Pump not priming

[lockhart flawse]

Nice today so thought I'd get the car out of the garage for a check over. But for the first time in 12 years the fuel pump is not priming. Both my clickers operate the door locks OK but they will not prime the pump. I assume I change the fuel relay but is there anything else I should check first?

[jimed]

I understand that sometimes the relays in the immobiliser can stick when the immobiliser is old and has been left unused for a while (IE. When it has been left for some time on an accumate or similar without switching the alarm/immobiliser off) so it is worth checking that the winker by the key slot is not blinking when you try and start. I had this problem and it became not bad but a bit intermittent so had to have a new immobiliser.
Jim

[Loubaruch]

There are numerous connections in the fuel pump circuit, several plug/sockets, a relay and connectors on the fuel pump itself.

If the relay change does not cure it, I would check the connectors on the fuel pump they pick up a lot of crap and are easily corroded.

Once cleaned check that you are getting +12volts at the pump. If not this may help:

http://www.bertram-hill.com/fuel-pump-schematic.ht...

One plug/socket is behind the B post and damp here can cause problems.
Another is in the passenger foot-well, again damp can be troublesome.
The third is behind the dash, but I would try the others first as they are much more accessible.

Best of luck.

[lockhart flawse]

Thanks chaps. I'll check out the connectors this week.

[lockhart flawse]

Had a chance to look at the car today. Things not helped by the fact that my bible has completely disappeared. I have looked at other similar threads and I found one chap whose pump didn't prime but the engine did turn over (his turned out to be the relay in the end). My engine doesn't turn over - ignition comes on as normal but nothing happens when I push the blipper buttons and turning the key to the on position results in nothing. I tried using the emergency "key" for the meta system ( I shoved it in and pulled it out again?) turned on the ignition again but nothing.

Should I be thinking immobiliser rather than the fuel pump as the problem? Car was driven into the garage at the end of October and the battery is well-charged.

[ClassicChimaera]

Sounds like immobiliser to me

On my Chim mine used to sometimes prime the pump but not release the starter motor so no start up. eventually after on off with keys locking and unlocking car etc it would eventually fire. This was usually heat related so I'd just let it all cool down and then it would work again. Then it started to do it even when cold!
Then on other occasions not even the pump would prime. The immobiliser cuts both the pump and starter circuits. When mine was causing even the pump not to prime I gave up and had it sorted by Powers.
It's never done it since

[Colin RedGriff]

Sounds like the immobiliser to me as well.

Dave at HF solutions should be able to help you out.

http://www.hf-solutions.co.uk/

[jimed]

If the immobiliser is on the little red light on the thing you push the immobiliser key (by the ignition key on the steering column) into should be winking. If it is not (and otherwise does) then the immobiliser should be off. One thing to note that I hadn't realised is that the liittle immobiliser key actually connects to the key pad thingy when you push it in so if it has not been used for some time there could be some muck on the key slot so worth giving that a good spray with some electrical cleaner. I had some issues when I had the new immobiliser fitted and that was pretty well sorted by using the cleaner stuff and pushing the little black key thing in and out of the slot a few times. Worth a go rather than just going for a new immobiliser.
Jim

[Loubaruch]

If you are competent with electrics there is an easy test to check the problem actually lies with the immobiliser, you can bypass it.

If you are not happy poking about in the wiring better to get someone who is, as you can damage things quite easily.

[lockhart flawse]

Thanks all. I had never used the emergency key fob thing before until yesterday so I will spray some stuff in as suggested. I have made contact with Dave at HF this morning (and thanks for the suggestion) and he thinks it's likely to be the immobiliser at fault as well. Sigh. I hate faffing around with TVR electrics and the car will probably have to be taken somewhere to be fixed.

[lockhart flawse]

It works!

I had set aside Saturday morning to look at it. I took the glovebox off and got the radio out with the help of two skewers from the kitchen drawer so I could get access the back of the immobiliser. Red plugs connected OK - so no easy fix there. Fiddled with reset button above glovebox. Still nothing. Read lots of old threads on PH.

Next I heaved the battery out. Fiddled with the relays - nothing.

Disconnected battery. Left for 5 minutes. Re-connected the battery and to my amazement the pump primed immediately and then the car started as normal. Great joy. Battery disconnect was my last hope and had been imagining a long recovery somewhere and a large bill so very happy now.

Anyway I've learnt a bit more about the car and will be slightly less concerned about taking the dashboard off for the new veneer next winter. Thanks for the help everyone.

Back on the road 1st May.

[Penelope Stopit]

lockhart flawse said:

It works!

I had set aside Saturday morning to look at it. I took the glovebox off and got the radio out with the help of two skewers from the kitchen drawer so I could get access the back of the immobiliser. Red plugs connected OK - so no easy fix there. Fiddled with reset button above glovebox. Still nothing. Read lots of old threads on PH.

Next I heaved the battery out. Fiddled with the relays - nothing.

Disconnected battery. Left for 5 minutes. Re-connected the battery and to my amazement the pump primed immediately and then the car started as normal. Great joy. Battery disconnect was my last hope and had been imagining a long recovery somewhere and a large bill so very happy now.

Anyway I've learnt a bit more about the car and will be slightly less concerned about taking the dashboard off for the new veneer next winter. Thanks for the help everyone.

Back on the road 1st May.

It may be worth your while to replace the immobiliser or wire a by-pass switch

[Oldred_V8S]

Penelope Stopit said:

lockhart flawse said:

It works!

