04 F150 Cold Start Questions

Harritwo

Chief Petty Officer
Joined
Oct 4, 2011
Messages
586
My 2004 Ford F-150 Supercab Lariat with the 5.4L 3V engine has developed a quirk that I am wondering if anyone can shed some light on. I purchased the truck new in Jan 04 in Aransas Pass, Texas, Moved to Jacksonville Florida and have never really been in a cold environment. Now I am in Seattle Washington, I park on an incline with the front end pointed uphill.

On cold start, the engine surges to 2000+ RPM for a second, then comes down to a normal high idle of 1200 rpm until it warms up. The engine was rebuilt at 156,000 miles, has 187,000 miles on the clock.,

Ford TSB stated to change spark plugs at 60000 miles instead of the 100,000 miles previously published. Ford TSB also states to use 5W-30 motor oil with a filter that has the silicon check anti-siphon valve and that is what has been used in this engine since overhaul.

The current temps are between 45 and 65 degrees F. This issue just appeared after moving to Seattle.

Can anyone shed any light as to the cause of the idle surge on cold start? What to check, what to look for?

George
 

hungupthespikes

Master Chief Petty Officer
Joined
Sep 25, 2009
Messages
814
Read this for the plugs:

http://forums.iboats.com/forum/other/non-boating-technical-topics/8583996-ford-spark-plugs

The MAP and MAS sensor are both in the air intake, so clean them (inside the intake) with some contact cleaner or the auto parts store sells a safe cleaner.
I always cleaned them and checked the air filter as the motor oil drained. Both will last the life of the truck and not give you any problems if keep clean.

The Throttle Position Sensor is just a rheostat and that's mechanical..... with 187+k, it's time to change it out.... if the rebuilt didn't replace it.
A bad/worn TPS will made it surge. My 01, 5.4L did at about the same mileage, but at all temps, cold or warm start.
I got lucky with an ohm meter, The TPS was erratic at the low/closed end of travel so I never had to look up the range of the sensor.

Cold weather will make it idle/surge high, but 45° ?? I wouldn't think so.

huts
 

MTboatguy

Fleet Admiral
Joined
Jul 8, 2010
Messages
8,988
The cold moisture in the Seattle area causes all kinds of problems you don't see in other areas of the country, replacing the TPS would be a good place to start and you might need to have a shop running the on board computer to see if any dealer specific codes are stored. Have you taken it through DEQ yet to get your new Washington plates, if not when you do, their sensors will also catch quite a few things such as running to rich or to lean due to the climate changes. I know my newer fords don't run the same when I am visiting my Dad in Vancouver, WA as they do here in the Rocky Mountains at home.
 

Harritwo

Chief Petty Officer
Joined
Oct 4, 2011
Messages
586
Ran the diagnostics, talked to my buddies, took it to Ford, and finally found the issue. The Lift pump was worn out. When you turn the key on, the lift pump should cycle and pressurize the system. The issue was being that it is parked overnight on a sloping drive, (Got to love the Pacific Northwest), the system was taking longer to pressurize. On cold start, it would start, have a "Momentary lapse of fuel" which was causing the idle surge. Replaced the in tank fuel pump and the issue is gone. According to the Ford Dealer, I was supplying insufficient fuel pressure on start. Never heard this described like this before, but the issue is gone.
 

hungupthespikes

Master Chief Petty Officer
Joined
Sep 25, 2009
Messages
814
:clap2: Great news....props to you for the updating, always a good thing, but few do.
Enjoy Seattle, great city. Loved the traffic reports in the morning, which ferries are running behind/on time and why.
huts
 
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