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Fuel injection module gone bad - update Tue Nov 10, 2015 2:13 am
tonybob
active member
Hi all -
A follow-up on my 85 K100RS posting on Oct 9th. I finally got some time to start troubleshooting using the EFI guide from the portal. Here’s what I’ve found so far.
Fuel injector resistance is close to 16 ohms per injector. I’m getting 19.4, 19.8, 16.8 and 17.1 for injectors 1-4 resp.
Checks of the injection module resistance and voltage values are for the most part good, for what I was able to measure. However, I’m seeing these potential issues (or maybe I’m not measuring something correctly?):
1) power to hall sensors measured at the hall plug after the ignition module measures 10.60V, not 12V
2) pin 7 reads 11.58V with the starter running, not 0-1V – it does read 12.15V with just the ignition switch on, per the guide
3) pin 8 reads 2.5mV with starter running, not 10-20mV
4) pin 11 reads 11.60V with ignition on, drops to around 10V with starter running – not 0-1V per the guide.
5) I also checked the voltage at the coil end of wiring to see what pins 9/10/14 should be pushing to the coils (1.5-4V per the guide). I’m seeing 0.08V for pin 9, 11.62V for pin 10 and 0.15V for pin 14 all with starter running.
Resistance at coil primaries checks good. However, high tension leads DO NOT measure any resistance (as if there’s an open circuit). I suspect the coils have gone bad, but I’m curious if other owners have had this experience. Both go faulty at the same time due to age?
Hall sensors check good. I used a 12V LED and found that a feeler gauge of 0.012” or greater would break the signal. Anything thinner (or Al foil) would not break the signal.
If I were to replace anything at this time I’d swap out the coils, although with the different readings I’m seeing with the ignition module I’m not so sure.
I’m going to continue troubleshooting, next up is the Fuel Injection module check.
Thanks,
Tony Marts
A follow-up on my 85 K100RS posting on Oct 9th. I finally got some time to start troubleshooting using the EFI guide from the portal. Here’s what I’ve found so far.
Fuel injector resistance is close to 16 ohms per injector. I’m getting 19.4, 19.8, 16.8 and 17.1 for injectors 1-4 resp.
Checks of the injection module resistance and voltage values are for the most part good, for what I was able to measure. However, I’m seeing these potential issues (or maybe I’m not measuring something correctly?):
1) power to hall sensors measured at the hall plug after the ignition module measures 10.60V, not 12V
2) pin 7 reads 11.58V with the starter running, not 0-1V – it does read 12.15V with just the ignition switch on, per the guide
3) pin 8 reads 2.5mV with starter running, not 10-20mV
4) pin 11 reads 11.60V with ignition on, drops to around 10V with starter running – not 0-1V per the guide.
5) I also checked the voltage at the coil end of wiring to see what pins 9/10/14 should be pushing to the coils (1.5-4V per the guide). I’m seeing 0.08V for pin 9, 11.62V for pin 10 and 0.15V for pin 14 all with starter running.
Resistance at coil primaries checks good. However, high tension leads DO NOT measure any resistance (as if there’s an open circuit). I suspect the coils have gone bad, but I’m curious if other owners have had this experience. Both go faulty at the same time due to age?
Hall sensors check good. I used a 12V LED and found that a feeler gauge of 0.012” or greater would break the signal. Anything thinner (or Al foil) would not break the signal.
If I were to replace anything at this time I’d swap out the coils, although with the different readings I’m seeing with the ignition module I’m not so sure.
I’m going to continue troubleshooting, next up is the Fuel Injection module check.
Thanks,
Tony Marts
