K Series Cold Running issue - Page 2

mbonwick · 7th June 2020, 17:04

Thankfully I didn't open the filter up, just screwed it back up and fitted the clip.
The FFS episode made no effect on the running issue - just as bad both before & after, so I'm confident it's not the filter.

When I said low pressure, I was thinking more along the lines of "what if the pump is a bit weak?"

T-Cut · 8th June 2020, 09:49

It's very unlikely to be the pump, but I guess everything eventually wears out.

Maybe try reducing the spark gap further? I set mine at 0.7mm.

TC

planenut · 8th June 2020, 12:16

You've probably gone over this but have you tried alternative ignition coils? I would be tempted to replace the inlet manifold gasket and check that wonderful little "jiggle valve" while you've got access to it.

Good luck.

mbonwick · 8th June 2020, 17:17

I've not tried new coils, but they are only a couple of years old, and produce a good strong spark on a spark tester. Plus I'm not seeing any of the more typical signs of failing coils.

IMG gasket is fine - especially being the flat VVC type - and so is jiggle valve.

mbonwick · 11th June 2020, 21:06

So the past two days it has been noticeably more reluctant to start (I took a video yesterday and no, it didn't need any throttle to eventually start) but running OK when warmed up.
Then today driving it felt like it was bogged down and running rich all the time.

I'm thinking it might be best to focus on the starting? And that might be a quick way to an answer.
Have ruled out:
Compression
Plugs/coils/leads
Cam sensor (was swapped for a new one and then back to original)

There can't be many more things 'required' for it to start? The crankshaft sensor springs to mind but that's about it.

T-Cut · 12th June 2020, 09:03

I think I'd take a closer look at the inlet manifold seal. You said earlier that spraying brake cleaner around it failed to indicate any problem. I'm not sure that proves anything really, so in the light of the ongoing symptoms, I'll suggest fitting a new IMG/seal. Get the black/Viton version. I note you've got the VVC version. Is the poor starting coincident with that?

TC

genpk · 12th June 2020, 10:16

maybe have a check of any o2 sensors .
Had a faulty o2 and did all sort of things, ran fine at idle but started missing etc as soon as i put the accelerator down.
A faulty brand new sensor!!

mbonwick · 12th June 2020, 15:06

T-Cut - the VVC manifold doesn't use an elastomer seal, it's a more traditional flat paper type affair.
The cold running problem did start at the same time the VVC manifold was fitted, but then the ported cylinder head also went on that day too, so can't point the finger definitively anywhere. The starting is a more recent development, at first very intermittent but gradually becoming more regular. I have noticed that unless I wait for the fuel pump to time out, there's absolutely no chance of the car starting; it'll just crank and crank. Not sure if that's normal or not?

genpk - a good suggestion, but the O2 sensor has already been changed twice - once for aftermarket, and once for OEM - no difference.

COLVERT · 12th June 2020, 21:20

You say it gets worse if you open the spark plug gap up.

Therefore it has to be spark related.

The voltage increases as the plug gap increases and gets less as the plug gap decreases. This might indicate faulty plug leads that start to break down at the higher voltage and will allow the spark to track through the casing to earth. It can also indicate a break down in the coil windings with an internal break down to earth.---

mbonwick · 13th June 2020, 11:21

Or it could just be that the spark gets drowned more easily at the larger distance.
As it's two different sets of plugs I'm using (Bosch/NGK) I don't think we can directly conclude it's an ignition issue.

If it was spark related, I'd expect to be seeing issues at higher revs/hard acceleration which there just aren't. I also find it hard to imagine that I've got 2 failing coils, especially as they're only 3-4 years old.

12th June 2020, 09:03	#16
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,751 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	I think I'd take a closer look at the inlet manifold seal. You said earlier that spraying brake cleaner around it failed to indicate any problem. I'm not sure that proves anything really, so in the light of the ongoing symptoms, I'll suggest fitting a new IMG/seal. Get the black/Viton version. I note you've got the VVC version. Is the poor starting coincident with that? TC Last edited by T-Cut; 12th June 2020 at 09:05..

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7th June 2020, 17:04	#11
mbonwick Gets stuck in Connoisseur SE 1.8 Auto Saloon Join Date: Jul 2015 Location: Kendal Posts: 633 Thanks: 129 Thanked 176 Times in 147 Posts	Thankfully I didn't open the filter up, just screwed it back up and fitted the clip. The FFS episode made no effect on the running issue - just as bad both before & after, so I'm confident it's not the filter. When I said low pressure, I was thinking more along the lines of "what if the pump is a bit weak?"

