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I'm seriously considering pushing this car into a river. I started a project to remove the electrical gremlins from my 1993 LX hatchback. I had spark, but could not get my fuel pump to prime; however, if I hit the fuel pump relay the pump would turn on(did this with 4 different relays, don't tell me to buy a relay). During this time the car would crank and had spark(how do I know, I put a timing light on it and turned the key and voila the light turned on) SOOOOOOOOOOOOOO what I did was put a switch on the blue wire with the orange stripe to ground so I could get the car to start, after I did this I no longer had spark, however my ignition (msd 6AL) turns on.

To review at this point, My fuel pump turns on and runs, but does not prime on its own. Spark which I had has gone away and the car no longer cranks.

Every god forsaken wire in this car has been exposed and traced to each of its origin points except for one white and purple wire which comes from the transmission and routes under the seat with the neutral safety switch. The only pinout I could find suggests that this wire is for automatic cars, mine is a 5 spd and as mentioned above I had spark, but now its gone AND the starter does not turn over the engine. Just dead at the turn of the key, no noises, nothing.

Clearly I am missing something stupid/simple/asinine etc etc here.

The car is a 1993 5.0 LX Hatchback. The engine is a 331 stroker capable of just under 400bhp. It is not a smog car and I drove it to where I started this electrical overhaul that was supposed to be mainly a headlight/tail light rework. When I turn the key on I get all of my accessory power etc but the pump doesn't prime itself but I have a switch and can turn the pump on at will which means if I still had spark, this car would start. How did I lose spark? How advanced are these OBD1 computers? What can they pick up on that would not let the car even crank. All I get now is power to the pump when I hit the switch. PCM/ECU relay is brand new as well.

My computer is an A3M.

What is keeping this car from starting? I live in a house of carburator guys. I am completely on my own with fuel injection; however, I was an electronics tech in the navy so reading schematics etc is not a challenge. I just don't know what is missing from this equation.

I really need this car to start so I can put lights in it and drive it up and down I5 to visit/take care of my children in California and also to get to work and this part of the project has put me at my wits end. I don't know what I am overlooking, everything electrically is in place and spliced in accordance with the schematics. I just had my other car repoed. I own the title to this car and cannot afford to get rid of it or replace it with anything else(crippling debt after relationship with the mother of my children ended). It's a nice drivetrain and fairly straight car, but its from florida and sat thru Katrina so it's an electrical nightmare.

somebody please tell me what is causing this. It would appear the PCM/ECU stopped powering up, yet I have voltage at the relay. I can only trace the wires so many times before I take a crowbar to my own face.....

How can I just wire this car to start and run?

Spending money, buying parts, is no longer an option and unnecessary anyway. Whatever is causing this can be fixed by a simple splice or something along those lines, I just have no f-ing clue what is left to check without being a damn Ford engineer. I'll gladly provide a VIN number to someone who can get me more schematics, but I'm pretty confident in what I have found so far.

I have started this car with this engine set up without a tuning chip and with a tuning chip in the past, so that rules out "oh it HAS to have a dynotune" no, it doesn't, it just needs to f-ing run.

This car currently has no interior, all wires are visible. Bypassing nonsense is acceptable. Car just needs to run, period.

Thanks for any help in advance

Frustrated and Confused,
-Smokey
 

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I'm seriously considering pushing this car into a river. I started a project to remove the electrical gremlins from my 1993 LX hatchback. I had spark, but could not get my fuel pump to prime; however, if I hit the fuel pump relay the pump would turn on(did this with 4 different relays, don't tell me to buy a relay). During this time the car would crank and had spark(how do I know, I put a timing light on it and turned the key and voila the light turned on) SOOOOOOOOOOOOOO what I did was put a switch on the blue wire with the orange stripe to ground so I could get the car to start, after I did this I no longer had spark, however my ignition (msd 6AL) turns on.



To review at this point, My fuel pump turns on and runs, but does not prime on its own. Spark which I had has gone away and the car no longer cranks.



