'98 EV low rpm surging

[ampm7]

I promise that this will be my last question...just kidding! I purchased a '98 EV after my 2016 Eldo's demise and got the EV going quite well but it has that nagging surging/bucking in lower gears with partial throttle especially down hills. I've had this problem before and if I recollect it was this reason why I got out of Guzzi's and went to the dark side. What I want to know is how do I change the fueling? I have the Guzzidiag and Lonelec cables (leftover from the Eldo). Without going into extreme computer lingo, let's cut to the chase. What do I do to improve the situation in the least amount of terminology and the simplest step by step method for improving the fueling down low as it works fine when you get on the bike although not any where the same amount of power as the Eldo-but that's apples vs. oranges. Or do I live with the condition...

[fotoguzzi]

Use the search function for how to set TPS. .. not sure if your cables will work on the 1998, might have to probe the tps wires to read it.

After you have the throttles sync'd and tps set you can fool with a little dial on the side of the big p8 computer box, probably covered by a plug. It can richen or lean out the idle and low speed fueling.. caution, only turn a quarter turn at a time then ride for at least 10 minutes before going further. Note, the dial only goes so far and then can get past the stop and be useless.

[lucian]

You really have to make sure the basic state of tune is achieved before messing with the fi map.  Valves adjusted to spec,  TPS base voltage setting proper, throttle bodies synced. I would check for any active or stored faults to make sure all is good to go. While your there I would read  and identify the map you are now running.  From here a shout out to Beetle is the way to go. He already has corrected maps for most models and the improvements are well worth his asking price considering the time involved in all the data logging that goes into building his maps. To change cells in the current map without the benefit of logging the results in real time will be an exercise in futility. But to answer your question , you need to open your map in tunerpro or similar to actually make adjustments to the map. Make sure you read and store your map before you do anything else so you can always go back to where you started if things get weird. 

[fotoguzzi]

You really have to make sure the basic state of tune is achieved before messing with the fi map.  Valves adjusted to spec,  TPS base voltage setting proper, throttle bodies synced. I would check for any active or stored faults to make sure all is good to go. While your there I would read  and identify the map you are now running.  From here a shout out to Beetle is the way to go. He already has corrected maps for most models and the improvements are well worth his asking price considering the time involved in all the data logging that goes into building his maps. To change cells in the current map without the benefit of logging the results in real time will be an exercise in futility. But to answer your question , you need to open your map in tunerpro or similar to actually make adjustments to the map. Make sure you read and store your map before you do anything else so you can always go back to where you started if things get weird.

thats assuming the program even works with the P8 CPU

Read through this,
https://wildguzzi.com/forum/index.php?topic=96869.0

[guzzisteve]

I use it on my 98EV, works fine. You can change it meet your models ECU

[fotoguzzi]

Here's the FI supplement for your bike, it has fault codes detailed and how to read them,

http://www.dpguzzi.com/efiman.pdf

[Wayne Orwig]

The Lonelec cables and GuzziDiag will indeed CONNECT to the P8 computer, and display the readings. Nice for diagnostics.

But, the fuel maps are burned into a EEPROM. So to change the map, you need some blank EEPROMS and a prom burner. You aren't going to do it with software and a cable.

But, in this case, you are wasting your time. The 98 EV, and the P8 computer, generally don't need anything like that. If you have the throttle bodies set right, the TPS set right, you are going to be good. There is a small potentiometer on the computer box, to let you tweak the mixture if needed. And you are good to go.

If proper setup, and tweaking that pot, don't fix it, something is broken. You don't want to spend time trying to mask it with a map tweak.

[pehayes]

+1 what everyone else says.  Start with valves, set the TPS base, set the throttle balance.
Inspect the intake rubber boots carefully as you may have a crack leak which would have more effect at lower speeds.
Inspect the spark secondary cables as they can chafe, especially the right side where it passes the base of the cylinder.
Yes, the software and cable will read the various FI parameters of the P8.  Won't adjust anything, but just reads the outputs so you know that sensors are working properly.  BTW,  you can put the software into 'graph' mode and then slowly turn the hand throttle with the key on motor off.  You will get a nice, moving visual graph of the TPS voltage change and can visually see any blips or dead spots in the TPS sweep.

Now, as to the trim pot.  It controls fuel air mixture ratio.  Under a little round rubber plug in the P8 box.  It can turn about 3 rotations in each direction.  You can then 'feel' it bump up against the end stop.  It has an internal slip clutch.  You can keep turning and turning but it doesn't have any further electronic change.  Look at the adjuster screw slot.  Do about 1/4 turn and document the direction and amount.  Test ride.  You might try both directions to see what goes better or worse.  As long as you have documented or marked you can always get back to where you started.

