Starting From Scratch!

[lx5091]

I had another post on this, but out of 14 replies, 9 were from me.

I have some hard evidence now!

OK, please help me fix my car. It is misty outside and it will not start right now. I bet later today, or tomorrow it will. This has been going on for weeks. It started when I left it buried under snow for a week and happens everytime it is wet or foggy or misty outside, it also happened when I went through a high pressure car wash with under carraige spray.

The symptoms:

#1. It only SEEMS to happen in moist or wet conditions.

#2. The car will stall when going through a car wash.

#3. When I turn the key to the accessory position (when all the
lights come on) the fuel pump primes, but DOES NOT stop. It
will keep priming until I turn the key off. When this occurs, if
I attempt to start it, the starter will engage and the motor
will crank, but not start.

The evidence:

#1. I have tested the fuel pressure at the shrader valve and it
reads 40PSI when the fuel is priming. And immediately after
turning the ignition off drops and holds at 37PSI
#2. If I crank it, the guage stays steady at 40PSI but the car will
not start.

New Developement:

after writing the first half of this I decided to try to start it again and it started! Immediately after starting, the pressure settled at 33PSI. After running for a few seconds, it almost stalled and when this happened the fuel pressure dropped significantly and then immediately went back up, then it dropped again and it did stall, but immediately after stalling I heard the fuel pump start to prime again and it brought the fuel pressure back up to 40PSI. When the fuel cuts out, the dash lights DO NOT come on, until it actually stalls.

Questions:

Is this the fuel pump cutting out on it's own?

Or is the computer cutting it out?

Facts:

I changed the fuel pump relay a few months ago, I bought a brand new one from Ford and it did not fix the problem.

The whole ignition system in the car is only a few months old and has worked flawlessly since it was installed.

The distributor cap is dry inside and out.

Here are some pictures of some damage to the cap, sorry they are not very clear, it's an autofocus camera.

[lx5091]

pic 2

[lx5091]

pic 3

[429mustang]

It's probably not the problem, but did you clean the battery terminals?

[srv1]

exactly what did you change? list all the parts.

to me it sounds like wires or cap, but you said you replaced them. did you replace the plugs? if you did, did you accidentally drop one? could be a cracked plug.

James

[srv1]

oops, i almost forgot. do this test. after you got the car running, shut it off. use a spray bottle with water and wet down the wires cap and hit the spark plugs if you can. se how it runs then.

James

[lx5091]

Brand new battery 1 month old, with clean posts. These parts are all relatively new replaced all at once a couple of months ago: Distributor, TFI Module, Coil, Wires, Plugs and I've replaced the fuel filter and fuel pump relay very recently.

I was driving it around yesterday and the performance is all there! I rocketed to 100MPH on the highway and back down, got off in a nearby town, drove through it for a few minutes, got back on the highway and hit 100 again. I then got off the highway in my city and readlined first gear......then it started bucking. I then had to go up a very steep hill to get home and there was alot of bucking and coughing....not like a general loss of power, but rather it kept cutting on and off( I have a full tank of gas). I parked it and haven't touched it since.

I've heard that fuel pump symptoms would be cutting out under load....does it sound like this? Last fuel pump I had go on me was in a Nissan Pulsar and it was very obvious, this is not like that.

[sn95gt19]

your fuel pressure seems pretty normal.....try swapping out your mass air with someones that you know works. i had a 90lx that would buck and run like shi* when it was moist or raining out, and when it wasnt raining out it would not like full throttle, it would run better at half throttle.
if you know someone else with a mustang just swap sensors, its free

from your pics it looks like you have a small crack in the cap, that could be letting moisture in also, try that too

[lx5091]

I hadn't considered the Mass air. Now that I think of it my in-laws had a plymouth sundance that would stall every time it rained. It turned out to be the MAP sensor in that car. HMMM....I'll definately look into it. The cap is new but has little pieces that are pitted, I think it's due to the powerful spark from the Blaster coil! Maybe I'll replace it.

[lx5091]

Ok It seems to be fine right now, I'll see if it starts in the morning....I cleaned the MAF sensor and pulled out the computer and it was dry inside and out. I haven't yet been able to recreate the problem, we'll see.

[lx5091]

Well, the car has been fine, I'll just chaulk up the problem to water being trapped in the car during a freezing cold, and wet period of time.....now that it's been in the 50's and dry it may have all dried up.

Thanks for the replies