New member/car/problem

[my67falcon]

Hello all,
Just joined and already need help. I will soon be acquiring a 'Stang from my brother. It's an '85 GT 'vert. 5spd. The problem he is having has stumped him so he is passing it on to me. The car runs great some times and dies others. He says it's as if it stopped getting fuel. After it sits a few minutes it will start again and go for a few miles and it dies again. Dies, stop for a few and goes again. He has a new carb, fuel pump, and re-ran the fuel lines. What should I look for first? What kind of computer stuff is on this year(if any)and could it be the problem. I do have an '85 H.O. 351 I could drop into it, but then I'd have to find another engine for the Falcon when It's finished next spring. If I did go the 351 route what would be required for the swap. I would like to retain the 5 spd (Falcon has a C-4). Thanks for letting me ramble and for any advice.

Aaron Roots and Family
Warrensburg Missouri
'99 Stang (hers)
'67 Falcon (mine)
'85 Stang 'vert (next month)
'95 Corsica 2.2L (what the hell happened there? Oh yea, gas prices)

 

[superhuaman]

'85 is carb'd so the only electronics on there is the duraspark ignition box. Get a spark tester so that when it dies you can see if it has spark. The boxes like to fail when they get hot. If you have spark after it dies, spray something down the carb and see if it will fire.

 

[Moffa]

fuel pump relay maybe?

 

[superhuaman]

fuel pump relay maybe?

It's carbureted, it doesn't have an electric fuel pump that I am aware of.

 

[PuterAmI]

Nope, it has no electric pump. The machanical driven off an eccentric is on the driver's side of the timing cover.

I have to agree with a weak ignition. My first thought is the coil heating up. The coil is mounted on top of the intake. The second is the Duraspark IV box as mentioned. You can have Autozone test the thing out for free. A third is a bad ignition switch.

How does it run before it dies? Also, I had the same issue and had to move over to an electric pump even after I bought a new mechanical one (stock replacement). I have had no issues since. I figured it by running a glass filter before the carb.

Welcome, and come on over and join some folks at FourEyedPride.com where the 79-86 Mustang and Capri are catered to.

 

[my67falcon]

Thanks for the responses.
I won't get the car until the 22nd of Dec. My brother is hauling it up for me from Texas. As far as how it runs before it dies, he says it runs great. He can sometimes drive all day without a problem. Other days it will die 3-4 times. I'm trying to get a good list of possible problems so I can get the car back on the road quickly. I'm giving him my daily clunker so I need to make a quick decision on either fixing the problem or switching (last resort) the engine.

 

[jadedinpa]

has he replaced the fuel filter at all?

 

[my67falcon]

Yep.
From what he's told me he has replaced the filter,computer module box thingy (plus all the previously mentioned stuff) and has taken it to a mechanic or two. I thought trash in the tank/lines might occasionally cause a blockage but wouldn't the sock in the tank keep that from happening?

 

[superhuaman]

You're right...sort of. If the sock in the tank is real dirty, the engine will run for awhile, until it sucks all the dirt against the sock, shutting off the fuel flow. Contours had this problem too.

 

[PuterAmI]

The 85 does not have a sock like other cars. It is a small cylindrical screen at the end of the pickup.

 

[superhuaman]

Oh, I see. I'm just used to EFI, I guess.

 

[my67falcon]

The 85 does not have a sock like other cars. It is a small cylindrical screen at the end of the pickup.

Is it positioned in such a way as to allow debris to collect on the screen, or would this not be a possible cause?

 

[PuterAmI]

It can get dirty as I thought that was my problem a couple of months ago on my 84, so I dropped the tank to check. Yet, mine was completely free and had no restriction to flow. I also blew compressed air through my lines thinking I had a kink someplace, yet that also did not help me.

I think it is a very small chance that it could be the screen to your pickup.

My best advice is to go to Autozone (or whatever) and put in a glass filter just before the carb so that you can see it. Once the engine shuts down, check the filter. Also, when I pulled off the fuel hose connection at the carb, I had no fuel in the line at that point. I knew that even though I had a new pump, I had a fuel issue. Another thought is to splice in a fuel pressure gauge and watch it.

 

[my67falcon]

It's arrived. Got my Christmas present on the 22nd . Didn't drive it until Tuesday the 27th. Drove on the highway and in town all day. Ran a half tank tru her with no problems. Drove to work on Friday with out a single sputter. On the way home it died 6 times . It starts with the sensation of hitting a governor. no matter how much you try you just can't gain speed. That's quickly followed by the inability to maintain speed. After downshifting the rpm fall off quickly. Still no sputter, just a loss of power. I tried revving it with the clutch in. I got some response, but it was intermittent at best and soon became non-responsive all together. Then the engine died. I was still going around 50 mph and coasted to the shoulder. After waiting 15 min. I managed to go about 4 more mile. Then it was a half mile at a time till I got it to my brother-in-laws house. The next day him and his brother took it for a spin. Ran great. They took it to his shop and ran a compression test, checked the grounding, timing, carb and fuel pressure and spark. They were all good except the coil was rather weak. They suggested a new coil and ECM. The ECM was replace several years ago, but I'm sure it wouldn't be the first time one went bad before it's time. Got the coil, but the ECU won't be in until the 5th. Hopefully I'll be up and running by next weekend.