Every god forsaken wire in this car has been exposed and traced to each of its origin points except for one white and purple wire which comes from the transmission and routes under the seat with the neutral safety switch. The only pinout I could find suggests that this wire is for automatic cars, mine is a 5 spd and as mentioned above I had spark, but now its gone AND the starter does not turn over the engine. Just dead at the turn of the key, no noises, nothing.



Clearly I am missing something stupid/simple/asinine etc etc here.



The car is a 1993 5.0 LX Hatchback. The engine is a 331 stroker capable of just under 400bhp. It is not a smog car and I drove it to where I started this electrical overhaul that was supposed to be mainly a headlight/tail light rework. When I turn the key on I get all of my accessory power etc but the pump doesn't prime itself but I have a switch and can turn the pump on at will which means if I still had spark, this car would start. How did I lose spark? How advanced are these OBD1 computers? What can they pick up on that would not let the car even crank. All I get now is power to the pump when I hit the switch. PCM/ECU relay is brand new as well.



My computer is an A3M.



What is keeping this car from starting? I live in a house of carburator guys. I am completely on my own with fuel injection; however, I was an electronics tech in the navy so reading schematics etc is not a challenge. I just don't know what is missing from this equation.



I really need this car to start so I can put lights in it and drive it up and down I5 to visit/take care of my children in California and also to get to work and this part of the project has put me at my wits end. I don't know what I am overlooking, everything electrically is in place and spliced in accordance with the schematics. I just had my other car repoed. I own the title to this car and cannot afford to get rid of it or replace it with anything else(crippling debt after relationship with the mother of my children ended). It's a nice drivetrain and fairly straight car, but its from florida and sat thru Katrina so it's an electrical nightmare.



somebody please tell me what is causing this. It would appear the PCM/ECU stopped powering up, yet I have voltage at the relay. I can only trace the wires so many times before I take a crowbar to my own face.....



How can I just wire this car to start and run?



Spending money, buying parts, is no longer an option and unnecessary anyway. Whatever is causing this can be fixed by a simple splice or something along those lines, I just have no f-ing clue what is left to check without being a damn Ford engineer. I'll gladly provide a VIN number to someone who can get me more schematics, but I'm pretty confident in what I have found so far.



I have started this car with this engine set up without a tuning chip and with a tuning chip in the past, so that rules out "oh it HAS to have a dynotune" no, it doesn't, it just needs to f-ing run.



This car currently has no interior, all wires are visible. Bypassing nonsense is acceptable. Car just needs to run, period.



Thanks for any help in advance



Frustrated and Confused,

-Smokey


I've found the same issues with headlights. I would make sure each has a ground hooked up for its harness or area. It's not like old fords where there is one ground for everything more or less :).



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Have you checked the eec ground at the driver fender apron?? Its a 12ga wire that runs from the neg battery post to the fender apron then forks off and has a black tubular connector that you squeeze to unplug from its mating connector.This mating connector then splits from one wire into two and leads all the way to the ecm at pins 40 & 60.These grounds are tied to the Signal Return ground (pin 46) on the ecm printed circuit board.Make sure the eec ground is tight and corrosion free at the fender and disconnect that plug,clean the terminals thoroughly and add dielectric grease before reconnecting.This is the power ground for the ecm and the sensors are affected by it also because of it being tied into pin 46.
If this ground is loose,corroded or disconnected,the fuel pump will run when the key is turned to the start position,but it'll shut off as soon as the key is released to the run position.A diagram is shown below of this ground circuit.

If you try to run a koeo test,it will most likely throw some codes considering the issues youre having.The ecm will cycle the actuators,solenoids,etc to verify whats functioning or not.It will also id an internal ecm fault with the signal return circuit too.
Before you run this test,turn the key on and make sure the check engine light comes on briefly.
Test= Run a jumper wire from the Signal Return terminal (@ the self test connector) to the STI terminal then turn the key on.If the check engine light doesnt start flashing the codes out and sits there doing nothing,theres an open in that signal return circuit.If the test doesnt begin,move one end of the jumper wire over to the neg battery post and see if the test starts now.If it does,the signal return circuit is definitely open.
The ignition switch should also be checked at the steering column.
1) 2 Yellow wires= 12volts "hot at all times"
2) 1 Red/Green= 12volts "hot with thethey on"
3) 1 Red/Blue= 12volts "hot with the key in the start position"
Red/Green powers the eec relay and ignition components
Red/Blue triggers the starter at the solenoid
Yellow powers the ignition switch.
If the Y wire doesnt show correct voltage,the fusible link is probably blown.
If the R/B or R/G dont show correct voltage,the ignition switch is bad.

