High speed, low throttle stumble/power dip

Steve, you should try to hook up with Brock (Landman here) while you are up there.  He is currently going to luthier school up there on the island.  He's a great guy and I'm sure he wouldn't mind sharing a piece of road or two with you while you travel through.

You can reach him at this number:  

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Tres bien Pete, tres bien...

Hi
Yes it's me !.

Really funny, well found.  

Hopefully MotoMT will explain how he has settled his problem.

Well, my 1400 mile 'road test' is complete, and I am positive this stumble/drop off at 6000 RPM is NOT a  fuel problem but is an Ignition problem, likely one cyl dropping off at high RPM.  I initially thought it was clogged injectors and mine were gummed up but after many tanks with cleaner, and having an extended time to 'feel' the problem out, it came to me like a vision of a time (15 years ago) when on my XS1100 the vacuum advance unit had moved so much that it had worn a break in the pickup wires that caused 2 cyls to drop off, with the same loss of power and blapping sound.

I dont know enough about this ignition system, but figure it uses a typical optical crank sensor that triggers the ignition cycle and advance in the CPU which sends a signal to the coils in sync with the fuel, timing, etc.  I think one cyl is cutting out at high RPM.  As I was riding over the weekend, I started checking off the blocks. It has new plugs, the new NGK caps, and the solid copper core wires, so I think they are NOT suspect.  This leaves the coil itself, or something deeper in the ECU, or the crank sensor itself. Something can not maintain the spark cycle at 6K RPM or higher. I was planning on passing this info off to MI when I bring it in for the appt for fuel sender, and hope that they can run down the issue quickly.

Then as if on cue, at 11pm last night riding back from the Ferry, a very strange thing happened..... I flicked my high beams on, the bike stumbled, then caught and ran fine, and the red triangle of death popped up..... Pulled off and pulled the code, is the #23 coil ground error for coil #1.

Now This is the 3rd time this has come up, but the first time while riding. Both of the others came with a goofed up start attempt where my thumb slipped off the starter switch abruptly causing a half start attempt.  The code will not clear from the dash, but clears up after a while while riding, or with Guzzi Diag. As part of my prior attempts to figure this out, I checked the coil ground wire, coil connectors, and even swapped coils and plug wires side to side respectively, with no change, but what I really need is a known good coil and plug wire to rotate in to see if this cures it.

I have yet to trace wires to the ECU or try to find the crank sensor. I'm hoping it is something simple and not something in the ECU. I'm going to dig up the wiring diagram and see where the wires for the coils go to and from.

Could be:
1 - Bad Coil
2 - Bad Crank Sensor/Ignition Trigger
3 - Bad ECU
4 - Bad wiring/ground in between something

Oh the ride was awesome, other than day 3 being mostly in the rain......

Vancouver Island is beautiful, though Many of the roads are Gravel ;-) and ended up on several active logging roads. Had to crank up the pre-load all the way on the shock and forks to get a little more ride height due to potholes and fear of bottoming out, but the views were amazing. My favorite view was at the end of the road in Port Alice. Sat and drank in the beauty for an hour.  Route 30 to Port Alice was also amazing. saw one car both ways, and did it 2X just for fun. The main route up the Island, especially North of Campbell River was wide open with little traffic and I happened to meet two local constables who only cost me 20 minutes of time and camaraderie....    The Norge really likes 85-90mph. Chassis is settled and responsive, handling stable, sweet spot in teh power band. The road to Tofino was crowded, and rained most of the way but still beautiful. Overall a great trip, though I will say that capping out at 6K is NO FUN...... Love the roll on power of the Big Block, but could have really used that extra 2K RPM "Kick" the 8V is known for. Almost got in trouble a few times passing.......... Kept expecting FJR rocket capability........

Still the 8V is sweet. Cant wait to get it running 100%
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Hello Bulldog9

Thank you for sharing your experience and the history of your journey with the Norge.
beautiful images

Off the other week to the Ragged Fringe Rally. High Idle once again, reared it's head. Purchased some 8mm bolts and plugged the stepper tube, still a bit ordinary. When home cleaned the spring mechanism under the R/H throttle body - it was well and truly gunked up and had been for some time - probably from the oil level being a tad too high.

