DFI problem

[RAYZ1]

Guys

I have a zx1100 A1 in std condition, ust bought it and when hot the engine behaves like new. When cold the the cold start lever makes no difference and the bike is lumpy and wont idle until warmed up. When hot the cold start lever has a minimal effect of raising the revs by about 500rpm - It is just a fast idle lever but it should bring the revs up at least a couple of 1000 rpm

Any ideas where to start ?

[j.wilson]

Temp sensor- failure mode is prob hot- so starting is a prob.

[z1bman]

start the engine + see it the green light is flashing on the fuel injection control unit which is fitted in the tail unit

[RAYZ1]

start the engine + see it the green light is flashing on the fuel injection control unit which is fitted in the tail unit

I thought your were meant to check it before you started the engine ?, but I will recheck with it running , when its hot it runs like a new bike, its only done 7k miles

[RAYZ1]

Temp sensor- failure mode is prob hot- so starting is a prob.

My thought went to the sensor as well - is there a way of checking it ?

[j.wilson]

Easy, measure the resistance when hot and cold- should be different. There should be instructions for this in the manual- also make sure the connections to the sensor are sound (together and not corroded).

Sometimes these sensors have an internal ground and a single power cable to them, sometimes they have an external ground and there is a cable earth somewhere you must also check. I'm talking here about generic systems- others on this forum will have a better idea about the set up on the Z.

The sensors are usually quite reliable- the connections are the weak point- ....however a bike that has been sitting around for a long time will suffer from moisture getting into the sensors (not water, simply atmospheric moisture) that is not driven out by regular warm-up cycles. However when it comes to the eventual start-up the moisture within gets driven out rapidly and can damage the sensor.

[RAYZ1]

Easy, measure the resistance when hot and cold- should be different. There should be instructions for this in the manual- also make sure the connections to the sensor are sound (together and not corroded).

Sometimes these sensors have an internal ground and a single power cable to them, sometimes they have an external ground and there is a cable earth somewhere you must also check. I'm talking here about generic systems- others on this forum will have a better idea about the set up on the Z.

The sensors are usually quite reliable- the connections are the weak point- ....however a bike that has been sitting around for a long time will suffer from moisture getting into the sensors (not water, simply atmospheric moisture) that is not driven out by regular warm-up cycles. However when it comes to the eventual start-up the moisture within gets driven out rapidly and can damage the sensor.

thanks I will get a manual, Ive only just bought it, I have the turbo manual and supplement but although similar its bound to be different

[Ginger Bear]

Ray,

The temp sensor screws into a boss, that itself screws into the head, any corrosion between these threads will give a higher resistance, which would probably make it run rich. Also it's worth replacing the female bullet that connects to the sensor.
There is an air temp sensor on these as well, your problem could be there.

It would be worth buying the supplement manual, as it will give you some simple resistance values to check on the various sensors. I can copy the relevant pages if you want.

[RAYZ1]

Ray,

The temp sensor screws into a boss, that itself screws into the head, any corrosion between these threads will give a higher resistance, which would probably make it run rich. Also it's worth replacing the female bullet that connects to the sensor.
There is an air temp sensor on these as well, your problem could be there.

It would be worth buying the supplement manual, as it will give you some simple resistance values to check on the various sensors. I can copy the relevant pages if you want.

Thanks - that would be great, Im also searching for a pdf , I saw a supplement manual on ebay usa , but would be happy to get the bits I need - I dont know if its rich, it seems to be fine when hot and starving or choking when cold , I suspect it isnt getting enough fuel when its cold - maybe dfi works different ! ?

[z1bman]

they do sound like they are running very rich from cold anyway. as already mentioned check the engine temperature sensor + lead as the lead is normally stretched to fit onto the sensor. the cable is a little short + sometimes the cable breaks where it connects to the bullet connector. also air temperature in the side of the air box.check the breather pipe from the engine which goes into the underside of the air box. could also be the throttle position switch requires adjustment

[Ginger Bear]

Ray,

PM me your address & I'll get something in the post asap