lp9820

well my 86 is refusing to start, i've aready replaced the dist. cap and the rottor and still same problem. the car seams to be trying to start but there is a lot of stuttering and when we finally get it to start it won't start after turning it off. i'm pretty sure its not the starter and my dad thinks it might be the fuel pump and i've noticed it only does this when its hot out side so i'm wonderring if it is related. any help would be appriciated

KEEP

If you are sure that it is getting spark all the way to the plugs then start looking for a fuel problem.. It could be many things but it sounds like a fuel pressure problem. How many miles on the car? Have you changed the fuel filter? Please keep us up to date on what you discover... good luck

lp9820

most likley factory fuel filter and the car has about 97000 miles on it. i'm pretty sure the spark is reaching the plugs, theve been changed within the past two years although the wires are probably factory not to sure though

KEEP

Just start eliminating one thing at a time.. Once you know what it isnt, all thats left is what it is...

svopaul

First thing to check is the Ignition switch in the column.....I've been bitten by this gremlin so many times that it is the first place I check. There was a recall on this from Ford as the switch starts to come apart. I had a Capri once that wouldn't start and wouldn't start and then finally when it did start no power would work(windows, locks etc) then it wouldn't start again after shutting it off. This is not they key cylinder but the slider switch that the key operates to start the car.

Check that first....it's cheap and should be replaced if it never has anyway as they can be a potential fire hazzard.

If that is not the problem then the first thing to do is to check to see if you have spark at the plugs and fuel pressure....if you have both of those the car should run.

lp9820

i don't think it is the ignition switch because the car still runs, but after driving it and turning the car off it'll only start after cooling off for a while

svopaul

Check the coil.....but I'm telling you, check that switch. I only recommend it because I've had a LOT of experience with these cars and been bitten by that switch more times than I can count. I had one car that would run fine but occasionally die....after a lot of playing with it I realized that it died only when the steering wheel was turned to the right....turns out when the wheel turned it moved the column just enough to cause the electrical connection to disconnect in that switch and kill the car.

It's a part that costs less than $10 and is easy to check and replace....and if it has never been replaced I can promise you that it WILL cause you headaches down the road at some point....hopefully that headache isn't the car burning to the ground...yes, I've seen that too from these switches.

lp9820

is there any way that the ignition switch can cause the idle to fluctuate from above and below the normal idle position and eventually cause it to cut off

svopaul

If your idle is surging up and down then it is most likely your idle air control motor(IAC)...they can get dirty and need to be cleaned out. Disconnect the battery, remove and clean the IAC out, reinstall, reconnect the battery and go drive it for 15 minutes. That is the most common problem but if that doesn't fix it you could have other issues.

hi5.0

Recently spoke to someone with a similar problem with his '91 5.0 LX. Turned out to be a faulty throttle position sensor. Replaced and now starts and runs great.

foxhtn

Try changing your wires. My buddies car done the exact same thing. After he let it cool off it would start with no problem. wires were breaking down inside the coating.

hi5.0

may also want to consider the TFI/ignition module - a while back, helped swap an engine on a relative's Tempo with similar issues (yuck!) only to discover it was just that simple part causing the problem.

lp9820

well my car is stuck at the gas station just after putting half a tnak in it, and we think the problem is being caused by vapor lock, only thing though is we don't know what causes it, how to fix it when it happens or how to prevent it

svopaul

Everyone always jumps to the vapor lock conclusion and while I have seen that on older cars I have NEVER seen it happen to a newer EFI car.

Read this: http://en.wikipedia.org/wiki/Vapour_lock

To help give you a better understanding of Vapor lock.....I'd bet that is not your problem.

lp9820

well forget vapor lock at about 8:30 my car has officially died.... well not really the fuel pump was and has went out so i will have to get a replacement. we tried using some starter fluid and were able to get a crank but wouldn't stay on so now were getting a tow in the morning and i have to return my new Oakley Half Jackets since i don't have the money right now for a pump

lp9820

well took a shot in the dark and changed the fuel pump relay, but to no avail, unless the fact that it was one for an 87' although i don't think there is any difference between the 86' and 86' fuel pump relay

svopaul

Stop throwing parts at it and figure out what the problem is....you are only costing yourself more money by tossing parts at it in the hopes it fixes it. A fuel pump relay is simple to check, if you feel it click when you turn the key on then there is a 99.7% chance it is still good...if you cannot hear your fuel pump then THAT is most likely the problem...and a VERY common problem with older Mustangs.

A multimeter is something very useful when tracing things like this but you have to know how to use it....otherwise you are best served by just biting the bullet and taking the car to a shop to have it fixed.

lp9820

well we returned the relay, it ws only $10 any ways, and we just changed the pump and i can confirm that the old one is bad, and we are getting ready to fire it up so we can put more gas in it

lp9820

well the car is up and running for the first time since tuesday evening, so the problem was the fuel pump

hi5.0

LOL. (Your) Father knows best...

My '88 had a similar problem. I just "primed" the pump by switching the ignition "on" and "off" 2x to build enough fuel pressure to get the car to start. Afterwards, it would run fine - just repeat the process every time to start. Kind of suspected trouble... The fuel pump finally did quit. The car would start after multiple tries, but it kept sputtered and backfired on acceleration and died at stop lights. Ironically on that day I was trying to get home from a junkyard with some parts for the 'Stang - a fuel pump not being one of those parts.
Glad it was a simple fix. Well, now you can put in a better fuel pump in the tank to support future mods, right? =)