VTS Engine problem any ideas?

31st March 2007, 21:22

It was running fine, I parked it up and turned the engine off then when I tried to start it again (about 10 minutes later) It sounded like it was running on 2 or 3 cylinders, barley idling (about 500rpm) and backfiring every 5 seconds or so.

I thought that maybe it could be a loose HT lead?
But I took the air intake off and started it up and noticed that when it backfires it seems to come through the exhaust and through the throttle body?
Could this mean some valve damage of a slipped cambelt?
But how as it was running fine 10mins earlier and it seemed to not idle straight away when I started it?

I dont really know where to begin on this one Im really low on cash atm and dont really want to take the head off.
Im going to try and borrow a compression tester tomorrow and test the compression and also test for sparks.

Has anyone got any other ideas of what could be wrong or any other tests I could do to try and work out whats wrong?

Any help will be greatly appreciated and rep will be given

Its a 1998 VTS

31st March 2007, 21:42

Is it still doing it? If so, it might pay to take it to a dealership and get an ECU faults report done. There's lot's of possible causes, so there's probably not that much point discussing it here, get it looked at pronto.

31st March 2007, 21:44

any lights come on

31st March 2007, 22:10

Yeah it’s still doing it I just started it up then… no warning lights are on and it’s sounding really unhealthy.

I don’t know whether it’s going to damage it further by starting it?

I think I’ll probably end up taking it to Citroen on Monday for diagnosis though its undriveable – I had to get a tow home before.

31st March 2007, 22:32

Yer mate could be anything. I wouldnt keep starting it incase you have blown somethin cause it could sieze and cause real damage. Just get it towed to a garage.

31st March 2007, 22:37

is there nothing leaking

i dont think its snapped a cam belt as i dont think it would start

if theres no light on i dunno if it would show up on a machine it might do

dont need to take it to citroen to get it put on a machine most garages have them now anyway as there important for modern cars

1st April 2007, 00:16

Most obvious would be cracked head gasket or bent valves, making it hard to get enough compression to turn over. Check cam timing, then compression, spark and fuel.

1st April 2007, 17:07

Just checked the sparks and they seem ok... don’t think I’ll be able to get hold of this compression tester till tomorrow now and Citroens not open on Sundays!

I really can’t think what it could be… it would make sense it being a bent valve or stuck valve or a cracked head or gasket because of the backfire out the throttle body but then why would it suddenly break while the engines off?

So it would also make sense if it were an electrical fault but what could make it backfire through the throttle body? lol

Think ill get a compression test done first before I pay for a diagnosis

Also when I was testing for sparks a few warning lights came on… will these stay on or will they need to be reset somehow? And could this muck up any diagnosis test?

Also how would I check the cam timing?

Thanks

1st April 2007, 17:15

could be a injector on the fuel rail mate, maybe blocked or buggered all together, could be many things tbh, best thing to do is get a diagnostic test on it

1st April 2007, 20:23

Just done a quick compression test… ill do it again in the morning to confirm and try putting oil down the cylinders to see if piston ring wear is the cause.

1 - 205psi
2 – 195psi
3 – 170psi
4 – 217.5psi

The Haynes states any difference more than 2bar between cylinders indicates a fault… the difference between 3 and 4 is about 3.3bar.

Anyone with any experience know how bad this difference is?

And would this mean it’s defiantly a mechanical fault rather than an electrical one? Because I don’t really want to tow it to a garage and pay for a diagnosis.

Thanks

1st April 2007, 20:29

id say cylinder 3's piston rings are fucked mate, haynes says that more than 2 bars indicates a fault

2nd April 2007, 10:24

It's probably your coil pack mate. It would spit back out through the throttle if it was firing at the wrong time as the spark would be going when the inlet valves are part open. Those compression differences aren't that bad mate and they certainly wouldn't lead to what you are experiencing. The spread on the average is only about 10% which is nothing.

2nd April 2007, 10:34

whats the plug like what come out of number 3

was it like the rest or diff colour or soaked in oil or anything like that

2nd April 2007, 11:09

Just checked the plugs and they all seem to be ok – all very similar
And just got it booked in to Citroen for a test tomorrow morning so will wait and see what they say…

Don’t know if I’m going to be wasting my money though as when I was testing for sparks a few warning lights came on… will this muck up any test?

Gonna try pouring oil down number 3 later on to see if this makes a difference in the compression reading…. maybe this would eliminate a piston ring problem and mean some sort of valve damage?

If it was the coil pack wouldn’t none of the plugs spark or only a few? They all seemed to be sparking

Thanks for the help

2nd April 2007, 13:11

Might also be worth checking the valve timing as it's possible the timing belt has jumped a tooth maybe? With the timing cover off you could check the condition of the belt and how tight it is anyway. Has the belt ever been changed as far as you know?

The sparks may be firing but they could be firing at the wrong time (story of my life lol!)

2nd April 2007, 19:14

id maybe take it somewere else rather then citroen as whatever they do will be very expensive

unless its under warenty of course

2nd April 2007, 23:50

Thanks for the advice! Your right they are expensive!

Im only going to pay £40 for the test as Ive had problems with it cutting out and not running right before and I went to two different garages for a diagnosis and they couldnt pick up any faults. It was only Citroen who could pick them up

And theres a dealership just down the road from me, which is a plus as its getting a tow and the mechanics in there have been really canny and helpful in the past. Ill probably try and do the work myself once I know whats wrong with it.

VTS123 the cambelt was changed 5000miles ago and its been running spot on since then?

Will let you know what the outcome is tomorrow

4th April 2007, 18:28

Just got my car back now after 2 days at Citroen! They have spent hours trying to work out whats wrong! Timing correct no faults on ECU they suspect bent or burnt valves

but would have to take the head off to find out! Dont have a clue how thats happened though!?

Ive never done it before but Ill attempt to dish some rep out to all who helped!
Thanks again and await the next question.

4th April 2007, 20:23

So what's the next step?

4th April 2007, 21:17

All repd apart from Gabbastard said I have to spread some around before I can rep you?

Getting a cheque tomorrow so got to wait until that clears before I can buy anything I aim to take the head off on Friday/Saturday to see how bad it is Im in two minds as with what to do I could take the head to get fixed - that would be the easiest option. But the mechanics at Citroen told me it runs ok on high revs so I drove it back into my drive on high revs and noticed its also making a knocking sound so Im thinking it would probably be best to get a whole new engine!

Got a few prices theres a few low mileage mk2 lumps kicking about £400 delivered so probs end up getting one

Just I think it's going to be a right bastard to fit!...

4th April 2007, 22:56

If you choose to bin your old engine, giz a shout dude, I like having a few spare parts

If its knocking, that a weird one. Im surprised Citroen didnt do a leakdown test to be honest. Only way to tell now is take the head off and strip it down, see if the valves are all bent.

Dunno why you cant rep me LOL