EPROM Available for troubled 888?

Amovida

I've just restored my 1993 888 and am now pulling my hair out. The bike dies when it comes up to temperature or when I put it under load (like try to actually drive it). It backfires through the throttle intakes. You can see the ignition/spark of light backfiring under the throttle butterflies and then it gasps for air before dying. I've checked the fuel pressure and it's at 44psi. . I'm wondering if maybe I've got a corrupted eprom...anyone have any other ideas or a stock eprom I could buy? The bike has Ferrachi slip-ons and a K&N. Any help or ideas would be appreciated!

Things I've done up to this point:
1. I've tried moving the air sensor out of the air box and tried to run it connected and disconnected
2. Unplugged and replugged the cam, air pressure, water temp sensors and ECU
3. Powered the fuel injectors manually (I see more of a squirt and less of a spray) but they're the same for both (I have the green single injectors).
4. Replaced all the fuel lines both internal and external and made sure they're are no kinks anywhere in the system.
5. Replaced the fuel filter
5. I'm sure I've done more....I just can't remember because this Ducati is driving me crazy 😉.

Jasper

Have you tried the TPS?

Amovida

Thanks Jasper. Negative on calibrating the TPS. Honestly I was a bit intimidated since I don't know how to do it. I have a good multi-meter. I used to work as a Beemer mechanic so I'm quite handy. Is it that hard? Could the TPS cause the symptoms I'm describing?

marvin

Check this out,,,from Brad's site.

http://bikeboy.org/ducati4vthrottleb.html

Marvin

Amovida

Thanks Marvin. I had read that before posting but I'll need to read it again. If the TPS was giving the wrong values to the ECU it might run rich or lean. I'll add that to my list of things to work on....any other ideas from anyone? I have a video of the intakes backfiring and the gasping...am I able to post that? Thanks to everyone on the list for this awesome resource.

Foggy 888

If the bike is popping back through the intake, then the mixture is too lean. A lean mixture burns much slower than a rich mixture.

When the mixture is way too lean, the fuel is still burning when the intake valves open up during valve overlap. It ignites the fuel in the inlet track and pops back through the intake.

Amovida

Thanks Foggy, for the explanation. I wondered exactly what was happening. Now I need to figure out what is causing the mixture to be lean. What's the likely culprit? I'd assumed it was going to be fuel pump but I have a constant 44psi, which I assume to be enough? It seems to happen more once the bike is really warmed up...but it can happen under load when it's cold as well. I'll take a look at the TPS as suggested...could it be the chip is corrupted..do they go bad? Anyone know where to order a new one?

Foggy 888

Chips usually either work or don't work at all. I have never seen the software on a chip get corrupted on a bike that was running fine and then started to have problems. It sounds more like an input to the ECU
(TPS, temp sensor, etc) that is causing the lean condition. Did the bike run fine before you restored it?

If it has been sitting for a long time, you might consider having the injectors cleaned and flow tested.
It doesn't cost very much ($24 each), and then you will know that they are not at fault. I highly recommend RC engineering: https://www.rceng.com/Fuel-Injector-Cleaning-P43C0.aspx

They have quick turn-around time and provide you with flow specs of before and after cleaning.
My 851 SP3 had bad fuel contamination from the in-tank hoses and rubber fuel pump mount coming apart. After I installed a new pump, mount, hoses and had the injectors cleaned it ran like perfectly.

Foggy 888

The main inputs that the ECU uses to calculate fuel mixture are RPM and the TPS sensor. The temp sensors and barometric pressure sensor also affect the fuel mixture, but getting the TPS sensor and throttle bodies adjusted correctly is crucial to getting the bike running right.

freqrider

Tps was my first thought. Balance the thottle bodies, check the timing pick-ups. (Gap-resistance) And check timing. Have you changed the belts? Off a tooth? Have you checked valve lash lately? Go through these and you should find the problem. I had a bad FIM eprom cause trouble like this once. Changed it out and voila. It was fixed. Doubt your chip is bad unless it has a daughterboard like my FIM chip? Then it could be susceptible to damage.

