Bit of a stange one missing and back firing

[titch]

Got a bit of a stange problem with the 306, it's a x reg 2001 HDI on 160K stage 1 & de cat.
I reversed out the drive the other day and stopped to chat to my neighbour, the car was idling, i then pulled off and the car popped and back fired out the exhaust ( never heard it do that before ) then for the next mile or so it was missing and stuttering as if it was just about to run out of diesel, i went and stuck 20 quid in just in case as my gauge has never been that reliable, and then it was fine and it has been for 100+ miles.
Then this morning i drove out the drive and on the way down my road it popped again just the once and stuttered once or twice and then it has been fine for the rest of the day ( maybe 30 or so miles), i have noticed that it is a little more smokey than normal when booting it, but nothing else really. No fault codes or management light.

Any ideas or suggestons where to start looking please fellas.

Cheers Titch

[Seb_Ryan]

Maybe abit of air getting in the system?

[Poodle]

It's a pressurised fuel system, air can't get in. I have no idea how it might have back-fired, diesels don't do that lol.

[titch]

It's a pressurised fuel system, air can't get in. I have no idea how it might have back-fired, diesels don't do that lol.

Thats the only way i can describe it, a pop/bang out of the exhaust just like it was backfiring. Its weird. it only does it the once then stutters for a bit as if it is just about to run out of fuel or being starved of fuel. Then it clears but when it is doing it the car is near enough undriveable.

[Toms306]

I have seen an XUD backfire before, so it is possible, don't ask me how though lol...

Do you do a lot of short journeys? Exhaust may be blocking up with soot somewhere?

[titch]

I have seen an XUD backfire before, so it is possible, don't ask me how though lol...

Do you do a lot of short journeys? Exhaust may be blocking up with soot somewhere?

No i do about 600 miles a week mostly motorway and A roads and the exhaust is straight through. I have unplugged the egr vlave solanoid this morning and it seems better.

[Toms306]

Ah ok, not that then!

Seems odd to not bring up the EML or fault codes tbh.

[titch]

I know, i have had the code reader on there, and the scan gauge is always on, and Nothing.

[titch]

Bit of an update, car has been fine for a while then yesterday there was a bit of a judder and that was that, then i popped up to the shop this morning and the car started to judder/ surge as if it was running out of diesel, i pulled over the idle was lumpy as hell then the car cut out.
It restarted but the revs were all over the place from 500 up to 2000 then it cut out again, i tried to pull off to get it home and it was just poppng and banging, i know diesels don't back fire but this was or it was doing a very good impression of a car back firing ( got some funny looks ) no management light at this point.
Then just went for it was only a mile or so to get home, then the management light came one, so pulled over and read the codes and i had:

P0560 system voltage
P0220 throttle pedal position sensor switch B circuit
P0190 fuel rail pressure sensor A circuit
P0120 throttle pedal position sensor switch A circuit
P0403 Exhaust gas recirculation control circit ( this is because i have unplugged the EGR solanoid)

Any ideas??

[Toms306]

Hmm, it sounds f*cked!

EGR you can ignore, as you say you've caused that one.

If both sides of the TPS had failed you wouldn't be able to drive it at all (well, maybe on the clutch for the pedants lol) so I'd guess those are all caused by a loom or earth problem. If your battery and terminals are good, check the main gearbox earth, and then the ones under the ECU on the chassis. That's where I'd start anyway, Poodle might be along to prove me wrong shortly!

[titch]

Yeah it didn't drive very well !

Cleaned up the battery terminals yesterday, and the battery is not that old. This is exactly what the car did when the lift pump went a few years ago ( have done 70k on it now ) apart from it only threw up the one code p0190.
So whipped the fuel filter out yesterday to check just in case and there were a few little filings in the bottom of the housing, no where near as many as last time. Could it be the lift pump again ? If it was why the tps codes.

This might sound a bit stupid, I know the gearbox earth is on the gearbox but whereabouts on the gearbox?

Cheers Titch

[Toms306]

Its right on top of the gearbox, just under the battery tray, its the main battery negative so just follow that.

Could be the lift pump I guess but that's an odd set of codes if it is!

[titch]

I know, just been out and had a look at the gearbox earth, its there and its tight, Is it worth undoing it and cleaning it?
Started the car lift pump primed ok car started fine and ticked over fine, I went round and wiggled all the wiring loom for the fps and tps and nothing changed car ticked over fine no fault codes.

Bit annoying as it will probably be ok for a little while now which will make it a right ball ache to find.

[Toms306]

Hmm...

Not seen a 'dirty' gearbox earth myself so that's probably fine, its the ones on the chassis that can rust. What usually happens with the main earth is the cable frays and is just left hanging on by a few strands lol.

Intermittent faults like this are so annoying! Does it happen to be wet/rainy days when it happens?

[titch]

Not that I can recall to be honest, it is just really random and might be ok for a few hundred miles now, and then will play up again at the worst moment possible

I am so tempted to change the lift pump gsf down the road have one in stock, but don't want to waste that amount of money, but seeing those few filings in the filter bowl yesterday has sort of convinced the little voice in my head :

[Toms306]

Stuff always breaks at the worst possible moment lol. I'm not convinced its the lift pump though tbh, feel free to prove me wrong though!

[titch]

Stuff always breaks at the worst possible moment lol. I'm not convinced its the lift pump though tbh, feel free to prove me wrong though!

I am not 100% convinced which is why I have not gone and bought one yet
Its doing my head in.

[Ruan]

The pops and farts are when they inject at the wrong time or very late in the combustion cycle. Check the cam and crank sensors and wiring etc.

Could also be struggling for fuel, they make quite a bang when they cut out suddenly for some reason, especially if you have a straight through exhaust.

[titch]

Ok will have a look at the sensors, yeah straight through exhaust so the pops and bangs were pretty loud, is the crank sensor easy to get at ?
When you say struggling for fuel, what do you think that could be?

[Toms306]

...is the crank sensor easy to get at ?

Only if you have tiny hands and double joints tbh. Cam sensor is easy though!

[titch]

...is the crank sensor easy to get at ?

Only if you have tiny hands and double joints tbh. Cam sensor is easy though!

That's me out then

[DeeTurbo]

I would say earth fault or your TPS is shorting out causing the voltage to drop.

My. TPS is playing up at the moment, the one I had on the car was losing power very now and again. The used replacement is making the engine sound like it's pinking. Very strange sound but I know it's due to the TPS as that's the only thing that's been changed.

[titch]

I have put another tps on that I got from the scrappy and the car did the same, so cleaned the old one up and put it back on.
I am kind of running out of ideas now, I have checked the gearbox earth, would it be worth checking all the earths?

[Poodle]

Theres something not right with your electricals somewhere, I only ever see that voltage code when theres unexplained shenanigans going on. Any issue with cam and/or crank sensors brings up codes in my experience, so wouldn't expect it to be that. Will be tedious, but i'd suggest going over your loom looking for any wire damage and bad connections. Bear in mind the hdi has a tendency to cut out when the ecu sees something it doesn't like, voltage drops included.

[titch]

I was starting to think it was going to be a random fault, that I will probably never find, what sort of thing would bring up the voltage code ? just done 40 miles in her today and she was great, I don't see how it can be that random if something is broken or damaged .