Stalling Problem; HELP

[84 Ford]

I've had this stalling problem re-occouring since I bought my stang, here is what I got;

1985 Mustang GT 5.0 Carb.
50,000 Miles
2nd Owner

Drove it up from Seattle and it had this problem where it would randomly stall at any RPM, at any speed, hot or cold.

Took it into Kyle, he told me the problem wa that someone had changed the valve cover seal and this was causing the pistons to not completely close at the right time and therefore not firing properly.

Kyle adjusted them and then it ran great for about 3 months without stallling or even hesitating.

About one week ago it started stalling again, stalled in 3rd gear @ 2200 RPM going uphill at 60 HM/H under a fairly decent load. I pulled over waited 5 minutes then ti started up again, then on the way home about 30 minutes later it stalled in 4th gear @ 1600 RPM at about 80 KM/H. Both times the engine was warm, but I wasn't driving hard, and it was a hot day out.

I ignored this then 3 days later it started stalling alot more. Stalled 5 times between Abbodtsford and langley. I would have to wait 5 minutes before it would fire again then drive another 5 minutes and it would stall. This was doing about 60 KM/H in 4th gear @ 1400 RPM, and it was driven nice and easy that day.

Took it to a mechanic in lanlgey, we pplayed around with the float bowls adjusted them, checked the gas line into the carb and it was loose, so I assume that air was getting into the gasline and causing it to stall. We fixed all that up and then tested it out. Got alot of power out of it, ran fine, without even a hint of stalling.

2 Days later it stalled again. A short 10 minute drive not driven extremely hard but accelerating up to about 4000 RPM once in a while before shifting from a stop, then it stalled making a left turn @ a light in 1st gear.

Kyle seems to think its an ignition problem, perhaps getting hot, or a coil issue, You guys got any other ideas? Carb seems to be running great and deliving gas nicely, I got no more ideas and I would really liek to get this fixed, Thanks.

[JPJP]

Easy try to toss a known working coil on it......the symptoms scream coil.

[84 Ford]

I was thinking something along the lines of ignition coil or perhaps the ignition box itself getting to hot or shorting out, not being a huge engine buff I not quite sure of these things, so any thoughts are appreciated.

[JPJP]

I believe you are right on. Keep us posted what you find out.

[negusm]

I agree...Duraspark/Coil

-Mike

[JACook]

Or ignition switch...

[84 Ford]

Picked up the coil today gonna throw it in tonioght see how it goes.

[84 Ford]

So I came home and set up the Ohm meter to test the new and old igntion coil. The old one seem to test out fine, here are the readings I got;

OLD COIL:
Primay Resistance 1.3 Ohms
Secondary Resistance 8.9 K Ohms


NEW COIL:
Primay Resistance 1.4 Ohms
Secondary Resistance 9.4 K Ohms


ACCEPTABLE FORD MANUAL READINGS
Primay Resistance .8 to 1.6 Ohms
Secondary Resistance 7.7 to 10.5 K Ohms

So I am not sure if I should even bother putting the new coil in, the only weird thing was when i tested the primary resistance on both coils to old one took along time to settle on a reading, the new one however took only seconds.

Not sure what to do next.

[bob85gt]

you have a problem that comes and goes. you say the primary resistance took alaong time to settle down. i have changed parts based on what you just said. or try reading it again with a few taps to see if the reading bounces around. but i would change it and see what happens. also if you do a little reading on this site quite a few people has had trouble with the ignition switch. open up the steering column and take a look.

[84 Ford]

Ok so I just put the brand new coil on it and took it for a drive, didn't help at all, stalled about 6 time over what should of been a 5 minutes drive took 25.

I noticed the following;

1) The MSD Ignition box was extremely hot to the touch, could only hold my hand on it for about 10 seconds, is this normal?

2) After it stalled it would not start untill I opened the hood and pumped gas with the rod next to the carberator, and sometimes it looked like it wasn't getting fuel, but I already had the fuel pump checked out and the carb adjusted

I am not quite sure what to check next I might try using this 2 Channel scope for some ignitio testing and other things you guys think I should check?

[JPJP]

Wait I thought you were bone stock. Is this the MSD 6A type box or is it an ignition module? If it is the former, simply take it out of the equation.

[JACook]

2) After it stalled it would not start untill I opened the hood and pumped gas with the rod next to the carberator, and sometimes it looked like it wasn't getting fuel, but I already had the fuel pump checked out and the carb adjusted

It doesn't matter what you had checked out, if you cycle the throttle linkage, and
you're not seeing any fuel come out the accelerator pump squirters, it sure seems
to be telling you it's not getting fuel.

Fuel pump and filter are only a couple parts of the puzzle. You could have a stuck
float valve in the carb, or an air leak on the suction side of the fuel pump, such
as where the fuel line connects to the tank.

If you dribble a bit of fuel down the carburetor and it tries to start, it's not spark.

[84 Ford]

The ignition box is a "Motorcraft 12A199" not asn MSD, I must of been thinking about too many htings at once. I just finished pulling all teh spark plugs and distributor Cap, The plugs seem OK, but I may replace them anyways.

So in my personal opinion I think it seems to be starving for fuel, but im not 100% sure, the carb seems to work fine when its cold but once it gets hot I dont think it is delivering enough gas. Also still wondering if the ignition box is supposed to get that hot.

[JACook]

They do run fairly hot, as much because of where they live than anything.

Take a sports top water bottle with some gasoline in it with you next time
you go out. When it stalls, if it won't start, give it a bit of a squirt and see
what happens.

[84 Ford]

So I just took it for another drive after checking all the plugs, wires, distributor, and everythign checked out I took my buddy out for a drive with me, and we are almost sure it has to be a fuel delivery problem now.

The logner you drive it and the harder you drive it the worse the problem gets, after it stalled the second time we counted 4 pumps of the throttle arm assembly next to the carb before we saw any fuel squirt into the carb. We attmepted to pour some gas in out of a 2L Coke bottle, and we did get a baff but did not fire probably due to the inconsistent delivery of fuel.

The fuel pump seems to check out alright and the carb has been rebuilt once already, any ideas fella's?

[JACook]

Fuel hose at the tank? Clogged fuel pickup sock inside the tank?

(You -did- try replacing the fuel filter that's behind the large nut
where the fuel line screws onto the carburetor, yes?)

[negusm]

I had an old jeep as a kid with something similar. I pulled the hose from the tank off the full pump. Then I blew HARD thru it until I felt it clear out and air going to the tank.

It ran fine after that. But I knew there was probably some junk in the tank to bite my ass later.

[JACook]

Fuel pickup/sender is pretty easy to remove on an '85 GT. As long as the tank
is almost empty. While that's apart is a good time to blow out the line.

[84 Ford]

Sweet guys, thanks for the tips ill giver a try this weekend.