no fuel, pulse width 0 while cranking
#1
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Location: Nashville/Knoxville, TN
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ok heres the deal:
-dsm 450cc injectors on honda resistor box
-95 1.8L with 99 head
-ms1 v3.0
- toyota cops, checked spark on all cylinders, sparks great
attached is ths msq. tested the fuel injectors with a spare injector plugged in and held to my ear. it clicks once when you flick the car to 'on' then it seems like it clicks a few times on cranking and then stops clicking. megatune shows a pulse width of 5.0ms when you turn the key to the on position, then drops to 0 and does not do anything when cranked. i checked all the connections in the engine bay, and this car did run badly for a little while, but now won't start. does this indicate a ground issue?
-dsm 450cc injectors on honda resistor box
-95 1.8L with 99 head
-ms1 v3.0
- toyota cops, checked spark on all cylinders, sparks great
attached is ths msq. tested the fuel injectors with a spare injector plugged in and held to my ear. it clicks once when you flick the car to 'on' then it seems like it clicks a few times on cranking and then stops clicking. megatune shows a pulse width of 5.0ms when you turn the key to the on position, then drops to 0 and does not do anything when cranked. i checked all the connections in the engine bay, and this car did run badly for a little while, but now won't start. does this indicate a ground issue?
#5
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I thought it was a noisy cas signal so I re-wired the signal wires in their own separate shielded wire, away from the other harness wires. confusingly, this helped the rpm signal only slightly. At first, when you'd go over about 50% throttle the signal would start to act up. Now, it's more like 75%. However, I also noticed that all the values on the log would occasionally peak, seemingly unrelated to the cas issue:
![Name: graph-1.jpg
Views: 391
Size: 45.9 KB](https://www.miataturbo.net/attachments/megasquirt-18/198305d1501238154-no-fuel-pulse-width-0-while-cranking-graph-1.jpg)
as you can see, all the values go nutty, then the unit resets once. Looking back throgh previous logs, I noticed these where I hadn't before becase I was only looking at the cooky rpm signal. What can cause this? Now that I rewired the cas, I'm beginning to think it's bad grounds. But why would the cas act up by itself, then all the sensors act up, then the megasquirt reset? The car runs great and starts every time, jst takes a **** when you gank it.
And randomly, one or two datalogging runs, the cas did not mess up (or messed up about 1/10th as much) and we were able to floor it, hit max boost, then redline, several times with no incident. We had actually thought that somehow we had unwittingly solved the problem. This datalog is similar to the post-cas-wiring log, it does have a couple of rpm spikes here and there, but they werent that noticable while driving the car.
Enclosed are two more logs and the msq that I have modified since the first post.
btw, we plugged this ms into my car and I loaded my msq on it, and it ran 100% fine. I never did a datalog though.
![Name: graph-1.jpg
Views: 391
Size: 45.9 KB](https://www.miataturbo.net/attachments/megasquirt-18/198305d1501238154-no-fuel-pulse-width-0-while-cranking-graph-1.jpg)
as you can see, all the values go nutty, then the unit resets once. Looking back throgh previous logs, I noticed these where I hadn't before becase I was only looking at the cooky rpm signal. What can cause this? Now that I rewired the cas, I'm beginning to think it's bad grounds. But why would the cas act up by itself, then all the sensors act up, then the megasquirt reset? The car runs great and starts every time, jst takes a **** when you gank it.
And randomly, one or two datalogging runs, the cas did not mess up (or messed up about 1/10th as much) and we were able to floor it, hit max boost, then redline, several times with no incident. We had actually thought that somehow we had unwittingly solved the problem. This datalog is similar to the post-cas-wiring log, it does have a couple of rpm spikes here and there, but they werent that noticable while driving the car.
Enclosed are two more logs and the msq that I have modified since the first post.
btw, we plugged this ms into my car and I loaded my msq on it, and it ran 100% fine. I never did a datalog though.
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