Amovida

Thanks for the input.

Foggy...that is super helpful info regarding which sensors are critical and others not so much. As you'll see below I'm good on the air and coolant sensors. The barometric...I'm not so sure. I pulled mine and then got one in good shape (visually) off FleaBay. I jumped a lead with 5V off the ECU as shown in the 888 workshop manual....I can't get a milliVolt reading off either one...not sure if I'm doing some wrong. Anyone have any experience with this? Sounds like it might not be that crucial of a sensor.

This intake backfire/gasping/low power/no power problem was intermittent when I parked it last time about a year and a half ago. Surprise...it didn't fix itself while I as away. The bike only has about 5K on it...ran fine up until then.

I have a new fuel pump on order...should be here tomorrow. Even tho I tested the pressure at 44psi I wanted to put a new pump in just to take that out of the equation...I was thinking you can get pressure but as you rev...maybe my pump isn't able to give the volume..not sure I'm thinking about this right...cause if that was the case pressure would fall and it doesnt? I also wanted to share a tip that I got (that prolly everyone knows about). That the rubber fuel pump holder that is unavailable for the 888 can be substituted with one from a ST4...hope that helps someone. Sure helped me...mine was looking like an evil deep sea jellyfish 😉

Once I have the fuel pump in I'll then attempt adjusting the TPS..I need to get my vacuum manifold from storage first...I'll be sure to follow Brad's instructions carefully on how to do this.

To report what I've tried so far:

Belts: I did change them...I pulled the covers again and aligned the lowest pulley/gear mark. All the marks seemed to be in their proper place...Vertical cylinder marks aligning above and horizontal off to the sides (sorry if that's confusing). Note I tuned the belts using an iPhone app named "fine tuner" using the chord:A2 for 110 Hz.

Air and coolant sensors: they are in spec using an ohm meter to check values. I didn't have a thermometer...not the right kind anyway...but using boiling water and the freezer and also a hair dryer (my girlfriends, I use my motorcycle when it's running) I got a pretty good idea. They seem to be OK

Flywheel sensor and engine sensor (not sure what the 2 sensors are called). I was able to measure resistance on both...values are in spec. Do you have to pull the left cover to measure the gap? How do you measure the gap?

Battery: I have an Odyssey AGM battery and I've made sure it's well charged 13V. This seems to affect the pin voltage output for the "5V" on the ECU...I only get 4.7V here. Never tried it with the belt running

Coils: I pulled them both and tested them...they are in spec, both windings...didn't think that was the problem as it seems only one would go. Unless they're both failing when the bike warms up....seems unlikely.

Intake Manifolds: I did a visual inspection to see if there were any tears, cuts, etc in the intake manifolds...can't see anything.

Trim Sensor: I rotated it to the right and heard the click and then backed off 2 full turns counterclockwise. At one point maybe I'll open the ECU and check voltage.

Injectors. I pulled the injectors and soaked them in solvent. I then gently blew them out. I operated them manually using some leads and a 12V battery. They gave more of a squirt than atomizing the fuel...thoughts...should they be "misting". I'm open to sending in the injectors...I'll wait till after I put in the fuel pump.

Valves: Haven't checked yet...on the list.

EPROM: I pulled it and then put it back just to check on any loose connections. That's a delicate enough op that I'm not looking forward to doing that again. 😉 I ordered a proper tool in case I need to.

I'm also thinking about the rectifier or alternator getting weak with heat...don't have a ton of experience with this but I'll test the output at the alternator leads and then figure out how to test the rectifier.

Thanks again for all the help....you guys are rockstars!

freqrider

Pickup gap can be checked through the ports by removing the screwcaps adjacent to the pickups if you have thin feeler guages. I just try to get them as close as possible without touching. They tend to swell when hot so leave some room for expansion!

Get the odbII and fiat adapter cables and download guzzidiag/iawdiag. It will tell you right away if there is a sensor fault. It will do datalogging as well so you know the actual values from the sensors.

