Arctic M7 EFI -05 Only gets to 5500 rpm.

[Myzkoo]

Hi there buddies. Calling this one to the experts. Can't seem to figure this one out by myself. Max rpm is 5500. Fail safe mode? No trouble codes.

Bought this sled as a little project as it didn't run as it should and the previous owner didn't have time to go over it.
Sled is a 2005 M7 EFI with brand new top end. Piston, cylinders, rings, gaskets etc. I did the top end 2 weeks ago but the problem didn't go away (didn't think so either but one piston was a little scuffed and the nicasil did have some flaws so it was more or less needed anyways)

Things i've done so far:

New rewinded stator - made no difference at all.
New spark plugs BR9EYA.
Ignition coil from a known running sled.
APV-servo from a known running sled.
Tested my ECU in a F7 -05 revved all the way to red line.
Scoped the TPS with osciloscope - OK
New cylinders.
New pistons.
New rings.
Checked reedvalves - like new.
Intake boots - like new.
Checked airtube from ECU - like new.
Ohmed water temp sensor on different temps - OK
Ohmed air temp sensor on different temps - OK
Checked groundings.
Put a fuel pressure gauge on - steady 42psi.
Disconnected everything on handlebars.
Disconnected tail light.
Ohmed the rewinded stator with results in pic below:

Looks OK except for the charge coils wich is a little low? This was done in indoor room temperature.
Ignition Timing Sensor ohms at 98,1 but i've read there's two types of sensors so this one should be ok.

How the sled runs without the belt on, primary clutch spinning freely
http://www.youtube.com/watch?v=jQzwxgkGTZU

TIPS APPRECIATED!

 

[Myzkoo]

TPS signal through the scope:
https://www.youtube.com/watch?v=Yu8HFEQ__vA

Charge Coil 1 - looks a little wierd/messy?
https://www.youtube.com/watch?v=klzwJaARQCk

Charge Coil 2 - looks ok?
https://www.youtube.com/watch?v=H4kQiYzp5Ao

 

[sunbather1969]

pv cables

I bet

 

[Phizzer]

Max RPM is 5500?? Is it a smooth 5500 or a cutting in and out 5500 and thats all she's got?? Is it stock clutching?? That second video of the charge coil on the o-scope doesn't look right when the scale is set to 2.5 microseconds. Maybe under load and at that RPM you are losing your spark.

 

[rabbi87]

Check and see if your power valves are moving freely if 1 sticks your servo motor will kick it into limp mode

 

[Rixster]

Did you happen to check the crank? could be WAY out of phase. Something is seriously wrong, that thing sound horrible.

 

[snosurfer]

Did it run that way before you changed your stater? Check your key way on your flywheel make sure it's not misaligned or a sheared keyway. My flywheel bolt loosened up and allowed my key to shift a few degrees by smashing it sideway it ran just like that till a discovered the problem just one more thing to look at.Also check your plug wires and make sure one is not broken it sounds like its running on one cylinder.

 

[Myzkoo]

I bet

PV cables is fine. As the cylinders were replated they got 100% clean inside were the valve slides.

Max RPM is 5500?? Is it a smooth 5500 or a cutting in and out 5500 and thats all she's got?? Is it stock clutching?? That second video of the charge coil on the o-scope doesn't look right when the scale is set to 2.5 microseconds. Maybe under load and at that RPM you are losing your spark.

As you can see in the video it's like it cuts out at 5500 rpm. Stock clutching, but the belt is off so clutches should'nt affect at all. Well thats what i think too, feels like the spark goes away when i reach 5000 rpm. It spits out pretty much gas through the Y-pipe too, the underside of the hood is all sticky and oily. I've ordered two new probes to the osciliscope so i will be able to look at the secondary side of the ignition coil (will not fix my problem though).

Check and see if your power valves are moving freely if 1 sticks your servo motor will kick it into limp mode

They are fine. Thing is I don't even reach 7200 rpm wich is the opening rpm on my machine.

Did you happen to check the crank? could be WAY out of phase. Something is seriously wrong, that thing sound horrible.

Well i did check that when i put the new pistons and cylinders on. Piston "changes direction" at the very exact same time. Should be ok. Yes it does sound horrible.

 

[Myzkoo]

Did it run that way before you changed your stater? Check your key way on your flywheel make sure it's not misaligned or a sheared keyway. My flywheel bolt loosened up and allowed my key to shift a few degrees by smashing it sideway it ran just like that till a discovered the problem just one more thing to look at.Also check your plug wires and make sure one is not broken it sounds like its running on one cylinder.

Yes it did run exactly like this before i changed stator and rebuilt top end. Both key and keyway looked fine when i put the new stator on. It does run on both cylinders. Ive tried to unplug one spark plug at a time and its kinda big difference when only one cylinder is firing. Ive put on another igntion coil with belonging wires and caps, didnt make any difference. Will have a look at the timing with a strobe light tonight. Manual states it should be 16 degrees @ 4000 rpm.

 

[RACINSTATION]

Who rewound stator? It may just be my blurry vision, but it looks like most of your stator test values are off. If I saw these values I would replace the stator. You need a tps test tool to check tps and insure proper throttle angle values. I would also check the voltage regulator.

