COLD START PROBLEM
 

I have a 2001 7.3, hard to start when cold.oil is good and correct weight,cam sensor new gpr new.Plenty of smoke when cranking over.If not to cold (above zero) it will start,but very hard,cycle the glow plugs,crank it over it will start but shut right down,if you give it a little fuel it will stay running,but it will lobe if you keep giving it fuel it will start to run normal.I`m thinking glow plugs,is there anything else it might be.

Sounds like glow plugs...

How long are u waiting for your glow plugs to cycle? Let them cycle about 20 seconds and see how that works.

Still have cold start prob here`s what i`ve done so far,oil change to correct wgt,glow plug relay,checked glow plugs,all good,cam sensor,good fuel,still will not start when it`s cold unless plugged in.any suggestions?

X2 glow plugs, possibly also loose undervalve cover harness plug. $18 at dealer for clips to keep it together better, and if you replace the GP's, you'll be in there anyhow

Do you have good/big batteries

2 die hards new two years ago,spins motor out of truck when warm or plugged in,any other suggestions?

Do you know the GPR is working? Have you tested it? Ground a test light, then touch one side or the other until you find the hot side. Then turn the key on and check the other side.

It sounds like a GPR issue.

How are you testing the glow plugs?

not gpr,that is new,test glow plugs by pulling them out and touch them directly to a battery.could it be idm or ecm?

Thats not a good test. You need to see if they have resistance and what not. Theres a post somewhere on how to check them

How do you KNOW the GPR is good without testing it... I have seen brand new ones that come out junk.

Wish I was closer I would give you a hand...

Buy a STANCOR GPR and be done with it

I have been quite happy with my GPR109's from napa...$32.00 and I am done.

Now truck will start but will not stay running unless you give it fuel,but as before, if plugged in will start and stay running?

Its time to take it somewhere that has the equitment to data long and see whats going on.

Just did cylinder contribution test,computer stated cylinder 8 contribution fault or balance fault,code po284.any ideas/

#8 almost always fails... Its the Long lead injector...

I would check HPO pressure when cranking, Duty cycle when cranking, Check the fuel pressure, Buzz test it...

hpo psi is 1750 when cranking,buzz test done good,fuel psi unknown but wouldn`t there be other issues if fuel psi was low?also would #8 cylinder fault cause cold start problem?

#8 is nothing to worry about. 90% of the trucks on the road right now would fail a cont test with #8.

Check your ICP sensor and see if there is oil leaking into the plug area. Check your HPO res and make sure it is full apon first crank in the morning...

Just a thought but are there not two relays to change? One for the glow plugs and one for a air intake pre heater?
I know on the 2000 F350 I have we just went through the same thing, poor cold starting. There were two relays for pre heat so we just changed them both.
Starts great now.
Just my 2 cents.

Intake air heater has nothing to do with starting, infact it will not even turn on until voltage is up and oil temp is between a set limit...

good thought, but nothing to do with this issue. Unless he swapped the wrong relay.

Thats what I was wondering, if the wrong relay was changed. They are right beside each other.

My 2001, 7.3 was hard to start. Wait to start would come on. Plenty of white smoke. It was the glow plug SOLENOID. It's on the passenger side on top the head. There are two solenoids there. The one in back is for the glow plugs. The front one is for the intake air heater. It comes on after the engine starts. Put your hand on the back one, and have someone turn the key on. (wait to start comes on) If you don't feel or hear it engage, that should be the problem. 64 bucks at AutoZone. DO NOT OVER TIGHTEN. Breaks easily!

it needs glow plugs

36 at NAPA... GPR109...

We have been over this... He says he has tested everything...

I am thinking it needs a relay... I have asked if he has tested it...

will the GPR109 work on a 97 7.3 ?

yup... work just fine.

I have found with my 99 F350 when it is under 20deg it is best to plug in the engine block heater.
or else I'm out there cranking to heck out of it and hoping for it to start. i have spend lots of time on this issue and just have come to realize that spending to $ in electricity is well work the less strain on the engine parts. if you don't have a engine block heater you should get one it make a night and day difference.

Sean