Amovida

Problem seems to be solved. Yesterday I recommitted to yet another day in the garage tinkering...I've lost count. I had pulled the regulator/rectifier and the tank. I removed the fuel pump and hosing. I noticed that the screened pickup attached to the bottom of the pump had a hole and about a third of it was melted away???....I can only guess that the heat from the vertical cylinder caused this and that I had pushed the pump far enough down that the screen contacted the tank bottom. WTF?

I tested the flow of the new fuel filter by blowing on the line...it felt restricted (it's a new Napa filter)...apparently it had clogged with less than 20 miles. This seems unbelievable....this had happened so quickly in a tank I had just cleaned. I put a new KL 145 fuel filter and carefully reassembled everything after cleaning out the tank again. I made sure that every hose had no kinking and reassembled everything as if I was performing surgery. Right away I noticed that the degasser outlet was shooting fuel further than before and that the pump sounded much different. My fuel test had shown 44psi. I think that the fuel was just able to squeak thru the clogged filter and reach the desired pressure.

It still doesn't explain why the bike died when it got warm. It should need less fuel as it heats up....mystery. I reinstalled the R/R after cleaning what looked like a corroded ground wire. She then fired right up and I took her to a dinner in the mountains last night with friends as a test ride and the bike just purrs. Still not totally sure what happened but I posted this in the hope it will help someone else. When you put your fuel tank innards together assemble it with surgical precision and check every ground/earth wire. That's my lesson.

My other lesson is that the apple doesn't fall that far from the tree. I had started checking every sensor and complied a long list of things that could even remotely be the problem. I need to remember to go over all the really obvious stuff with more attention to detail. Huge thanks to those that posted to help with my problem....I'm walking on air and am looking forward to getting as many 888 rides here in Colorado before winter!

marvin

That's strange considering that you just cleaned the tank! I would cut that fuel filter apart and see what's plugging it. I have been using the NAPA #3032 filter for over 60K miles on my bike with nary a problem.

p.s. Not just one filter for that many miles. Probably 4 or 5K on each new filter.

Amovida

Marvin. Thanks for the reply. I did that right away. I pulled out a grinder and cut the filter in two.

The corrugated paper inside was dark....it looked like it might have been contaminated with very fine sediment but it was hard to tell. Because I had cleaned the tank before I can't figure out what caused it, if that was the case. My only thought would be that I'd had some really dirty fuel in the pump (that I didn't clean) and it restricted the filter or it was defective from the get go (being cheap I bought the new kit "new" off of FleaBay).

I'll see if the problem comes back and try to narrow it down. If it doesn't my money is on the filter, if it does I'll look further into the rectifier/regulator. Just glad she seems to be running right again!

Foggy 888

How old are the fuel hoses? They could be coming apart and clogging the fuel filter. The old hoses do not like the new gasoline that is sold these days. If you replace them, make sure to get submersible hose.

Amovida

I think I solved the mystery of the clogged fuel filter. Thanks for the suggestion re the fuel hoses Foggy...every fuel hose on the bike is less than 2 years old and most are brand new. When I cleaned the tank before I cleaned it with a small amount of muriatic acid. It gave the inside of the tank a lovely even grey color and rinsed off all the rust. I then neutralized the acid with baking soda and a very small amount of water and then quickly filled the tank with gas. Apparently this did not work as well as I was hoping and I think the inside of the tank flash rusted...a very very light coating of rust.

When I put the new fuel in this light coating of rust must have rinsed off and clogged the fuel filter...who knew? I hadn't really noticed it the first time but I suppose that's what happened because I paid more attention this time and it didn't rust at first but after a day it rusted even though there was gas in the tank. A really thin coating of rust all over the inside.

Really glad to have solved the mystery of what's been happening....it's been a long road (and I went down many wrong ones). Doing a little reading on some auto body forums some guy suggested a light rinse of phosphoric acid to prevent the flash rust after the cleaning with muriatic acid. If anyone has a better solution for removing the rust (I know muriatic acid is controversial) I'm open to hear it. By the way, I wear heavy rubber gloves for this with appropriate clothing and eye protection.

Again thanks to everyone for your help and hard won experience...this knowledge doesn't come easy 😉