Help - Car occasionally won’t start until I give a little bit of gas when hot

[Justin J]

My 2006 Ford Explorer Eddie Bauer 4.0 “occasionally” won’t start until I give it a little bit of gas, WHEN ENGINE IS HOT; once started, it idles normally in my opinion. If I didn’t give a bit of gas, it would hesitate to start, and sometimes fails.

COLD START is 100% normal and fast!

I cleaned MAF sensor, throttle body (the plate only), which hasn’t helped. I searched around and seems this car has no IAC.

I plan to replace the fuel filter soon, but I have no idea it will resolve it or not. I want to know some HOWs to diagnose such an issue. What else should I check please? Thanks!

 

[Fbird]

you can expect a fuel pump module in you near future. Whats happening is the pump is allowing the fuel line pressure to bleed off. When you hit the key (not crank just ignition on) the fuel pump should buzz for about 3-5 seconds to pressurize system. If it does NOT the injectors will only dribble a little fuel in...not enough to run.
Also note pushing the gas pedal does nothing on a fuel injection vehicle because there is NO MECHANICAL means to add fuel, in fact just the opposite. With an injected vehicle if it is flooded (or you are checking stuff but do NOT want it to RUN, you hold the gas pedal wide open while cranking and this will tell the ecm to turn OFF the fuel pump for diagnostic tests.

 

[Justin J]

Thank you Fbird!

 

[Bazz270]

What HS/MS CAN DTC's do you have?

 

[Justin J]

Replaced the fuel filter, still no help.

And I find the issue only happens when the engine is hot; it cranks and starts fine when the engine is cold.

Any ideas?

 

[Fix4Dirt]

if you cycle key to prime fuel pump a few times does it start? if so, maybe leakown w faulty valve... or ECT... or IAC heat soaking

 

[Justin J]

if you cycle key to prime fuel pump a few times does it start? if so, maybe leakown w faulty valve... or ECT... or IAC heat soaking

I’ll try and get more info. Thanks!

 

[Fix4Dirt]

no problem! let me know if this works!

 

[Justin J]

if you cycle key to prime fuel pump a few times does it start? if so, maybe leakown w faulty valve... or ECT... or IAC heat soaking

I monitored my fuel rail pressure via a OBD2 scanner this morning, and it stabilized around 39 Psi. Is this valve normal?

 

[Fix4Dirt]

I monitored my fuel rail pressure via a OBD2 scanner this morning, and it stabilized around 39 Psi. Is this valve normal?

it sounds about normal to me (iirc mine was 40 or so so its bery close!) ill rule it out for now... whats your coolant temp and age/clndition of iac?

 

[Justin J]

it sounds about normal to me (iirc mine was 40 or so so its bery close!) ill rule it out for now... whats your coolant temp and age/clndition of iac?

ECT sensor is working fine.

This car has no IAC if I’m right.

Now I’m suspecting a vacuum leak that is affected by temperature.

Thanks for your help!

 

[Fix4Dirt]

ECT sensor is working fine.

This car has no IAC if I’m right.

Now I’m suspecting a vacuum leak that is affected by temperature.

Thanks for your help!

oh! i didnt know there was no IAC! guess lots has changrd aince the 2nd gen! my only other thought is fuel pump relay... or (highly ubliekly) a computer issue? doubt it though, they aint too common...

 

[BrownsFan42]

2007 Eddie Bauer 4.0. I'm the sole owner.

I'd check the radiator coolant temperature sensor. It, among other things, regulates the air/fuel mixture into the engine. It's right on top of the engine and it's cheap and simple to replace.

A couple months ago I noticed a problem that when starting cold, it seemed like there was crap in the fuel line....but it eventually started. That went on for a couple weeks. Soon thereafter while driving, a radiator hose blew. During that event, the temp gauge went between redlining and normal. I had it towed to a shop.

I had the hose fixed, new coolant, etc. But after that, the temp gauge was off a little....ie, not like was since '07. The gauge said the engine was running too cool. I replaced the radiator coolant temp sensor, and it's starting/running like new.

 

[Justin J]

2007 Eddie Bauer 4.0. I'm the sole owner.

I'd check the radiator coolant temperature sensor. It, among other things, regulates the air/fuel mixture into the engine. It's right on top of the engine and it's cheap and simple to replace.

A couple months ago I noticed a problem that when starting cold, it seemed like there was crap in the fuel line....but it eventually started. That went on for a couple weeks. Soon thereafter while driving, a radiator hose blew. During that event, the temp gauge went between redlining and normal. I had it towed to a shop.

I had the hose fixed, new coolant, etc. But after that, the temp gauge was off a little....ie, not like was since '07. The gauge said the engine was running too cool. I replaced the radiator coolant temp sensor, and it's starting/running like new.

Thanks! It is the ECT sensor I mentioned above. I’ll double check it by unplugging it and see what happens. Thanks!

 

[Justin J]

I double-checked my ECT sensor with a hot engine:

1. When it’s unplugged, OBD reads -40F;
2. When it’s plugged in, OBD reads 200F or so;
3. The sensor valve changes as engine warms up.

So I’ll exclude ECT.

 

[Fix4Dirt]

I double-checked my ECT sensor with a hot engine:

1. When it’s unplugged, OBD reads -40F;
2. When it’s plugged in, OBD reads 200F or so;
3. The sensor valve changes as engine warms up.

So I’ll exclude ECT.

hows the fuel pump relay when the vehicle is hot? thats the only other idea ive got at the moment

 

[Justin J]

hows the fuel pump relay when the vehicle is hot? thats the only other idea ive got at the moment

How should I test it please?

 

[Fix4Dirt]

How should I test it please?

How to: - Ford Explorer Fuel Pump Electrical Procedure

Background This procedure was written for a 2000 Explorer Sport with SOHC V6. The wiring should be very similar for 1998 thru 2000 models. The energizing of the Fuel Pump Relay is controlled by the PCM. If the PCM does not have power then neither will the Fuel Pump Relay. The Inertia...

www.explorerforum.com

im not too sure if this applies to later mdoels though, as i have a 2nd gen

 

[Justin J]

TTT

Just want to share: All my research points to leaky fuel injectors, which floods cylinder at warm start! It won’t be an isssue in cold start as the leaked fuel would have evaporated by then.

 

[Blackhawkxx]

Also note pushing the gas pedal does nothing on a fuel injection vehicle because there is NO MECHANICAL means to add fuel, in fact just the opposite. With an injected vehicle if it is flooded (or you are checking stuff but do NOT want it to RUN, you hold the gas pedal wide open while cranking and this will tell the ecm to turn OFF the fuel pump for diagnostic tests.

I know this is old but just for general info, I had a 3.0 1999 Ranger that would sometimes do that. The only way to get it to start was to flat foot the gas peddle, then it would fire right up. It did have a IAC and after I replaced it, there was no more issues. I have also got a chevy to start using the same method.