Fuel injector driver failure??

For discussing injector selection,manifold modifications, throttle bodies, fuel supply system design and construction, and FIdle valves and IACs.
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wtfman2
MegaSquirt Newbie
Posts: 2
Joined: Fri Oct 12, 2007 3:54 pm

Fuel injector driver failure??

Post by wtfman2 »

Hey Guys I have MS2 Pcb 3.57 and High impedance injectors(ford 42lb/hr) It was running and just seemed to need tuning.
Now it wont start even with the old files it used to run on. I finally took it back out of the car and put it on the stim again and I got 1 injector bank that works (bank 2) and one that dosen't. When zi turn the revs up the D17 diode starts to smoke so I turned it down and it quit and I unplugged it and sat down at the Computer to type this. I had this problem before on a differant car with MSnsextra on v2.2 board and put in the flyback board and had no problems since but those were low impedance injectors (dsm450cc) I thought I shouldnt have these types of problems with the new boards and high impedance injectors. any how I could use some advice as to why this could have happened and where i can get the Surface mount diodes and what else might be bad Thanks in advance.




Clinton
Matt Cramer
Super Squirter
Posts: 2951
Joined: Sat Jul 03, 2004 11:35 am

Re: Fuel injector driver failure??

Post by Matt Cramer »

What were your settings for the PWM current limiting?
wtfman2
MegaSquirt Newbie
Posts: 2
Joined: Fri Oct 12, 2007 3:54 pm

Re: Fuel injector driver failure??

Post by wtfman2 »

Well they are 25.4 and 100 since they are high impedance as per the Manual. I also made an LED tester and I get signal out of the pin 7 on U4, but not to the pin 1 on Q1. There is a resistor on the board at R15 that showed heat damage and i thought I saw some smoke from it at higher revs on the stim. I get signal to it but not thru it. I replaced it with a 22ohm 1/4 watt thruhole style resistor that I got localy as i cant find the correct surface mount piece and i got the same thing( no smoke I left the revs down) Is it possable that the Q! is shorted to ground so it is soaking up the signal ?????




Clinton

Thanks Matt
Matt Cramer
Super Squirter
Posts: 2951
Joined: Sat Jul 03, 2004 11:35 am

Re: Fuel injector driver failure??

Post by Matt Cramer »

It sounds like Q14 is damaged.
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