MS3X injector circuits
#1
MS3X injector circuits
Hi there, can anyone please let me know what voltages should be present on the MS3X injector outputs, if everything works correctly?
Took race car to Thunderhill last weekend - car ran fine for one lap, then engine started to cut out and eventually stopped working - wouldn't start at all. We traced the problem down to injectors not firing. Wiring between ECU and injectors checked out fine, rpm was present and crank/cam sensors registered without sync issue. Voltage measured on injector outputs was less than 1V and fluctuating, so we are assuming that somehow the MS3X injector driving circuits went out / got damaged. Does that assumption sound reasonable or are we missing anything else, here? We also found that one of the belt pulleys had eaten through the crank sensor wiring protective sleeve and exposed a bit of the black wire going to the cam sensor, so there's a chance that that black wire made contact with engine ground via the belt pulley - could that potentially have damaged anything inside the ECU?
Thanks much in advance.
Cheers
Took race car to Thunderhill last weekend - car ran fine for one lap, then engine started to cut out and eventually stopped working - wouldn't start at all. We traced the problem down to injectors not firing. Wiring between ECU and injectors checked out fine, rpm was present and crank/cam sensors registered without sync issue. Voltage measured on injector outputs was less than 1V and fluctuating, so we are assuming that somehow the MS3X injector driving circuits went out / got damaged. Does that assumption sound reasonable or are we missing anything else, here? We also found that one of the belt pulleys had eaten through the crank sensor wiring protective sleeve and exposed a bit of the black wire going to the cam sensor, so there's a chance that that black wire made contact with engine ground via the belt pulley - could that potentially have damaged anything inside the ECU?
Thanks much in advance.
Cheers
#2
SADFab Destructive Testing Engineer
iTrader: (5)
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Injector outputs are grounding outputs. So the MS3x pulls the injector to ground. 1v sounds reasonable without a load.
Really you need to get a scope on the output and see what its doing.
Really you need to get a scope on the output and see what its doing.
#8
Senior Member
iTrader: (1)
Join Date: Sep 2011
Location: Lambertville, NJ
Posts: 1,215
Total Cats: 74
If you have 9V on one side and 0-1V on the other, then your injectors are firing. The battery is not the greatest, but it doesn't seem like an MS problem.
When you say you traced the problem to "Injectors not firing", how was that determined?
Maybe it's a fuel pump issue?
When you say you traced the problem to "Injectors not firing", how was that determined?
Maybe it's a fuel pump issue?
#9
Fuel pump is brand new (less than 2 month old), but we took it out and checked it anyway, but couldn't find any issue - we also replaced the fuel filter just to be sure. Fuel pressure gauge in the engine bay was reading a constant 40psi. The engine would start right up when we sprayed some brake cleaner into the intake, so it was clear it didn't get any fuel. Since we had eliminated most of all other typical reasons for not getting fuel, injectors not firing was the last remaining plausible clause (we didn't take the intake off in order to get the injectors out, though) .
#12
Turns out that we have some log files on the SD card, but they are all in ".ms3" format. Seems like MegaLogViewer HD is unable to read the logs in this format directly off the SD card. Is it possible to convert the logs to a format the MegaLogViewer can read? The MS3X is out of the car so not hooked up to 12V power.