BTW- if you want an easy way to trigger the fuel pump for trouble shooting purposes,connect one end of a jumper wire to a good ground then connect the other end to the Fuel Pump trigger terminal at the self test connector,located behind the driver strut tower.(Lt Blue/Orange wire) This wire runs from the ecm (at pin 22) to the fuel pump relay then splits off and runs to the self test connector fuel pump trigger terminal.This is the ground wire for the fuel pump relay and its turned on/off at will by the ecm.If the ecm doesnt turn this ground on,the fuel pump relay and fuel pump wont operate.
The ecm turns this ground on for the 2-5 second prime period,shuts the ground off,then turns the ground on again once it sees the engine is rotating(cranking) It looks for a signal from the pip sensor to verify the engine is rotating & then it turns the ground on again to energize the fuel pump relay.The 92-93 ecm schematic is listed below.

If the pip sensor is defective,it'll cause a no spark and no injector pulse condition plus the ecm wont receive the signal from the pip pulse which means the ecm wont turn the fp relay ground on again to re-energize the pump after the priming period has stopped.Sometimes you can id a bad pip sensor by removing the spout plug(at the tfi module wiring harness) then attempting a startup.If the engine starts now,the pip is bad.
You can also check one of the injector harnesses for the pip sensor pulse.Disconnect a injector harness and insert a paperclip into each terminal.Turn the key on and check the red harness wire for voltage using a multimeter.You should get battery voltage.If battery voltage is present,that indicates the eec relay is powering up.Now attach a test light clip to one of the paperclips and touch the test light probe to the other paperclip then get someone to turn the key and crank the engine.The test light should be flashing repetitively.
** NOTE ** If a helper isnt available to crank the engine,just remove the distributer cap and draw a mark on the distributer where the rotor is pointed,so you can put the distributer back to the same position after this test.Turn the key on,loosen the distributer holddown bolt and rotate the distributer left,right,left repetitively.The test light should be flashing repetitively.
If yes,youve got injector pulse.
If no,you dont have injector pulse.
JFYI- when you turn the key on and the fuel pump runs for 2-5 seconds then shuts off,the injectors dont spray fuel during this period.The fuel pump is just pressurizing the fuel lines and fuel rail,but fuel doesnt get sprayed during this time.Once the engine begins rotating (cranking) and the ecm sees the pip pulse,the ecm then triggers the injectors to spray fuel.

Another thing you need to check is the ecm itself.Remove it from the kick panel then take both of its covers off.Inspect the 3 blue capacitors for leakage,buldging and eroded posts.The printed circuit traces also need to be inspected for shorts/opens,especially the Signal Return trace which is a well known failure point on these ecms.If there is an issue within these components,they can be repaired for less than $10-$15,if youre good with a soldering gun.I can post pictures if needed.

** EDIT= Additional Info **
You also need to check to see if the ecm is powering up.If you dont hear the fuel pump prime when the key is turned on,do this.Pierce the Orange or Red tps wire with a needle,turn the key on,touch the red lead of a multimeter to this wire then touch the black meter lead to the neg battery post.The meter should read 5volts.If not,the ecm is not powering up.
If this is the case,do the following tests.
*Source* Joel 5.0

Check the EEC relay located on top of the ECM in the passenger kickpanel, make sure it has 12-vdc "always hot" at one of the relay terminals....if not, you need to trace the "always-hot" wire to the correspondent fuselink located in the starter solenoid.

Make sure the IGN ON relay terminal switches to 12-vdc when you turn the ignition key....if not, you either have a wiring open, a bad ignition switch assy., or an open fuselink.

