Hello all
I have two Fords, one being a 1991 F150 that has developed a couple of quirks. I'm sure somewhere in the posts this has been covered, but I'm short on time. I will continue to surf them.

The colder it gets outside the harder it is to start the truck. This morning it was -14C and the truck was not happy. Usually when the temperature drops to -20C I plug it in. When the truck starts the RPM's go up and then drop to an almost stalling point and then the computer picks the rpm's up and it idles fast for 1 - 1.5 minutes and then lowers to normal idle.

I installed a new sensor for monitoring the coolant temperature as I thought this would be the problem. I have no manual so I guessed it was the sensor above the thermostat housing on the 5.0 litre engine. I cleaned the IAC, etc, but there's no difference. I know if I plug the truck in I don't have this problem which is why I'm thinking it must have something to do with a sensor that monitors temperature.

Is there more than one temperature sensor in these 5.0 litre engines? Any tips and\or tricks would be appreciated. Anyone have a list of sensors and their locations for these 5.0 litres

Thanks
Gerald

 

Could be a problem with your EGR, my 5.0 Mustang has the same problem, and it makes it even worse with an upgraded cam, I tried new temp sensor, EGR, o2, and TPS, but no difference

 

I went to plug the truck in Sun as the temperature was -29C. I decided to see if the truck would turn over. Be darned if it didn't start. The RPM's were not fast and the truck was running rough, but I left it running. As I was brushing the snow off the truck, which had been running for about 2 minutes, the engine RPM's dropped and the engine quit (actual silence) for a 1/2 second. The computer then picked up the RPM's and the truck continued to run rough with the RPM's not as high as it should've been. I turned the truck off and restarted it. The RPM's went up to high and the truck ran smooth.

Now I'm wondering about the IAC, but the EGR is still on my list. The temperature is -35C without the wind chill at the moment so I'm not checking anything for a few days.

Gerald

 

glyoungca,
My truck just had that same problem, where it doesnt like to start or stay running unless you have the throttle pushed down. Turns out that when they replaced the EGR, they didnt clean the system and i had a carbon buildup in my throttle body.. hope that helps....

 

Good to know about the carbon buildup. As soon as the cold snap lifts I will have to check into this.

It's -29C and with the wind chill it's -44C. By next week it's suppose to warm up.


Gerald

 

Thank God the temperature outside has gone up.

I had the truck put onto the scope Sat to check my timing and it was at 10 degrees just where it's supposed to be. The engine likes to ping under a load. One of the mechanics pulled a plug wire and broke it. Of course I was busy and I was told after everything was done that if the truck displays a miss then this would be the problem. N\C for any work as the mechanics are friends of mine. I got one block away and had to pull over. The number one plug wire was literally broken. The jacket was on the plug so I pulled it off, pushed it into the boot as far as it would go
and this stopped the missing. I will be replacing the plug wires in the near future. The pinging has reduced a fair amount. I also noticed that the truck has Bosch Platinum's. Gas mileage is fine, but in the back of my head I seem to recall that these plugs in a Ford are not the best combination. I thought these plugs can cause carboning in a Ford? That would explain some more of the pinging. Time for Motorcraft or Autolite
.
I decided to check the IAC although the garage has told me they cleaned it. It was sticking. I cleaned it out and blew air in to help dry it and the valve is now free moving. Put everything back together, started the truck and it idled a lot smoother. Next morning it started and the RPM's stayed up. What an improvement. I will see what happens during the next cold spell.