98 5.0 mountaineer one hell of a starting problem

[98 MERC]

So i have had my vehicle for 2 years and has always been a ***** to start.Really bad when its cold outside and i live in MI.If i let it sit for a week untouched and its like 40* OR below it takes like 5 key cycles on and off and just about burns my starter out to get it started ! lol.But the funny part is most of the time when the motor is warm she starts up with a couple key cycles.I have been plagued with this embarrassing problem for to long.I will go to the gas station and turn the vehicle off and fill it up and it cranks for ever and other times i turn it off and get back in and it starts right up with just 1 key cycle on and off.Its soooo random ! I have never had it start up right away ! EVER.

My mechanic thinks the pcm is bad but i would think a bad pcm would run terrible all the time and have no obd2 port communication.

I think its the fuel pressure regulator or fuel pump.

Or it could be the ECT sensor ? or the MAF sensor ?
Sometimes when it finally fires up after 5 mins of cranking, It smells rich out the tail pipe ! Hell i have even had it backfire out the tail pipe during starting before.

When she runs tho wooooo Its like a raped ape.


I even saw another mountaineer have the same problem and watched him cycle his key a couple times to get it to start up.

 

[98 MERC]

Some maintenance items are

New battery,new starter,new plugs and wires and coils,new crank sensor.Engine rebuild.The problem still exists after all of that !

Also sometimes when i go to take off from a stop sign it cuts out and comes back to life.Like i loose function of the gas pedal for 5 secs and then i get power again.No check engine light or codes at all.

 

[1997XLTRollover]

That's going to be a fun issue to find. I would start by checking fuel pressure to see where it's at when the issue presents itself. Then I would go get an ELM327 adapter and Forscan and look at all the sensors when you have this problem to see if something is out of wack.

 

[98 MERC]

Was thinking about bringing it to the dealer and let them deal with it as i am sure they have high end computers.I know they will just bend me over but i am going insane with this problem.I almost wonder if the pressure regulator is leaking fuel into the vac line and flooding the engine sometimes.

 

[VR4]

Monitor fuel pressure bleed off and how long it takes to build up after sitting. Sounds like faulty check valve in the pump.

 

[98 MERC]

Monitor fuel pressure bleed off and how long it takes to build up after sitting. Sounds like faulty check valve in the pump.

Funny you mention this....Sometimes when i go to the store and come back out to start the vehicle,The pump actually makes a squealing sound up on priming and sounds slow to prime.Other times no problem.

Also....I hear gurgling sounds coming from the pump as the vehicle primes.Its sounds like a half of the fuel doesnt even make it to the engine up on priming.Sounds like its shooting back into the tank.

I have been in older fords in the 90's and NEVER herd gurgling or squealing come from a fuel pump EVER.All electric pumps i hear are very QUIET.

Its sounds like a squealing animal in my tank ! lol but other times its quiet


The vehicle has plenty of power and can go on road trips with no issues.

I did have a mechanic look at it last year and he said the fuel pressure primes and drops.Every time the key is cycled.Like 50psi and then 25psi.I hear a click and another click when it drops to 25psi but goes back to normal psi when started.

 

[VR4]

Need a fuel pump. I can't remember the spec off hand but immediately dropping to 25 is no good. Replace the entire assy with a motorcraft part

 

[98 MERC]

Need a fuel pump. I can't remember the spec off hand but immediately dropping to 25 is no good. Replace the entire assy with a motorcraft part

But what does it mean when it primes then drops down ? But its completely drive able ?

Also the weird random squeeling in the tank and gurgling ?

 

[Dono]

You could have a cracked hose in the pump assembly, could be lots of things?
If its not your daily driver, you could pull the assembly to inspect before buying anything.

The pump its self can be purchased inexpensively, but the whole assembly is probably expensive. If I needed a whole assembly, id look at RockAuto, or the wreckers.

 

[98 MERC]

You could have a cracked hose in the pump assembly, could be lots of things?
If its not your daily driver, you could pull the assembly to inspect before buying anything.

The pump its self can be purchased inexpensively, but the whole assembly is probably expensive. If I needed a whole assembly, id look at RockAuto, or the wreckers.

I store it during the winters so its a project vehicle.Also funny you mention a cracked hose in the fuel pump as i mentioned this situation to a ford dealer and he said the same thing.Like it could be sucking air.