Ignition Problems - Help!

[tvr_pete]

I've recently bought a TVR Cerbera 2002 4.2.

Loads of problems with misfiring - I've replaced HT leads, coils and ECU... still got problems.

Took it to Jim King autotune and discovered that one coil is not getting a solid pulse from ECU - ECU is fine - same fault on both the new Emerald K3 and original MBE system.

Wiring looks fine - any ideas? I've bought a spare coil and a new ME0159 ignition control unit as a last resort.

[FarmyardPants]

Have you checked the earthing, eg measure resistance between battery -ve, chassis and block. Does that coil have a good earth?

Probably about as much help as Stevie Wonder with a knife (just a stab in the dark) but good luck though.

[HarryW]

Do you know what cylinders are misfiring, it would seriously help you in what you are looking for .

It would appear you have changed everything unit wise and now you are down to wiring. There are numerous block connectors in TVR's I recommend you just pull them apart, check condition of the pins clean up if necessary and put back together.
I assume you know the MBE fires in pairs for each bank independently (inners and outers in pairs)i.e. 1+7, 3+5, 2+8, 4+6 so there is lot of wiring to go wrong between the ECU and the coils. I had a pair of mine misfire once on 3+5 turned out to be the plug wiring on the coil pack pin 2 if I recall.

[GreenV8S]

If you trace the low tension voltage while the engine is running you would be able to tell whether the problem is on the positive side (presumably nominal constant 12v) or the negative side (presumably nominally pulsed between floating and earth). Then you could do a continuity check back through the relevant circuit until you find where the voltage drop is occuring.

[tvr_pete]

I solved the problem - I believed what I was told.

If you have spark and fuel - what's missing? Air...

The guy working on my car must have fallen asleep - the odd bank throttle was not balanced with the even bank so the engine ran fine on the even bank since its hard against the throttle stop.

The odd bank however had its butterflies closed - I noticed this since the intake noise was obvious on the even but quiet on the odd. Also, exhaust on odd was cold = no combustion.

I removed the throttle link, took the injector connectos off the odd bank to purge the excess fuel and then manually opened the odd bank while running on the even bank - immediately I got a solid bang as the old fuel burnt off and I then slowly re-connected the injectors. Its running fine now.

I've bought two Lambdas from Graham Goode and I'm waiting for the Innovate LM2 so I can sort the car out myself - you can't trust anyone it seems...

Thanks for the advice guys. I'll be tuning the car up over the next few weeks on the Emerald K3 ECU - beware the base map - its not very good.