fuel pump not priming - search results

[jesfirth]

I assume you have tried a new relay already?

[Chimp871]

Need to restart thread due to more tests.

Fuel pump won't prime.

Will work with direct 12v feed.
Ecu and fuel pump relays tested and fine (yes, did try a spare pare of relays)
Relay sockets are ok and blue plug shows 12v for 2 or 3 seconds when immobiliser engaged (85/86).
There is 12v across contacts 30/87
Only getting 7 or 8 v to pump live cable at pump (yellow) and the same to the cable in the connector block in passenger b pillar. Not sure why.... Battery is 12.4v
Fuel pump black wire seems to have good continuity when measured against exhaust (0.2)

So ecu seems to be working as both relays are firing, just don't know why I have a voltage drop.

Any way linked to the stty immobiliser?

Edited by Chimp871 on Sunday 22 July 19:04

[Belle427]

Not sure if you have read this but it’s a case of working backwards with a voltage drop.
If it’s a meta immobiliser chimpongas has some excellent bypass instructions to try out.
https://www.pistonheads.com/gassing/topic.asp?h=0&...

[Chimp871]

Cheers, will take a look.

Is the bypass designed to take out the fuel pump relay? Just curious

[Belle427]

Chimp871 said:

Cheers, will take a look.

Is the bypass designed to take out the fuel pump relay? Just curious

No just the switches inside the immobiliser.

[Steve_D]

Pull the fuel relay. There should be permanent +12v at relay base pin 30.
Put a jumper wire from pin 30 to pin 87 (the one that comes out as a black wire). This has eliminated the relay and one stage of the immobiliser.

After the relay base the black wire goes to a connector in the footwell and comes out as a Yellow/Black wire. then the immobiliser, from there as Y/B to the inertia switch. Then comes out as a Yellow wire. I think there may be another connector near the passenger A post. Then down the A post and along the door sill to the connector in the B post. You know the rest.

Steve

Edited by Steve_D on Monday 23 July 08:22

[Belle427]

Dirty corroded connections are favourite.
In this case and if the route is as described then I would run a new wire from fuel pump relay base direct to fuel pump just for test purposes.

[Penelope Stopit]

I will need to delete this post once you have replied

Ok you've got it

• ***DELETED*****

Edited by Penelope Stopit on Tuesday 24th July 19:00

[Steve_D]

Chimp871 said:

........I was scratching my head trying to figure the wiring route and the bible schematic gave only half the info.........

If you have Microsoft Visio I can send you my full wiring diagram. You can then amend it to suit your car or if you don't have Visio I could send it as a PDF.

Steve

[Steve_D]

If you have not done it yet you will need to get the top off the dash as most of the bits you now need to test are in there above the passenger footwell.

Steve

[Chimp871]

Well thanks to all, this weekend job is lined up.

I'll probably do more multimeter tests along the wires to terminal points listed above before cutting wires, but it gives me plenty to go off.

SteveD - I'll message you.
peneloppeatoppit (ever thought of a shorter username ) - please delete your post , I've noted it down, and agree it needs to go. I've deleted my earlier post outlining fuel relay wiring to pump.

Ps - I secretly hope its the immobiliser as I'm down to only the 1 working dongle to disengage the immobiliser and I've not trusted it for a while.

Pps - have already installed the infamous bypass but is currently in 'factory' mode. I suppose changing it to bypass will help determine if immobiliser is at fault.

Edited by Chimp871 on Monday 23 July 22:59

Edited by Chimp871 on Monday 23 July 23:03

Edited by Chimp871 on Monday 23 July 23:06

Edited by Chimp871 on Monday 23 July 23:09

[Chimp871]

Just wanted to get back on what happened but it all works now

After using the multimeter more and more, it was pointing towards to immobilizer after everything checked out ok including the inertia switch.

So I whacked the immobiliser and presto the pump primed but only then for the car to refused to crank. Another whack on the immobiliser and it worked!

So there you go, I know my starter circuitry very well now and am pleased all is well and the problem isolated.

I'm tempted to spend £350 at abacus and get a replacement alarm system (with boot release) or just leave it and see how I get on.

Thanks to all for their input and help.

[Belle427]

It’s only a matter of time before it fails totally so I’d sort it sooner rather than later.
You could identify the immobiliser cuts yourself, at least then you know what to do in the event of a break down.

[Steve_D]

The Abucus will come already modified to overcome TVRs install fail. It will also come with new fobs programmed in. And should come with instructions for the boot release wiring mods.
It should be a very simple install so well worth the money.

Steve

[ou sont les biscuits]

Steve_D said:

The Abucus will come already modified to overcome TVRs install fail. It will also come with new fobs programmed in. And should come with instructions for the boot release wiring mods.
It should be a very simple install so well worth the money.

Steve

It's so simple even I managed it

The Abacus replacement is completely plug and play, with the exception of having to run an extra wire from where the alarm is to the boot release switch, if you want the remote opening facility. And who wouldn't? The TVR original way of opening the boot is completely bonkers.

[Chimp871]

So did get the abacus alarm kit with boot release and 2 keys around 380 to 400 quid.

It is indeed plug and play and colour coded, basically you can't mess up. Boot release is a 5 minute job, you spend more time threading the wire than soldering it.

At first though the car would turn but not start as the fuel pump didn't prime and thought here we go again. Unplugged and replugged the immobiliser to alarm connection and it started up. The instructions do say to do this last....

Anyway, should have done this years ago and works flawlessly. Nice touch being you do get a new siren and all new cables, I only used the siren cable as the old one near the bumper was looking horrible.

[Belle427]

Just out of interest which route did you take with the new siren cable?
I’ve got to run mine soon and it looks as if over the top of the engine is the easiest route, but maybe under the inlet air pipe work would be better.
I may be able to reuse the existing cable depending on how many wires are on the new one but it’s not due until later in week.

[Chimp871]

i spoke to abacus about this and they recommended to put inside the car as it'll crucify the burglars ears and won't destroy neighbour relations.

So using the new cable I kept it under the dash.

[Belle427]

Fair enough, I’d probably silence it anyway if possible as I’m more interested in the locking/immobiliser side of things.