Hard Start Cold Engine

[podsquad]

1998 EB 5.4 328,000 miles....For sometime now truck is hard to start in cooler weather especially when sitting overnight. Once it starts it's a nearly perfect idle and there are no other issues during the day once the engine stays somewhat warm. New plugs, coil wires and a fuel pump(15,000 miles ago...it went) all original injectors. At the top of my list of the causes are the ECT (engine coolant temp sensor) and maybe the IAT (intake air temp sensor). Further down the list MAF, throttle body, fuel rail regulator(was recently replaced during the recent tuneup...probably didn't need to be changed), fuel pump(check valve). I ordered the ECT. Correct me if I am wrong....if the issue were with a fuel pump or pressure in the fuel rail that it would be a problem in a cold or warm start. I think the key here is that the hard start only occurs on a cold start and not when the truck has been used during the day and the engine is still warm. During the warmer summer months I generally never experienced the hard start. It is almost like the engine was 'flooded' or if it were a carb engine a choke plate stuck. Sometimes though rarely you can hear a slight pop on the left front of the engine I did try and depress the gas fully and that did not work. You can hear when it's about to turn over...there is a slight sputter. Anything else that I should be looking at as a possible cause for a hard start?

 

[podsquad]

The truck drained the 5 yr old battery today trying to start. Replaced with a new battery today from Costco. 3rd crank it started right up annd idled perfectly. You would never know there was any issues. Though I reported earlier it seems the engine was 'flooded'...it actually seems the reverse is true. Maybe no gas/no spark. Now at the top of the list is the Crankshaft Position Sensor.....Found this article .......

99 Ford Expedition Cold start problems​

99 Ford Expedition Cold start problems - Ford F150 Forum

I'll leave it up to my mechanic to test for the pulsing DC sinewave.

 

[podsquad]

It turned out to be the Coolant temp sensor. Replaced with TX61(gauge wasn't working)...needed part TS380(w gauge). Replaced the crankshaft position sensor and air temp sensor.....all feed into the ECM....and can cause difficult cold start....so all done and were easy enough to replace. Has been starting on one easy crank for weeks now....just hit 333,000 miles and 25 years that I have the 98.... original engine/transmission.

 

[wpatters1229]

Can someone explain how the ECM can control the cold idle when first starting? The throttle is controlled by a cable to the accelerator pedal. The throttle has a throttle position sensor but what controls the idle? There is no idle control motor like other engines. Where can I go to fine the process for this 4.6 triton engine?

 

[Yupster Dog]

Can someone explain how the ECM can control the cold idle when first starting? The throttle is controlled by a cable to the accelerator pedal. The throttle has a throttle position sensor but what controls the idle? There is no idle control motor like other engines. Where can I go to fine the process for this 4.6 triton engine?

Start your own thread and tell us about your truck, no one can follow what is going on thru multiple old threads.
https://www.expeditionforum.com/threads/correct-way-to-start-a-thread.47954/