r1_pete
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| posted on 13/8/18 at 10:51 AM |
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Rover V8 on ms2 stumble/misfire
I’m running ms2 v3, on a rover 3.5 V8, with Thor injection and coils.
Engine starts, warms up, and ticks over well.
But, accelerating off tickover I’m getting an almighty stumble / misfire.
I’ve changed coils, leads, plugs, checked vr cable routing, earths, all wiring several times.
One thing I have noticed that previous ms installs havent done is the tach needle swings to max when cranking, I’m using the tach out with pull up
resistor.
I’ve tried many many fuel and ignition tweaks, nothing makes any difference to the stumble..
Any ideas where to look next guys??
I just need it running well enough to get to the MOT station, then a proper set up at Bailey....
Edit to add, the only thing I dont have is 25mf supressors on the coils, could that make the difference??
[Edited on 13/8/18 by r1_pete]
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40inches
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| posted on 13/8/18 at 10:54 AM |
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Have you tried it without the pull up resistor Pete?
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r1_pete
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| posted on 13/8/18 at 04:02 PM |
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I’ll give that a try Dave, I put a fuse in so an easy test...
My vr lead runs under the coils, I wonder if I’m getting noise on the sensor causing the missfire??
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40inches
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| posted on 13/8/18 at 04:07 PM |
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I tried the pull up resistor and the tacho didn't work
Never got round to fitting the suppressors, but it works fine without both 
Isn't the VR lead shielded and earthed at the MS end?
[Edited on 13-8-18 by 40inches]
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scudderfish
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| posted on 13/8/18 at 04:20 PM |
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Any resets in the log file?
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r1_pete
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| posted on 13/8/18 at 04:23 PM |
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Yep, the vr is screened.
I think my next move is to try another pair of coils and leads, I just ordered some new leads, and have a few coils..
I’ll try them away from their mounting and the vr lead...
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Agriv8
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| posted on 13/8/18 at 04:36 PM |
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If its ticking over but not revving.
are all you headers getting hot while ticking over ?
are all the plugs a similar colour does it smell running rich.
Have you checked the TDC marker Rover can be 10 Deg out when buit IIRC
Which coils are you running in what combination wasted spark individual ( need more info here )
what advance are you running at tickover and while accelerating have you had a timing light on it and seeing the advance when you hit loud pedal
Plug leads so easy to get wrong ( been their got the tee-shirt )
post back
Regards Agriv8
Running a Rv8 on Vems ( or was 6 years ago when last fired up :-( )
Taller than your average Guy !
Management is like a tree of monkeys. - Those at the top look down and see a tree full of smiling faces. BUT Those at the bottom look up and see a
tree full of a*seholes .............
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r1_pete
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| posted on 13/8/18 at 04:51 PM |
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quote:
Originally posted by scudderfish
Any resets in the log file?
Not seen any, but then again not sure what I’d be looking for, how do they show??
[Edited on 13/8/18 by r1_pete]
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r1_pete
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| posted on 13/8/18 at 05:01 PM |
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quote:
Originally posted by Agriv8
If its ticking over but not revving.
are all you headers getting hot while ticking over ? Yes, all getting hot, will check again from cold in the morning.
are all the plugs a similar colour does it smell running rich, yes they look reasonable, all pretty much the same.
Have you checked the TDC marker Rover can be 10 Deg out when buit IIRC, yes it is almost spot on, I set the pointer correct when I built the
engine.
Which coils are you running in what combination wasted spark individual ( need more info here ) They are the THOR coils, 2 x 2 wasted spark, similar
to the ford 4 cyl coils. Driven directly from the ms, its an extraefi unit from Phil.
what advance are you running at tickover and while accelerating have you had a timing light on it and seeing the advance when you hit loud pedal, I’ve
tried anything between 10 an 20 degrees, yes I can see the marks advance with the light...
Plug leads so easy to get wrong ( been their got the tee-shirt ), I’m sure they’re right, but worth another check.
Wired like this
 
thor coils
post back
Regards Agriv8
Running a Rv8 on Vems ( or was 6 years ago when last fired up :-( )
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scudderfish
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| posted on 13/8/18 at 05:11 PM |
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quote:
Originally posted by r1_pete
quote:
Originally posted by scudderfish
Any resets in the log file?
Not seen any, but then again not sure what I’d be looking for, how do they show??
