Ford 5.0ltr Computer issues

[Chris L]

Hi all;

Just looking for some opinions, but it looks like I have a buggered computer, should know for sure by middle of next week. But in the meantime this is what happened.
The car has sat idle for over 12 months as we have been travelling. At the end of 2013 I drove it into the old mans farm shed and covered her up. I asked him to run it whenever he could, but the first time he tried it wouldn't start. I thought he wasn't getting the immobilizer sequence right on start up, but my brother tried and still no go, and he knew how to do it, so I ruled that out. Basically we had no fuel pump prior to crank up and this had happened before and was fixed by swapping a few relays around and she fired up. Tried that, no good, a test revealed no power to the fuel pump ( external Bosch, sits under tank) and also no spark. Tried also to re program remotes for immobilizer as this had been a previous issue also before we realised there was no spark.
Onto the trailer and to the auto elec. Told him to rip the immobiliser out as I was over it and also told him I feared the computer may have an issue, talking to him today he thinks the same after trying without success to fire it. Computer has been sent for diagnosis.
Does anyone here think we have overlooked something ?. The computer came with the motor (1993 HO 302 injected Mustang unit from the US). Also who would you recommend I chase for a similar replacement unit and what sort of dollars can I expect to pay, I would prefer a second hand unit as a new power plant and computer is due soon and when this motor goes for sale, I want it to be complete. Hopefully the diagnosis will reveal a simple and cheap fix...........but the way my luck is running I'll prepare for the opposite.

Appreciate the insight and ideas

Regards
Chris & Melissa Lidgerwood

[gjkrv8]

Just wondering if the computer has lost it stored settings such as "no Body computer Security module" blah blah. i.e. It might not be faulty, just needs re-programming to tell it not to look for a Body Computer module etc? (Note: I am thinking in my LS1 ECU/BCM terms so not sure if it is the same for Ford ECU etc) Cheers Gregg

[Chris L]

Cheers Gregg,........ when I lost things I was told it would be where I left it!!. Anything electrical like this is foreign to me...........absolutely hopeless !
Thanks
Chris

[gjkrv8]

No worries Chris- I work in Electronics/IT - first rule of troubleshooting is "turn it off - then on again", second rule "reset it to factory default and try again". Fixes 99% of Electronic/Computer stuff :-)

[Chris L]

Thanks Gregg, will keep that in mind............if I mention that, they may think I know a bit !!
Cheers
Chris

[dave295]

What kind of system are you running?
Is it a Ford EECIV or a PCM or a ?

[Chris L]

Its a standard system Dave, came with the motor, the whole lot was lifted from a 93 Mustang to my knowledge. I'm 4 hours from the car at present so I cant double check for you.
Cheers
Chris

[07cob]

Chris

Did your auto sparky check to ECU for any error codes?

I also had some issues early on with a bad earth. Similar symptoms. Power to ECU but no pump. And the earth that was causing a problem was nowhere near the ECU. Storage could have played havoc with earth connections. May be unlikely but could be something to check.

On another note, what is the plan for the new power plant?

Geof

[stephen low]

Chris

Why don't you bite he bullet and buy a good aftermarket ECU now that can be programmed to the 5L for now and then re-programmed for your alternate engine later.

Not cheap but am sure it would help spread the expenditure.

Just a thought mate.

[dave295]

OK Chris,
1, does it have a distributor at the front middle of the engine and a coil above cyl. 8
2, is the computer a silver rectangle with a long connection plug about the length of the shorter side.

[PSB]

The fuel pump not running is a classic sign of a dead computer. You can get a used one for ~$150-200. I'd suggest e-bay, The Corral classifieds, or FFCars classifieds to find one.

Pete

[Chris L]

Thanks fellas for the tips, I will be mentioning them when I speak to the auto elec.
Dave, I will say yes to both questions, but cant access the car at present to check.
Geof, I started a thread on the new engine so if you search ' New 331 Windsor build' something should come up. Hoping to add more details and pics soon as the heads are just about done, but with the endurance season here with the V8s, it could be slow going. But Im sure the wait will be worth it.

Cheers
Chris L

[dhs.buckley]

Hi Chris, My python still has the computer sitting in it, was never removed from when it was swaped to a carb, is it the black box about 120mmX200mm long from memory last time i looked in the passenger foot area?
I am not sure if anything is still running off it.

