Spark in one cylinder

fordkid · Dec 1, 2009

Ok, tried to start the 86 5.0 that I put in my 66 mustang. leaving everything stock for the 86, two things that are going on, first, the fuel pump does shut off. I can hear it running and running and running while the key is turned on. the fuel pump shuts off once the key is turned off. I am thinking it's the regulator but I don't know where it is.

the other problem, the main problem is I am only getting spark to one cylinder, the 2nd cylinder back on the drivers side. what could cause this, I have been thinking about it and trying to find stuff online for a while and can't come up with anything other then the distributor is stuck in one position but that doesn't make any sence at all.

Thanks
Ford Kid

Celeb · Dec 1, 2009

fordkid said:
Ok, tried to start the 86 5.0 that I put in my 66 mustang. leaving everything stock for the 86, two things that are going on, first, the fuel pump does shut off. I can hear it running and running and running while the key is turned on. the fuel pump shuts off once the key is turned off. I am thinking it's the regulator but I don't know where it is.

the other problem, the main problem is I am only getting spark to one cylinder, the 2nd cylinder back on the drivers side. what could cause this, I have been thinking about it and trying to find stuff online for a while and can't come up with anything other then the distributor is stuck in one position but that doesn't make any sence at all.

Thanks
Ford Kid

As far as the fuel pump, the f/p relay could be stuck.

Have you had the distributor out? If so, how did you restab it?

fordkid · Dec 1, 2009

How do you check to see if the relay is stuck?

Never had the distributor out. took the complete engine and trans in one unit and transfered it over to the 66. only unplugging what I needed to, to remove the engine.

Thanks
Ford Kid

BlackGT89 · Dec 1, 2009

Ford Kid (I like the name !). I assume you are using fuel injection still, the FP regulator should be on the fuel rail near the intake on the passenger side. The fuel pump relay went under the drivers seat I believe for that year, but you may have relocated that. I would check all of your grounds and make sure the ones used for the '66 are the same as the ones that were used on the '86.

As far as the single spark, guess it would be good to take the distributor cap off and have a look at the rotor, inside the cap, etc. Turn the engine over with the cap off and make sure you are getting rotation of the rotor and everything is good in there.

HISSIN50 · Dec 2, 2009

As noted, the regulator is not the run-on issue.

With the FP relay, is the ground for the relay (which is computer controlled) manually grounded? If so, this will cause the pump to run anytime the ignition is on.

If you only have spark through one plug wire, I'd check injector pulsing at that cylinder and the others. The results will help narrow things down.

Good luck.

wv109323 · Dec 2, 2009

66 stang

We need to know more.
Are you running a carb or FI?
Is the fuel pump in tank or aftermarket external ? Was the fuel pump already existing on the 1966? An aftermarket external fuel pump will run constantly with the ignition-on and start.
Are you using the 1966 fuel tank or did you fit up one with an internal Ford fuel pump?
There are two firing orders for 302s One for the H.O. motors and another for non H.O. motors. Make sure you are using the right firing order for your motor. IIRC the 86 was a non-H.O. motor. The H.O. firing order is :1-7-3-2-6-5-4-8. Sorry I don't own any Non H.O. motors.
You said you did not have the distributor out but did you remove the spark plug wiring?
Are you using the 1986 ignition coil or the 1966? Answer and we will try to help.

fordkid · Dec 2, 2009

Sorry-

I am keeping the Fuel Injection.

The fuel pump is aftermarket external, and did not come on the 66. so if I am understanding correctly it is normal for the aftermarket fuel pumps to run constantly.

I am using the stock 66 fuel tank.

the motor is a H.O motor.

I only removed one spark plug wire. all the others stayed in place.

I am using the 86 ignition coil.

as for the wiring I am doing it the hard way because I am broke and want to keep extra factory options. like cruise control.

I have taken all the wiring out of the 86. 3 harnesses all together

1)The main computer wire harness,

2)The Front head light wire harness which ties into the computer harness and also has the hook up for the ignition coil.

3)the real tail light wire harnness witch also has the fuel pump wiring. I simply cut off the connecter at the end of the wire and spliced the two wires onto the aftermarket external fuel pump. so I still have the stock fuel pump relay and was able to mount it under the seat in the 66.

Popped the distributor cap off and sure enough it turns.

I have no idea how to check for injector pulse?

Thanks
Ford Kid

BlackGT89 · Dec 2, 2009

fordkid said:
Sorry-

I am keeping the Fuel Injection.

The fuel pump is aftermarket external, and did not come on the 66. so if I am understanding correctly it is normal for the aftermarket fuel pumps to run constantly.

