So, I've tried to get the mustang guys to help but they reply very slow and it's been days :(

Here's my detailed thread over there (http://www.corral.net/forums/showthread.php?p=7584442).

Basic run down.
-Gets 12v when it primes/key-on.
-Gets 6.5v constant key-on.
-Gets 9.5v attempting to start.

I've replaced:
-Fuel Pump Relay
-2 Other relays in engine compartment (ECC and somethign else I think)
-Fuel Pumps
-Fuel line in tank
-Fuel Filter
-Wires that were resistant/caused weird voltage drops.
-Checked wires between pump and relay
-Checked wires between computer and relay

I`m sure there's more, checkout the thread on the forum I linked above.

Any ideas are much appreciated.

Ok I think I found the problem this is weird....


So i get 6.5v on 1 side of the watherpak connection.
On the other i get .1mv
if i try to start i get 9.5v on one side on the other i get 30mv
IF IT STARTS i get 12v on each side (using starter fluid to get it going)

Is that weird or is that weird? I was under the assumption voltage could go through the tiny wire it was the amount of amps that would be limited by a bad connection... but for my voltmetere to show mv then jump to 12v and not register the 9.5 or 6.5 WTF?!? So obviously it's not getting power to the pump when I'm trying to start it... :(

New weatherpak coming up to test!

have you tried another EEC just to eliminate that as a culprit. Almost sounds like a bad ground internally. I know that with mine, when the key is turned to on, the pump runs for a second, and when the key is turned to start, the pumps is running (i can see this through the FP gauge on the dash).

that is bizarre.

Seems like the Corral guys would know this pretty well.

have you tried another EEC just to eliminate that as a culprit. Almost sounds like a bad ground internally. I know that with mine, when the key is turned to on, the pump runs for a second, and when the key is turned to start, the pumps is running (i can see this through the FP gauge on the dash).

that is bizarre.

Seems like the Corral guys would know this pretty well.

If by EEC you mean computer then ya I swapped out to a different computer.

When I turn the 'key' to on I hear it run a few seconds then kick-off. When I try to start it I don't think it starts running again and there lies the problem. HOWEVER if I start it w/fluid the computer says 'hey look a running engine we need to send fuel' then sends fuel.

SO, for some reason it's not sending fuel when I try to start it. Inertia switch is only thing that comes to mind that would cause this since it gets fuel @ prime/on and while running. However, I'm 99% I eliminated that earlier, it was just a plug with 2 wires connecting (already eliminated essentially) and I just removed it entirely and made the wire flow right through.


The weaterpak didn't fix it but it made it not have voltage before the connector while attempting to start or sit idle. SO the 9.5v and 6.5v must have been a short :shaking: This thing has wire spliced all over and lot of of it's gotten old and crispy.

I also jumped the power from battery to fuel pump so it ran ALL the time and tried to start... no go. Computer not giving spark since it thinks no fuel now.. ? (inertia switch saying no fuel? no clue)

Any other ideas would be appreciated!

Found wire under dash that could be problem of it all.
It's the power wire that goes from the harness to the fuel pump, apparently where it connects to the plug it's heavily corrodied as I pulled and it just ripped in half (wire and all). This is why it was reading 6.5v/9v and then now nothing :shaking: The wire was hanging on by a thread probably, and why it worked sometimes and not others also could be why I wasn't getting enough power to pump to store.

Going to replace the wire and see what I have.

-Todd

Ok this is weird (maybe only to me).

But I fixed the connection, and I get 6.5v to the fuel pump + wire now no more loose wire .

However, as soon as I connect/plug in the fuel pump connector it dropps to like 1mv. Disconnect connector and it's 6.5v at the + wire from the harness.

Why does connecting the fuel pump drop the voltage on the line, and why does it register 12v when priming then drop to non-existent when it reads 6.5v on + when not connected.

Is something weird going on or is this normal!

It still wont start, and it doesn't register any voltage when attemping to start but when I stop trying to it shows 12v then drops back down to 1mv.

$10 paypal to first person who correctly identifies problem and how to fix.

So it will prime when the key is switched to on, and then cycles off.
When you are keying to start, the computer is not getting the signal from the distributor that the engine is turning and time to fire the injectors. This would explain why it will start with the addition of an external fuel source in the start mode. I don't have a diagram in front of me, but something is not making that connection. It could be related to the TFI module, or the wiring related to it. It could be distributor related, or it could just be the keyed source to the battery. Ford is very specific in wiring and clearly explains that all connections should be soldered and sealed with waterproof heat shrink. Grounds must connect to the battery.

Is this the first time this motor is being fired, or has this been an intermittent issue and progressively gotten worse?

