Help me fix and make $50!

5.0fox · Jul 14, 2007

Ok heres the deal. Im having problems with my car and really want to fix it. Im tired of diagnosing and am ready to start throwing parts at it. Tell me what to buy and if it fixes the problem I will send you $50 with paypal or possibly a MO. Heres the problem. Car runs great until it gets up to operating temp and you shut it off. Then it will not restart until it cools back down. It doesnt matter if youve been driving for 10 mins or an hour. Allready have a new PIP and tfi module. Timing at 10* without spout and fp at 40 psi with no vac. line. What else can cause this problem? Give me the right info and I will pay!

ej95cobra · Jul 14, 2007

When did you notice the symptoms and had you done any mods prior to this problem starting? One possibility is heat soak; e.g., wires will not carry as great a charge when hot, they will also degrade over time under continuous heat. Some people notice the problem when installing LT headers or other exhaust mods. You can check the large cable to the starter for degradation. Check your connections to the starter as well. Possible cure is to replace the wire; they also sell heat wrap material that you can wrap the starter with to prevent heat soak.

Keep the $50 if this is it. Glad to offer something to consider.

5.0fox · Jul 14, 2007

No it cranks over great it just wont start. No recent mods. problem just showed up randomly. Spark was checked but looked a little weak.

corvetteguy · Jul 14, 2007

It
sounds to me like the same problem
with my 1939 Ford Tractor.
In the tractor it is the spark coil that has
many windings that gets hot and shorts
out winding making the spark too weak.
Once it cools down the short goes away and it starts
great cold.

I suspect your coil is too temperature sensitive.
It is also possible the ignition switch has
a weak connection.

You can buy a can of COOLING spray. after the car is
hot and not starting try spraying the coil till it
feels really cold. Then try to start...

jrichker · Jul 14, 2007

Engine start problems whith a hot engine:
1. PIP sensor
2. TFI module. The TFI module will also cause a high speed miss when the engine is warm.
3. Coil.
4. Press the throttle to the floor & try starting it if you get this far. If it starts, replace the ECT.

Get your voltmeter out and start checking voltages at the coil when the engine is hot and not starting.

As always, the Cranks OK but no start cheklist I posted on your last inquiry is the place to go for more information.

Diagram courtesy of Tmoss & Stang&2birds

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pinout
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

v8only · Jul 14, 2007

find a buddy with a 5.0 and try swapping that tfi module.

daviszx3 · Jul 14, 2007

its gotta be fuel or spark..make sure you got good fuel pressure when it wont start and check for spark when it does this and go from there no spark coil or distributer and no fp then needs a pump

urban96 · Jul 14, 2007

if you floor the gas while cranking will it start? (let off the gas as soon as it starts to catch of coarse)

when the pedal is floored it cuts off the injectors, and if it starts you know the troubled starts are from too much fuel.

Mr. Rustypwnz · Jul 14, 2007

hold on.....

v8only · Jul 14, 2007

i'm not thinking it's too much fuel. If it only does it while warm, that would have no effect on the fuel pump, the fuel pump is way in the back of the car where the engines heat doesn't effect it.

you're looking for a problem under the hood caused by heat soak, and my first guess is electronics.

Mr. Rustypwnz · Jul 14, 2007

im gonna say its the coil in this situation, your getting heat soak obviously and its somewhere in that area, coil, tfi, pip, ect.

5.0fox · Jul 14, 2007

tfi and pip are both brand new. Msd ingnition box has been bypassed. Coil was switched while it wouldnt start for another working coil and it still wouldnt start. fuel pressure looks good. Im 90% sure it is electrical.

FobraR · Jul 14, 2007

pull KOEO codes first to see what the computer has stored as past problems. run the car for about 5 min and shut it off and try to restart it to do a KOER test to see what codes are thrown while running (hopefully it will start...dont know how long you usually have to wait for your car to cool down enough to start again...). then run the car to full temp, shut it off and do a KOEO test again see if anything has changed. if you dont know hoe to pull codes there should be a thread sticky you can check on.

bill302 · Jul 14, 2007

how to pull codes click on link....http://www.muscularmustangs.com/test1.php also have you tested to see if you have spark during the no start period before it cools?

5.0fox · Jul 14, 2007

It has spark during cranking. Codes are showing nothing. Replaced the act and ect sensors and it didnt affect the problem.

HISSIN50 · Jul 14, 2007

If not noted, how is fuel pressure when it craps out. I have indeed had a pump fail when hot (and work again when it cooled).

Good luck.

Jaswir · Jul 14, 2007

MAP Sensor?

5.0fox · Jul 14, 2007

fuel pressure holds AT 40 PSI Pumps not even a year old. Jaswir is there any reasoning behind your map sensor suggestion or are you just guessing?

Mustang5L5 · Jul 14, 2007

I'm going to say coil.

Go to a boneyard and take one from another vehicle with a 5.0 like a lincoln or something and just test it out. That way you only spend $5 on the part. If the problem disappears, then go buy a good coil.

Usually with stuff like this it helps to have a good buddy with a 5.0 so you can swap out parts and see if it fixes it before throwing money at it. If you don't have a buddy, then you gotta improvise

LordMustangGT · Jul 14, 2007

I have a stock coil to try if you want. And I have the map senor thats on my car if you want to borrow it. It should run without the thing anyways so I wouldn't think MAP. what about The MAF sensor have you tried your stock one to see if that changes? We can always get together and swap ECU if needed sometime.

Matt

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