Won't restart when hot. 2002 V6 175K miles.

12Ounce · 06-26-2009, 06:56 PM

2002 V6 175k miles. Bought new. Well maintained. Transmission recently replaced by Ford. Runs well when running. No engine check messages.

There is no cranking issue ... plenty of battery/starter oomph at all times! Starts and runs right away early in mornings when everything is cool. Cranks but does not run/restart after engine is hot ... several minutes must pass before successfully restarting.

This has been going on for some months now, but has worsened in hot weather. At first, beating on the IAC valve seemed to help ... but after replacing the IAC, we know we have greater issues. To date, we have done the following:

1. Replaced IAC control valve.

2. Replaced in-line Motorcraft fuel filter. We thought this was a winner because of the black gunk that spilled out of inlet end of filter ... no change!

3. Replaced fuel pump/sender. Used Ford PFS-399/YL8Z-9H307-AG. Heads up! Round tank seal and fuel line clips must be salvaged from old assembly .. are not included in new package! (Fuel in tank was surprisingly clean by the way.) ... no change.

4. Replaced ECT (Engine Coolant Temperature sensor). No change.

5. Replaced spark plugs. Cleaned/inspected coils. Original plugs were a bit worn ... but clean, looked pretty good. Coils were dirty ... so this was good, needed maint action.

So this is where we are ... all the above has made the vehicle run a bit better (perhaps) ... but the hot non-restart is still with us. And never a single code! Any ideas??

JFUSION21 · 06-26-2009, 07:07 PM

man this was a common problem with many Fords about 20 years ago, I thought that they got this corrected a long time ago. Back then it was a relay or module that would stop working when it got too hot from engine heat that was given off. I doubt it's the same part, but the symptoms sound very similar. Sorry I couldn't be of any help, but it sounds serious enough to have a dealer/technician diagnose it, likely something that is common to the vehicle that they have seen before.

12Ounce · 06-26-2009, 07:15 PM

Thanks for the input. Its S's car, and we haven't been together very much when problem occurs ... so we haven't tried yet tried some tests/queries:
1. Are measure voltages across all test points (fuse tops, etc) normal?
2. Are the injectors "clicking" when problem occurs?
3. ??

We may end up at dealer yet .... (Man! I hate too!).

12Ounce · 06-29-2009, 07:42 PM

Switching the EEC relay with other relays did no good! The mystery/nuisance continues. Hopefully we get a chance to "listen" to the injectors next ...

12Ounce · 07-05-2009, 08:43 AM

Little update on (non) progress:

Finally were able to "listen" to injectors during a nonstart event. No injector clicking! This moves us to a different area ... The PCM, sensors, harnesses, etc, etc.

Since we could not find any easy means to thoroughly test sensors, we thought we would just throw some more money at the problem. Beware!, after much wasted time and effort, we have detemined that the cam and crank sensors for this vehicle are cataloged wrongly at AutoZone ... will not hook properly to the harness, with pigtail lengths as provided. However, found AdvanceAuto (a longer drive) to have exact replacements ... and lower cost!

Hopefully these sensors get installed today. (It looks as though the crank sensor has been upgraded ... now has a metal sleeve over the sensor probe ... for heat perhaps?)

Stay tuned ....

12Ounce · 07-14-2009, 06:47 PM

Well, its been a few days now ... no more failed starts ... and its running better than remembered.

The solution? ...the answer sems to have been the crankshaft position sensor! Time will tell ... but we THINK this is it! Strange that we never got a CEL!

BroncoJoe19 · 07-14-2009, 07:47 PM

Good troubleshooting, sorry I wasn't around to throw Ideas at ya, it looks like you worked this one out by yourself.

It is strange that you didn't get a code. Oh.. wait, did you not get a code? or did you not get a CEL?

12Ounce · 07-15-2009, 06:25 AM

Did not get a CEL. As I am scanner-challenged, I'm not 100% sure about codes. We did run some on-board code display routines (not using scanner) ... found some tranny range sensor issues, but nothing on the engine.

Of course, since the engine never ran when there was a problem ... maybe the situation for code generation was never met.

theoldwizard · 07-15-2009, 07:23 AM

Quote:

Originally Posted by 12Ounce

Finally were able to "listen" to injectors during a nonstart event. No injector clicking!

...

Hopefully these sensors (cam and crank) get installed today. (It looks as though the crank sensor has been upgraded ... now has a metal sleeve over the sensor probe ... for heat perhaps?)

...

Well, its been a few days now ... no more failed starts ... and its running better than remembered.

First let me congratulate you on some excellent diagnostics !

Many folks don't realize that you must use all of your senses (In the case, hearing) to get the correct diagnosis !!

Theory : Most folks don;y realize that underhood (and coolant) temperatures actually rise the first 5-10 after shutting a car off. Obviously that additional heat was causing the sensor to malfunction !

theoldwizard · 07-15-2009, 07:47 AM

Quote:

Originally Posted by 12Ounce

Did not get a CEL. As I am scanner-challenged, I'm not 100% sure about codes. We did run some on-board code display routines (not using scanner) ...

If the computer doesn't see the engine turning, well ... the engine is not turning and there is no problem !

Newer Ford systems now have direct starter control (as opposed to starter inhibit). Hopefully the current on board diagnostics will take note of the fact that the starter is engaged and the the engine is not turning !