So it will prime when the key is switched to on, and then cycles off.
When you are keying to start, the computer is not getting the signal from the distributor that the engine is turning and time to fire the injectors. This would explain why it will start with the addition of an external fuel source in the start mode. I don't have a diagram in front of me, but something is not making that connection. It could be related to the TFI module, or the wiring related to it. It could be distributor related, or it could just be the keyed source to the battery. Ford is very specific in wiring and clearly explains that all connections should be soldered and sealed with waterproof heat shrink. Grounds must connect to the battery.

Is this the first time this motor is being fired, or has this been an intermittent issue and progressively gotten worse?

Yep, runs a few seconds when keyed on then stops (like normal), go to start and it doesn't turn back on. If I get it running on fluid it (pump) starts up.

This is in a buggy, so the battery grounds directly to the frame. Also there is 0/?g wire ran from battery/rear frame mount to front frame mount (for winch). So the entire frame is 'grounded', as well as the engine block to frame. From my battery to front of frame there is like .001v drop.

Not the first time, it's sat a long time >1yr, previously it had some issues but they were just loose wires, relay, etc that I pretty much 100% fixed up today! [Since I`m sure you saw my post of what I did.]

Like you said I'm starting to think it's not the fuel power source/lines but more-so what dictates when to start/send power to the pump (key pressed).

What should I look for in regards to the TFI ?

Maybe I missed it somewhere, but have you checked your fuel pressure yet?

A pinched fuel line can wreak havoc. I once rebuilt damn near an entire 89 5.0 only to find out I had a pinched fuel line.:shaking:

Maybe I missed it somewhere, but have you checked your fuel pressure yet?

A pinched fuel line can wreak havoc. I once rebuilt damn near an entire 89 5.0 only to find out I had a pinched fuel line.:shaking:

I haven't checked actual pressure only that it was that and squirted out... Also, wouldn't it not run if it wasn't getting fuel? Or am I not thinking that through?
(Since it does run and drive after I start w/fluid.)


-Todd

Going to test pressure and TFI module tomorrow.


-Todd

after doing a 5.0 swap in my jeep it ran great for about a month then the fuel pump relay started acting up on me.it did similar things it would prime sometimes but then it would also cut out while driving. so after changing it out the same thing happened. now i just run my fuel pump off a toggle switch on my dash.it should run if you wire it hot off the battery if not then i would think TFI or computer prob. from what i understand when using factory wiring your computer sends a ground signal to the fuel system once the key is on..make sure the computer is grounded properly it should have two ground wires if i remember correctly one coated and one bare wire..check your fuseable links too unless you already removed them

keep us posted it seems like you tried almost everything suggested..does it ever cut out while driving or hitting a bounce..try to jerk some wires around under the hood while its running see if anything happens

Ok, maybe I am all wet, and it has been a long time since I looked at an EEC4 (or any other) Ford computer system.

Is there an oil-pressure switch to run the pump (through the computer or otherwise) or is it run by the computer (turns the relay on when it gets a tach signal)?

I remember something fuzzy from way back when about furds and a 'pip signal'

peace / good luck
Dave

I think I need a special tool to remove the TFI?
I can't see what's in the holes but so far I can't get a phillips or flat-head in there to grip anything, then again it's super tigtht and I can't even get a tiny screwdriver in there properly.

I`ll stop by NAPA ask for a `tool` and a TFI to use.

I`ll report back.

Thanks guys!@
-Todd

I think I need a special tool to remove the TFI?
I can't see what's in the holes but so far I can't get a phillips or flat-head in there to grip anything, then again it's super tigtht and I can't even get a tiny screwdriver in there properly.

I`ll stop by NAPA ask for a `tool` and a TFI to use.

I`ll report back.

Thanks guys!@
-Todd

yes, you need a tool for the tfi screws. do yourself a favor and change them out for something else.

yes, you need a tool for the tfi screws. do yourself a favor and change them out for something else.

Stopped by NAPA on the way home and they hooked me up with the lil-5.5mm hand socket, and the new TFI module.

If I can i`ll re-locate the TFI to the firewall or right inside to prevent heat damage which I guess is reason they fail.

I hope this fixes it :)

-Todd

So, I tested my current TFI per-haynes and it checked out ok :( Was hoping that was it!

I am still going to stick the new one in there and keep the existing as a spare, hell maybe I tested wrong and it will fix it :p Anyway, I can't do that tonight I can't find my dielectric grease. SO! That will wait till tomorrow.

Any more ideas on what to look for or change?

I`m getting ready to go buy a brand new pump and try that since the one I swapped was my spare and was working but ya`never`know. (still runs but maybe its old and wont build up pressure?)

I think I've tried everything ?!?!?

So, I tested my current TFI per-haynes and it checked out ok :( Was hoping that was it!

I am still going to stick the new one in there and keep the existing as a spare, hell maybe I tested wrong and it will fix it :p Anyway, I can't do that tonight I can't find my dielectric grease. SO! That will wait till tomorrow.

