engine dies when warm?
#1
engine dies when warm?
I have a 86 f-150 with a 302 FI V8. Here is a summary: My truck kept stalling/loosing all power whenever it warmed up to normal Temp. and whenever I went over 3,000 RPM. I had fuel pump replaced in engine, didn't work, then I replaced the one in the tank. It now runs better under a load (over 3,000 rpm) but it will not run at idle at normal temperature now??
I checked the battery and alternator and both are fine. Once the motor cools back down, it will crank again and run fine until the engine warms up to normal temperature? Does anyone have any ideas what this might be?
Thank You!!!
I checked the battery and alternator and both are fine. Once the motor cools back down, it will crank again and run fine until the engine warms up to normal temperature? Does anyone have any ideas what this might be?
Thank You!!!
#3
Pull the codes.
You can also try to unhook the vac line feeding the EGR valve and plug it. Run it and see what happens.
Here are some links for the codes:
http://www.troublecodes.net/Ford/
http://www.dalidesign.com/hbook/eectest.html
I found the analog meter to be the easiest to read.
You can also try to unhook the vac line feeding the EGR valve and plug it. Run it and see what happens.
Here are some links for the codes:
http://www.troublecodes.net/Ford/
http://www.dalidesign.com/hbook/eectest.html
I found the analog meter to be the easiest to read.
#4
I can only guess since I missed about 20 years of automotive progress but let me say this. The vehicles in my day had an automatic choke that was a spring that would change as it heated up and adjust the throttle on the engine for the correct air/fuel mixture. Todays vehicles seem to know the engine temperature and adjust the length of time that the injectors fire in order to maintain the correct Air/Fuel ratio.
It sounds like your Air/Fuel ratio may be incorrect when the engine warms up or some other component starts to fail when it heats up.
Another problem that can occur is vapor lock. The gas in the gas line can get so hot that it changes from a liquid to a gas.
http://autorepair.about.com/library/faqs/bl828.htm
It sounds like your Air/Fuel ratio may be incorrect when the engine warms up or some other component starts to fail when it heats up.
Another problem that can occur is vapor lock. The gas in the gas line can get so hot that it changes from a liquid to a gas.
http://autorepair.about.com/library/faqs/bl828.htm
Last edited by temp1; 05-11-2004 at 09:55 AM.
#5
Is the engine shutting down just like you're turning off the ignition? I had a problem like this with my 88 F150. It had a 300 I6 with the coil mounted to the engine. I finally found out that the coil was cracked and when it got hot, it would short out internally. The fix cost me about 12 hours of my time, but only $38 for the coil.
Hope this helps you,
Sidewinder
Hope this helps you,
Sidewinder
#7
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#10
Did you try the suggestion about pulling the vacuum line off EGR valve and plugging the vacuum hose?
The way I understand it the EGR valve does not start working until the engine is warm and the rpms are high. If the EGR valve is open too wide then the engine may stall/die/quit running.
The way I understand it the EGR valve does not start working until the engine is warm and the rpms are high. If the EGR valve is open too wide then the engine may stall/die/quit running.
Last edited by temp1; 05-13-2004 at 06:45 PM.