[dave295]

Hi Chris'
It sounds like your engine is using Fords EEC IV. The control units are pretty bulletproof.
They use two relays to power the system, these are bigger than your standard "box" relay.One runs the pump and the other the ignition. If either doesn't work the engine won't start. Take the cover off the fuel relay and close it with your finger (with key on). If your pump runs your relays faulty. Do the same with the EEC relay (with key on). Your EEC LIGHT or CHECK ENGINE LIGHT should illuminate. If it does then its your relay.
If it is the relay clean the contacts and carry a spare in the car.
Eec iv is the Ford Electronic Engine Control iv (four) system. Google eec iv and learn heaps, like how to read all your engine info with nothing more than a test light and a short piece of wire.

[olddog]

A 1993 mustang gt with 5.0 manual transmission should be an A9L bin code. These were once highly sought after as the best of the EEC4. There are some capacitors in them that are starting to fail, now. 21 yrs is a long time for a capacitor to last. They are not hard to replace, but require soldering skills. Some experts recommend changing them out, before they fail, as when they fail they can cause other damage. Other than that, they are bullet proof.

You can chip these ECUs and have full access to change anything in the tuning parameters. Moates sell a QH (quarter horse) chip that gives amazing access. Moates.net has a write up with pictures on how to change out the capacitors. The do it yourself route will run you about $500 for chips and software, or you can take it to a dyno tuner that will cost about the same. Of course you do not need to do anything until you modify the engine. If you chip the EEC4 it can be tuned to run any engine.

An aftermarket ECU that will give you the access that the maotes chip gives you will run $2000 - $3000.

Here is a link to Moates, if you are ever interested
https://www.moates.net/

PS.
When the Key is on the ECU is required to turn the fuel pump off. If the ECU becomes corrupted, the fuel pump will run continuously with the key turned on. I doubt the ECU is your problem. A relay or fuse is much more likely.

[DaleG]

I have lots more, but the files are too large to post here. If anyone wants them, PM an e-mail address and I'll send as attachments. Hi Baz!

Cheers, Dale

1987-1993 computers: You can use either the A9L or A9P in a five speed fox body mass air car. Some say the A9P has a slightly aggressive spark and fueling tables and does not retard timing between shifts and the A9L does but I have no verification on that. The A9L computer came in 1987-1993 5 liter-manual transmission Mustangs. The A9P computer came in 1987-1993 5 liter-automatic transmission Mustangs. The A9S came in 1988-1993 California emissions Mustangs. The X3Z computer came in all 1993 Cobra Mustangs.

86-93 Mustang idle issues: Idle issues are common on these cars, especially 5-speed cars. EGR Valves, Idle Air Bypass solenoids and Throttle Position Sensors are common causes. A bad connection with the 10 pin (salt and pepper shakers) black and white engine electrical connectors can also cause poor idle quality. To ensure a good connection on the 10 pin connectors a little modification can be done which is fairly easy and will cure some surging and hanging idle issues on 86-93 Mustangs and should be the first thing done when tackling any idle issues.

10 Pin Connector modification:
1. Take the 10 pin connectors apart (salt and pepper shakers).
2. use a pick like tool to spread the male terminals open more so they make better contact. In the center of each male terminal there is a small seam and seams down the sides of the terminal which allows you to spread them open.
3. Apply some dielectric grease to the terminals
4. Plug the connectors back in.

Throttle Position Sensor (TPS) adjustment:
Without the proper adjustment, the throttle position sensor (TPS) will give the computer false reading as to the exact throttle opening. A false reading will limit wide open throttle performance. A voltage reading must be taken using a digital volt/ohmmeter (DVOM) with the Key On/Engine Off and with the Key On/Engine Running.

The TPS is located directly on top of the throttle body and is adjusted by loosening the two phillips mounting screws and swiveling the sensor until the highest reading is found. It may be necessary to elongate the holes with a small drill bit or small file to achieve the desired reading. The spec range for Key On is from .88 to 1.0 volt; shoot for the .90 to .98 volt. Make sure voltage reaches/exceeds 2.71v at WOT.