I am using the stock 66 fuel tank.

the motor is a H.O motor.

I only removed one spark plug wire. all the others stayed in place.

I am using the 86 ignition coil.

as for the wiring I am doing it the hard way because I am broke and want to keep extra factory options. like cruise control.

I have taken all the wiring out of the 86. 3 harnesses all together

1)The main computer wire harness,

2)The Front head light wire harness which ties into the computer harness and also has the hook up for the ignition coil.

3)the real tail light wire harnness witch also has the fuel pump wiring. I simply cut off the connecter at the end of the wire and spliced the two wires onto the aftermarket external fuel pump. so I still have the stock fuel pump relay and was able to mount it under the seat in the 66.

Popped the distributor cap off and sure enough it turns.

I have no idea how to check for injector pulse?

Thanks
Ford Kid

So you are keeping the stock fuel tank and you are using an aftermarket fuel pump. The EFI system uses a fuel return system and the pressure is usually run around 40 PSI. An aftermarket fuel pump for a carb usually operates at below 10 PSI and uses a different kind of regulator. Also the stock 66 fuel lines would not be up to the task of the increased fuel pressure. I'm not sure how one gets around the obstacles of mixing and matching parts from '66 to '86, especially fuel line and wiring issues. You might be better off to go carbed, but I understand the need for FI dependability ! Maybe you could hook up with someone who has actually done the swap.

Some aftermarket fuel pumps run constantly and some don't, it depends on the type (rotory usually run on and piston type usually build up pressure and cut off).

Good point about the firing order being different for the non-HO also. The F.O. for the 289 was 1-5-4-2-6-3-7-8 (Number 1 cylinder on right bank, nearest radiator) Also keep in mind you will be using speed density as opposed to mass air metering used on '89 and up.

347HO · Dec 2, 2009

Check your "salt and pepper" connectors at the firewall. Or at least that's where they used to be located in the 86'.
Just unplug them and clean them up.

fordkid · Dec 2, 2009

Salt and pepper connectors, not sure which ones those are. you talking about the ones right there on the firewall as the main harness comes through on the passenger side.

Thanks
Ford Kid

Celeb · Dec 2, 2009

fordkid said:
Salt and pepper connectors, not sure which ones those are. you talking about the ones right there on the firewall as the main harness comes through on the passenger side.

Thanks
Ford Kid

The ones in this image as the 10 pin connectors.

fordkid · Dec 3, 2009

Checked Salt and Pepper connectors cleaned them up, same deal.

Thanks
Ford Kid

fordkid · Dec 3, 2009

Just a thought. what if I have the fuel lines reversed. I have the hard line running from the tank, that's the easy part. then I have some rubber hosses connecting the hard line to the fuel rails. maybe I crossed the lines right before the fuel rails, I have been trying to find some pictures of the rails where they run down the side of the engine but can't find any. How do I tell for sure which fuel rail is intake and which one is return. I am fairly certain I have it hooked up right but just want to double check to cross it off the list.

Thanks
Ford Kid

jrichker · Dec 3, 2009

Fuel Pump Troubleshooting for 86 Mustangs

Clue – listen for the fuel pump to prime when you first turn the ignition switch on.
It should run for 2-5 seconds and shut off. This on and off again cycle helps to prevent
flooding the engine when cranking. To trick the fuel pump into running, find the ECC
test connector and jump the connector in the upper RH corner to ground.

If the fuse links are OK, you will have power to the pump. Check fuel pressure –
remove the cap from the Schrader valve behind the alternator and depress the
core. Fuel should squirt out, catch it in a rag. A tire pressure gauge can also be
used if you have one - look for 37-40 PSI. Beware of fire hazard when you do this.

No fuel pressure, possible failed items in order of their probability:
A.) Tripped inertia switch – press reset button on the inertia switch. The hatch
cars hide it under the plastic trim covering the driver's side taillight. Use the
voltmeter or test light to make sure you have power to both sides of the switch

B.) Fuel pump power relay – located under the driver’s seat in most stangs .
C.) Clogged fuel filter
D.) Failed fuel pump
E.) Blown fuse link in wiring harness.
F.) Fuel pressure regulator failed. Remove vacuum line from regulator and inspect
for fuel escaping while pump is running.

The electrical circuit for the fuel pump has two paths, a control path and a power
path.