I must say that I had the throttle bodies of around 6 months ago to clean the internals. But you would think I would do the outside bit again wouldn't you? No, lazy bones here didn't.

Anyway, with the stepper blocked and the spring mechanism cleaned, idle was good, if a tad low. Yesterday I unblocked the stepper hose and put it back on the airbox. Idle is again very reluctant to return to circa 1200 RPM. Stepper issues again - will have to drip some carby cleaner down there again...

Update - Just took the bike to MI today, looks like the issue is the left coil. I cant remember if they reset the history and error codes, but it had an active fault for the left (and the triangle of death) as well as a stored fault for the right coil, and I did switch the coil side to side to see if it made a change. I'm a bit sceptical of this on reflection, because I think when I had it in last time it showed no faults, but I dont really know the piaggio software. EIther way it had the active coil fault left, memory right and the lambda heaters as a fault. My gut says it is more than just a coil that cant hold the cycle at high RPM, but we will see.

The dash said it was a coil 'ground' I pulled and cleaned the ground wires on the coils as well as plugged/unplugged the coils. I also unplugged and plugged the connections to the ECU and the main ground on the engine by the starter, but is there another ground for the coils?

They have one on order under warranty. We will see. I hope it is this simple, but I'm thinking it is a bit deeper, possibly the pickup itself, and the gap neds to be set, or it cant reliably trigger at high RPMs. Will report when I get the parts on. It may be a while, I will be training in Idaho Most of October, then in PA for November.

Congratulations Steve. The little bugger looks just like you!

Bulldog9 wrote:

Update - Just took the bike to MI today, looks like the issue is the left coil ...

Thanks for the update Bulldog. I've been parked mostly. Not likely to get around to fixing until the spring it's looking like.

Let's assume I have the same issue for a sec ... is there a reason why no error codes show up in GuzziDiag for me? Maybe I'm doing it wrong (user error always the first guess), or does the factory software do something different that's not available in GuzziDiag regarding error codes?

Or, does this mean that my issue is something that isn't tracked by sensors/ecu and I can rule out ignition coils?

Guzzi Diag didn't show anything for me either, but I didn't use it to check when the triangle of death (CEL) came up, only the dash codes. It is notable that the problem doesn't generally trigger the CEL. After MI reset it and cleared the codes I took the long way home, 400 miles and beat the snot out of it, the light did not come back on but the problem exists. We will see..............

MotoMT wrote:

Bulldog9 wrote:

Update - Just took the bike to MI today, looks like the issue is the left coil ...

Thanks for the update Bulldog. I've been parked mostly. Not likely to get around to fixing until the spring it's looking like.

Let's assume I have the same issue for a sec ... is there a reason why no error codes show up in GuzziDiag for me? Maybe I'm doing it wrong (user error always the first guess), or does the factory software do something different that's not available in GuzziDiag regarding error codes?

Or, does this mean that my issue is something that isn't tracked by sensors/ecu and I can rule out ignition coils?

UPDATE:

Swapped out the coil yesterday, NO change. A bit irritated by this, couldn't sleep last night so out to the garage, set valves to .1 and .15 balanced TB's then loaded the Beetle Map, reset TPS and learning parameters. THe Result is a sweeter running motor to 6500 RPM then falls flat on its face. Grrrr. Frustrating as I like to run in the 4-7K rev range.

The low RPM torque and power of the motor makes it very rideable and enjoyable, but I'd really like to have that top 2K RPM to play. Starting to regret the 'deal' I got. Still need to explore the Fuel Delivery/pump/filter, and clogged Cat-Crossover Box, but as it does feel electrical, am thinking it may be the crank sensor/pickup. Maybe cant trigger at high rpm, or needs alignment?

I still need to try to do some logging with GD to see if I can see anything but I have to be able to interpret it and though I can handle the mechanical aspects, I am a dummy with the software.

Heading back out tomorrow to do some training, will revisit after Thanksgiving.

Bulldog9 wrote:

UPDATE:



... I still need to try to do some logging with GD to see if I can see anything but I have to be able to interpret it and though I can handle the mechanical aspects, I am a dummy with the software.