Any more ideas on what to look for or change?

I`m getting ready to go buy a brand new pump and try that since the one I swapped was my spare and was working but ya`never`know. (still runs but maybe its old and wont build up pressure?)

I think I've tried everything ?!?!?

Check the main ground for the eec. If it's bad, it won't fire.

http://www.fordfuelinjection.com/?p=64

No help on the firing, but the injectors not squirting on start mode sounds logical. I thought I'd address the fuel pump mistery though. When you turn the key on and it primes, it then stops per a safety pressure switch I'm pretty sure. Where it is I don't know, but when you get it running, vacuum is applied to the FPR and allows the fuel to return to the tank as if it were running, even if the injectors aren't squirting. Since the fuel is running at a more normal pressure, the pump runs as it normally would because it no longer has excess pressure.

More information to read that may lead you in the right direction. Look for PIP signal.
http://www.veryuseful.com/mustang/tech/engine/EECIVInnerWorkings/

http://www.gt350mustang.com/eec.htm

something in there may help isolate the issue. The problem has got to be something related to ignition. The EEC is not getting the signal that the engine is in start mode so it's not firing the injectors during this event. This is why shooting starting fluid into the motor while trying to start it gets it to run. Spark is there, just no fuel. Once the engine catches, and the start function is released, the computers start firing the injectors normally. Something is not letting the computer fire the injectors in start mode.

Interesting problem. I have had problems with my 5.0L in my Jeep more often than i would like. It seems to not like the winter time, cause thats when i have the most problems.
I'd have to have the Jeep infront of me to help you sorry. I hope you get it fixed soon.

I'm totally sorry I can't help, as I had something exactly like this happen to me with a Ford Ranger I was given. :mad:

It was running fine aside from an oil pump issue, when I put it in the garage. I go to start it up after replacing the oil pump, and I'll be damned if I can get it to fire up. I tried *everything* I spent months trying to fix this stupid piece of crap.

I poked and prodded and multimetered, I checked fuel pressure and pumps and fuel filter, I electrical connection diagnosed, removed and replaced God only knows how many things attempting to get it to start.

It would start and run like a champ if I sprayed starter fluid in the throttle body (up until it ran out of the fluid) and then die. Hell, I think I could get it to run when I sprayed wd40 in it:laughing:


I finally had enough and admitted defeat, had it towed off to the dealership, and guess what? It fired up the second it was unhooked from the tow truck. :shaking::shaking:

It was a loose wire/connection somewhere in the damned rat's nest of a wiring harness, apparently, but I could've never found it in a million years. I got rid of it instantly:laughing:

We had a problem on the 5.0 buggy. It was the wiring at the module on the dist. Ford uses a start ign wire and a run wire. we unplugged one of the wire, dont remember which, and it runs fine.Call Ford motor sports tech. They helped us figure it out.

turn the key on and check the 5vdc ref voltage at one of the sensors. The 5v ref is tied to the crank trigger in the ecm. If you have a sensor (or o2) shorting it will drag the ref voltage down and the ecm will shut down to protect itself.

If you have under 4 volts on the referance line (most are gray w/red tracer) start unplugging sensors until the voltage comes up.

I had this as my test on Advanced engine diagnostics and turns out to be the EGR position sensor shorting and it did exactly as you describe. It would prime, then shut the whole system down when it found the referance voltage too low.

oh, and you would still have spark as the whole ignition system, with the exception of timing advance, is independant of the computer/injectors system.

turn the key on and check the 5vdc ref voltage at one of the sensors. The 5v ref is tied to the crank trigger in the ecm. If you have a sensor (or o2) shorting it will drag the ref voltage down and the ecm will shut down to protect itself.

If you have under 4 volts on the referance line (most are gray w/red tracer) start unplugging sensors until the voltage comes up.

I had this as my test on Advanced engine diagnostics and turns out to be the EGR position sensor shorting and it did exactly as you describe. It would prime, then shut the whole system down when it found the referance voltage too low.
Sounds like the problem i was having except my ecm wouldn't shut the engine off. I got the code 31 which says something about the voltage being low. When i'd drive my Jeep it would hesitate or act like it didn't have the power when i'd floor it. I just unplugged the EGR sensor and it runs fine now.

I had a problem a while ago where my Jeep wouldn't start when the motor was warmed up. i was going to replace the TFI but decided i wanted an MSD dist. The TFI wasn't the problem and i don't remember what it was that i needed to fix.
You can try replacing the ECT or ACT.

Ford Motor Sports Tech. They will figure it out!

Check all your wiring hook ups at you're power source. Make sure the specific wires that are supposed to go to "hot in run (on)", and "hot in crank and run", are connected correctly. The TFI needs 12v when in crank and run I would bet it's not.

Tom