neighbor brought me up his 94 c3500 gmc to look at....he says it smokes on start....wasn't here when he dropped it by....so this morning i fired it up and man!!!!!....see pic


ok tore into it and this is what i found....see pic

I HATE MECES TO PEICES!!!..LOL

said it was lackin' in power:eek::eek::eek::eek::eek:


got that dug out and it's still missin'...so i'm diggin' deeper:D

WOW-so he parked it how many months/years ago?

been settin' for about 2 years

Jeeze!!!

nothing like the smell of rodent in the morning eh? that must have stunk like all hell. hope you didn't chop up one w/ the turbo, as funny as it would be before the talk of a new turbo comes up. :eek:

EDIT: my truck had a meces nest in it. no tennants but it was before the air filter thankfully, and they hadn't managed to chew through it, they just pi$$ed all over it.

:D Looks like BREAKFAST ! :D

http://www.dieselplace.com/forum/attachment.php?attachmentid=61042&d=1206034012


Cu,
Sven

I'm surprised it ran at all... And if it did It should have smoke like it was Coal Powered.

ok got that all cleaned up.....Lp was dead so replaced with HD LP....still have bad smoke and rough idle till it warms up...then runs great....this morning i pulled the ECT plug and it started great no smoke, no rough idile......i remember seeing an ohm chart for the ECT....guess i need to look harder....i can't find it will someone post it if the have it..thanks

ok got that all cleaned up.....Lp was dead so replaced with HD LP....still have bad smoke and rough idle till it warms up...then runs great....this morning i pulled the ECT plug and it started great no smoke, no rough idile......i remember seeing an ohm chart for the ECT....guess i need to look harder....
In my best chrisk1500 font,.... "search"
but i couldn't find it,.:) i replaced my ect as it slowly went bad,.also i,m told (by chris) that you should pay close attention to the plug as the iwres there can become brittle and break inside their plastice coating, right where the wires go into the plug,.
nick

i'll check the plug....i used the "search"...always do....this what i put to it....Engine Coolant Temperature sensor ohms...... and got this..http://www.dieselplace.com/forum/search.php?searchid=4385907

EDIT; just ohmed it out...at 87 degrees i get 1061 ohms....anyone know if this is right?

i found the chart....had to google it

White smoke on startup that dissappears when warm sounds like glow plugs? Perhaps mixed with worn injectors?

when i pull the ECT wire starts first crank with no smoke...checked the glows all seem good...as far as injectors....it's got 199k on the clock so it wouldn't hurt i'm sure....i'v searched for hours and read 100's of post and have still not found a good thread on the ECT unplugged....as for ohm readings...@190f i get 224 ohms which is right with chart...but when it cools to around 80f it gets about 1500 ohms off from chart...so i'm going to try a new ECT and see what that does..

read post #20. search, search and search. your welcome chris. Ed

ok i read it....thanks ed....

Bad ect makes the ECM think the truck is warm when it really cold, so the
glows don't get activated?

ok i replaced the ECT and i'm getting the same.....blue smoke on cold start and runs ruff and misses ...unplug ECT and no smoke and runs great....rechecked the glows and there all working....is it the timing chain?...IP timing?..

with the ECT plugged in glow times are 4 seconds shorter than when unplugged....when cold..

did you get a bad ECT sensor? i'd say ohm it out and see what you get. when the ECT is unplugged the ECM thinks its - 40 degrees so the glow time is longer.

did you get a bad ECT sensor? i'd say ohm it out and see what you get. when the ECT is unplugged the ECM thinks its - 40 degrees so the glow time is longer.


engine temp is now at 135 and ohms are 674...right on with the chart..

i know you replaced your glow plugs. does it start hard? maybe the wires to the plugs are a little tired? too much resistance in the wires will prevent the plugs from heating up enough. the wires i believe should have some resistance to regular voltage to the plugs, but too much resistance will cause problems.

i know you replaced your glow plugs. does it start hard? maybe the wires to the plugs are a little tired? too much resistance in the wires will prevent the plugs from heating up enough. the wires i believe should have some resistance to regular voltage to the plugs, but too much resistance will cause problems.

even with all the smoke and running ruff..it only takes maybe 2 rotations to start dead cold...starts the same plugged or unplugged

the only other thing i can think of is worn injectors. i'm sure i'm missing something but thats nothing new. :rolleyes:

the only other thing i can think of is worn injectors. i'm sure i'm missing something but thats nothing new. :rolleyes:

wouldn't if the injectors where bad wouldn't it smoke and run like s#$t even with ETC unplugged?

wouldn't if the injectors where bad wouldn't it smoke and run like s#$t even with ETC unplugged?


one would think so. like i said i'm probably missing something here.