[Edited on 13/8/18 by r1_pete]
Log the engine doing it with TunerStudio or MSDroid and then send the .msl file to me at dave.g.smith@gmail.com (msq and ini would be good as well)
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rusty nuts
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| posted on 13/8/18 at 05:29 PM |
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Is the engine a known good runner ? its not spitting back through the throttle bodies? I had a P6 years ago that had a worn cam and wasn't
opening the exhaust valves even though it showed good compression .Found the problem after running the engine with one rocker cover off at a time .
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r1_pete
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| posted on 13/8/18 at 07:35 PM |
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quote:
Originally posted by scudderfish
quote:
Originally posted by r1_pete
quote:
Originally posted by scudderfish
Any resets in the log file?
Not seen any, but then again not sure what I’d be looking for, how do they show??
[Edited on 13/8/18 by r1_pete]
Log the engine doing it with TunerStudio or MSDroid and then send the .msl file to me at dave.g.smith@gmail.com (msq and ini would be good as well)
Cheers, I’ll get a fresh set in the morning.
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r1_pete
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| posted on 13/8/18 at 07:36 PM |
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quote:
Originally posted by rusty nuts
Is the engine a known good runner ? its not spitting back through the throttle bodies? I had a P6 years ago that had a worn cam and wasn't
opening the exhaust valves even though it showed good compression .Found the problem after running the engine with one rocker cover off at a time .
Ita all new or re machined mate, cam and follower# are new, shimmed the rocker posts too to to the correct tollerance....
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Agriv8
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| posted on 13/8/18 at 08:47 PM |
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quote:
Originally posted by r1_pete
quote:
Originally posted by Agriv8
If its ticking over but not revving.
are all you headers getting hot while ticking over ? Yes, all getting hot, will check again from cold in the morning.
are all the plugs a similar colour does it smell running rich, yes they look reasonable, all pretty much the same.
Have you checked the TDC marker Rover can be 10 Deg out when buit IIRC, yes it is almost spot on, I set the pointer correct when I built the
engine.
Which coils are you running in what combination wasted spark individual ( need more info here ) They are the THOR coils, 2 x 2 wasted spark, similar
to the ford 4 cyl coils. Driven directly from the ms, its an extraefi unit from Phil.
what advance are you running at tickover and while accelerating have you had a timing light on it and seeing the advance when you hit loud pedal, I’ve
tried anything between 10 an 20 degrees, yes I can see the marks advance with the light...
Plug leads so easy to get wrong ( been their got the tee-shirt ), I’m sure they’re right, but worth another check.
Wired like this
thor coils
post back
Regards Agriv8
Running a Rv8 on Vems ( or was 6 years ago when last fired up :-( )
Ok Pete look like the obvious on the spark side is covered and it's timed up ok.
While ticking over pulling a lead with insulated pliers should change engine note if one does not could indicate an issue but here again a
discoloured plug would also indicate an issue so maybe move on for now
A few further things to cross off good clean 12v seen on coil feeds, injector feeds and ecu at tick over and while reving up ?
So if spark is ok that leaves fuel and air.
Assume ecu is also switching injectors again batch injection or individual ? have you checked fuel-pressure on the back of injecors at tick over and
at revving up ? assuming there is a release / pressure valve that not maintaining correct pressure stuck or incorrect
Fuel pump or in line fuel filter restricting flow not enough to affect tick over but enough when Erving up.
How is fuel pump plumbed in ?
Is your fuel pump driven from ecu / ignition ? Again clean feed and earth
Regards agriv8
Taller than your average Guy !
Management is like a tree of monkeys. - Those at the top look down and see a tree full of smiling faces. BUT Those at the bottom look up and see a
tree full of a*seholes .............
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Agriv8
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| posted on 13/8/18 at 08:57 PM |
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Always found thisuseful for injection and spark
https://goo.gl/images/u1n9Yi
Taller than your average Guy !
Management is like a tree of monkeys. - Those at the top look down and see a tree full of smiling faces. BUT Those at the bottom look up and see a
tree full of a*seholes .............
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r1_pete
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| posted on 13/8/18 at 09:01 PM |
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Its a new cambiere fuel pump, and porsche filter, the pressure is constant at 3 bar tickover, when revved it rises a little then drops back, I have
another regulator, which might be worth trying. I’m sure its something physical, and not in the tune as changes to VE or ignition have next to no
impact.
Should fuel pressure rise as vacuum drops and stay at the higher pressure??
