Hi
Got a problem with my 94 VT Diablo.
Left exhaust is not getting hot after running it for approximately 10 minutes.
The heat reading was 53 degrees celcius while the right exhaust was 98 degrees celcius.
To me the obvious was the coil needed replacing but I swapped them over from left to right to see if I needed to purchase a new coil. The problem was still on the left side with the manifold and exhaust not getting hot (like the other side). No problem with coil. So I then checked the coil leads and the spark plug leads. No problems with any of the leads. Next I checked to see if there was spark on the spark plug itself and there was. I then proceeded to swap the computers to see if that may do anything but it didn't.
There is a strong smell of petrol in the left exhaust and every few minutes, it back fires but not really loud. When the car starts, white smoke comes out the left exhaust for a second or two.
Overall, it seems to be getting spark right through to the spark plug, fuel because of the strong smell and air.
Gas is coming out of the left exhaust but not as much as the right.
I have a tubi exhaust on the car and it still has the cats. The right side of the engine controls the right exhaust and the left controls the left exhaust.
Did an ohms test on all the leads and they are less than half the reading of the genuine leads. I have after market leads on the car. Example reading as folllows 1.73 compared to 3.65, 2.06 compared to 5.18 etc. This is the same for all the leads. I don't know whether this is important but it may mean something to someone. The car has ran fine with the after market leads.
Got an error reading on the left side referring to the oxygen sensor rich with fuel. After 5 minutes running, the error message turns off.
Thanks for your help again.

If all you say is true, and you have tested the coils and tested for spark at the spark plugs on the bad bank, I would check the distributer cap and rotor. They have a nasty way of getting gunked up all the time, pull it but leave the wires on, and check for any kind of deposits or cracks, clean or replace, and re-try.

Dear Lamborghinisti,

Bruce, look at the plugs on the offending bank. What condition and color are they?

For comparison, I would look at the plugs on the working bank while I'm there. See if there are any differences between the banks and if there are difference between cyl to cyl.

Let us know what you see.

BTW, the white smoke, does it sting your eyes (fuel ) or is it sweet smelling ( coolant )

Let us know.


Shamile

__________________
Freeze....Miami Vice !

97.5 Lamborghini Diablo VT Roadster
91 Ferrari Testarossa

A Diablo is like a hot tall thin blonde. Sooo seductive, you just keep putting up with her crap. Buying her high-heels or headers, you know she costs you a fortune. But riding her....oh soooo good!

Check dizzy cap & rotor button.

Thanks for the quick response.
The smoke coming out of the exhaust is a strong smell that hurts your eyes.
I have purchased a distributor cap and rotor which should arrive in 48 hours.
The plugs are very fuelly. They are totally different to the side running good.
Will keep you updated.

Please make sure you are getting good quality intense spark coming from each coil! Start the engine and pull each wire from the coil and hold 1/2 inch away from coil, use an insulated tool. There should be gobs of spark, if not you need to check the coil or the modulator on each coil.

OK, the left bank exhaust is cold. The left bank smells "fuelly". Think about it for a moment ..... Smells like fuel is present and accounted for!!!! The exhaust is cold? Hmmmm, that means no combustion temperatures to send out the exhaust from the cylinder. How can that be? No ignition within the cylinder. OR ..... Way too much fuel injected into the cylinder!!!
So how do we inject too much fuel? Either we have six equally faulty injectors (what are the odds?) or the computer is getting eroneous data to act upon. If the left bank o2 sensor is bad and telling the computer you have a very lean condition, then the injectors may be held open long enough to give an overly rich mixture that never burns fully enough to bring up the exhaust temperatures.
Acrid exhaust fumes that burn your eyes are indicative of incomplete combustion processes. The burning comes from acidic irritation due to the acids (sulpheric and hydrochloric) that form during incomplete combustion cycles. These symptoms all point towards an incomplete combustion process that is a result of one or more fuel/ignition problems.
Personally, after all that you have done diagnosing this problem, I would suspect the left bank Bosch injection fuel delivery head if your car is fuel injected. If it is carbueurated, I would suspect too high a fuel delivery pressure to the left side carbs holding the inlet needle off it's seat. Or it could be a myriad of other small problems compounding upon each other.
Cold exhaust (no combustion expelled from the cylinders), "fuelly smell" (too much fuel to air ratio), it all points to an ignition problem or a massive vacuum leak affecting all of the left cylinders.
Good luck!!!

Hi
Replaced coil, distributor cap and rotor. Unfortunately no change.
I am having all the injectors removed and cleaned tomorrow and also will get the oxygen sensors checked.
Does anyone have a wiring diragram for a 94 VT Diablo?
Will keep you updated.

What are the plugs looking like on the bad bank? Are you getting spark all the way down to the spark plugs on the bad bank? You did not say if you were getting any spark from the coils, you just said that they are new...........still sounds like an ignition problem to me, it is obvious you are getting plenty of fuel.

The spark plugs are very fuelly on the bad side. The good side's spark plugs are normal.
There is spark on the bad side to the spark plug. The plugs on each side show the same spark.
Hope this helps a little more.