Engine Rebuild complete - wont start

[philbrooker]

Good afternoon guys,

2.8 Engine

After rebuilding the engine and refitting it I have had enough !

The engine is timed correctly, has excellent compression, new plugs, coil, roter etc. Engine has a good spark and fuel is getting though, pump working. No visible air leaks either.

The engine will fire up on the key but will not "catch" I can even rev as long as thge starter is still engaged (naughty i know)

Any ideas, I wasted my whole day off messing around with this!

Thanks,
Phil

[mep12345]

philbrooker said:

Good afternoon guys,

2.8 Engine

After rebuilding the engine and refitting it I have had enough !

The engine is timed correctly, has excellent compression, new plugs, coil, roter etc. Engine has a good spark and fuel is getting though, pump working. No visible air leaks either.

The engine will fire up on the key but will not "catch" I can even rev as long as thge starter is still engaged (naughty i know)

Any ideas, I wasted my whole day off messing around with this!

Thanks,
Phil

If it will rev with starter engaged I assume this means the key is at the position 2 on the ignition switch. If so then is the electrical circuit being broken when you allow the key to spring back to position 1 (normal on position) and thereby cutting the circuit that powers the ignition system. Yopur problem certainly sounds ignition related to me.

Would suggest you check the yellow connector as a starter and if ok do continuity checks through the ignition control circuitry.

HTH as arm chair diagnostics is not easy

Mark

[TJC46]

I had the same problem after a full bodyoff, engine out and overhaul etc. Petrol getting thru, spark at the plugs, etc, etc. Driving me crazy......then rechecked the firing order and the leads were in the wrong positions. Remove, replace in the correct order and car started first time. Recheck everything, and good luck. Was the engine a runner before you rebuilt it?

[greymrj]

This may sound daft ut it is worth a check as I had exactly the same problem. Is the revcounter working correctly, if not take it out of circuit. A faulty revcounter was causing the ignition circuit to earth. Talked to another S owner who had had exactly the same issue!

[Barkychoc]

Run a temporary wire from the + on the coil to the + on the battery.
It should then fire up if it is an electrical problem. You may have to remove the wire to make the engine stop.

[Jed-S]

Faulty ballast resistor???

When you're cranking the car over the ballast resistor is bypassed giving the full voltage to the coil but as soon as you stop cranking the coil should draw power through the ballast resistor.

[philbrooker]

Thanks, that was fast!!

The leads are definatly correct, I will try the 12v to the coil tommorow as its too dark now ! I didnt even think about the rev counter.

All the systems were working before strip down.

Thanks so much guys, ill keep you posted !!!

[Gerald-TVR]

greymrj said:

This may sound daft ut it is worth a check as I had exactly the same problem. Is the revcounter working correctly, if not take it out of circuit. A faulty revcounter was causing the ignition circuit to earth. Talked to another S owner who had had exactly the same issue!

Me too

[philbrooker]

Right, after a weekend of not being able to play i have finally got out today, put the key in and it fired straight away. Ran fo about 2 mins, quite well actually then stopped.

Nothing now, turns over and doesnt even try to fire. I dissconnected the Rev counter. Nothing. wont even fire

The weird thing is when i dissconnect all the electrical plugs around the engine it fires but wont hold or run.

I am now thinking the little silver box ?

[Barkychoc]

Have you checked yellow connector under the dash?
Doesn't sound like it is anything serious - just a simple connection problem.
Do you have an immobiliser?

[NTEL]

Probably a stupid question, but did you remember to ground the engine to the chassis? I forgot once and had similar symptoms until I noticed the big black cable dangling in space. Worth a check?

[philbrooker]

I have double earthed the engine, i have been there done that with a beach buggy i did a few years ago. the fabled yellow connector !! Mine is half yellow and half black, seems ok though. My head hurts now !!!!

I just dont see how it can fire then not catch !

[Gerald-TVR]

philbrooker said:

I just dont see how it can fire then not catch !

Try taking a direct feed to the fuel pump, could be loosing power when ing switch goes back to position II

[GreenV8S]

Gerald-TVR said:

Try taking a direct feed to the fuel pump, could be loosing power when ing switch goes back to position II

Yeah, I'd say hotwire the pump, ignition and ECU and see if it'll run like that. Also stick test lamps across all those supplies and see if any of them are dropping out before the engine dies.

[philbrooker]

I will try that, i have about 10 test lamps made up from my TR7/8 escapades, i will let you know how i get on, Iwould have tried tonight but had a wedding meal tasting. As the groom i was expected to go (with clean hands).

[Barkychoc]

GreenV8S said:

Yeah, I'd say hotwire the pump, ignition and ECU and see if it'll run like that. Also stick test lamps across all those supplies and see if any of them are dropping out before the engine dies.

Pete as its a 2.8 S1 with mechanical injection I don't think there's much in the way of ECU - its more just electronic ignition I think.

[GreenV8S]

Barkychoc said:

Pete as its a 2.8 S1 with mechanical injection I don't think there's much in the way of ECU - its more just electronic ignition I think.

That ought to simplify things.

[Le TVR]

philbrooker said:

Right, after a weekend of not being able to play i have finally got out today, put the key in and it fired straight away. Ran fo about 2 mins, quite well actually then stopped.

-The original symptoms were exactly those of faulty ballast resistor (or rather the usual corroded bullet connectors they used)

Nothing now, turns over and doesnt even try to fire. I dissconnected the Rev counter. Nothing. wont even fire

-Dont disconnect the rev counter, the ignition supply comes from it.

The weird thing is when i dissconnect all the electrical plugs around the engine it fires but wont hold or run.

-Which plugs exactly? Can you post pics?

I am now thinking the little silver box ?

-The ignition amplifier (so they told me) was so reliable that it wasn't even stocked as a spare part.
Mine had definitely gone U/S.

[philbrooker]

SUCCESS!!!!!

Finally got her running yesterday.
What can i say ? I know that ignnition sytstem inside out now.

However I have no idea what i did to fix it.

I did everything all you heros suggested though.

Got the exhaust fitted and really pi**ed of the neighbours. Only body work / wiring and interior to go oh nd wheel refurb

Thanks alot guys!!

[Le TVR]

philbrooker said:

Got the exhaust fitted and really pi**ed of the neighbours.

You need to remove it if you really want to p**s them off.

Well done on fixing it but I expect there was a dodgy connection somewhere. Maybe take each connector apart and give it a spray of WD40 etc whilst checking it still works each time. You dont want it re-occuring any time soon.