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Agriv8
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| posted on 14/8/18 at 07:30 AM |
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if it has a vacuum pipe on it should rise slightly IIRC but on most after market ECU people tend to go for static pressure as you have more control
over the injector fuelling / timing.
unplug the vac pipe to the pressure reg and see what happens.
does your ecu have a Vacume input on it can you see the value change when you suck on the vac pipe
also assume you have checked TPS takeover (0) 50% 100%
can you fire up some photos of trigger wheel and VR ?
fuel lines injectors ?
Agriv8
Taller than your average Guy !
Management is like a tree of monkeys. - Those at the top look down and see a tree full of smiling faces. BUT Those at the bottom look up and see a
tree full of a*seholes .............
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Agriv8
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| posted on 14/8/18 at 07:30 AM |
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if it has a vacuum pipe on it should rise slightly IIRC but on most after market ECU people tend to go for static pressure as you have more control
over the injector fuelling / timing.
unplug the vac pipe to the pressure reg and see what happens.
does your ecu have a Vacume input on it can you see the value change when you suck on the vac pipe
also assume you have checked TPS takeover (0) 50% 100%
can you fire up some photos of trigger wheel and VR ?
fuel lines injectors ?
Agriv8
Taller than your average Guy !
Management is like a tree of monkeys. - Those at the top look down and see a tree full of smiling faces. BUT Those at the bottom look up and see a
tree full of a*seholes .............
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r1_pete
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| posted on 14/8/18 at 02:43 PM |
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Thanks for all the replies chaps, its really great to get ideas and pointers, I think I have it sussed from a hardware viewpoint.
The Range Rover fuel rail I’m running only has one fuel entry point, and a shrader valve, originally in the RR the pump pressure is controlled by the
ECU, and the schrader valve is to bleed the system after servicing...
I had my pressure feed into a tee, one leg of the tee to the regulator, the other into the fuel rail, in a dead head config.
I’ve done a temporary re pipe, going from the pump into the rail, removed the schrader valve, and piped that into the regulator, so I now have a more
conventional feed rail regulator config.
The stumble off idle is gone, obviously the fuelling is way too rich now I’m getting more pressure at the injectors, but it does seem to pick up off
idle quite smooth now.
One last question, what do people think about 2 or 4 squirts per cycle for these old rover lumps??
Thanks again for all the input, it certainly helped me ...
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Agriv8
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| posted on 14/8/18 at 08:09 PM |
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Result !
Fuel feed should be one end rail regulator at the other one with a pressure gauge is useful for fault finding if you can get one
One squirt or two would depend on engine cam and head spec. I would keep it simple for now but keep it in the bag for engine tunner rolling road. RV8
really struggle to get enough air so no point adding more fuel than tha air will hold so to speak
Drop me a u2u with email and I will send you a v8 doc with lots of usful info and insight.
Have fun Agriv8
Taller than your average Guy !
Management is like a tree of monkeys. - Those at the top look down and see a tree full of smiling faces. BUT Those at the bottom look up and see a
tree full of a*seholes .............
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BaileyPerformance
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| posted on 24/8/18 at 11:21 AM |
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quote:
Originally posted by r1_pete
Thanks for all the replies chaps, its really great to get ideas and pointers, I think I have it sussed from a hardware viewpoint.
The Range Rover fuel rail I’m running only has one fuel entry point, and a shrader valve, originally in the RR the pump pressure is controlled by the
ECU, and the schrader valve is to bleed the system after servicing...
I had my pressure feed into a tee, one leg of the tee to the regulator, the other into the fuel rail, in a dead head config.
I’ve done a temporary re pipe, going from the pump into the rail, removed the schrader valve, and piped that into the regulator, so I now have a more
conventional feed rail regulator config.
The stumble off idle is gone, obviously the fuelling is way too rich now I’m getting more pressure at the injectors, but it does seem to pick up off
idle quite smooth now.
One last question, what do people think about 2 or 4 squirts per cycle for these old rover lumps??
Thanks again for all the input, it certainly helped me ...
Hi, 4 squirts Alternating, injector output 1 wired to all 4 injectors on the left bank, output 2 to right bank.
Msg me if you need anything :-)
Cheers Dale
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r1_pete
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| posted on 24/8/18 at 10:39 PM |
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Thanks Dale, I’m running 4 squirts, and the banks are fed from an injector output each, I can’t be sure which is left or right, doeas that make a
difference? Its a fair stripdown to change them over, but I’ll check.
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