'84 ZX1100 GPZ Engine Will Not Stay Running

Sorry for not replying sooner. I've read all the threads and they all seem to contain good information. I did check the resistance of the temp sensor and the voltage on the wiring as the manual sugggests and everything came out normal. I think the suggestion about the grounding for the motor might be the best bet. When I replaced the wiring harness, I had to remove a ground that was attached to the motor. The bolt holding the ground on was frozen solid. After using penetrating oil and waiting a few days, I got a little too aggressive with it and broke the bolt. I don't remember how I attached the ground, probably to another bolt on the engine. It's been a while since I fooled with it. I kinda got discouraged because I couldn't fix it. I am planning on getting busy on it tomorrow and I can promise you that I will follow the advice of each post on this thread. I haven't read the story yet that Polar_Bus posted, but I'm doing that next. Thank all you guys for the help and I'll let you know something by Monday of the outcome.

Follow and check that sensor resistance from the main plug-in at the computer/ control unit. That should tell if there is to much resistance from a wiring/ connector issue.

If you have the service manual and the engine itself is in good condition, then YES, you will get it to run again.

Using the engine codes and just trying to think of the part that is causing the problem is frustrating as hell.

Use the manual, and check every electrical component independantly. Perform all the maintenence. Pull it, test it thoroughly, clean it properly, etc.

Its going to take a while, but have patience, it will be fine soon enough...

Best of luck.

There's another current thread where the small hidden fuel strainer at the fuel pump intake (or inside the fuel line itself) has become clogged over the years and preventing sufficient fuel flow.

If not already done, would inspect and probably remove this troublesome little inside filter, and replace it by installing a typical in-line strainer-type filter.

Good Fortune!

Motor Head wrote:

I remember that thread, and you still show the voltage on the grey wire?
This fellow posted that he has changed the Computer, and still had the same code. But he so far has only posted the 1 time, still a problem, or fixed?
Hopefully you can fix yours, polar_bus.

I've tried swapping several major electrical components and after each swap, checking voltage at the temp sensor gray wire, and I keep showing about 1.7V (even with the key off. With key off there isn't supposed to be any voltage. I was hoping it was the main fuel pump relay, but swapped that too and still got voltage... it's just too dam cold right now to really dig into the electrics. Once it warms up a bit, i'll get back at it. I'm sure sooner or later i'll figure it out !

Keep us posted. It aint that cold down here, so I'm hoping to make some headway tomorrow. I don't have a parts bike to swap pieces, but I've changed most of the major electronics already. I plan on going at it tomorrow until its fixed or until I collapse from exhaustion.

kevsell wrote:

Keep us posted. It aint that cold down here, so I'm hoping to make some headway tomorrow. I don't have a parts bike to swap pieces, but I've changed most of the major electronics already. I plan on going at it tomorrow until its fixed or until I collapse from exhaustion.

I am extremly fortunate in the sense that I have a complete spare set of compoenets. (I even had 2 complete DFI setups as well. So if my GPz starts giving me grief, I got it covered !

Hey guys, hers's an update of what I found over the weekend.

I once again measured the resistance of the sensor and found it to be about 2.4KOhms. I ohmed out the grey wire from the ECU connector to the sensor and found about 3kOhms. While I had the meter on both ends of the wire, I wiggled it around to see if there was an intermittent short or open. Sure enough I found that when I wiggled the wire near the fuse box, it would read open intermittently. Upon further investigation, I found a place jsut to the rear of the fuse box that the grey wire came out of the wiring bundle and a 30Ohm resistor was crimped inline on the wire. I thought that the problem was the cripms, but upon further investigation it seems that the wiring problem is between the resistor and the computer. I had to quit working on it because of rain. I am planning on replacing the section of wire between the computer and the resistor. I also have to wait until I can afford another battery for it because the one I have is deceased and they cost too much for me to just go out an buy one. I'll let you know more once I get it fixed and get a new battery in it.

When you first posted about the fire, you say you replaced the wiring harnesses. Where they used? I wonder if that resistor is factory? Of course the wiring and test I have posted is for the previous year model, but I don't know why they would add a resistor to the circuit. I can't think of 1 application I've ever seen with a Factory in-line resistor for the Temp sensor, whether a single wire type or 2 wire type.
Get the new battery, a weak battery and fuel injection will be very bad for your old electronics. Check your charging system, there are many threads on this. I've done a couple myself, checking the Current flow in AMPs as well as voltage. Watch the voltage drop between the regulators brown wire and actual battery charging voltage. As the brown is the main ignition power as well as the Load Sense for the regulator. If there is a drop on the brown, the regulator will up the voltage to the battery possibly over charging/ boiling the battery, even e new one ruining it.

The way that the resisitor is crimped, it looks like a professional job. Also, the section of wire that the resistor was attached to was routed outside of the main wiring bundle just to the rear of the fuse box and it was looped towards the ECU and then back towards the sensor, allowing for about 4-5 inches of slack. That whole 4-5 inches of wire and the resistor was covered with a black, plactic wire protector, just like what is found wrapped around the main wiring harness. Looks to be factory to me. I have been plagued with electrical problems since I bought the bike. Before the fire, I had to plug a battery tender every night so that the battery wouldn't be dead in the morning. One of the indicator lights, I think it is the left turn signal, would continuously stay on, but very, very dim. Other than that everything worked fine electrically. Once I replaced the main wiring harness, I thought the short may be in the instrument cluster wiring. I checked and double checked the wiring by performing continuity checks as well as megging the wires to ground, but couldn't find anything. I have replaced the voltage regulator and taken apart the stator, but I can't seem to locate the wiring problems. I'm OK with keeping it on a charger when not in use, if only I can get the damn thing to stay running. Also, my wife has taken away my funding for this project, so I'm left with what I have in parts. Of course, I'll have to come up with a new battery, somehow.

The problem with your light staying on, is that just the small indicator in the cluster? Or is it also getting voltage to the bulb sockets at the signals? Sounds like you could have some corrosion at the handle bar switch. You may not see the Signal bulbs illuminate, but check with your meter to see if voltage is there, if so take the fuse for that circuit out, it should be gone then. Probably in the switch, as it is exposed to weather.
I wish I could see the FSM for your year/ model to look at the wiring for the EFI, to see if that resistor is indeed mentioned.

I can only see the light on the indicator and not the bulb. And only if I shade the indicator with both hands and put my eye in my hands. Also, I have a Clymers manual for 1000&1100 cc fours 1981-1985. The wiring diagram states that it is for a 83-85 ZX1100 A1 & A2 US & Canada. The electrical schematic does show a resistor in line with the temperature sensor. The only other schematic that I found that even has an engine temperture sensor is for a 81-82 KZ1100 B1. It does not show a resistor in line. The only bikes that even have engine temperature sensors are the bikes that have an ECU. All other bikes do not have them.