Fox '87 GT can't get to stay running

[DadLife0724]

I bought my car and it had major fuel issues. Screwed around for a few months here and there trying to get it right. Finally pulled ecu and it was beyond bad. I would check that before beating your head against the wall too much man.

 

[AeroCoupe]

So to swap an 87 car over to MAF using a stock harness you need one out of a 1989 car only. This is due to the dash wiring connectors at the brake booster. 1990 is a one year only, 1991 though 1992.5 is another harness and 1992.5 to 1993 is another harness. Last two series have air bag wiring in them and the fuel pump relay got moved on the 1992.5 to 1993 harness. All of them have different dash wiring connectors.

This is why I suggested you just use your existing harness and swap pins around and add the couple of wires for the MAF.

Mass Air Conversion Harness. Fits 86-88 5.0L

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www.andersonfordmotorsport.com

 

[spilly]

Hey thanks for all the replies everyone. I haven't been able to work on the car for a few days here but I did check fuel pressure and it seems ok. Roughly 32 psi on prime and holds that pressure. Roughly the same pressure when idling. Pulled the vacuum line off the regulator and it jumped up to just over 40psi so that seems to be working also.

I picked up one of those inova Ford obd1 code readers but that didn't give me anything. Plugged in ita just reading 000. A quick Google search suggests it's just not communicating with the ECU. Possibly something wrong with the harness or maybe it's because of that intermediary adapter.

I'm starting to consider just going to a standalone setup to eliminate the old messed up harness and any potential issues that could be in the ECU.

Going to order a rebuild kit for the injectors and get those cleaned here soon. Fwiw I was able to start and move the car out of the garage under its own power. But after giving it a bath it's back to not starting, just cranking endlessly and smelling of fuel.

 

[AeroCoupe]

Typically if the code reader does not get any codes (should get an 11 then. 10 and then another 11 if everything is good to go) the ECU has problems. You can verify this by checking for codes the old school way.

Electrical Thread 'How To Pull Codes From EEC-IV In 86- 95 5.0 Mustangs'

Jan 27, 2016

@Noobz347 - The code dump procedure isn't in the sticky - you may want to add it...



Dump the codes: Codes may be present even if the Check Engine Light (CEL) isn't on.

Dumping the computer diagnostic codes on 86-95 Mustangs

Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.

Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.

Here's the way to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for...

• jrichker
• Replies: 10
• Forum: Fox 5.0 Mustang Tech

• 

If you do not get codes using this method then it’s most likely the ECU which isn’t a surprise as they are now 33+ years old. Best place to send it is here:

Ford Mustang 5.0 A9L A9P C3W A3M X3Z ECU Repair Service

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www.theecuexchange.com

 

[CAMTWO1070]

Hi everyone. First post on the forum.

A little back story on the car. I recently inherited this '87 GT from my uncle. I remember this car very fondly from my childhood and am very happy to be the one to bring it back to life. Through my teenage years I remember the car was a constant work in progress.

The car has been parked for a very long time. Last time it was insured was 2008. It has been parked since then. I took possession of it a few weeks ago and have been going through it attempting to get it running. Rodents had gotten into the car and made a bit of a mess of things, the odd wire chewed sort of thing. I've been able to get it to start and idle (very poorly) but that has been about it. I'm not able to touch the throttle without stalling the engine instantly. When it does eventually idle half decent it's running very rich. Still can't touch the throttle tho.

Here's some details about the car;

'87 GT 5.0
Powerdyne supercharger
Cobra intake
Fully rollerized
Don't know what heads are on it
Bbk equal length headers
Msd boost timing controller
Built AOD w/ high stall torque converter
B&M hammer shifter
5 lug conversion

New gas tank, new walbro 255 lph pump, new fuel filter, new sending unit. New spark plug wires, spark plugs and new fluids, new TPS sensor.

Smoke testing the vacuum system didn't reveal anything either.


Now the stuff that's got me confused...

The car has an ecu from a 93 cobra (according to my research)

The engine harness is from '87

There is a MAF sensor on the intake with wires going up to the firewall and seem to have never been connected to the ecu?

Map sensor on the firewall has vacuum line removed and the line coming from the upper intake has been plugged. The car actually idled worse when I reconnected the vacuum line to the map sensor.

There are all kinds of vacuum lines pulled off and plugged near where the engine harness goes through the firewall. Presumably some emissions related stuff?

The engine bay isn't super tidy and seems like things have been eliminated but left behind. There are several plugs on the engine harness that are not connected to anything and I'm not sure if that has been intentional or not. Not sure if there is a tune on the ECU to tune out the maf or not. It's been a little difficult going through things because I don't know where things were left when my uncle stopped working on the car and unfortunately he's longer around to ask.


Anyone who can help point me in the right direction would be greatly appreciated.

Thank you!

Heres what I would do....Id go to Moates website and buy a QUarterhorse and a Binary Editor license...You have too much stuff disconnected to keep the cera running right especially the EGR as your timing is basically locked out..The 255lph pump will need an adjustable fuel regulator...I use a Kirkey..



Pull the ECU and post the catchcode..If its an A9L youre gonna need it probably rebuilt as the clutch pedal wiring is different and in the 87 grounded to the body...In the A9L the clutch pedal is hooked into pin #46..There are other differences too.

 

[86HO5.0]

The car will start and run fine with the EGR disconnected, no need for a Moates to alleviate that.

Adjustable FPR is a waste of money, LTFT will negate the changes.

 

[CAMTWO1070]

I bought my car and it had major fuel issues. Screwed around for a few months here and there trying to get it right. Finally pulled ecu and it was beyond bad. I would check that before beating your head against the wall too much man.

The first thing I do when I buy An A9L from a seller on eBay is have it instantly shipped to a ECU repair shop located in Florida and they change out the capacitors etc and send me a unit that gives me peace of mind and while the ECU is being rebuilt on vehicles I buy I unplug all the sensors and do a continuity test on the harness between the sensors and the ECU plug.

This way if there was an issue that messed up the ECU it won't happen if I catch one and that's where my ECU guy shines because he gives insight on where an issue may lay for vehicles that I buy...

A cheap worthwhile tool to have is a TFI module tester as it tells you the state of the TFI module and it's easy to use a multimeter to test the halls effect pickup sensor....it's the best $12 you'll spend but an even better worthwhile mod is doing the TFI module relocation mod and using the kits on the market either as they create an extra ground loop that causes high interference from rf and emi.

I've been building my own for a while but never considered selling any but won't mind sharing my methodology behind getting a more stabilized ignition system and it's quite complex too ..I plan on posting it maybe today .

Thanks for the public service announcement..

 

[spilly]

Just thought I'd update for anyone curious. After going through every possible reason the car wouldn't restart, I came to the conclusion that it had to be the ECU and/or harness. I installed a Holley terminator x and things have been running great ever since. Holley self learn got the car running ok but was in real need of a proper tune. Got the car on the dyno and made 340 rwhp and 370 trq on a mustang dyno. The AOD works great but I must admit it's not a whole lot of fun. I'm keeping my eyes open for a manual swap. Turns out my car was originally a manual car and has been converted to auto. Will be a whole lot more fun once I swap it back. In the meantime I'm enjoying the hell out of it for the summer months!