Make sure pin #1 at the ECM connector has 12-vdc "always hot", and that pins 37 and 57 have 12-vdc when the key is switched to IGN ON otherwise, you have an open fuselink, or an open wire between the EEC relay and the ECM connector.

 Also check pins 20, 40 and 60 at the ECM connector to ground (resistance check).....if you have >5Ω resistance to a good ground reference point, the ground wires have an open somewhere.

 If all the above checks OK.....the ECM is fubar..
 

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Discussion Starter #4
@wbrockstar ok, so, I do not have my computer grounded to the battery at all, but I do have all the ground pins grounded. Something I wasn't very clear about is that I am doing a full custom "I don't have money to buy the proper sh*t, but I was an electronics tech in the navy overhaul" of the electrical system.

I do know about the jumper trick, again, in my frustration I did not explain that well. I took a generic switch and put it inline with the blue/orange wire so I could ground it on. What I noticed today is that once I ground out the pump, it stays on when I turn the switch back to open.

The PCM itself has had those 3 capacitors in question replaced.

And for clarification, you can refer to any relays/switches/fuses etc as what they are because hardly anything is in a factory position. I was an avionics tech in the NAVY so I have this b*tch all the way apart down to bare bones. Car has no interior. restoring it to highway conditions.
 

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@wbrockstar THANK YOU for the post. With the information you gave me I was able to determine that yes, My ECU is indeed FUBAR. I don't have the money to replace it, and I'm sick to my stomach from all the effort I put into this current project but at least I know now. ....if anyone on this site has an A3M computer they are willing to part with for nothing or next to nothing I would appreciate it, otherwise it's in my best interest to go stand alone due to all the internal engine modification... I'm willing to try out/use stand alone units but I cannot pay for them. Thank you All Ford Mustangs Forums.

Peace & Chicken Grease
-Smokey
 

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@wbrockstar ok, so, I do not have my computer grounded to the battery at all, but I do have all the ground pins grounded. Something I wasn't very clear about is that I am doing a full custom "I don't have money to buy the proper sh*t, but I was an electronics tech in the navy overhaul" of the electrical system.

I do know about the jumper trick, again, in my frustration I did not explain that well. I took a generic switch and put it inline with the blue/orange wire so I could ground it on. What I noticed today is that once I ground out the pump, it stays on when I turn the switch back to open.

The PCM itself has had those 3 capacitors in question replaced.

And for clarification, you can refer to any relays/switches/fuses etc as what they are because hardly anything is in a factory position. I was an avionics tech in the NAVY so I have this b*tch all the way apart down to bare bones. Car has no interior. restoring it to highway conditions.
You need to have the eec ground tied into the neg battery post because thats the beginning and end of the ground circuit.The ground should end where it originated from.The oem ground circuit is:
1) Primary Ground= Neg battery post to engine block.
2) Secondary Ground= Cylinder head (rear) to firewall.
3) EEC Ground= Fender apron to neg batt post
+ pigtail to main harness.
Even if you dont have the oem neg battery cable setup present,you still need to run a 12ga-2ga wire/cable from the battery post to the fender apron then from there to the eec ground wire on the end of the main harness at the coil.This completes the full circuit.

You dont have to use a A3M ecm.You can use any 89-93 maf ecm you want,preferably one that matches your transmission type.Heres a list of all the Ford ecms available up to the 2010 year model.
Fuel Injection Technical Library » EEC Program Codes

I would still inspect the board,eventhough the caps have been replaced.There are plenty of traces to go over.You can start at the ecm harness plug,where the pins tie in to each trace and concentrate on the spark and fuel circuit traces.
Ive got a schematic of an ecm,but its such a terrible picture you cant see the text well enough to make anything out.



Its a small world,I was in the Navy myself back in the 90's.I was in the very first class of the SWSE program after it was moved to Groton,Ct from Kings Bay,Ga.SWSE (strategic weapons systems electronics) aka: missile technician.
USS West Virginia (SSBN 736)
 
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