ECU Daignostics

[John Neeson]

My 1997 Sport Injection will not start. The fuel pump runs for a few seconds as normal when the ignition is switched on. The starter motor turns the engine over, but it will not start. Removing a plug revealed that there was no spark.

 

This would suggest that the fault is with the ECU, a sensor, a fuel injector (based on the list of faults that

the ECU can diagnose), or a wiring fault.

 

Unfortunately the ECU diagnostic LED does not transmit any diagnostic blink codes: it stays off all the time - even when I unplugged the TPS to simulate a fault which should be diagnosed. It seems likely that I have more than one fault to find.

 

I have ordered the Technoresearch VDSTS diagnostic software, which should be delivered in a week or so....

 

Meanwhile, are there any other checks that I could make? I am not sure which types of sensor failure would cause this problem. I assume that the ECU software would use a default 'get you home' setting in the event of a temperature or air pressure sensor failure, and that the only critical inputs are the TPS and Phase/RPM sensor.

 

So much for the theory. What I really need is real world experience of how these bikes go wrong. If anyone has had a similar problem, I would be garteful for any advice.

 

thanks

[raz]

My 1997 Sport Injection will not start. The fuel pump runs for a few seconds as normal when the ignition is switched on. The starter motor turns the engine over, but it will not start. Removing a plug revealed that there was no spark.

 

This would suggest that the fault is with the ECU, a sensor, a fuel injector (based on the list of faults that

the ECU can diagnose), or a wiring fault.

 

Unfortunately the ECU diagnostic LED does not transmit any diagnostic blink codes: it stays off all the time - even when I unplugged the TPS to simulate a fault which should be diagnosed. It seems likely that I have more than one fault to find.

 

I have ordered the Technoresearch VDSTS diagnostic software, which should be delivered in a week or so....

 

Meanwhile, are there any other checks that I could make? I am not sure which types of sensor failure would cause this problem. I assume that the ECU software would use a default 'get you home' setting in the event of a temperature or air pressure sensor failure, and that the only critical inputs are the TPS and Phase/RPM sensor.

 

So much for the theory. What I really need is real world experience of how these bikes go wrong. If anyone has had a similar problem, I would be garteful for any advice.

 

thanks

I can't see why a missing spark would suggest a fuel injector fault. Did you check both spark plugs? The following is by no means any rocket science but anyway: Check relays, fuses, grounds. Check the connections between the ECU and the phase sensor. And last but not least, check that you don't have water inside your ECU... I've seen it once and recently some guy (here?) reported permanent damage due to lots of water inside the ECU. As you know, the fuel pump is a very good sign, the missing LED is a bad one.

[Cliff]

Try this test.

 

Key on, wait for prime to finish, crank for 1/2 sec. Do you hear prime now? If not it sounds like the phonic sensor (rpm pickup).

 

I'd try jiggling connectors.

[Murray]

The obious question what is the condition of the battery (do not be temped to jump start it then you will have and ecu fault). The battery will get to the piont it will turn the motor but not enough left over to run the ignition.

[guzzijack]

Try this test.

 

Key on, wait for prime to finish, crank for 1/2 sec. Do you hear prime now? If not it sounds like the phonic sensor (rpm pickup).

 

I'd try jiggling connectors.

 

 

We had a V10 Centauro do exactly the same thing recently while I was test riding it, (getting over to the hard shoulder at 120mph with a dead engine was fun ).

 

That was a phase sensor as Cliff suggests and on a '97 bike as well. I checked my own '97 Centauro when we got back and the sensor on that was exhibiting the same bulging around the circumference. Might be worthwhile getting a sensor from Moto Ecosse for £32.50 and even if that is not the cause it will be handy to keep a spare on the bike - a duff one will kill your engine dead.

 

You'll need to tell Stuart or Robert if it's a 2 or 3 wire one

 

GJ

[John Neeson]

Try this test.

 

Key on, wait for prime to finish, crank for 1/2 sec. Do you hear prime now? If not it sounds like the phonic sensor (rpm pickup).

 

I'd try jiggling connectors.

 

Did as you suggested Cliff: The fuel pump did not restart. I will buy a new rpm sensor and see if that fixes it - probably worth having as a spare anyway. Would a TPS failure not show the same symptoms?

[dlaing]

Would a TPS failure not show the same symptoms?

I don't think it would cause you to have no spark.

But worth checking.

[Cliff]

Just note with the phase sensor, they have shim washers to get the clearance just right. The main thing to check is you have no contact with the rotor.

[dlaing]

From the shop manual,

Air Gap should be set to between 0.7 and 0.9mm

Shims are available

(average delivery time slightly less than the average gestation period for homo sapiens <_>

in the following thicknesses:

mm ~~~~~ Part number

0.3mm ~~~~~ 01 72 27 00

0.4mm ~~~~~ 01 72 27 01

0.5mm ~~~~~ 29 72 27 60

0.6mm ~~~~~ 01 72 27 02

0.8mm ~~~~~ 01 72 27 03

1.0mm ~~~~~ 01 72 27 04

1.5mm ~~~~~ 01 72 27 05

[luhbo]

How do you check the initial gap? With something like chewing gum, or can you see the gap? Or do you measure from the hole down to the wheel and compare this with the length of the sensor?

 

Hubert

[raz]

How do you check the initial gap? With something like chewing gum, or can you see the gap? Or do you measure from the hole down to the wheel and compare this with the length of the sensor?

 

Hubert

It's checked with cam sprocket removed, with a feeler gauge (it's called that isn't it?). There's probably no need to check it unless rebuilding the engine since it won't change over time, but I suppose it's possible with some imagination, like your examples.

[guzzijack]

How do you check the initial gap? With something like chewing gum, or can you see the gap? Or do you measure from the hole down to the wheel and compare this with the length of the sensor?

If you can get the 'blunt' end of a verier caliper down the hole just measure from where it bottoms out to the machined face the sensor sits on. Measure the length of the sensor body, subtract it and you should be able to deduce how much shim is needed. If it's a sensor replacement job and the bike was running fine before it went bad, just compare the two sensors and (hopefully) you can leave well alone.

 

GJ