GPz 1100 1984 Injected

[dru]

Hi everyone. I am having a ton of trouble with this bike. I am rebuilding it. The injectors are Ok. It has a 2nd hand ignighter, TPS & computer. It will idle OK for a bit then the revs will go up by 1000 or so. The throttle hangs and at times it just stops & is difficult to start when hot. I have been told that these injected bikes never ran well. Is that so? I really want to keep it original but as a last resort what carbs would fit & what jets would I need??

Many thanks, Dru

[steell]

Sounds like maybe the TPS is bad, but it's hard to do a diagnostic over the net.

There will be a bunch of people along soon to tell you to ditch the EFI and put carbs on it, but I'm not one of them.

[doebag]

Possibly the temperature sensor.

If it is not signalling the ECU to lean off the mixture after starting, then it will run rich [high idle] and then cut out and be hard to start.

When it cuts out, take the spark plugs out and see if they are coated in fuel, also does the exhaust smell of unburnt fuel ?

[StarGate]

IMO Those injection systems did fine when they were operating normally. I won't recommend carbs over injection but the majority of those bikes were converted to carbs for the simple reason that parts were hard to find and unless you wanted to convert to mega/micro-squirt all the parts are usually 25+ years old. Of course some were converted just because the owner didn't know how to work on injection but could work on carbs. If you should decide to convert to carbs I'd say look for some BS34 CV or some VM 28 carbs that are from an 81+ KZ1000/1100 just so the rack spacing is the same. I think the suzy GS1100 also used the same spacing and BS34 carbs but, I'm not sure about that.

[Polar_Bus]

Originally Posted by dru

Hi everyone. I am having a ton of trouble with this bike. I am rebuilding it. The injectors are Ok. It has a 2nd hand ignighter, TPS & computer. It will idle OK for a bit then the revs will go up by 1000 or so. The throttle hangs and at times it just stops & is difficult to start when hot. I have been told that these injected bikes never ran well. Is that so? I really want to keep it original but as a last resort what carbs would fit & what jets would I need??

Many thanks, Dru

Start the engine, pull off the seat, and look at the ECU unit to the right and you will see a round green light, you might see it flashing multiple times. This flashing is an onboard "fault code". I have the OEM suppliment manuall for the GPz DFI's and can help you diagnose a trouble code if you need.

The GPz DFI's did have some relibility issues, but once you learn the issues and react accordingly in preventing them, the DFI system functions excellent.

[MFolks]

The TPS on these injected bikes will get a buildup on the variable carbon resistor and needs cleaning. On my 82 GPz 1100 B2, I disconnect the electrical cable(don't loose the small wire securing clip) and spray up inside while opening and closing the throttle with some De-oxit D5 electrical contact cleaner/preservative.

Do this of course with the engine off. De-oxit can be found at most Radio Shacks or other electronic supply stores. caig.com - Home of DeoxIT - CAIG Laboratories, Inc. is their website.

Never use WD-40 on electrical contacts as I found it later becomes a non conductor(more like an insulator) I used to routinely spray the glass tubes fuse clips on my bike and thought nothing of it until the day I turned the key and nothing happened!

No lights in the instrument console,no fuel pump sound, no horn,headlight,turn signals or taillights/brake lights.

A real puzzle, and that same day I rode the bike to downtown San Diego for jury duty and was talking to a man who had a similar story when he used WD-40 on his truck's electrical system. He had to clean the fuse clips and fuses to make his vehicle work.

I happened to have some 400 grit sandpaper in my bikes tool kit,scuffed the fuses and clips, put them back in, turned the key and it fired up!

I've since avoided using WD-40 on anything electrically related(even though it says on the can it will remove moisture from switches), so be careful where it's used.

[dru]

Thanks for all the replies, you folks are priceless. I have been told that the timing may be out one tooth. Although it runs eratically when it does run it runs OK. I checked the timing & am happy that I set it up according to the Clymer book I have. The TPS comes up OK in the resistance tests. The air temp sender does also. I checked the engine temp sender at cold & it is within spek. When the engine is hot & running the engine temp sender resistances are all over the shop. Does this mean that it is telling the comp to richen then lean, will it work that quickly???

When I run the bike with the air & engine temp sender disconnected I get a signal in the computer as described by Polar Bus, but when I stop the bike, reconnect them and go again I get no code. Can I rely on this even though the resistance of the engine temp sender can be doubted when engine running.

I am told hat there is an instrument that can accurately locate the position of the TPS. Is that so? At the moment it is just trial & error.

When I work out how to do it I will attach some shots of my ride.

Many thanks to all of you

Dru

[dru]

Thanks for the info, Mike. I'll keep it original & struggle on with the injection probs till solved, but am getting toey to ride the damn thing. How do you attach pics to the messages???

dru

[dru]

OK have just set up the TPS with the approved meter & so assume all is well there. I have three wires in the TPS connector viz: blue/orange, blue/white & blue red. Using a voltmeter checking at the computer the blue white at throttle closed is 5.07V & open 1.06V. The blue /orange stays on 8.19V throttle open or closed. The blue /red stays on 0.020V throttle open or closed.

When I blip the throttle she runs on really bad. The voltage on the blue/white decreases & then settles back on 5.07V so I am assuming that the TPS wire there is OK. The revs went up to about 2.5k & stayed there till I backed off the butterfly screw on the throttle body. Where to now folks????????

Dru

[kopcicle]

manifold air leaks, only after verifying that the valve adjust is at or near high limit .

~kop