The control path consists of the inertia switch, the computer, and the fuel pump
relay coil. It turns the fuel pump relay on or off under computer control. The
switched power (red wire) from the ECC relay goes to the inertia switch
(red/black wire) then from the inertia switch to the relay coil and then from the
relay coil to the computer (tan/ Lt green wire). The computer provides the ground
path to complete the circuit. This ground causes the relay coil to energize and
close the contacts for the power path. Keep in mind that you can have voltage
to all the right places, but the computer must provide a ground. If there is no
ground, the relay will not close the power contacts.

The power path picks up from a fuse link near the starter relay. Fuse links are like
fuses, except they are pieces of wire and are made right into the wiring harness.
The feed wire from the fuse link (yellow wire) goes to the fuel pump
relay contacts. When the contacts close because the relay energizes, the power
flows through the contacts to the fuel pump (light pink/black wire). Notice that
pin 19 on the computer is the monitor to make sure the pump has power.
The fuel pump has a black wire that supplies the ground to complete the circuit.

Remember that the computer does not source any power to actuators, relays
or injectors, but provides the ground necessary to complete the circuit. That
means one side of the circuit will always be hot, and the other side will go to
ground or below 1 volt as the computer switches on that circuit.

Diagrams courtesy of Tmoss & Stang&2birds

Now that you have the theory of how it works, it’s time to go digging.

Look for 12 volts at the yellow wire (power source for fuel pump relay).
No voltage or low voltage, bad fuse link, bad wiring, bad ignition switch or ignition
switch wiring or connections. There is a mystery connector somewhere under the
driver’s side kick panel, between the fuel pump relay and the fuse link.

Turn on the key and jumper the fuel pump test connector to ground as previously
described. Look for 12 volts at the Light Pink/Black wire (relay controlled power
for the fuel pump). No voltage there means that the relay has failed, or there is a
broken wire in the relay control circuit.

Check the Red/black wire, it should have 12 volts. No 12 volts there, either the
inertia switch is open or has no power to it. Check both sides of the inertia
switch: there should be power on the Red wire and Red/Black wire. Power on the
Red wire and not on the Red/Black wire means the inertia switch is open.

Make sure that the power is off the circuit before making any resistance checks.
If the circuit is powered up, your resistance measurements will be inaccurate.

You will have to drop the tank to inspect the pump power and ground connector
and the pump wiring chassis ground.

Pump wiring: Anytime the ignition switch is in the Run position and the test
point is jumpered to ground, there should be at least 12 volts present on the
black/pink wire. You should see less than 1 Ohm between the black wire(s)
and ground. The chassis ground is up near the spare tire shell. To get some
idea of what a good reading is, short the two meter leads together and
observe the reading. It should only be slightly higher when you measure
the black wire to ground resistance.

The Tan/Lt Green wire provides a ground path for the relay power. With the test
connector jumpered to ground, there should be less than .75 volts. Use a test
lamp with one side connected to battery power and the other side to the
Tan/Lt Green wire. The test light should glow brightly. No glow and you have a
broken wire or bad connection between the test connector and the relay. To test
the wiring from the computer, remove the passenger side kick panel and
disconnect the computer connector. It has a 10 MM bolt that holds it in place.
With the test lamp connected to power, jumper pin 22 to ground and the test
lamp should glow. No glow and the wiring between the computer and the fuel
pump relay is bad.

Computer: If you got this far and everything else checked out good, the computer is suspect.
Remove the test jumper from the ECC test connector located under the hood.
Probe computer pin 22 with a safety pin and ground it to chassis. Make sure the computer
and everything else is connected. Turn the ignition switch to the Run position and observe
the fuel pressure. The pump should run at full pressure.
If it doesn't, the wiring between pin 22 on the computer and the fuel pump relay is bad.
If it does run at full pressure, the computer may have failed.

Keep in mind that the computer only runs the fuel pump for about 2-3 seconds when you turn
the key to the Run position. This can sometimes fool you into thinking the computer has died.
Connect one lead of the test light to power and the other lead to computer pin 22 with a safety pin.
With the ignition switch Off, jumper the computer into self test mode like you are going to dump
the codes. Turn the ignition switch to the Run position. The light will flicker when the computer
does the self test routine. A flickering light is a good computer. No flickering light is a bad computer.
Remove the test jumper from the ECC test connector located under the hood.

Fuel pump runs continuously: The fuel pump relay contacts are stuck together or the Tan/Lt Green wire
has shorted to ground. Remove the fuel pump relay from its socket. Then disconnect the computer and use
an ohmmeter to check out the resistance between the Tan/Lt Green wire and ground. You should see
more than 10 K Ohms (10,000 ohms) or an infinite open circuit. Be sure that the test connector isn’t
jumpered to ground.
If the wiring checks out good, then the computer is the likely culprit.

