98 Chimera Random White Smoke

[redgriff500]

Ok, sometimes, now frequently, my 4.0 Chimera is producing LOADS of smoke out the back.

When it does this it isn't running on all cylinders and liquid is seen coming from the exhaust manifold welds (petrol we presume).

It seems that some of the injectors are being fully opened and petrol is going in the oil too.

We have swapped the ECU to no avail so what else could it be ???

It comes and goes but always comes back within 24hrs.

I guess I'm asking what else apart from the ECU causes the inj to hold open ?

[brummiewedge]

White smoke usually means water in the combustion chambers, which could be head gasket or porous liner. Sorry to be doom and gloom!

[tvrforever]

doesn't white smoke mean a new pope? Perhaps it's a pope mobile?

[redgriff500]

No, it's not overheating or using water.

There is DEFINATELY fuel in the oil.

[Cider Andy]

All the injectors have a permanent 12V supply with the ignition on. The ECU switches the negative side of the injectors in two banks, ie. there are two wires returning to the ECU, one from each bank. If one of these has chafed and is earthing it would leave one bank of injectors open. If this was the case, the most likely place to look would be in the engine bay, where everything metal is earthed, there are sharpish edges and things move around and could cause chafing.

Alternatively, one injector may be sticking open. There may be other reasons, eg. fuel pressure too high, but I wouldn't know - someone will be along to say whether or not that could cause these symptoms.

[redgriff500]

Now that sounds like it could well be it.

I'll go and have a good look

Thanks

[redgriff500]

Nearly right !

It was the resistors that had packed up, so holding the injectors open.

Sorted now after 2 days of messing about.

Cheers.

[Griffter]

redgriff500 said:

Nearly right !

It was the resistors that had packed up, so holding the injectors open.

Sorted now after 2 days of messing about.

Cheers.

What resistors? (Not meant to sound as arsey as it does!)

[redgriff500]

My mech. was looking for faults as the inj were being held open.

According to him there are some resistors (I think near the ECU) so that the inj were being held open on one bank.

[Cider Andy]

The only resistor near the ECU is the tune resistor, which needs to be refitted. If removing this has solved the overfuelling problem, it's only masking the real problem. Check the ECU connections for corrosion and dirty contacts as a start.

[redgriff500]

He said they no longer resisted and were letting full 12v through.

He replaced with new and it seems ok (but it was an intermittant problem)

[tahiti450]

Sorry to be awkward but none of this thread is making any sense to me. The complaint was of intermittent white smoke from the exhaust associated with a misfire. Injector/s sticking open could cause a misfire and rich running but not white smoke, and if they all stuck open the engine would stop. There is mention of fluid around the manifold welds..... it is hard to see how any fluid could escape from inside the exhaust on this route - unless the manifold was seriously holed, and if the engine is running any fuel near the manifold would evaporate instantly and would not be seen as liquid (large flame tho possibly! ).
The only time I have ever experienced these symptoms was when on my Rover P6B when a leaking servo was allowing the servo to fill with brake fluid until the engine was able to suck brake fluid down the vacuum pipe directly into the inlet manifold, usually during braking. If there was a master cylinder leak it is conceivable that this could occur on the integrated servo / master cylinder on the TVR.
Other things that cause white smoke are coolant being dumped into the engine (someone raised the specter of block porosity / liner probs)which could come from a variety of sources. Also oil or PAS fluid leaking onto the outside of the exhaust will produce a trail of light coloured smoke.

How do you know that fuel is going into the oil? Is the sump level rising and have you drained some off to examine it? If the engine was over fuelling so seriously that fuel was getting past the rings and into the sump i very much doubt that the car would be drivable at all.

Edited by tahiti450 on Monday 21st August 13:46

[chassis 33]

The other resistor feeding the ECU is the resistor that sits inline from the coil to ECU pin 39, but again I fail to see how this would cause over fueling.

Regards
Iain

[Griffter]

The Bible refers to early RV8s using lower voltage injectors which have a resistor inline. Not supposed to be on Griffs/Chims though (according to the Bible). Interesting.

[marco]

Check the u-shaped hose beneath the power steering pump on the near side of the engine. It sounds unbelievable but if it leaks the oil drips on the manifold join and over night can drip into the exhaust chamber and produce loads of white smoke a few miles after startup that lasts a couple of minutes then dissappears.

I thought my block was knackered until the PH massive correctly diagnosed this on mine. new hose clip and its all good again.


Marco

[redgriff500]

There must be pinholes in the welds, seems fine when running correctly but yes fuel does seep out.

Only wasn't running on one bank of four (was undrivable but ran)

So far it seems cured.