 

[Myzkoo]

Who rewound stator? It may just be my blurry vision, but it looks like most of your stator test values are off. If I saw these values I would replace the stator. You need a tps test tool to check tps and insure proper throttle angle values. I would also check the voltage regulator.

I bought it from a company here in Sweden (www.skoterdelen.com). Its a replacement stator from what i've been told. But i doubt they are tested.

I actually built a TPS tester myself with a voltage regulator (MC7805 from ON Semiconductor) wich is fed with a 9V battery and puts out 5V. This way i can "run" the TPS with the connector disconnected from the harness. TPS looks as good as it can be to be. 0,688V with the throttle at idle position and rises steady up to 3,688V on WOT. TPS is just a potentiometer.

I would be very happy if someone with access to a osciloscope could hook it up and check their charge coils through the grey connector that comes up from the stator, and compare what they see to my videos. All 2005-2006 700/600 EFI uses the same stator. That would be very interesting!

I've checked the voltagereg too thats located under the APV-servo. Works like a charm.

 

[007]

Try swapping your ecu with another.


KJP

 

[Myzkoo]

Try swapping your ecu with another.


KJP

Ive put my ecu in another F7 and that sled ripped with my ecu.

 

[Rixster]

Who rewound stator? It may just be my blurry vision, but it looks like most of your stator test values are off. If I saw these values I would replace the stator. You need a tps test tool to check tps and insure proper throttle angle values. I would also check the voltage regulator.

I thought the same thing, it looks to me like your stator is out of spec on almost every test.

 

[007]

then its your stator.

KJP

 

[89sandman]

i'd put a belt on it run it while applying partial brake to load the engine and see what happens.

 

[Myzkoo]

I'll go and put a ground wire between the engine and chassis frame tonight as i cant find a ground wire that goes over to the engine from the harness.

If nothing happens i will pull stator out again and have a look at that.

 

[Rixster]

The ground is in the mag side, under the coolant bottle on the inside of the bulk head. hooked to the top bolt on the bottom of your steering post support bracket. Its a single brown wire. The bolt goes through a threaded insert and there should be a jamb nut on the back of that holding the ground wire on. A missing ground will cook a stator in no time.

 

[Myzkoo]

The ground is in the mag side, under the coolant bottle on the inside of the bulk head. hooked to the top bolt on the bottom of your steering post support bracket. Its a single brown wire. The bolt goes through a threaded insert and there should be a jamb nut on the back of that holding the ground wire on. A missing ground will cook a stator in no time.

Yes im aware of that grounding point, that was one of the first things i did check

However, i put a extra ground wire from the recoil to the chassis but that made no difference at all. Then i proceeded with the timing gun and @ idle it seems to be like 16-18 degrees BTDC. When i squeeze it up to 4300 rpm it advances to 12 degrees BTDC (like the manual states it should be) then if i continue to give it more throttle it retards back to 16-18 degrees and if i floor it and let go off the throttel it retards to 24-26 degrees BTDC. I guess this is normal?

I did unplug the TPS too just to see what happens to the timing, and its constatly at 12 degrees BTDC when disconnected. Not moving at all when i give it throttle.

Tomorrow i'll pull flywheel and clutch off and inspect crank seals and stator.

 

[Myzkoo]

Troubleshooting continues. Bought a fully working F7 Black widow -05 with 3500 miles on it for troubleshooting the M7.

I pulled the stator, flywheel timing sensor, flywheel, throttlebody with injectors and TPS, ignition coil (with wires and caps) as well as the spark plugs from the F7 and put it on the M7. Made no difference at all. But then i realized that running with the hood open, it pulls almost 7000 rpm, and with hood closed - 5500 rpm. This was probably because i didn't put the pipe on = engine inhaled the Co2 coming out of the Y-pipe instead of fresh o2-air. So i put the pipe on with a new clutch belt, i didn't realize this sled had been converted to the 10.4" secondary so it didn't have the right belt on it before. Now if i let the engine heat up and slams the throttle to WOT it peaks at 7000 rpm and comes down to 6500 rpm, this is on a stand with the track lifted of the ground in my garage.

Now the really creepy part begins. I started to log my peak EGT's on a piece of paper when doing pulls on the stand and noticed that PTO-side peaked to 850F and MAG-side peaked 450F. Quite a big difference eh?

So i checked the plugs and they did confirm the EGT's. PTO-side was light brown/grey and the MAG-side was almost a bit wet. So first of i switched the injectors between the cylinders - no difference, so injectors ruled out. Then i lifted the plug caps and put them down with wires crossed - no difference, ignition coil ruled out i guess. Then i pulled the spark plugs and switched them - heat moved from PTO-side to MAG-side. Well i pulled out plugs and replaced them with a brand new set of never used BR9EYA's and the EGT's are still way of each other!! Switched the new plugs over the cylinders again and the heat moved to the other cylinder as before. WTF? Plugs are NEW.

Can somebody please explain how this is possible? Is it possible that one of my new plugs was faulty when i put them in?