92 smoke on start

[kit05]

I had just purchased my 92, I am having the following problems.
smokes and runs rough for 20 to 30 seconds on cold start when i say cold i mean when the truck sits overnight, even if the temp is warm outside, blueish grey smoke. the head has been replaced, no oil consumption, turbo seals appear to be ok, the truck will start very quickly , I had checked the glow plug system and all is well, resistance for each individual glow plug is good,have both cycles working, runs very well no issues with fuel consumption no black smoke when accelerating,I had reset the ecu and the truck started with no problems then quickly returned to the problems stated above, if a cycle the glow plugs 4 times on a cold start it will start up with no smoke or problems, i am at wits end, was thinking maybe change the capicators in the ecu as well as blocking off my egr pipe.was thinking maybe have air in the fuel lines?

[Koi]

Hi
Are you testing the voltage? as the voltage to the plugs i think is 10.5 then 6.5 volts so unless using a multi meter the lower voltage will not be picked up by test lights etc.

The Glow Plugs rely on a signal from the Coolant Tenperature Sensor. If they are not staying on at the lower voltage until engine starts to warm up then check the sensor in the block. It's above the starter motor and under manifold.

Did you test resistance with plugs in situe ? you will get continuity by testing this way.
To test a glow plug properly you should remove them and test individually for resistance. Resistance should be less than 1 Ohm. High resistance or open circuit means they are no good.

[kit05]

yes i have tested the glow plugs for resitance, they are under 1 ohm, yes i have tested to see if i am recieving voltage for both cycles 10 volts 1st stage and 6.5 volts 2nd stage,the 2nd stage only satys on for 10 or so seconds, i can hear the 2nd rely but i dont have any voltage after the engine is started, should I have voltage while the truck is running and warming up? i have done alot of reading in the past 2 weeks and cant figure it out, im stumped

[Hazzo]

I think the voltage/power automatically switches off from the rail within seconds of starting, I wouldn't think there was any reason for it to keep heating as once a diesel is started they're pretty hard to stop. The smoke on start up I wouldn't worry about, condensation in the exhaust pipe and the initial firing do the same on mine, once warm all fine.

What I do recommend though is either the egr mod or at least strip the intake manifold off and give it a good cleanout, mine has only around 80000 on the clock and after blowing the head I took this off to find it choking the intakes with gunge and tar. H

[Calos]

I think the voltage/power automatically switches off from the rail within seconds of starting, I wouldn't think there was any reason for it to keep heating as once a diesel is started they're pretty hard to stop. The smoke on start up I wouldn't worry about, condensation in the exhaust pipe and the initial firing do the same on mine, once warm all fine.

What I do recommend though is either the egr mod or at least strip the intake manifold off and give it a good cleanout, mine has only around 80000 on the clock and after blowing the head I took this off to find it choking the intakes with gunge and tar. H

Guessing you'd need a new gasket after doing this ? would quite like to give mine a clean out too.

peace
cal

[kit05]

when you say intake do you mean the throttle body? or intake manifold gasket.

[Koi]

Should still be voltage after the engine has started, the plugs continue to heat even after the engine has started. After the engine has been started the plugs continue to heat the incoming diesel for a further period of time. This helps to improve cold fuel combustion whilst the engine is warming up, this improves cold running, which results in quieter, smoother running and reduced emmisions (the black smog). Again this length of time is measured by the water temp sensors allowing the plugs to pre heat the fuel until the required engine temperature is reached.
Could be the coolant sensor then not keeping the plugs energised after the engine has started, which could result in lumpy running until the engine has warmed up slightly.

[Hazzo]

The whole of the intake manifold including the throttle body, you'll find its pretty full of gunge from the egr valve, get plates made up and block this mother off if your local roadworthiness test allows it, if not I still recommend the cleanout, this crap can't do engine breathing any good whatsoever. H

[kit05]

I spent a good part of today doing all the recomondations from the above, I will see how this works out in the morning. it seemed better when started cold, a long wait will tell for sure.

[Hazzo]

I've not had any smoke issues till the head went, with the blockoff egr plates fitted and the gunge cleaned out there appears to be nothing coming out the exhaust at all till you put your hand there, even then there's no sooty spots on my hand after so I reckon I've got a clean burner now. Injectors/glow plugs goosed and pump overfuelling would be other smoke causes so if it persists I'd go plugs first, then injectors. Hazzo

[kit05]

I went and started the truck this morning and noticed my plug cycle is working alot longer now, and it stumbled very little on start, but it still stumbled, only a puff of smoke, i will monitor and see how it goes, i did not need to clean the intake as it was farely clean already, the new coolant temp sensor has made a difference i guess, and i can notice a slight difference from the egr mod.

[kit05]

10* outside this morning and apearently there is still no change, runs like crap and smokes on start up unless i cycle the plugs 3 or more times, I guess ill change the glow plugs and see what happens, i know the ones i have in there are working to spec, but maybe it will help.

[kit05]

Anybody have input on what are the best glow plugs, was thinking of toyota oem as they are the only ones available to me here in Canada

[kit05]

still searching for a solution,

1- checked glow plug resistance each one, all is good.
2- checked glow plug cycles, all is good even when running till warm.
3- replaced ecu temp sensor.
4- had compression checked, all is good.
5- checked for blow by, all is good.

so not really sure where to look next?
ran a diagnostic and get a code 11 wich i believe is a code for not in park or in nuetral but not quite sure what it means, all i can really think of is the altidude i work at is alot different then where i live, when i am at home it seems to start alot better

[dirtydog]

mine is exactly as you describe, ive just had new plugs fitted and its the same.