8th June 2020, 09:49	#12
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,751 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	It's very unlikely to be the pump, but I guess everything eventually wears out. Maybe try reducing the spark gap further? I set mine at 0.7mm. TC

8th June 2020, 12:16	#13
planenut Regional Secretary Rover 1.8T Tourer Join Date: May 2007 Location: Heathrow Posts: 6,948 Thanks: 1,551 Thanked 2,036 Times in 1,264 Posts	You've probably gone over this but have you tried alternative ignition coils? I would be tempted to replace the inlet manifold gasket and check that wonderful little "jiggle valve" while you've got access to it. Good luck.

8th June 2020, 17:17	#14
mbonwick Gets stuck in Connoisseur SE 1.8 Auto Saloon Join Date: Jul 2015 Location: Kendal Posts: 633 Thanks: 129 Thanked 176 Times in 147 Posts	I've not tried new coils, but they are only a couple of years old, and produce a good strong spark on a spark tester. Plus I'm not seeing any of the more typical signs of failing coils. IMG gasket is fine - especially being the flat VVC type - and so is jiggle valve.

11th June 2020, 21:06	#15
mbonwick Gets stuck in Connoisseur SE 1.8 Auto Saloon Join Date: Jul 2015 Location: Kendal Posts: 633 Thanks: 129 Thanked 176 Times in 147 Posts	So the past two days it has been noticeably more reluctant to start (I took a video yesterday and no, it didn't need any throttle to eventually start) but running OK when warmed up. Then today driving it felt like it was bogged down and running rich all the time. I'm thinking it might be best to focus on the starting? And that might be a quick way to an answer. Have ruled out: Compression Plugs/coils/leads Cam sensor (was swapped for a new one and then back to original) There can't be many more things 'required' for it to start? The crankshaft sensor springs to mind but that's about it.

12th June 2020, 10:16	#17
genpk Posted a thing or two Rover 75 Saloon MGZT Join Date: Jul 2012 Location: Perth, AUSTRALIA Posts: 1,662 Thanks: 3 Thanked 461 Times in 299 Posts	maybe have a check of any o2 sensors . Had a faulty o2 and did all sort of things, ran fine at idle but started missing etc as soon as i put the accelerator down. A faulty brand new sensor!!

12th June 2020, 15:06	#18
mbonwick Gets stuck in Connoisseur SE 1.8 Auto Saloon Join Date: Jul 2015 Location: Kendal Posts: 633 Thanks: 129 Thanked 176 Times in 147 Posts	T-Cut - the VVC manifold doesn't use an elastomer seal, it's a more traditional flat paper type affair. The cold running problem did start at the same time the VVC manifold was fitted, but then the ported cylinder head also went on that day too, so can't point the finger definitively anywhere. The starting is a more recent development, at first very intermittent but gradually becoming more regular. I have noticed that unless I wait for the fuel pump to time out, there's absolutely no chance of the car starting; it'll just crank and crank. Not sure if that's normal or not? genpk - a good suggestion, but the O2 sensor has already been changed twice - once for aftermarket, and once for OEM - no difference.

12th June 2020, 21:20	#19
COLVERT This is my second home R75 Saloon. Join Date: Feb 2009 Location: France/or Devon. Posts: 14,003 Thanks: 3,851 Thanked 2,167 Times in 1,816 Posts	You say it gets worse if you open the spark plug gap up. Therefore it has to be spark related. The voltage increases as the plug gap increases and gets less as the plug gap decreases. This might indicate faulty plug leads that start to break down at the higher voltage and will allow the spark to track through the casing to earth. It can also indicate a break down in the coil windings with an internal break down to earth.---

13th June 2020, 11:21	#20
mbonwick Gets stuck in Connoisseur SE 1.8 Auto Saloon Join Date: Jul 2015 Location: Kendal Posts: 633 Thanks: 129 Thanked 176 Times in 147 Posts	Or it could just be that the spark gets drowned more easily at the larger distance. As it's two different sets of plugs I'm using (Bosch/NGK) I don't think we can directly conclude it's an ignition issue. If it was spark related, I'd expect to be seeing issues at higher revs/hard acceleration which there just aren't. I also find it hard to imagine that I've got 2 failing coils, especially as they're only 3-4 years old.