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Author Topic: No signal to fuel injectors  (Read 2073 times)

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Offline denmach1

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No signal to fuel injectors
« on: August 28, 2014, 10:51:54 PM »
Hey, I have installed a 85 cougar turbo setup in my 77 Cruising wagon. I am using a LA2 ecu and an msd ignition system. I have 12v at the injectors with the key on but no signal from the ecu when I try to start it. I am wondering if there is something I need to run to pin 4(IDM) or pin 36(spout) or pin 30(NDS/NI)? There is currently nothing run to these pins because I am using a MSD  system. I have correct power and grounds at the correct pins everywhere else. I am getting a good spark but no fuel. I have good fuel pressure on the rail but the injectors aren't getting a signal. Any help is greatly appreciated

Offline amc49

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Re: No signal to fuel injectors
« Reply #1 on: August 29, 2014, 06:40:57 AM »
Maybe missing the timed input to set up the injection timing, dunno about that early stuff, it may be tied to the spout which registers blips which could be read to get that. If PCM does not know where the cylinders are in relation to timing it cannot send injection pulses.


Offline denmach1

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Re: No signal to fuel injectors
« Reply #2 on: August 29, 2014, 09:17:48 PM »
GOT IT!!!!!!!!!! I know more about EFI systems than I ever cared to. My first mistake was using a aftermarket distributor. I installed the factory one and immediately got the injectors to work. Then I couldn't get fire to the coil. I had power to the coil but no spark output. After much cussing and head scratching I replaced the ballast resistor and BAM! She sounds awesome!

Offline Wittsend

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Re: No signal to fuel injectors
« Reply #3 on: August 31, 2014, 05:13:34 PM »
Glad to hear you got it going!    Ironically mine fired up on the first turn of the key..., then it took a few years to find a solution to running poorly. And, that was all it was, a solution (running 12V directly from the battery to the + side of the coil).  So, I'm not even sure what the specific problem was, only that it fixed it.  BTW, that 12v comes through as  relay so when I turn the car off, - it actually shuts off.

Offline denmach1

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Re: No signal to fuel injectors
« Reply #4 on: August 31, 2014, 11:01:04 PM »
That is good to know. I am still running the MSD ignition box and coil with the factory distributor. I compared the spark to the factory coil and there is a world of difference. The MSD provides a MUCH hotter spark. The coil gets its power from the box. I am moving on to the interior and body work now. A few more weeks, and there will be one more Pinto on the road!!!!!(and probably the only one in my town)  8)

Offline 65ShelbyClone

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Re: No signal to fuel injectors
« Reply #5 on: September 01, 2014, 11:52:44 AM »
GOT IT!!!!!!!!!! I know more about EFI systems than I ever cared to. My first mistake was using a aftermarket distributor. I installed the factory one and immediately got the injectors to work.

Sounds like either the TFI (thick film integrated) module on the aftermarket distributor or the PIP (profile ignition pickup) inside wasn't working. Aftermarket versions of these parts are notoriously low quality compared to Motorcraft replacements.

Quote
Then I couldn't get fire to the coil. I had power to the coil but no spark output. After much cussing and head scratching I replaced the ballast resistor and BAM! She sounds awesome!

Are you using a stock round coil, the Cougar TFI (square) coil, or something else? I don't think TFI coils use ballast resistors because dwell is controlled by the module.
'72 Runabout - 2.3T, T5, MegaSquirt-II, 8", 5-lugs, big brakes.
'68 Mustang - Built roller 302, Toploader, 9", etc.

Offline denmach1

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Re: No signal to fuel injectors
« Reply #6 on: September 01, 2014, 07:45:04 PM »
I am currently using a Blaster coil with the MSD box. I tried a Procomp distributor with a magnetic pickup. That distributor wouldn't work with the ecu. I then installed the factory distributor. I was having problems with the coil intermittently firing.(the MSD coil and I also tried the factory coil without the MSD box,and it didn't work either) I traced the wires and there is a resistor in line with the wire that sends the signal for the coil to fire. I replaced the resistor and everything works great now.

Offline 65ShelbyClone

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Re: No signal to fuel injectors
« Reply #7 on: September 02, 2014, 01:28:06 PM »
I tried a Procomp distributor with a magnetic pickup. That distributor wouldn't work with the ecu.

Well that explains at least part of it. The Pro Comp distributor is intended to be used with a Duraspark box or a GM HEI module due to the variable reluctor pickup that generates a sine wave signal that has to be conditioned into a square wave before a digital system can use it (aftermarket ignition boxes usually do it internally). The Ford TFI distributor has a Hall Effect sensor that outputs a square wave signal to begin with and I think the TFI module takes it down from 12v to a microprocessor-friendly 5v, but I'm not certain.

Just throwing this out there in case anyone else runs into a similar problem and uses the search engine to find answers.
'72 Runabout - 2.3T, T5, MegaSquirt-II, 8", 5-lugs, big brakes.
'68 Mustang - Built roller 302, Toploader, 9", etc.