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Topic: Engine died on freeway -- ECU? (Read 1726 times) previous topic - next topic

Engine died on freeway -- ECU?

Background -- the engine was hesitating a bit the last couple of months (I was trying different things to troubleshoot) usually when warmed up and under load i.e. accelerating from low rpms.  It always runs well on the freeway.  Today it just died all of sudden while driving 70 mph on the freeway.  I thought maybe it was my fuel pump because when I turn the key to run, the fuel pump just runs continuously.  When I got it home, I checked the schrader valve while the pump was running and gas came spraying out.  Pulling codes no longer works when connecting the proper jumper and the car will not start.    I found this comment on the forum that does describe my situation (except my car won't run at all).  Does this mean my ECU (A9P) is blown?  Is there a way to get it out of LOS?  Thanks in advance!

You said the pump runs continuously when you try to pull codes.
Does it also run continuously with the ignition in RUN without the STI grounded?
It should shut off after a second or two when the EEC senses that the engine is not running.
The pump running continuously can mean the software in the EEC is not running and the EEC has gone into a hardware only mode called LOS (Limited Output Strategy)
This means the EEC cannot look at any of the input sensors. The TFI goes to base timing (just like the SPOUT being unplugged) and the injectors are pulsed at a fixed pulse with.
It is supposed to be able to run like this to 'Limp Home" but not very well. It will run rich at low RPM. Does it smell like it's flooding?
'88 Bird 5.0, TW 170s, HO cam, Scorpion rockers, Explorer intake 70mm TB/EGR, MAF conversion, 24# injectors, 8.8 3.73 disc rear end swap, console swap, leather seats, 11" front discs, 15-1 rack, TC springs all around, x-pipe, BBK headers,  welded sub-frame, unlocked digital speedo.

Engine died on freeway -- ECU?

Reply #1 –
I'd run through an ego no start, it shows you the proper grounding points for the computer and all the sensors. The grounding pins to the computer are 20 40 and 60. If you verify all the grounds are correct, you can check for a blown cap (what usually fails) by applying a ground to any or all of those pins. If you can get the computer to work again that way, then its time to pull the computer out and go over it real well

Hopefully its just a bad ground or connection.

http://sbftech.com/index.php?topic=588.0
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

Engine died on freeway -- ECU?

Reply #2 –
Quote from: Haystack;465292
I'd run through an ego no start, it shows you the proper grounding points for the computer and all the sensors. The grounding pins to the computer are 20 40 and 60. If you verify all the grounds are correct, you can check for a blown cap (what usually fails) by applying a ground to any or all of those pins. If you can get the computer to work again that way, then its time to pull the computer out and go over it real well

Hopefully its just a bad ground or connection.

http://sbftech.com/index.php?topic=588.0


thanks Haystack.  I didn't know what you meant by blown cap until I stumbled on this:  http://support.moates.net/capacitor-repair-ford-a9l-ecm/

Coincidentally,  I had been using a bunch of those cheapo battery tenders on my other vehicles and after a year or two they started to fail.  I ended up replacing the 'caps' in the failed ones and they work fine again.  It's definitely worth a try with the ECU -- better than paying $350 for another one unless I have to.
'88 Bird 5.0, TW 170s, HO cam, Scorpion rockers, Explorer intake 70mm TB/EGR, MAF conversion, 24# injectors, 8.8 3.73 disc rear end swap, console swap, leather seats, 11" front discs, 15-1 rack, TC springs all around, x-pipe, BBK headers,  welded sub-frame, unlocked digital speedo.

Engine died on freeway -- ECU?

Reply #3 –
A1Cardone will rebuild them through AutoZone. I shipped my A9L years ago and requested that I get my ECU back and they did it for $100. I think the cost has gone up but if you don’t need the car everyday this may be your cheapest option. I have a working spare but it took me a couple months of randomly checking the classifieds on several Mustang forums.

83 351W TKO'd T-Bird on the bottle


93 331 Mustang Coupe - 368 rwhp

Engine died on freeway -- ECU?

Reply #5 –
Thanks guys.  Great to have additional options.
'88 Bird 5.0, TW 170s, HO cam, Scorpion rockers, Explorer intake 70mm TB/EGR, MAF conversion, 24# injectors, 8.8 3.73 disc rear end swap, console swap, leather seats, 11" front discs, 15-1 rack, TC springs all around, x-pipe, BBK headers,  welded sub-frame, unlocked digital speedo.

Engine died on freeway -- ECU?

Reply #6 –
quick update.  opened up the ECU.  sure enough the positive lead on one capacitor had disintegrated and the other lead wasn't much better.  The other two caps looked ok.
I replace the bad one only but it didn't fix the issue.  Maybe the other capacitors are bad but just not showing any signs.  I think what I need to do at this point is get another A9P and make sure that it fixes my problem.  Then I'll replace the other two caps and see if I have a working spare.
'88 Bird 5.0, TW 170s, HO cam, Scorpion rockers, Explorer intake 70mm TB/EGR, MAF conversion, 24# injectors, 8.8 3.73 disc rear end swap, console swap, leather seats, 11" front discs, 15-1 rack, TC springs all around, x-pipe, BBK headers,  welded sub-frame, unlocked digital speedo.