White smoke only at idle

[JSVD]

Our truck a 89 7.3 idi blows white smoke at idle. It does not blow notable smoke at any other point .. WOT, crusing, etc.. But at idle it blows a lot of white smoke (smells like diesel).

My first thought is that the IP is tired. The truck is our beater, so we don't want to pour money into it.

What do you think? What could cause smoke only at idle?
Should I advance the timing a bit?

Thanks

 

[icanfixall]

Make a center punch mark in the joint between the injection pump and the housing its bolted to. Then move it about 1/16 inch towards the passenger side fender for advance. My guess is you have a bad injector or 2 or that and a bad injection pump. You have not mentioned how many miles are on the injectors or the pump.

 

[Koch13351]

I had this issue with mine. Wasn't a ton of smoke, but it would get progressively worse the longer i let it idle. Problem was 2 leaky injector nozzles. They'd leak at about 1200 psi on the pop tester. It doesn't smoke anymore now that I changed them out.

 

[JSVD]

Not sure about mileage but I imagine over 100k which is why I think they're tired.

When your truck was blowing smoke was it also making an odd noise?

The reason I don't want to put money into this truck is I thought it had a knock. However the noise doesn't drastically get louder with RPM increase, and seems to be related to the white smoke. (when the smoke is worse, the noise sounds worse). Perhaps it is missing at idle/lower RPMs? The noise is also louder out of the exhaust than anywhere else.

I'd love to know before i dropped $500 into it, but that's just how it goes.

 

[riotwarrior]

Carefully grab injector lines feel for one or more significantly hottet than the others...be a stuck injector

 

[icanfixall]

Not wanting to spend 500 bucks is understandable so why not buy some GOOD rebuilt injectors from our known sources.