Patrick Hayes
Fremont CA

[ampm7]

PeHayes you are talking about the unit under the left side cover? The trim pot might be the answer. Like I say, the bike runs fine except in that problem area that I stated before. I assume that the P8 unit is under the left side cover with heat sinks in it. Correct me if I am wrong. Thanks.

[pehayes]

No, the P8 used on the 1998 EV and earlier is a huge box, maybe 8" square sitting under the passenger portion of the seat.  Only the later M15 computer is small enough to go under the side cover.  If your computer is under the sidecover you must have a later model.  How about a photo?

Patrick Hayes
Fremont A

[Wayne Orwig]

PeHayes you are talking about the unit under the left side cover? The trim pot might be the answer. Like I say, the bike runs fine except in that problem area that I stated before. I assume that the P8 unit is under the left side cover with heat sinks in it. Correct me if I am wrong. Thanks.

No, the big box under the seat. The trim adjust screw is beside the big connector.

The box under the left cover are the ignition coil drivers.

Has it had a good tuneup, with the throttles balanced?

[John A]

No, the big box under the seat. The trim adjust screw is beside the big connector.

The box under the left cover are the ignition coil drivers.

Has it had a good tuneup, with the throttles balanced?

If you have to turn that screw, use a plastic screwdriver or don’t touch the sides of the access hole. Don’t turn it more than 3/4s of a turn either way, but read over it, I think it’s about that

[JoeB]

If someone already mentioned it I apologize, I missed it.
Pull the sensor on the flywheel housing under the right throttle body and clean it.
It's magnetic and runs dry sometimes picking up metallic particles.

[ampm7]

The trim pot is what I am looking for and will find it as the bike runs fine and I want to thank you guys for the info.Will send a picture when I take the bike in the back hills.

[Wayne Orwig]

The trim pot is what I am looking for and will find it as the bike runs fine and I want to thank you guys for the info.Will send a picture when I take the bike in the back hills.

You do have the box box under the rear seat, right?

Make sure the engine temperature is pretty close when you adjust the trim pot. The engine temp sensor, in the left valve cover, is a bit screwy on that model and can give you confusing results. That is the only real negative I know of on the 98 EV system. As Patrick said, tweak it a little, record what you did, and give a couple test rides before more adjustments. I believe counter clockwise is richer.

[ampm7]

I found the trim pot in a recessed housing just aft of the wiring harness to the P8. Luckily, I have some hollow ground screwdrivers and did not need to remove the pillion. Just tuned it a bit counter-clockwise as I used to build vacuum tube guitar amplifiers and almost all potentiometers open counter-clockwise. We'll see what happens...

[Lee Bruns]

Just to be clear . . . . . is your crankshaft position sensor clean? It is prone to picking up debris and giving the symptoms you describe.

[ampm7]

Haven't checked the crankshaft position sensor as I am looking for it and don't see it in any of my books. I did take the bike for a ride about 120 miles today and it works better however, it does have a tendency to occasionally "hiccup" just like my Harley did. I did come up with a strategy for the throttle is to roll on, roll off, roll on and so on, and it doesn't have tendency to surge as when keeping the throttle partially open in lower gears. 4,000-4,500 rpms seems to be the sweet spot and the longer the bike runs the better. I think I will tweak the trim pot just a tiny tad more and just live with the slight problem. Doesn't seem to be any problem with the throttle bodies and TPS but further down the road I will check. Incidentally, a beautiful day to ride about 42deg-54deg and a lot of snow in the back hills.     

[fotoguzzi]

You really should set valves and do a TB sync before messing with the trim dial.

[ejs]

Haven't checked the crankshaft position sensor as I am looking for it and don't see it in any of my books. I did take the bike for a ride about 120 miles today and it works better however, it does have a tendency to occasionally "hiccup" just like my Harley did. I did come up with a strategy for the throttle is to roll on, roll off, roll on and so on, and it doesn't have tendency to surge as when keeping the throttle partially open in lower gears. 4,000-4,500 rpms seems to be the sweet spot and the longer the bike runs the better. I think I will tweak the trim pot just a tiny tad more and just live with the slight problem. Doesn't seem to be any problem with the throttle bodies and TPS but further down the road I will check. Incidentally, a beautiful day to ride about 42deg-54deg and a lot of snow in the back hills.     