Pulling ECT connector tells PCM that ambient temps are -40degF, which requires more glow and more advance, which is why it starts easier - can't imagine why anyone wouldn't notice the extended glow by observing extended WTS duration and listening for the glow controller 'click' - the G60 gp's require more glow than the G11's, but the G11's burn out quickly where the G60's are almost indestructible but the G60's require more glow - what's needed is extended glow, so search for various posted methods, incl putting a spring-loaded (you may fergit but the switch won't!) spst switch and 270kohm resistor in the ECT sensor wire

In mild ambients, also indicates need for new air filter (less air, same fuel = rich, white vapors), and with hi-mileage: IP maintenance (wore-out), injector service (wore-out), timing chain-set (wore-out)

air filter

fuel filter

HD LP

OPS

ECT

are new...

all grounds have been clean...glows pulled and are heating..i don't know if there G60"s or not?

would turning the IP to the drivers side help the smoky start?

Is that 2yr old fuel?

And did you clean out the cool-air duct in the fender?

Seeing how the unplug wire works so well,How the pump is now in a high advance state that the timing should be next in line of things to address.
Moving the pump alone would not do much as the TDC off set learn would need to be done with the timing change. And this could help the smoking issue as you have a good cold start.

Couldn't even be the extended glow, could it, or that the engine runs well after it warms up?

It needs a oil change .

tank was drained and fresh fuel,power service + 911 added..

air box removed,new cone filter...

how to do "TDC off set learn" without a scanner?

it runs better warmed up and no smoke..but still has a miss with ECT plugged in(unplugged no miss no smoke runs great and good power, but high idle)

oil and filter changed...

could it be something in the advance in the IP?

A '94 at 14yrs old is way long in the tooth, and a dump truck would have been rode hard and put up wet during most of it's life, so Inj Pump, Injectors and Timing Chain-set are prolly way past over due, somewhere around 60k on the injectors and 100k on the IP and timing chain

Those symptoms are a combination of:

- worn injectors - advanced timing required to get the fuel into the cylinder on-time when cylinder pressure\temperature is high enuff to ignite the poor spray-pattern
- more glow required to increase cylinder heat to compensate for the bad spray-pattern and retarded injection event

- worn inj pump - same, requiring additional advance for on-time injection event, Fuel Solenoid due to crater any time, now

- worn timing chain - same, delayed timing opens valves late, reducing intake-air volume necessary for high cyl pressure\heat, then delayed injection puts the fuel in the cylinders as pressure and heat are dropping below combustion temps = white unburned fuel vapors

TDCO is compensation for hi-rpm operation, moreso when IP has been advanced, moving power band upward, not good for a dump truck needing to be in the hi-torque low-rpm band - takes a scanner to advance IP and change TDCO

Find out what mileage on truck and if\when injectors and IP were replaced and any other service

I had the same problem with my 95.I replaced the glows,injectors,computer,LP,heads then GM replaced the IP.After all that it still smoked at cold start-up.The only thing that cured it was the optic bump.Check compression,Put it on a scanner to verify timing ect.If every thing checks out there do the optic bump or a momentary switch in the cab to disconnect ECT while starting.As GMCTD says also could be a combination of things.

ok how does one optic bump?(dance move?!!! LOL)......i searched it alot of talk about it but no instructions on how to do...

Remove the upper intake.Take the top of the pump off(do not pull the cover off as there is a wire connection).There is a torx head bolt on the optic assembly.Loosen it and hold the block below.move the top part to drivers side.Try a little at a time.When I did it,I put the top of the pump back on then started it to verify no smoke start-up.Then I put the rest back together(intake,ect)Do a search on optic bump just to verify my instructions are correct since it has been two years since I did it.

ok how does one optic bump?(dance move?!!! LOL)......i searched it alot of talk about it but no instructions on how to do...

Look here: http://www.dieselplace.com/forum/showthread.php?t=28752

Look here: http://www.dieselplace.com/forum/showthread.php?t=28752

thanks ..have alot of readin' to do...

optic bump has seen to help just one puff of blue at start....it didn't keep smokin'..now for a test drive..

You will notice a major increase in power with the bump.At least I did anyways.Was like a whole new truck and imroved fuel mileage.

yes truck runs alot better and i started it this morning and just 1 blue puff and thats it....no fog like in the pic's...thanks for everyone's help!!!