Electrical issue SPF GT40

Hi
Odd electrical malfunction; ignition on, fuel pumps on and buzzing, pressing starter button, a "click" and then fuel pumps stops. Indicators etc dead.
Switching everything off, trying again, fuel pumps do not start, etc as above. Scratching my head.

Next day in the garage; ignition on, fuel pumps work, lights, horn, indicators etc all work. Pressing start button, repeat of the above scenario.
???
Any ideas?
Rgds
Lars
 
I assume that there is a relay on that circuit. Might try switching out for a known good one. Do you have a wiring diagram? I've got one, but it's at home. I'll tell ya, mine has had/does have some perplexing electrical issues. I believe some resistors etc were added over the years to combat some of the gremlins.

As there were some changes over the years, what year is your chassis?
 

Chris Kouba

Supporter
Dead battery?
I second this, but assume you've checked that.

Barring that, check for loose terminals on the battery posts. They could be arcing and creating an insulating layer at the point of almost contact causing insufficient current or open circuit.

Or your lead to the starter.

Or your ground(s).
 

Paul Hendrickx

Supporter
Odd electrical malfunction; ignition on, fuel pumps on and buzzing, pressing starter button, a "click" and then fuel pumps stops. Indicators etc dead.
Switching everything off, trying again, fuel pumps do not start, etc as above.
Sorry to cut a little your story... same issue in a rally where I was mechanic on vw golf.... same story from the driver all light on the dash working no start... electrical fault...indeed yes!.. one con rod sat in the starter motor....
check you batterie terminals, the engine to chassis earth strip your battery switch itself
hope you find to quickly recharge your battery completely disconnected from the car, and outside the car...
Paul
 

Brian

Supporter
If you put a little heavier load on the battery like headlights, you can probably find the weak connection with a volt meter. Check drop from chassis to battery post and check voltages at post and various connections along the way. I have seen when the wire corrods internally at the battery terminal and giving the same response. It'll carry light loads just fine, but when you throw it the beans like a starter, it goes open.
 
Thanks for all ideas. Battery is not dead, well at least it has enough power to support high beam lights in a good way. And if it was dead it would hardly function day 2 with head lights etc. Will check battery terminals. And starter terminals. Plus charge the battery anyhow. There is no relay feeding the solenoid on the starter, it goes direct from the ignition key. I have a wiring diagram. My chassis no is 2208.
 
Had a similar type of problem with a car of mine, a C7 Corvette, took it to a dealer and had the battery checked. I was told that the battery checked out fine. Next week the same problem. Took it back to the dealer and insisted they check it again. Lo and behold they discovered that it had a bad cell. It was replaced under warranty, it was less than a year old. Problem solved.
 

Ian Anderson

Lifetime Supporter
Supporter
Do you have a battery isolator switch?
Something like this https://www.halfords.com/motoring/tools/garage-equipment/battery-chargers/halfords-battery-isolator-switch-hef390-869552.html?istCompanyId=b8708c57-7a02-4cf6-b2c0-dc36b54a327e&istFeedId=367c5610-f937-4c81-8609-f84582324cd6&istItemId=xxrwwq&istBid=t&_$ja=tsid:|cid:17363835999|agid:|tid:|crid:|nw:x|rnd:96393888526223836|dvc:c|adp:|mt:|loc:9046893&gclid=EAIaIQobChMIyeaM-r-r-QIVYo9oCR0atgDREAQYBCABEgIlI_D_BwE

if so try cutting a circle of Manila card and dropping it in the switch under the key to add more pressure on the spring contacts.

I had a very similar problem on my DAX and it was the switch that caused the problem. My fix was a new cardboard disc each year as the old one wore out!

Ian
 

Davidmgbv8

Supporter
concur bad cell, secondly bad ground, third bad ground to relay or bad relay that is powering the majority of the harness
 
Pardon my ignorance, but who, or what is Blas? Since SPFs are “finished” by a number of companies/individuals, am I correct in assuming that the wiring can have some variations?
 
Pardon my ignorance, but who, or what is Blas? Since SPFs are “finished” by a number of companies/individuals, am I correct in assuming that the wiring can have some variations?
"Blas" is Blas Costagli who makes the wire diagrams in conjunction with Hi-tech, the factory. The wiring is factory supplied, installer only modify or change if needed for a particular build (EFI, etc.)
 
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