 

[93-331-29psi]

This may sound really out there, but pull off the plastic column covers from the steering column and check the ignition switch. It will have a flat connector with many wires running into it. Make sure that everything there looks and feels tight. I had a problem that sounds like yours and this is where I found resolution. I understand that you would think that you'd lose everything (radio, lights etc) but if only one side of the switch is broke/loose it won't affect the obvious. Let me know.

 

[Camman]

Are you replacing the ecm because you found a faulty circuit? Or because your mechanic is throwing darts? If you dont have comformation your computer is bad make sure you keep your current one so you have a spare. I would also recommend finding a new mechanic if there is no conformation of computer failure.

If your computer is bad, and it was replaced several years ago, you need to figure out what is killing them

 

[PuterAmI]

Those are the *exact* symptoms when I had a bad fuel pump. Even after changing it out, it started again about 4 weeks later (cheap stock replacement). You mentioned that pressure checked okay. What about flow? Also sounds like vapor lock.

Some folks just replace a computer because they know no better. Autozone checks them for free. Remember, most places will not take back electrical parts.

Have you taken my suggestions? As I mentioned, a glass filter is very cheap and can be put right inline. I also kept a screwdriver on me. When it died, I pulled over immediately and pulled the gas line from the carb inlet. There was no fuel there. Taking off the sight plug and shaking the car also showed no fuel in the bowl.

FWIW, I still have the stock 22-year-old ignition module. They do not just go out.

 

[my67falcon]

"This may sound really out there, but pull off the plastic column covers from the steering column and check the ignition switch."

There's something I would have never of guessed to look at. I'm picking it up Friday and I'll have him look at it.

"I would also recommend finding a new mechanic if there is no conformation of computer failure."

Can't fire family, + the labor is always free and no, he's not a shade tree mechanic .

"If your computer is bad, and it was replaced several years ago, you need to figure out what is killing them"

Thats it, throw another worry on the pile .

"Also sounds like vapor lock"

Fuel vapor lock or coolant vapor lock?
The fuel lines have been rerouted away from heat as much as possible. since I'm using a mechanical fuel pump at the block vs a near or in tank electrical I'm sure I'm susceptible to vapor lock, but a valiant attempted has been made to circumvent that. My brother-n-law / mechanic is also going to install another temp gauge to ensure I'm not getting a false reading. I suspect the thermostat is also stuck open as I get very little heat.

"a glass filter is very cheap and can be put right inline"

It already had the glass filter and it had fuel. I thought maybe it was a problem with the carb. or maybe it needed a spacer. He thought that was unlikely since it runs great 90% of the time. He said if it were it would have worsened over the last year or so that this problem has been occurring and would happen much more frequently.

Something I did notice was that right after it died, it wouldn't start. It would turn over, but act like it was not getting fuel, or was flooded out. It just tried and tried but wouldn't start. Fuel was flowing though. After a few minutes it would fire right up.

The ECU has already been replaced once due to it "frying". Wires were literally burned. Why, I have no idea. The coil is original and was producing low spark. Could that cause undue strain on the ECU or are they not intertwined that way?

I've had bad luck with ECU's before. The one on my Falcon went bad as well. It's running an '85 351 H.O. from an F-150. The guy I got it from jacked up most of the wiring in the steering column though, so it may have had help in going bad.

I'll pass on the advise and hopefully get this thing going.
Thanks guys

BTW: Got the wife a new Durango for Christmas, so she's feeling a little cheery. I found a truck with an '89 GT motor and auto tranny for $500 for an engine swap (that would cure the problem). She said buy it. Went to look at it and had to pass. got a little suspicious when I saw the F-150 style intake. He said he had documentation and showed me a hand written note saying (1989 GT H.O. 302 $1200). WOW, how could I argue with that kind of proof.

 

[Camman]

heh, yeah dont fire family. Lol at least if the comps not bad you have a spare incase you ever fry yours. My point was that computers very rarely go bad. I on the other hand have personally fried 2 . One of them was in a customer car As has been stated before this does sound exactly like a faulty pump, clogged fuel filter, vapor lock. Good luck

edit: Just reread everything, from the symptoms, and what has already been done I would be anxiously awaiting that new coil

 

[BlownFiveLiter]

This has an awfully eerie sound to it, like the PIP/stator/Hall Effect sensor (whatever you wanna call it) in the EFI Mustangs. Since the '85 has no electronics like that with the exception of the Duraspark ignition and a vacuum advance distributor, I suspect the problem lies somewhere in there. What kind of condition are the vacuum lines in? It sounds like your brother addressed all the possible fuel issues for the most part, so short of replacing the Duraspark box, check for spark when this is happening, and go from there. I'd start pointing my finger at the distributor, and vacuum advance unit.