Well, I'm a dummy with the mechanical and the software haha. I found used coils for $18. Figured what the heck, slapped em on and ... no change. I'm suspecting TPS, possibly (which was mentioned earlier in the thread). The reason being is that I finally took a look in GD at the TPS measurement while twisting the throttle. It sure does jump around a lot, like 4.8 to 8 to 15, etc. Even if I go as slow as I can it doesn't increase smoothly.

Also figured out, while riding if I let off the throttle ever so slightly when it craps out at around 5500, the bike actually goes faster and as if I am increasing throttle. It feels bizarre, but makes me think TPS

Looks like the TPS is an IPF2 c/b, the same one used in several Ducatis. Seems easy enough to swap out. It appears that it's not a separate Guzzi part? Anyone know if it's a direct replacement if I were to get the IPF2 c/b listed for a Duc? Searching around the interwebs resulted in a few hits on Guzzi owners who have done it. I'm willing to spend $60, just to see how easy/painful it is to remove and replace.

I'll update if I get to it. This'll likely be the last parts I throw at it before taking it to a pro in the spring.

MotoMT wrote:

Bulldog9 wrote:

UPDATE:



... I still need to try to do some logging with GD to see if I can see anything but I have to be able to interpret it and though I can handle the mechanical aspects, I am a dummy with the software.

Well, I'm a dummy with the mechanical and the software haha. I found used coils for $18. Figured what the heck, slapped em on and ... no change. I'm suspecting TPS, possibly (which was mentioned earlier in the thread). The reason being is that I finally took a look in GD at the TPS measurement while twisting the throttle. It sure does jump around a lot, like 4.8 to 8 to 15, etc. Even if I go as slow as I can it doesn't increase smoothly.

Also figured out, while riding if I let off the throttle ever so slightly when it craps out at around 5500, the bike actually goes faster and as if I am increasing throttle. It feels bizarre, but makes me think TPS

Looks like the TPS is an IPF2 c/b, the same one used in several Ducatis. Seems easy enough to swap out. It appears that it's not a separate Guzzi part? Anyone know if it's a direct replacement if I were to get the IPF2 c/b listed for a Duc? Searching around the interwebs resulted in a few hits on Guzzi owners who have done it. I'm willing to spend $60, just to see how easy/painful it is to remove and replace.

I'll update if I get to it. This'll likely be the last parts I throw at it before taking it to a pro in the spring.

I'm new to Grisos and Guzzis, having owned my 2008 8V GRiSO for slightly over a year, but I'm a electronics tech with a lot of embedded and automotive experience. Pete and Beetle will have the definitive comments I expect, but  until they weigh in here, I think that the jumpy TPS reading in GD is *very* suspect and a likely candidate.

Can you mark some points on the throttle end  and the handlebar with a white texta pen and see which ones line up with the crazy TPS readings on GD, then compare them to riding the bike, see if they correlate ?

techman-001 wrote:

Can you mark some points on the throttle end  and the handlebar with a white texta pen and see which ones line up with the crazy TPS readings on GD, then compare them to riding the bike, see if they correlate ?

Good idea! I'll try that later this week or over the weekend (hoping the weather holds out for another week or two).

The slight pick up in power as the throttle is rolled off may also be indicative of a blocked/restricted exhaust.

Incidentally Michael rollerised a Stelvio last week and has told me that it now has the 'Runs into a brick wall at 6,800' problem. While this is obviously of no help here it does mean that at least we now have a bike that is exhibiting the problem in our clutches so when I get back next week we can really get stuck in to finding out wtf is actually happening!

Pete

I spent the day working on some of Black Betty's innards - pesky oil leak from the sump (rear oil return was loose - but also treated the sump with a new gasket to be sure), throttle bodies not always returning to ground zero and idle hanging/hunting (removed, cleaned thoroughly and reinstalled), added a motorcycle handlebar mount dual USB outlet (Jaycar $30) and ran the wiring to the battery, then realised it probably should not be on all the time - at least it's mounted.

New oil filter and 3.2 litres of Mr Penrite's finest and all seems to be sweet. Haven't ridden it yet but at least it idles properly.

Happy Days.

Rode to work today and the idle is correct and works all the time when it should.

A couple months ago, Pete (I think) mentioned he had a Stelvio bike in the shop with the same 600-6500 drop off.  Any update on that Pete?

