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Author: Subject: Rover V8 on ms2 stumble/misfire
r1_pete

posted on 13/8/18 at 10:51 AM Reply With Quote
Rover V8 on ms2 stumble/misfire

Iím 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 Iím getting an almighty stumble / misfire.

Iíve 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, Iím using the tach out with pull up resistor.

Iíve 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

posted on 13/8/18 at 10:54 AM Reply With Quote
Have you tried it without the pull up resistor Pete?
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r1_pete

posted on 13/8/18 at 04:02 PM Reply With Quote
Iíll give that a try Dave, I put a fuse in so an easy test...

My vr lead runs under the coils, I wonder if Iím getting noise on the sensor causing the missfire??

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40inches

posted on 13/8/18 at 04:07 PM Reply With Quote
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

posted on 13/8/18 at 04:20 PM Reply With Quote
Any resets in the log file?
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r1_pete

posted on 13/8/18 at 04:23 PM Reply With Quote
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..

Iíll try them away from their mounting and the vr lead...

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Agriv8

posted on 13/8/18 at 04:36 PM Reply With Quote
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 :-( )





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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

posted on 13/8/18 at 04:51 PM Reply With Quote
quote:
Originally posted by scudderfish
Any resets in the log file?


Not seen any, but then again not sure what Iíd be looking for, how do they show??

[Edited on 13/8/18 by r1_pete]

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r1_pete

posted on 13/8/18 at 05:01 PM Reply With Quote
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, Iíve 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 ), Iím sure theyíre right, but worth another check.
Wired like this
thor coils
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

posted on 13/8/18 at 05:11 PM Reply With Quote
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 Iíd 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

posted on 13/8/18 at 05:29 PM Reply With Quote
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

posted on 13/8/18 at 07:35 PM Reply With Quote
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 Iíd 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, Iíll get a fresh set in the morning.

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r1_pete

posted on 13/8/18 at 07:36 PM Reply With Quote
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

posted on 13/8/18 at 08:47 PM Reply With Quote
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, Iíve 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 ), Iím sure theyíre right, but worth another check.
Wired like this
thor coils
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

posted on 13/8/18 at 08:57 PM Reply With Quote
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

posted on 13/8/18 at 09:01 PM Reply With Quote
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. Iím 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

posted on 14/8/18 at 07:30 AM Reply With Quote
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

posted on 14/8/18 at 07:30 AM Reply With Quote
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

posted on 14/8/18 at 02:43 PM Reply With Quote
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 Iím 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.

Iíve 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 Iím 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

posted on 14/8/18 at 08:09 PM Reply With Quote
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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