[pehayes]

There are TWO timing sensors.  The one shown in the picture from EJS above is in front of the left side cylinder. It senses against the cam timing gear.  It runs in oil spray and very rarely gets dirty.  The one you need to find is behind and below the right side cylinder and located on the curve of the transmission's bell housing just above the timing inspection hole.  That one runs in dry air and commonly picks up metallic swarf from the flywheel ring gear and clutch component degradation.  That's the one you need to clean.  I'll try to find a location picture.

Made a pic.  This is from a partially stripped EV.  See the flywheel sensor highlighted in yellow.





Patrick Hayes
Fremont CA

[Bill]

I'm sure I'm being too simplistic but I cured low RPM surging by adding Sea Foam to the gas tank. Problem solved for me.
Bill

[Wayne Orwig]

. Doesn't seem to be any problem with the throttle bodies and TPS but further down the road I will check. Incidentally, a beautiful day to ride about 42deg-54deg and a lot of snow in the back hills.   

Actually, the problem you are trying to mask sounds like a TB or TPS problem.
You should look into a valve adjust, TB and TPS setup at some point.

Also, inspect the spark plugs to see if they are getting sooted up after you tweak the mixture.

[JoeB]

+1 on what Wayne said.
Quick pic of sensor under right throttle body. Held by two allen screws and a gold like plate on the housing.

[Chuck in Indiana]

This is *not* rocket science. Do what Wayne and others say. A complete tune up, valve adjust, etc. Set the TPS. On the trim pot: it goes through 270 degrees. Looking from the left side, 8 o'clock is full rich, 4 is full lean. You can mask many problems by running super rich. Not a good idea. Do the tuneup.
Oh, almost forgot. Don't try to move the trim pot through any more than it's normal rotation. It will lose it's ju ju. 

[Joliet Jim]

I'm sure I'm being too simplistic but I cured low RPM surging by adding Sea Foam to the gas tank. Problem solved for me.
Bill

that's what i was going to suggest along with cleaning the tps sensor

[ampm7]

Pulled the crank sensor and was clean but I cleaned it anyway. Trim pot is set at about 9:30-10. Next stop is the TPS and throttle body sync however, I bought the bike from Mark Etheridge (MG classics) and he put in new plugs etc. I would think that if there was a problem with the throttle bodies that Mark would have noticed so, maybe I should contact him. I notice that whoever adjusted the TPS last time, put in marks in yellow paint as to alignment.  But I will check and clean. I had to adjust my TPS on my Yamaha FZ1 about 3 times in 80,000+ miles. But that one was easy as there was a fault code on the rev counter when the needle stayed at 7,000. Just move the TPS a tad and when the needle went down to 5,000 it was done. I guess I will have to break out the multimeter for this one. Unless there is an easier way...Thanks guys!

[fotoguzzi]

Pulled the crank sensor and was clean but I cleaned it anyway. Trim pot is set at about 9:30-10. Next stop is the TPS and throttle body sync however, I bought the bike from Mark Etheridge (MG classics) and he put in new plugs etc. I would think that if there was a problem with the throttle bodies that Mark would have noticed so, maybe I should contact him. I notice that whoever adjusted the TPS last time, put in marks in yellow paint as to alignment.  But I will check and clean. I had to adjust my TPS on my Yamaha FZ1 about 3 times in 80,000+ miles. But that one was easy as there was a fault code on the rev counter when the needle stayed at 7,000. Just move the TPS a tad and when the needle went down to 5,000 it was done. I guess I will have to break out the multimeter for this one. Unless there is an easier way...Thanks guys!

that yellow paint was put on at the factory,, if not broke it's a sign the TPS has never been touched (not saying that's a bad thing) Mark has a good rep so I'd expect it was set up right before you got it.

[Wayne Orwig]

This is *not* rocket science. Do what Wayne and others say. A complete tune up, valve adjust, etc. Set the TPS. On the trim pot: it goes through 270 degrees. Looking from the left side, 8 o'clock is full rich, 4 is full lean. You can mask many problems by running super rich. Not a good idea. Do the tuneup.
Oh, almost forgot. Don't try to move the trim pot through any more than it's normal rotation. It will lose it's ju ju. 

Actually, on the EV, I believe it is a 6 turn pot.
Not 100% sure on that though. It isn't like the Centauro 270 degree pot at all.

[Chuck in Indiana]

Actually, on the EV, I believe it is a 6 turn pot.
Not 100% sure on that though. It isn't like the Centauro 270 degree pot at all.

Oh, duh.. I forgot. My bad. I was thinking Centauro.