I had set aside Saturday morning to look at it. I took the glovebox off and got the radio out with the help of two skewers from the kitchen drawer so I could get access the back of the immobiliser. Red plugs connected OK - so no easy fix there. Fiddled with reset button above glovebox. Still nothing. Read lots of old threads on PH.

Next I heaved the battery out. Fiddled with the relays - nothing.

Disconnected battery. Left for 5 minutes. Re-connected the battery and to my amazement the pump primed immediately and then the car started as normal. Great joy. Battery disconnect was my last hope and had been imagining a long recovery somewhere and a large bill so very happy now.

Anyway I've learnt a bit more about the car and will be slightly less concerned about taking the dashboard off for the new veneer next winter. Thanks for the help everyone.

Back on the road 1st May.

It may be worth your while to replace the immobiliser or wire a by-pass switch

I agree. I am a great believer that if something went wrong once it will do it again. I never like when faults appear to fix themselves.

[lockhart flawse]

....prescient words perhaps. Today the car wouldnt start. The battery was in rude health 3 days ago when I put it in the garage, the pump primes but nothing happens when I turn the ignition switch to the 3rd position. No starter motor. Tried using the little FOB thing but that doesn't appear to have any effect on anything.

Are we looking at the immobiliser?

[Loubaruch]

It could well be the immobiliser but worth running a wire straight from the battery to the starter motor to ensure that the starter is OK.
Its not unknown for the starter and starter solenoids to fail

[Loubaruch]

It could well be the immobiliser but worth running a wire straight from the battery to the starter motor to ensure that the starter is OK.
Its not unknown for the starter and starter solenoids to fail

[ChimpOnGas]

lockhart flawse said:

....prescient words perhaps. Today the car wouldnt start. The battery was in rude health 3 days ago when I put it in the garage, the pump primes but nothing happens when I turn the ignition switch to the 3rd position. No starter motor. Tried using the little FOB thing but that doesn't appear to have any effect on anything.

Are we looking at the immobiliser?

The immobiliser is just an interrupter switch on two circuits you control with your IR key fob or by inserting the little dongle in the socket TVR mounted on the steering column shroud.

The two circuits interrupted are:

1. The ECU - The ECU in turn triggers the fuel pump

2. The starter motor solenoid - Connects the high amp feed to the starter motor itself to crank the engine

As we should all know by now TVR wired the Meta system back to front running the low current ECU through the the M36T2 immobiliser's higher rated 25a relay and the higher current starter solenoid through the M36T2's lower rated 10a relay, clearly Meta intended installers to wire it the other way around!

Because of the above the immobiliser problem typically first presents itself as a failure to crank the engine as the little 10a relay has a very hard life having to take current it was never designed for, while the system still runs a live feed to the ECU which in turn triggers the priming pulse (characterised by the audible 3 second fuel pump buzz) the car fails to crank.

However, because of the age of the car and the Meta system it's not uncommon for both circuits to fail or even just the ECU circuit, a Meta security system is after all a collection of late 80's Italian electronics so while TVR made things even worse on our cars with their wiring mistake you do also see the same issues on Alfas, Ferrais and Maseratis form the late 80's through to the mid 90's all of which used the same two paired Meta boxes (alarm & immobiliser).

In summary TVR used a system that's known to give trouble on other cars, they then wired it incorrectly which effectively implanted a reliability time bomb into every Chimaera and Griff they sent out the door, some lasted just a few years and some are only just failing now as proven by the number of immobiliser bypass instructions I'm still sending out every month.

If you need these instructions just PM me and I'll send them by return, my immobiliser bypass can be used on the starter solenoid circuit circuit, the ECU circuit, or both circuits. It is also completely reversible in seconds which allows you to conclusively prove where the problem resides, and in the unlikely event you discover the immobiliser is not your issue you can reinstate everything just as it was.

[lockhart flawse]

I was away for a lot of September and after a bit of fiddling around I got an auto-electrician in yesterday. He found that the 20amp fuse in the Modwise Hot Start kit had blown and after replacement the car started immeditaely. No idea what caused the fuse to blow.

Onwards and upwards.

Thanks to all for your suggestions.

[Penelope Stopit]

lockhart flawse said:

I was away for a lot of September and after a bit of fiddling around I got an auto-electrician in yesterday. He found that the 20amp fuse in the Modwise Hot Start kit had blown and after replacement the car started immeditaely. No idea what caused the fuse to blow.

Onwards and upwards.

Thanks to all for your suggestions.

Perhaps the following will help explain why the fuse blew

That circuit known here as a Modwise Hot Start Kit is laughable, relays have been used for many years by many people to switch power to various components
Someone decided to connect a few wires and fuse-holder to a relay and sell the thing as a kit to make some money

Unfortunately for some TVR owners.......The Modwise kit includes a 20 Amp fuse that the starter motor solenoids current is drawn through
The creator of the Modwise kit did not consider that pre-engaged starter motors have a pull-in circuit and a hold-in circuit and the current drawn by the pull-in circuit does vary depending upon the condition of the solenoid and motor or what make/type of starter motor was being or going to be used

Should your vehicles starter pull-in circuits current draw exceed the Modwise fuse rating the fuse will blow

Also note that the wiring needs to be good otherwise a short on the wiring will blow the fuse

Edited by Penelope Stopit on Wednesday 10th October 11:08

[lockhart flawse]

Thanks Penelope - that's clear. So what is the best once and for all fix - is it to upgrade the power lead/fit a fatter cable to the starter motor?