Prior to replacing the computer, check the computer power ground. The computer has its own
dedicated power ground that comes off the ground pigtail on the battery ground wire. Due to
it's proximity to the battery, it may become corroded by acid fumes from the battery. It is a
black cylinder about 2 1/2" long by 1" diameter with a black/lt green wire. You'll find it up
next to the starter solenoid where the wire goes into the wiring harness

If all of the checks have worked OK to this point, then the computer is bad. The
computers are very reliable and not prone to failure unless there has been
significant electrical trauma to the car. Things like lightning strikes and putting
the battery in backwards or connecting jumper cables backwards are about the
only thing that kills the computer.

See the following website for some help from Tmoss (diagram designer) &
Stang&2Birds (website host)

http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

BlackGT89 · Dec 3, 2009

Ford Kid, did you correct your single spark situation ? How did you determine you are only getting spark to one cylinder ? Hopefully we can narrow it down to a spark problem or a fuel problem with more information. Follow the good trouble shooting info above as much as possible !

fordkid · Dec 3, 2009

ok I believe the fuel pump relay is bad.however I don't think this is the main problem. the fuel pump was working, it was staying on all the time when the key was on. somehow I went around the fuse link and just wired it straight to the connector comming from the computer. that problem is fixed. Fuel pump relay and the inertia switch are now wired in. since I did that the fuel pump wont turn on. tested the connections at the relay, the red/black wire has 12 volts with key on, and the pink/black wire doesn't if I am understanding the guide correctly then I have a bad relay, so I will replace the relay tomorrow(hopefully) and then try again.

before when I had accidently byepassed the fuel pump relay I determined I only had spark to one cylinder by testing each and every spark plug one at a time, and I am only getting spark out of the second plug back on the drivers side.

any idea's at this point would be greatly appreciated. I will let you guys know how things go once I get that relay replaced. Hoping I am able to get it at a regular parts store for fairly cheap.

Thanks again, all your help is deffinitly appreciated.
Ford Kid

HISSIN50 · Dec 4, 2009

Does the yellow wire at the FP relay have constant 12 V?

Also, you talked about circumventing the fusible link. Was this the link on the Yellow wire (common feed into the relay)? If so, I would reestablish that circuit to a battery-source. You don't want to use the EEC circuit to power the pump itself. If Ford wanted to do that, they would have omitted the FP relay.

If yellow and Red/blk have 12V (Key-on), and tan/grn shows continuity to ground, the pnk/blk wire should show 12 V during the prime out period.

fordkid · Dec 4, 2009

ok replaced the fuel pump relay, and now the fuel pump comes on WITH SOME HELP, I have to turn the key ON, then run a ground wire from the pump to the chasis, something isn't right with the factory gound wire I guess. and I have that test connector under the hood jumped to ground, but the fuel pump turns on if all that is done. still only spark on one cylinder.

Thanks
Ford Kid

fordkid · Dec 7, 2009

One Spark Update

allright, a little update and a few more questions.

first off for anyone new to my problem I am working on a 66 mustang with a 5.0 motor and T5 from an 86 5.0 mustang, I am keeping the Fuel Injection and I have transfered all three main wireharnesses over to the 66, the Main ECU harness, the Front light Harness whitch also has the hook up for the COIL, and the rear light harness whitch also has the wireing for the fuel pump. I am using an aftermarket elecric fuel pump mounted outside the tank.

I am only getting spark in ONE cylinder, I have fixed the fuel pump porblem it comes on and shuts off just like it is supposed to do. I turn the key on and it comes on for a few seconds and then it goes off. Was very glad to get that part of my problem fixed, a Big thanks to everyone who helped me with that. I am also using the Coil and the Ignition relay from the 86, basicly bypassing the whole electrical system on the 66.

question on the one spark issue. I have 12 volts to both sides of the COIL, is that right. I was thinking one side should be hot and the other should be ground. but both have 12 volts with the key in the ON position.

also I am thinking my clutch saftey switch isn't working proprly, since it's not hooked up to the pedal since the pedal is the 66 pedal and not the 86 pedal. so to try and start the car I have just been jumping the Ignition relay with a screw driver from the Hot terminal to the small screw terminal. could that be my problem with only getting spark to one cylinder. I doubt it but figured I would ask.

I know I know, the harness kit would be easier but I am not willing to pay 600 bucks just for a wire kit. the head aches are FREE,

Thanks
Ford Kid

hotrodredneck · Dec 7, 2009

maybe this diagram can help....might not be specific to your car, but the wiring should be similar

Spark in one cylinder

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