One interesting thing is that on a semi warm start (after sitting 2-3 hours) the 8V motor seems to be running on 1 cyl for a bit. Feels weak, and doesn't rev freely until it is fully warmed up. This is not the case with the 4V GRiSO motor, it is very eager to rev.

I'm starting to think I just need to enjoy the low end torque of the Guzzi and set 6K as my redline..... stinks, as I prefer to run in the 4-7K Range, and when accelerating in traffic on the highway, on twisties, I like to stay in the higher revs. Would like to find that supposed 8V kick............

1 tooth out on the cam chain.




Pete will be along shortly to divulge all.

Yup. discovered this the hard way last week.

While I was away Michael had rollerised a Stelvio. One thing he had mentioned was that it took a BIG adjustment to get the TB's balanced. I didn't reallygive it a lot of thought as a lot of the bikes we get through are in a VERY ordinary state of tune. Anyway, it was pretty wet before the owner picked it upand I took it out for a run and it seemed OK, if a bit doughy, and I wasn't game to wind it right out due to the slippery conditions.

Anyway, long story short owner calls up and says 'Not Happy!'. Apart from anything else it "Goes Flat" at 6,800. Sorry about that, bring it back, leave it with me and take the Mana back to Orange where he hails from.

Sure enough it hits a brick wall at 6,800. Weird. Anyway I check most things, try a couple of different maps, still does it, sometimes worse than others depending on map. Decide it HAS to be mechanical and suspect cam timing so I run it back to Michael and say "Check it 'O' microcephalic one!".

Sure enough LH cam is out a tooth. I allow him to put it back together and re-tune it and then stick his head on a spike outside the top pub! Nah, really, sometimes shit happens. I know it shouldn't but we're all human.

Result? All good again and pulls cleanly through to redline.

Note if you want to check BEFORE actually pulling the cam sprocket just do a compression test. That will probably tell you the story.

Pete

Pete Roper wrote:

Yup. discovered this the hard way last week.

While I was away Michael had rollerised a Stelvio. One thing he had mentioned was that it took a BIG adjustment to get the TB's balanced. I didn't reallygive it a lot of thought as a lot of the bikes we get through are in a VERY ordinary state of tune. Anyway, it was pretty wet before the owner picked it upand I took it out for a run and it seemed OK, if a bit doughy, and I wasn't game to wind it right out due to the slippery conditions.

Anyway, long story short owner calls up and says 'Not Happy!'. Apart from anything else it "Goes Flat" at 6,800. Sorry about that, bring it back, leave it with me and take the Mana back to Orange where he hails from.

Sure enough it hits a brick wall at 6,800. Weird. Anyway I check most things, try a couple of different maps, still does it, sometimes worse than others depending on map. Decide it HAS to be mechanical and suspect cam timing so I run it back to Michael and say "Check it 'O' microcephalic one!".

Sure enough LH cam is out a tooth. I allow him to put it back together and re-tune it and then stick his head on a spike outside the top pub! Nah, really, sometimes shit happens. I know it shouldn't but we're all human.

Result? All good again and pulls cleanly through to redline.

Note if you want to check BEFORE actually pulling the cam sprocket just do a compression test. That will probably tell you the story.

Pete

So Michael invented the GRiSO 8v, ... "4v emulation mode switch"

4Vs don't run out of puff until the rev limit is exceeded, Terry. It's just different. I can take mine through said limit in lower gears - 5th and 6th probably would lead to a short free holiday, no licence and no bike.

The 4Vs have a more linear power delivery from about 4000 on - no surge around 5000, just strong all the way to the end - well it is with Beetle's assistance. Bog standard they were unlikely to get anywhere near to rev limit.

Oz1200Guzzi wrote:

The 4Vs have a more linear power delivery from about 4000 on - no surge around 5000, just strong all the way to the

This statement is not accurate. Well, it's inaccurate when the 8V has one of my maps.

Perhaps we shouldn't (well me anyway) compare the two engines. Mine is more linear than it used to be with the original map - and since I haven't ridden an 8V with Beetle map magic, I should just shut up, sit down and be quiet, lest I embarrass myself in a public forum. Me Talkum Shit... Me Apologise