No start hot. Has spark. has fuel *solved*

[Canner]

1997 mustang GT stock except for bbk intake.
The starts and runs great cold. As the temp comes up it stays to surge and full warmed up it will buck and surge under throttle.


Once warmed up it won’t start again for 3-4 hours. Has to be full cooled off to start. It will crank over fast but won’t fire.

Tested 40 psi fuel pressure cold and hot cranking.
Pulled a couple different spark plugs and cranked with them out, they have spark.

Crank and cam sensors replaced.
Not sure what to check next.
Any advice would be appreciated

 

[Bronco2Fan]

Have you checked the TPS? Mine would get hot and stall on me if I wasn't in the throttle. Clutch in and coasting, stall. Pop the Clutch and restart easily. Just a guess

 

[Canner]

Have you checked the TPS? Mine would get hot and stall on me if I wasn't in the throttle. Clutch in and coasting, stall. Pop the Clutch and restart easily. Just a guess

Yeah worth a shot. I test it tomorrow hot and cold
thanks.

 

[07GtS197]

Check the coolant temp sensor for the ecu as well and check for codes.

 

[Canner]

Check the coolant temp sensor for the ecu as well and check for codes.

Coolant temperature sensor was the issue. Thanks for the help!!!

 

[GTamas]

Glad you got it solved!
For my education, why does a faulty coolant temp sensor cause this issue?

 

[highplace11]

Essentially long story short... The ECU (TUNE) uses coolant temp to modify everything from SPARK TIMING, FUEL TRIMS, IDLE AIR CONTROL VALVE, ETC to work its magic... With it likely reading cold the entire time it eventually just runs like CRAP after warming up BUT it also surprises me some that it would cause a NO START situation warm...

I'd like to know why the OP didn't notice the coolant gauge never came up and suspect an issue would be my first inquiry...

God Bless, and HOTROD HARD... Never let anyone discourage you, we are a special breed of people with our Mustangs...

highplace11

 

[Canner]

Essentially long story short... The ECU (TUNE) uses coolant temp to modify everything from SPARK TIMING, FUEL TRIMS, IDLE AIR CONTROL VALVE, ETC to work its magic... With it likely reading cold the entire time it eventually just runs like CRAP after warming up BUT it also surprises me some that it would cause a NO START situation warm...

I'd like to know why the OP didn't notice the coolant gauge never came up and suspect an issue would be my first inquiry...

God Bless, and HOTROD HARD... Never let anyone discourage you, we are a special breed of people with our Mustangs...

highplace11

There are two temp sensors. The gauge is controlled by the other one. So the gauge read as normal.

 

[highplace11]

There are two temp sensors. The gauge is controlled by the other one. So the gauge read as normal.

ROGER THAT!!!... Noticed the year now that you mentioned it...

highplace11

 

[ttocs]

depending on the temp it sets the IAC at certain % open and controls fuel, ect while cranking. If it had bad data then it was set up to fail.

 

[highplace11]

+! ON THAT!!!

 

[ttocs]

Just curious op did ya try opening the throttle a little bit while you were starting it?

 

[Canner]

Just curious op did ya try opening the throttle a little bit while you were starting it?

Yes I did try that. Tried various throttle positions. Nothing other than letting the car sit and cool down helped.

 

[lwarrior1016]

It’s also likely the temp sensor read over temp after it got hot and wouldn’t let you start it back up because it thought you were trying to melt the engine down.