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hard start summer and winter

NCadam

NCadam

New Member
Messages
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Location
St louis MO
so for the lats few months I have been having start up problems after the truck sits for more than 6 hours outside temp dose not seem to matter. i have to crank it for several min to get it to start, I have found that if I give a little push on the gas pedal as im cranking it helps makes me think its losing its prime or something like that. Once i get it to fire it will start fine as long as i dont walk away from it for more than 6 hours..... I do get alot of white smoak out of it on start up but it goes away

here is what i got
96 3500 dually vin f 6.5 turbo with a auto trans
200,000 miles on it

here is a list of what i have replaced in the last 6 months
starter, both batts, fuel filter, air filter, injectors, block heater, glow plugs water pump, thermostat and housing to the dual, 5 blade to 9 blade fan

I have done the lift pump test and I get steady fuel out the hose on the front of the motor and I get fuel out of the release on the fuel filter.

If some one had some imput on this it would be great I have been on many many fourms reading on this and so far the truck stop has the most inteigent people on it thanks and sorry about my spelling
 
When are you testing the LP flow? If you are only getting the flow at idle your LP relay could be bad which controls LP power at all times, but the OPS (backup LP power) might pick up power once oil pressure builds. You should have flow with just IGN on, during wait to start at least. Is there a LP fuse you can check too?

Also, you didnt mention the glow plug controller. Make sure power is getting to the glows during WTS. Put a meter on them at the least to verify they are about 11V each during WTS. The controller is a common bad item. That or grounds. How long is your WTS light on before you crank?
 
runs good once warmed up

im from st louis mo

not sure what glow plugs i but in it i know thay where 12 bucks each.... i will look into that tomarow i will also test the voltage on them, and test the lift pump circut
 
I'd suspect air/bleedback. Put a piece of clear tubing on the return line out of the ip. Watch for air bubbles. You'll most likely have one in the top of the bend but you shouldn't see any more at any time. And they might be small.
 
Usually it would be caused by a small leak before the LP. You may not notice any fuel leak, but air will be drawn in.
 
i guess my question should be is there any compnets that are known to fail that I should look at first

I just went out and got it running I got it to start a lot faster today ( just below 32 here) I gave it more fuel with the gas pedal right away as I was cranking it with the starter so it def seems like its lack of fuel or air in the IP Im kinda lost on where to start looink for the problem
 
Known problem areas fuel sending unit and lines (they are subject to corrosion), fuel filter manager, and any rubber lines
 
The way you can test this fuel/bleedback theory is run the LP prior to turning the key at all. Pop hood and supply battery voltage to the LP diagnostic connector. Run the LP for like 10 seconds to prime the lines. Then go try to start it normally.

You never answered the original questions

(1) when were you testing flow. Does it flow with just Ignition on, not running? If not the relay is bad as it controls LP power during WTS and cranking until oil pressure is built.

(2) is there good voltage to each glow plug? A bad controller would cause your issue, and I did say this is common bad item. It could be intermittent too.

The pedal shouldnt do anything until youve reached past 500RPM. So that may be coincidence, or it fired up and the immediate pedal movement helped, which doesnt tell you if its fuel or glo related.

The way you can test the glo plug theory is plug in the block heater overnight and try to start it normally in the morning. if it fires up easy then your glo plugs or controller is bad. If the glows are bad you can crank and pull out some easy to get to one, and see if they are wet or dry.
 
ok so i got to take some time today and look at the truck better...

The glows work fine i got 10.70 volts

I tested the flow with just the ignition on not running and there was no fuel!! the relay for the LP still clicks on when you turn the key and the fuse is also good im going to lookinto this a little better tomarow if i get some time
 
It may only run for like 20 seconds with the ignition ON, during WTS and then slightly more time. It is supposed to prime the fuel line. If you had the drain open and switched on the ignition and got no fuel there is a problem with that relay, or the wiring. With it idling and you have fuel flow, unplug the connector to the OPS, to see if the relay is working during operation. Conversely if you unplug the relay from the socket, the LP should still operate through the OPS.
 
i turned the key on and ran to the drain and opend it, i got no fuel I do know the relay clicks when you turn he key on you can feel it donsent mean ts good.... the PCM suplys the power... and the PCM gets it signal from the CPS. Is it posaple the CPS is bad? The truck runs great no problems at all i would want to think if the CPS was bad I would have more than just hard starts...
 
Lift pump should run for the first few seconds regardless of cps. PCM runs it as a primer to help starting.
 
ok so from the way it sounds if its not a bad relay, blown fuse or bad wiring im lookin at a bad pcm
 
very rarely do they go out. we have an ongoing lift pump thrad right now that it appears the lift pump has a bad gound to the pump
 
NCadam said:
ok so from the way it sounds if its not a bad relay, blown fuse or bad wiring im lookin at a bad pcm
Click to expand...

No, you have to first rule out the relay. The relay sends the power to the LP, the PCM only triggers the relay by running power through the relay coil.
I would have the drain open with the hose in a bottle and turn the key on. If that doesnt work, put the truck in gear without turning it on, and then turn the ignition to START (it shoudnt crank), but the LP should be powered.

If the relay clicks that means the PCM did its job and trigered it. You can pull the relay out and test that the fuse center side that would be contact 30 or 87 of the relay has 12V on it. Then jumper those contacts together in the fuse center and see if LP runs, that would exonorate the power wires. Then try just putting a different relay in there, any automotive relay will work.

Just because it clicks doesnt mean its working right. And it may not be the relay, but its not the LP ground if it works fine during operation. You wouldnt get flow out of the drain during idle if the LP wasnt running.
 
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