99 7.3 white smoke on start

[Barryp]

I recently bought a 99 7.3 with 228k miles. Truck blows alot of white smoke until its up to operating temp. Weather has not been cold (around 45 at the lowest). It seems to start up fine, maybe a couple seconds at worst. The truck does have borderline too much blow by from the filler cap. I can fill some air coming out, the cap will somewhat move up and down but wont blow completely off. Im sure the motor may need rebuilt soon, but it seems to run fine after warmed up. Could this loss of compression cause all the white smoke or would this most likely be another problem. Thought about changing the GP and GPR, but wondering if this could be the cause since I dont have a problem with it starting. Also I plugged it in overnight and the smoke was very minimal.

[Barryp]

At 50 degrees this morning and sitting for 2 days, truck did have problems starting blowing smoke out as it was trying to start. Was not plugged in. After starting it blew the normal amount of white smoke and idled and ran ruff until up to temp.

[atvrider93]

On the next fairly cold start bridge the gpr with a screwdriver or something and see if it starts better. Or you could check the voltage across the gpr while it's activated and see how much drop there is. Then after you have made sure the gpr is good then test the resistance on the gps. I video of the oil cap flipped over would be helpful

Sent from my DROID BIONIC against my will

[Turbostang500]

Yes compression CAN cause your issues but it isnt likely.
gp system seems more likely but you need to diagnos and test to find out.

Dont just throw parts at it!!!

[Barryp]

Checked voltage on the GPR. Volts going in on the left side was just over 12, I checked volts after turning key over and was 0 on the right side. Went and bought a new GPR which tested the same 0 voltson right side after turning the key over while the 'wait to start' light was on. The truck was warm while doing this, should the relay still kick on even though the truck was at operating temp? if so what should i test next?

[Turbostang500]

Check to see if you are getting 12v on the small wire going to the gpr.
This is the control wire from the pcm.
if you do have 12v then the relay should work. If not, it isnt getting a signal to close.

It is up in the air on when the gpr functions. I thought it always came on just different intervals according to ambient temp and engine oil temp. Some have said under the right conditions (full operating temp) that is does not come on.

[kaya@bernhausen]

doubtful it's a glow plug issue, as you'd said it fires up fairly quick.
more likely sticking injector(s)
any codes?

[Barryp]

Check the relay voltage after sitting and did get voltage just under 12 on 3/4 post. The small post at the top read 0.6 volts. Cranked truck and still had the excessive smoke but did crank right up. Only one issue yesterday after sitting 2 days with a very slow start. Will try and get video of the blow by uploaded soon. It does huff a good bit, the cap will move up and down a bit but wont blow completely off. Engine runs good enough for me at operating temp and will run it till it dies unless this is causing the smoke on startup.

Need to get it checked for codes. Will the scanner used by autozone work on the f250 or do I need to find someone with the better scanner?

Truck is plugged in now so I will double check the amount of smoke when plugged in this morning. Last time it was minimal.

If the truck is low on compression would the smoke continue and get worse at higher temp or would it be possible it goes away

[Turbostang500]

When i had 2 bad gp's my truck started (what I thought) fine but blew alot white smoke until
it got a little heat in it. Then it would clear up and be good. This would happen in 40° weather.
Therefore i COULD be a gp issue. Im not saying it IS yet but it could be.

[Turbostang500]

Autozone scanners wont be very good to get the codes. Need to have a better scanner.