'84 ZX1100 GPZ Engine Will Not Stay Running

I have an '84 GPZ 1100 that I bought a few years ago as my first motorcycle. After one year of very enjoyable riding, the fuel pump started to leak, coinsidentially right on an exhaust leak. Needless to say, the bike caught fire and burnt up pretty good. With relatively low miles on the bike, I felt like I could salvage it. After spending over $1000 in parts, I got it to run, but it doesn't stay running. The main and sub wiring harnesses were replaced after the fire. Upon cranking up the bike after, it ran great. I took it for a trip down the road and after about 4 miles it began to run funny, like the battery was going dead. It left me on the side of the road 1 mile from my house. I got it back home and found the ECU code to be indicating a bad engine temperature sensor. I bought a new sensor and started the bike again. The bile ran for a few minutes and then the idle began to run up and down and then the bike killed. I couldn't restart it. I waited about 2 hours for the bike to completely cool and tried to restart it again. It ran again for about 5 minutes, then began experiencing the same problems as before. The ECU again gave a bad temperature sensor fault. I found an ECU on eBay and installed it, thinking that the fire may have sent too much heat throught the wiring and damaged the exisiting unit. The bike still behaved in the same fashion. I tried adjusting the fuel regulator, bought used coils from eBay and replaced the existing coils, and even thought about buying another ECU. I took the entire fuel injection system apart and cleaned it thoroughly. The bike continues to exhibit the same symptoms. I tried to jump on it and take it down the road as soon as it starts but I only get a few hundred feet down the road and it kills every time. I can't restart it until I let it sit for more than an hour. I am hestitant about spending any more money on this bike unless I know for sure that I can get it running. I would really like to get this bike running and would love for any suggestions. Thanks in advance.

I'm not sure if this info will be 100% as it was taken from the 81-83 manual;

The engine Temp sensor is a 1 wire, variable thermistor to ground. It MUST have a good clean ground connection, and so not just where it installs but the engine ground cable back to the frame. Also a good Idea took check the harness from the senor plug to the computer for loose or damaged/ high resistance problems.

a set of 29s would make your life easier

Also you are not confusing the code with the Air Temp Sensor that is in the Air Flow Meter/ Flapper box? You might want to check the sensor there as well, also the wiring.

Also
Member Steele is right I got you the wrong info. But I'm changing it. So it will be down the thread.


Also, Steele or any one else familiar with this system,
I see only 3 sensors. Engine temp, air temp, and throttle position. There looks to me no mass air flow sensor, or barometer. Or as it looks like it could be a speed density setup, there is no Manifold pressure sensor/ MAP, which would house a Barometer. Bit strange that set up.

And,
Read down, sorry.

I think you can skip the airflow meter stuff, it ended in 82 and the GPz1100 in question is a 1984.

Bad ground is a possibility though.

83-84 have a real TPS vs the on/off switch TPS that required the airflow meter on the early ones.

Thanks for the heads up, Steele!

Here should be the correct info for your bike, this time.

Also

And here is the wiring diagram,


So if you need something else I can hopefully get the info and post it for you.

kevsell wrote:

I have an '84 GPZ 1100 that I bought a few years ago as my first motorcycle. After one year of very enjoyable riding, the fuel pump started to leak, coinsidentially right on an exhaust leak. Needless to say, the bike caught fire and burnt up pretty good. With relatively low miles on the bike, I felt like I could salvage it. After spending over $1000 in parts, I got it to run, but it doesn't stay running. The main and sub wiring harnesses were replaced after the fire. Upon cranking up the bike after, it ran great. I took it for a trip down the road and after about 4 miles it began to run funny, like the battery was going dead. It left me on the side of the road 1 mile from my house. I got it back home and found the ECU code to be indicating a bad engine temperature sensor. I bought a new sensor and started the bike again. The bile ran for a few minutes and then the idle began to run up and down and then the bike killed. I couldn't restart it. I waited about 2 hours for the bike to completely cool and tried to restart it again. It ran again for about 5 minutes, then began experiencing the same problems as before. The ECU again gave a bad temperature sensor fault. I found an ECU on eBay and installed it, thinking that the fire may have sent too much heat throught the wiring and damaged the exisiting unit. The bike still behaved in the same fashion. I tried adjusting the fuel regulator, bought used coils from eBay and replaced the existing coils, and even thought about buying another ECU. I took the entire fuel injection system apart and cleaned it thoroughly. The bike continues to exhibit the same symptoms. I tried to jump on it and take it down the road as soon as it starts but I only get a few hundred feet down the road and it kills every time. I can't restart it until I let it sit for more than an hour. I am hestitant about spending any more money on this bike unless I know for sure that I can get it running. I would really like to get this bike running and would love for any suggestions. Thanks in advance.

Too funny, I am experiencing the EXACT same issue with my buddies '84 GPz. I've done a lot of component swapping thus far with no luck. I've diagnosed thus far something is backfeeding voltage to the temp sensor. Read my story:
kzrider.com/index.php?option=com_kunena&...ew&catid=4&id=420946

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.