It's back but now misfiring (Was: Won't start)

[robin]

At this point I really would be arranging for a trustworthy garage to come and either start it or collect it.

If it's not water in the plug bores or similar service item then you're looking at doing some more serious work on engine, so who would you normally turn to at that point? For me that would be MMC, but perhaps you have someone more local that does servicing, etc.

Compression test in bore unlikely to reveal anything you can fix, or might show nothing noteworthy if (for example) the timing belt has slipped a few teeth.

Things that need to be checked are:
* timing alignment (remove cam belt cover, rotate engine until timing marks line up, check they're in the right place).
* cylinder/piston condition (requires endoscope).
* live data check from ECU during cranking to see what it sees.

Forgotten original details now, but I assume it has petrol in it ... might be worth a 20L can of fresh fuel tipping in the tank in case it's actually a fuel pump problem (there are some weird failures where below half tank the fuel pump doesn't pick up fuel).

Cheers,
Robin

[sendmyusername]

When you finally find out what it is, you'll have to let us know.
I was thinking it could have been tdc sensor, but if it's sparking definately wont be that (if it even has one)
Need to get myself a rover haynes manual for the engine, so I get familiarise myself with it.

[robin]

It does have a crank position sensor (which is the same sort of thing as a TDC sensor) and on the S1 VVC a cam position sensor too. You can tell the crank position sensor is working if the rev counter climbs slightly during cranking (i.e. you can see 200-300RPM on the rev counter while cranking).

Cheers,
Robin

[tut]

I may have missed something, but do you have AA Membership, and/or P&L, if so use it.

tut

[sendmyusername]

Do we have an answer yet on what this was ?

[puffin]

The timing belt is confirmed as snapped so I'm just waiting for the full £££ worth of damage to decide what to do.

Apparently the VVC mechanism had been leaking oil all over the belt and they think this is the probable cause of the break. Even worse, I was planning the next C service for next month - typical!

[robin]

I have a complete S2 VVC head that will work fine on your S1 - I would need you to pay for it though, but probably cheaper than the repair if the VVC cams are damaged.

Cheers,
Robin

[puffin]

Thanks, Robin.

The garage are quoting a reasonable price for repair so I think I'm going to stick with what I have. Sounds like it's going to be full replacement of the valves and other bits and pieces.

I have an interesting update though - they are now saying that the timing belt snapped because it had been over-tensioned when it was last replaced. I doubt there's anyway to prove negligence 3 years later though

While the head is off - is there anything else that would be worth doing to it at the same time?

[woody]

Thanks, Robin.

The garage are quoting a reasonable price for repair so I think I'm going to stick with what I have. Sounds like it's going to be full replacement of the valves and other bits and pieces.

I have an interesting update though - they are now saying that the timing belt snapped because it had been over-tensioned when it was last replaced. I doubt there's anyway to prove negligence 3 years later though

While the head is off - is there anything else that would be worth doing to it at the same time?

Check the liner heights and fit a PRRT thermostat set-up. No point in just sticking the head back on if the liners aren't correct.

Sorry we never got to the bottom of it when I looked, but really didn't expect a snapped belt.

[robin]

Thanks, Robin.

The garage are quoting a reasonable price for repair so I think I'm going to stick with what I have. Sounds like it's going to be full replacement of the valves and other bits and pieces.

No worries. I don't think that you should not require a complete set of valves - maybe half of them, worst case? If it's inlet valves that have been bent then worth checking that the relevant half cam and VVC eccentric drive mechanism haven't been damaged in the process. There is no performance benefit from swapping an old valve for a new one so really no point changing them unless bust. Also you need to make sure that the valve guides haven't been damaged by the valve stem when the valve was bent - unlikely but worth making sure they at least look before putting in the new valve!

I have an interesting update though - they are now saying that the timing belt snapped because it had been over-tensioned when it was last replaced. I doubt there's anyway to prove negligence 3 years later though

I don't know how they would know that - did they explain? Once the belt is snapped you cannot tell what tension it was at. The position of the tensioner is a function of the belt length (subject to some tolerance) and the amount to which the head has been skimmed/type of head gasket fitted.

While the head is off - is there anything else that would be worth doing to it at the same time?

What woody said!

Cheers,
Robin

[puffin]

I picked up the car from the garage on Tuesday night and drove home from Fife to Glasgow without any issues. On the way to work on Wednesday the misfire detection started flashing then dropped the engine into limp home mode and this repeated itself every time I tried to drive it. Thinking it might be the new HT leads (Magnecor Blue) I today swapped back to the original OEM leads and the car purred at idle and low revs.

However, once it was warm and I started pushing it I noticed that whenever the throttle went above about half way the power delivery became really jerky. I was able to drive for 15 minutes - even with the jerky power delivery - without any misfires detected until I was just about home when the light started to flash. I put the car back in the garage then got out to have a listen and it is definitely misfiring now. I'm going to get it back to the garage as soon as possible but any suggestions from the experts here as to where to start would be good.

With the leads out of the way and the plugs all brand new, google suggest it might be the coil, the injectors, fuel pump or the fuel itself? The car has been sat idle for 6 weeks with under half a tank of fuel in it and it's close to empty now, if that helps. Also the fuel pump sounded much louder than usual after the 90 mins drive home earlier in the week.