TVR S Series Barn Find. No fuel pump or injectors

[Spacecowboyuk]

Hi all

New to the forum but not new to all things cars. Last year I pulled a TVR out of a barn but not had a huge amount of time to work on her.

Over the last few weeks I've managed to get spark back by replacing the coil and ignition module that sits on side of the dissy. I've also removed all the imboliser and alarm wiring which had itself rubbed into the main loom fraying one particular wire. That's now been fixed.

I have checked continuity across virtually all wires but I just do not seem to be able to get any signal/power to complete at the yellow and brown relays (injector and fuel pump).

The fuel pump runs fine when you squirt 12v into it via a power probe but try as I might nothing will energise the relays.

Any thoughts gratefully recieved.

[Adrian@]

2.8, 2.9, 2.9 catted, V8 is the question. A@

[Spacecowboyuk]

Good point.

It's 2.9 cologne engine. The car is 1989 vintage. As to whether it has a cat that's a good question. I don't believe so.

[phillpot]

More than likely you have a non cat engine. two big air flow meters and no Lambda sensors in exhaust?

Can you read a wiring diagram?

https://www.pistonheads.com/gassing/topic.asp?h=0&...

[Spacecowboyuk]

I have the Steve Heath book and been glued to the wiring diagram. No joy.

Yes two mafs on this one so must be non cat.

I've also spent many hours googling up broncos and old Ford's to try to get ahead of the game but nothing seems to tally. I won't let this beat me!

[Adrian@]

Could this be the yellow column connector issue. (Mike pop a link up to the yellow column thingymabob).A@

[Spacecowboyuk]

I've checked the yellow plug. It does show some signs of overheating and the white wires are a little 'dark' but everything else seems to work- indicators, hazards, lights, wipers, door glass up and down etc which I understand wouldn't if the connector had had it? I have power at the fuse board.

[Mercdriver]

Are you sure you have completely disabled the alarm system? You say you removed it and repaired wires could there be more to it?

[Spacecowboyuk]

Pretty certain yes. I mean, if there are any remnants left it's so incredibly well hidden that I'd have to take the dash apart even more than I already have.

I was given a spare engine loom so I could unstictch it and trace back all the main components in the engine bay to the ecu. I took the diode off that and reinstated it into my brown relay. I have power going to that diode and out the other side albeit it loses a little voltage on the way. Nothing on the larger black wire. Same for both injector and fuel pump relay.

The only wire that has at one time been cut cleanly and is not connected os a green wire coming out the back of the fuse board that corresponds with a green wire coming out of, I believe, some kind of dim dip module. Not sure why this has been cut but the wire coming out the module seems to be carrying power whereas the one in the board does not. Odd?

Edited by Spacecowboyuk on Monday 12th February 08:24

[Mercdriver]

Ah TVR electrics, I remember them well

[phillpot]

Spacecowboyuk said:

I've checked the yellow plug. It does show some signs of overheating and the white wires are a little 'dark' but everything else seems to work- indicators, hazards, lights, wipers, door glass up and down etc which I understand wouldn't if the connector had had it? I have power at the fuse board.

If it's burnt out you will lose all ignition fed circuits, should be good if you have wipers and indicators.

Hazards, windows and sidelights are constant live.

All fuses okay?

I would try putting a live to the injection relay coil or shorting the switching contacts?

Is the Diode okay, not open circuit or round the wrong way?

Edited by phillpot on Sunday 11th February 19:10

[Mercdriver]

All fuses ok said above , good point I would replace all the fuses with new unused ones sometimes they can be damaged if overheated, but still annoyingly work but do not carry the current.

[v8s4me]

Look on the underside of the fuse board to check nothing has burnt out on the back.

Remove the yellow connector and replace with a "choc-bloc" for now.

Try new relays.

Give that a go and see what happens.

Good move getting a spare loom

[Spacecowboyuk]

phillpot said:

Spacecowboyuk said:

I've checked the yellow plug. It does show some signs of overheating and the white wires are a little 'dark' but everything else seems to work- indicators, hazards, lights, wipers, door glass up and down etc which I understand wouldn't if the connector had had it? I have power at the fuse board.

If it's burnt out you will lose all ignition fed circuits, should be good if you have wipers and indicators.

Hazards, windows and sidelights are constant live.

All fuses okay?

I would try putting a live to the injection relay coil or shorting the switching contacts?

Is the Diode okay, not open circuit or round the wrong way?

Edited by phillpot on Sunday 11th February 19:10

The fuses appear to check out ok both visually and with a continuity check but I'll now replace them anyway to take it out the equation.

The diode appears to be operating correctly and I've mounted it the same way round as a photo on PH somewhere. Would it hurt anything if I tried it in reverse?

[Spacecowboyuk]

Mercdriver said:

All fuses ok said above , good point I would replace all the fuses with new unused ones sometimes they can be damaged if overheated, but still annoyingly work but do not carry the current.

Ok will try this this afternoon

[Spacecowboyuk]

v8s4me said:

Look on the underside of the fuse board to check nothing has burnt out on the back.

Remove the yellow connector and replace with a "choc-bloc" for now.

Try new relays.

Give that a go and see what happens.

Good move getting a spare loom

I've looked at the rear of the board and everything looks good. As mentioned the only wire hanging out the back which has been freshly cut sometime before me is the green wire.

I've installed a new yellow relay and a NOS brown relay (both have tested good) with no change.

[Spacecowboyuk]

phillpot said:

I would try putting a live to the injection relay coil or shorting the switching contacts?

Edited by phillpot on Sunday 11th February 19:10

I assume I can use the power probe to do this? Which pins/wires would I be hitting? If I was to short across, again which coloured wires/pins would I be aiming for?

Thanks for everyone's responses so far.

[Mercdriver]

The circuit through the relay is usually moulded into the plastic case. There will be a number moulded into the case too, google that number and you should get the relay circuit giving the PIN numbers which are also moulded into the case. You should be able to work out from that the live feed and earth for operating the relay and also the pins which are energised by operating the relay.

Good luck, TVR electrics are a pain, especially like any GRP car the earths. I had a 2500M and eventually made earth blocks out of copper bar one front one rear and run heavy cables to the battery. Everything was then earthed to the copper blocks using toothed washers and properly crimped terminations using a proper crimp tool, not one of these Micky mouse pliers. Everything worked perfectly, even the radio!

[Spacecowboyuk]

Unfortunately I ran out of light to do the things I wanted to today so these are all tomorrow jobs now.

Incidentally, does anyone know which pin/wire is the live into the ecu?

[Spacecowboyuk]

I'd love to upload some photos but PH has an odd rule that we can only post stuff after 14 days. Same as only being able to post up to 5 messages in the first 24 hrs. Seems a little archaic...