Misfire

Finally solved misfire on my car.
After changing leads plugs rotor arm cap, both filters, various vacuum piping. David Gentleman’s machine picked up the fault straight away.
Faulty RPM signal. Removed TDC sensor cleaned dirt of it repositioned slightly lower. Solved and thanks to DG, and Simon T for help.
Symptoms were intermittent only apparent on acceleration and lumpy idle.

Point to note,
In the injection manual there is a very good trouble shooting guide/chart.
Worth a look..

I'm experiencing an intermittent misfire which I first thought was down to the recent fuel problem. But since then it's either a bad earth or maybe a TDC problem?

Whereabouts do you find this TDC sensor, front or rear of the engine ?

Hello,
Firstly I would suggest you read the injection fault chart, it’s a free download has loads of areas to check. Then ask DG if you can borrow his kit.
Trust me you want to be sure it’s a botch to remove and refit.
Dave
Ring me if you want further
01962761897
Another good place to check for a fault is the battery with engine running, to check the alternator.
Should be reading 13.5 to 14 volts, manual says after engine warm and above idle speed. If it’s not your fuel pump may not be supplying enough gas.

But in answer to your question, the tdc sensor is located below the air intake pipe and hidden behind the oil return pipe from the turbo about half way down. (Front of engine it is located on the flywheel) If you are serious about removing it I will send you photos of the location. (Courtesy of Simon Taylor)
But seriously use the machine first, as I say it’s a cow to get at and an even worse to refit.
Dave

This is what it looks like, you "may" not have the shield over it.
You also may have the wires in some old rubbery crumberling heat sheathing


It goes here on the gearbox, the 2 bolt holes marked in red. The big bolt hole above holds the box to the engine block and the small one below is 1 of the 3 for the starter motor.

This is the picture that tells a thousand words, summerised by "it's hard to get to".
You have to get your hand down between the exhaust tube and the turbo oil drain tube. It may be easier from under the car, but I think Dave did it from above, with extreme patience and dexterity. He cleaned it up and filed out the retaining holes a touch to allow the sensor to be positioned downwards slightly to be closer to the flywheel.


Have fun and good luck.
On my car, I only had to crack the bolts loose and then they wound out easily, but I did have the engine out of the car at the time.

Thanks for the info.

Last evening I decided to check the earth strap beneath the battery. It was pretty well rusted again, hence I cleaned the strap, bolt and washers up and refitted.

Seem to be ok this morning and , unless it was my imagination, it cranked over slightly quicker than previously. I guess a poor earth there must have a big effect on the overall running of the car.

I'll wait to see if the rough running returns !

It appears the fault is still present.

I’ve check the HT leads and they seem to be ok (ran the engine at night, with open cover and no sparks appeared to be flying around). I’m just wondering if the RPM indicator could in some way effect the running of the engine. I drove this morning and while doing 60PMH the RPM indicator started flickering up & down which in turn made the engine feel a little strange. Although i didn’t lose power and maintained the same speed. So what’s that all about ?

If it was fuelling then I’d expect a drop in power.

Could a dodgy RPM or connections to the same have this effect?

That sounds like the crank pickup to me, so it looks like you will have to take the plunge and check it out!!

Good luck.

If your gauge is moving up and down,
But you are not losing power, would not suggest TDC sensor, more like a faulty circuit!
As I mentioned if the TDC sensor is at fault you will get a missfire which is more noticeable on acceleration.

Following Andrew's (Turbodog) advice I replaced the Renix unit with one I took off the car a while back (long story). Anyway, so far it seems to have sorted the problem out. Fingers, toes, eyes etc etc crossed.

This is an excellent thread, and tagging on to it to save creating another one to be lost in the mush that is this eclectic site... It is related, read on...

Well my issue, actually it's Jon V's car and it has been with me since the RR day as Jon is away... so I'm using it as a guinea pig for a new Renix map. Anyway, Jon's car has a nasty habit of dying on initial throttle opening depending on how you feather it. Snap it off idle and the revs die and can stall if not careful, then picks up and flies. Feather it, and you can get and go with out that issue, but pain in the rear off the lights… will she, won’t she…

new tdc sensor and ignition amp fitted by Jon: http://www.renaultalpineownersclub.com/ ... ight=renix
.. but you could have blimen well bolted it up mate, and no I ain't do'init By the way Jon your speedo is right on, it's not reading high, checked it

CO right on at idle, fuelling correct and "accel pump" action seems about right

TDC sensor is giving an error, and in fact off the X25 diag socket I can't read any good signal! But my PROM emulator is correctly picking up the ignition pulse change so it's there some where but getting lost in Jon's *rapped out wiring... So I may graft my X25 emulator straight into his ecu i/o pins to get a clean line.

Checked the throttle switch operation - low, mid, full and that is there... although I was thinking of adjusting the dead zone at low (idle) load to mid switch point, but would probably not achieve Full at WOT....

So what I'm after, having not spent that much time in a GTA car, and even less driving one, is this response to throttle change off idle normal on standard Renix ecu as fitted to the 2.5ltr turbot??