Incorrect Throttle Position Sensor (TPS) voltage will result in reduced performance including a possible hanging/surging idle. The best way to take a TPS voltage reading is by using two safety pins through the wires coming from the sensor. The positive lead is attached to the green wire, while the negative goes to the black wire. Always ground the meter through the sensor's black wire. This gives a direct, and more
accurate ground into the computer.



Resetting the base idle:
1. Clear the computer's idle memory by disconnecting the battery for 20+ minutes.
2. Disconnect the Idle Air Bypass solenoid
3. Reconnect battery
4. Start engine and set idle speed to desired RPM with idle screw on throttle body
5. Turn off engine and reconnect the air bypass solenoid
6. Set TPS voltage between 0.90 - 0.95 volts with a digital volt meter
7. Start engine and let it idle for 2 minutes with no accessories on.
8. Turn off engine for two minutes
9. Start engine again and run for 2 minutes with every accessory turned on.
10. Turn engine off again.

[Chris L]

Bit of an update, The box was sent to Injectronics in Melbourne and they detected some diode issues. So I thought bugger it I will get a second hand one and asked for it to be sent back so I could grab the numbers of it and match it up. The idea was to get one with the same numbers. The numbers on it are nothing close to what I was expecting so I suspect the computer was changed when the wiring was done and I either forgot or didn't know.

I thought I could get a 93 Mustang ECU box for a manual from the USA and be fine...........first mistake I guess.

The Number on the ECU is E8ZF-12A650-D2 and the box has "no smartlock' scribbled on it in texter...........and that's it, nothing more.

The D2 at the end is throwing all I have contacted, the rest appears to be from a late 80's Mustang. No one seems to be able to be sure.

Long story short...........back it goes to Injectronics to be fixed at twice what a second hand unit is worth, because I just cant be 100% of a direct replacement second-hand.

The fun of it all !
Cheers
Chris L

[byroncobra]

Chris,

I had no end of grief with my "93 mustang engine management and wiring,
to detail it all here would take pages.

Suffice to say that in the end I tossed the lot and installed a new engine loom and ECU from Massflo EFI. I already had their injection setup.

This promised to be a cure all......well, it wasn't quite but Chris Richards over there in the US supported the product well, tolerating lots of stupid questions and diagnosed many of my screw ups with patience.

This guy really knows engine management.

The car runs really well now.

Anyway, I see that you are persuing fixing the old A9L, if that doesn't work out PM me and I'll tell you more of the story

[Chris L]

Thanks Greg for the insight, I have a new engine on the way which will run a different brain, hence the reason no big spend on an aftermarket for this one, just want them to talk to each other and get along before the whole unit(Engine and ECU) is put up for sale.

Cheers
Chris
PS Thanks to all who offered their ideas.

[eschaider]

Originally Posted by olddog

A 1993 mustang gt with 5.0 manual transmission should be an A9L bin code. These were once highly sought after as the best of the EEC4. There are some capacitors in them that are starting to fail, now. 21 yrs is a long time for a capacitor to last. They are not hard to replace, but require soldering skills. Some experts recommend changing them out, before they fail, as when they fail they can cause other damage. Other than that, they are bullet proof.

You can chip these ECUs and have full access to change anything in the tuning parameters. Moates sell a QH (quarter horse) chip that gives amazing access. Moates.net has a write up with pictures on how to change out the capacitors. The do it yourself route will run you about $500 for chips and software, or you can take it to a dyno tuner that will cost about the same. Of course you do not need to do anything until you modify the engine. If you chip the EEC4 it can be tuned to run any engine.

An aftermarket ECU that will give you the access that the maotes chip gives you will run $2000 - $3000.

Here is a link to Moates, if you are ever interested
https://www.moates.net/

PS.
When the Key is on the ECU is required to turn the fuel pump off. If the ECU becomes corrupted, the fuel pump will run continuously with the key turned on. I doubt the ECU is your problem. A relay or fuse is much more likely.

Olddog is spot on. Check out Moates Quarterhorse. It will allow you to tune while the engine is running. You will need one other piece of s/w called Binary Editor from Clint Garity and your laptop. When you are happy with the tune you can burn it permanently to the EEC-IV memory through the OBDII port. The OBDII deal will require a J2534 cable from someone like Mongoose Technologies to read and write through the OBDII port.

Ed