between the two I can give you no suggestion as what to check next, my auto electrical work tends to be a bit "suck it and see" which is not ideal way to solve your problem.
If someone on here has a wiring diagram that may help you more
 
rigsby said:
[post]363190[/post] What the hell can it be and what can I test next?
Usually, you'd put a multimeter probe on the suspect relay female connectors and see what you get. Here, though, you are likely looking at loose/broken connector and/or associated wiring, so the method is slightly different. - wreck out (remove the cover) a spare relay and put it in position (this simulates normal operation and connection) and directly probe the output where the relay spades changes to wiring inside the relay. You are trying to establish if the problem is on the ignition/switch side of the relay or the power side. Once you know that, you hunt down the perp from the relay back to its source.

A multimeter is essential and so is a wiring diagram for the perp tracing. Either way, it will be a tedious business*. Incidentally, the reduced fuel pump pressure was probably caused by a constant make/break connection of the fault.

Personally, I would also do an OBDII test on the car and see what the ECU thinks of it all, as anything with a computer and sensors can easily seem make a nonsense of conventional troubleshooting logic.

* you could also get lucky and it just needs a squeeze with needle nose pliers on one of the female relay connectors and it's fixed.
 
UPDATE: Guys, I think I have got to the route of the problem. I took the fuel relay out and wired it up externally, that is to say took wires from the connector block to each leg of the relay and turned the engine over. And it started! I have now made some modifications to the fuel relay connector in the fuse box to make a better connection between the relay legs and connector contacts, and it starts fine. Bloody hell, what an arse of a problem. Worth people noting as something to check, if they begin to get intermittent cut-out of the engine and then not able to start.

I had previously done an OBDII test and interestingly there was nothing reported. I had also tried taking the pliers to the relay but it didn't work.

Thanks to everyone who helped with their useful ideas. :)
 

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