99 hard start

[ROLLING THUNDER]

Im working on a 99 f450 and im having a hard time getting it to start it turns over sounds like its hitting on a couple of cylinders and when i do get it to start it runs rough untill warmed up.

things that ive checked

:injector buzz test come back fine
: gp relay good
: gp are all good
: engine harness is giving 12v to gp's
: contribution test good
: tack it moving upon crank
: oil pressure rises upon crank
: no check engine light on
: checked fuses in engine compartment
: fuel in the fuel bowl
: hpop pressure at idle is 500-600

I noticed that the fuel bowl heater is broken inside.
I put a new fuel pump on truck last winter along with cleaning the tank and intalling a new tank liner at a radiator shop due to tank film wiping out the pump cleaned fuel line up to the bowl and cleaned fuel bowl and adding a new filter.

Im not getting vary much smoke upon cold start up.
the trick to starting it cycle the gp twice and then it will start but if i feed it fuel it will die and youll have to wait hours before the next start up.

what Im thinking
: injectors?
: fuel bowl heater not working due to being broken
: fuel pressure ? I dont have a way of checking


I hope this is enough info to make a good diagnosis

thanks stephan

 

[Arisley]

It's not the heater, many of those have been gone for years in cold weather with no issues.

How many miles, it could be injectors.
Could be fuel. Down and dirty way to check fuel pressure.
Attach a line from the fuel bowl drain under the truck. Open drain lever. Turn on key. You should pump about a quart in fifteen seconds.

Might try plugging in the block heater, see if that makes a difference.

 

[Justin@DP-Tuner]

How cold is it where you are?

 

[littleredstroker]

My GPS were good, my relay was good, my batteries were good, yet my truck wouldn't start at 0 degrees. It was not until I heard another 7.3 start that I realized my starter was cranking slow , it was not REALLY slow, but was slow enough she wouldnt pop. New starter fixed that problem . Just a thought

autocorrected by taptalk

 

[littleredstroker]

I guess I should have read all of it.

When I had injectors shot it wouldnt starte less than 40* outside without cranking for 10 minutes, once she started it ran horribly missing and sputtering ( no smoke) once it warmed up it ran better. It would pass buzz test

autocorrected by taptalk

 

[TARM]

Try plugging it in for a couple hours and see how it starts. If it starts easy I would be looking at injectors with worn poppets etc if what you have listed holds true.

 

[ROLLING THUNDER]

sorry i forgot to add that my fuel pressure is at 55psi, and when truck is plugged in the truck start "ok" but misses and low on power. Im sure the injectors are shot the truck has 260k on the odometer. I just hate to spend that money.

thanks stephan

 

[Justin@DP-Tuner]

sorry i forgot to add that my fuel pressure is at 55psi, and when truck is plugged in the truck start "ok" but misses and low on power. Im sure the injectors are shot the truck has 260k on the odometer. I just hate to spend that money.

thanks stephan

260,000 miles on injectors doesn't necessarily mean they are shot. If proper maintenance has been done on the truck they could easily go that long. But as with anything mechanical, stuff fails.

How does your ICP and IPR look?

 

[ROLLING THUNDER]

ICP is seeing 500-600 upon crank. IPR is doing fine, recently cleaned

 

[stroker2]

I know i had to plug my truck in at 20* or less or else i would have to crank on it a few times. Then i put my new injectors in and at 5* without being plugged in it would fire right up and be running on all 8

 

[Arisley]

ICP is seeing 500-600 upon crank. IPR is doing fine, recently cleaned

Recently cleaned does not mean crap. The clearances in there are very, very tiny. If the piston or the cylinder have any wear, the piston can cock a bit and stick a bit. It will have excessive blowby. Either of things can make a recently cleaned IPR go haywire.

Mine has 325K miles on it. It is perfectly clean. With a brand new oil change on it, it romps for a second or two. If I get on it hard, the pump can't keep up. Not the pump, it's the old beat up and beat on IPR.


Sent from my truck while eating, adjusting the radio and passing a Mustang sideways.

 

[Justin@DP-Tuner]

Recently cleaned does not mean crap. The clearances in there are very, very tiny. If the piston or the cylinder have any wear, the piston can cock a bit and stick a bit. It will have excessive blowby. Either of things can make a recently cleaned IPR go haywire.

Mine has 325K miles on it. It is perfectly clean. With a brand new oil change on it, it romps for a second or two. If I get on it hard, the pump can't keep up. Not the pump, it's the old beat up and beat on IPR.


Sent from my truck while eating, adjusting the radio and passing a Mustang sideways.

Very true Andy. To the OP, have you ever seen the inside of an IPR?

If not, here ya go...

Just like Andy said, they can go haywire if they are not within their tolerance spec, whether it is cleaned or not.

 

[krawlerhauler18]

interested to see what becomes of this. My truck is doing the exact same thing....even when it was 80 deg outside.

 

[stroker2]

interested to see what becomes of this. My truck is doing the exact same thing....even when it was 80 deg outside.

If its doing that at 80* then i would suspect low compression or your at really high altitude IF your hpop is draining back

 

[golfer]

can someone explain how an IPR can cause individual injectors to misfire?

 

[Arisley]

Sorta weak IPR, coupled with a sorta weak injector.

Kinda does rule out the IPR, never even thought about that. Thanks again.

 

[krawlerhauler18]

If its doing that at 80* then i would suspect low compression or your at really high altitude IF your hpop is draining back

definitely not at high altitude living in FL.....

I would think if the compression was low, it would continually do it and would not run well most of the time and would smoke more? It acts like there is a stuck injector, till it warms up or the ICP builds up and clears it out. Kinda odd. I can plug it in and keep the engine warm and it will run perfect......minus the low mileage

Brian

 

[stroker2]

Didnt know you were in Florida. It just sounded like yours was exactly the same as the op's but it was at 80*. Doesnt seem like there should be any engine running or starting issues at 80*. Thats why i am wondering if compression was getting lower.

I would rely on someone with more knowledge than me though haha. Just putting my 2 cents in

 

[ROLLING THUNDER]

I have cleaned numerous IPR's and checked them for abnormal wear. So im sure that the IPR isnt the issue.

Im pulling the injectors this weekend and tearing them apart to check for damaged internals.

thanks for the help guys