Dreaded miss fire

[S4CJO]

Started a couple of days ago but seemed to clear. Yesterday popped to the shops but at the lights about a mile down the road it was again running lumpy with a strong smell of petrol. Came straight back and into the garage.
This morning all the plugs out on the passenger side cleaned, gap checked and replaced car started ok. Then carried out the same on the drivers side, started but again lumpy.
The car is fitted with a full ACT system, so checked the individual pipes on the drivers side all nicely warm however those on the passenger side all cold.

Know stumped any ideas?......

[bobfather]

Fuel injector cable would be worth a check, that could take a whole bank out

Is the ACT header pre-catted? if so I'd suspect a header blockage

[QBee]

Also could be the fuel rail blocked that side - start it, make sure it is running lumpy as hell, stop it, take out a plug on the dodgy side and see if it is wet.

[Paulprior]

Please keep us updated with any progress, mine did something similar while in town at the weekend, I pulled over, the engine only just managed to tickover, I opened the bonnet to check the temperature of the manifold, as I had no equipment so I just used my hand, my passenger side felt cooler, but then it suddenly started working again so I continued my journey of 50 miles without any more problems.

[S4CJO]

Hi QBee, yes plug on that bank wet. Didnt get time this evening but will check with a new plug that we have a spark.

[S4CJO]

Bobfather, not sure if you can see the header pipes heres and the cats on the down section.

[bobfather]

If they're wet then fuel is getting in, it's sounding like a header blockage, there's no ignition issue that would take out one bank

[Sardonicus]

sounds like a duff 02 sensor for the faulty bank to me where are the 02 sensors situated on those manifolds? I take it your using them seeing as your running cats

[S4CJO]

Sardonicus said:

sounds like a duff 02 sensor for the faulty bank to me where are the 02 sensors situated on those manifolds? I take it your using them seeing as your running cats

The Lambda (O2) sensor in about the same position as the std pipes. See below, did drop the sensor out just to see if it was badly soothed but a first glance looks ok?

[Sardonicus]

Swap the sensors from one bank to another to see if you can recreate the same fault but on the other bank but allow time for the sensor to warm up to see i.e no quick spot diagnostics

[S4CJO]

Well now I'm at that point where I wish I could find something wrong.

Checked the ignition and sparking fine. Having removed the Lambda (co2) sensor to check, replaced and then tried to restart. Guess what, started fine and runs like a dream.........

Will not push the boat out yet, will try a couple of warm up starts during the day to see what happens. At this point I can only surmise that the sensor connector plug may have had a dirty connection?

Thanks all for your assistance, will keep you updated.

One thing I will be doing is changing the oil, the amount of fuel it must have dumped in the cylinders can only have made its way into the sump, up side oil change was due.

[NZ fan]

For what it's worth I have had an almost identical problem to this only mine was going very lean on one bank and dropping cylinders at the idle. Shot term fuel trim was on 100% r/h bank and there was a fault code for r/h lambda probe. I swapped the probe (which was white on the tip from the lean burning) with another out of a mates car and the problem persisted. In the end I put the original probe back in and had a scope on the signal wire ( showing 1.2v max. Fuel removal) so it obviously thought it was rich? With it running like this I removed a vacuum pipe from the plenum to try and make it "switch" which it did immediately dropping to .3v I then replaced the pipe and it carried on switching nicely and the fuel trim slowly came back to oscillating around zero? Like you I'm not convinced the problem wont come back as I don't know what cured it. Strange beasts these TVR,s good luck...Neville.

P.s. The lambda,s only come into play once warm so shouldn't affect things from cold start. ( unless fouled from previous running)

Edited by NZ fan on Wednesday 7th September 13:17

[Paulprior]

Are the Lambda sensors normally as black as that, I thought mine were white when I removed them ?

[bobfather]

Paulprior said:

Are the Lambda sensors normally as black as that, I thought mine were white when I removed them ?

Mine are white too

[S4CJO]

bobfather said:

Mine are white too

Now it's running will give it a fast road run then see what colour the sensor is.