Rough idle on start up

[matuva]

On my 1994 BLAZER, put a new IP, reman BOSCH injectors, new chip, new PMD, new OPS, good lift pump.

Took a long time to bleed the IP, but she now runs fine.

Problem is that, at start up, even though she fires almost easy,she runs very rough, smoke white. It talkes about a good minute before she
runs / idle fine, no more smoke.

she does it cold or hot (as long as she sits there for a while).

No code.

Any opinion?

 

[buddy]

Few questions,

Where did you get the IP? Did it come with a new PMD? Is it a stock chip?

Assuming the TDCO has been set, what is the value?

What is the desired and measured timing when you first get it started, and then when warm?

My first thought is the IP, if a rebuild might not be all that great. Check your warm idle fuel rate, maybe they screwed up the OS position in there. If its between 6 and 10mm^3 then thats not it.

Are you running some 2-stroke oil in the fuel, and assuming the fuel is regular diesel.

 

[matuva]

IP is a reman, GM stock.

Stock chip or Custom, same thing.

TDCO set a -1.54

Fuel is ULSD, slight 2 stroke oil, but not enough, I will put a few more in.

I will check warm idle fuel rate ASAP.

Could an air leak or sticky injector (Bosch reman) do that?

 

[ak diesel driver]

do you have clear tubing on the IP return to look for air?

 

[bison]

leaking nozzle can cause it too

 

[buddy]

Besides the fuel rate post up the desired and measured timing values. That could be telling.

 

[bison]

Good to see you back Buddy.

 

[handcannon]

Good to see you back Buddy.

X2

I appreciate all the info you've given in the past.

Don

 

[buddy]

oh you guys :blush2: fftopic: Im just heavily medicated this week sitting in a lazyboy all day. :sleepy:

 

[ak diesel driver]

then take more meds! LOL

 

[racer55]

Rough on start-up could be a dead glow plug or low compression on 1 cylinder or air entry from a leaky filter manager O-ring.

 

[matuva]

We could not find an air leak, though I was pretty sure there's one somewhere.

We notice the batteries were growing weaker and weaker.

With 2 brand new batteries, still the same low spinning starter. Put on a fresh reman 28MT which spins very strong and fast, changed fuel filter, ... and now she starts and run like a champ :thumbsup:

Sometimes in the morning, a little puff of white smoke, sometimes stumble for 1 or 2 seconds, but a true night and day difference from what she was doing before...

My theory is that the engine might be a few worn and has lost compression somewhere - even though she pushes strong - so to start, she needs a strong starter....

You know what? I'm Happy

 

[Brooklyn Tow]

Starter fixed a rough idle on start?............Sounds strange, but, good for you!

 

[buddy]

Could be the higher cranking speed is adding the necessary heat, because higher RPM will bleed less pressure while cranking for more compression. I would check out the glow plugs, might have a few bad ones. Measure them from terminal to threads/engine should be about 0.5 ohms. If glow time seems short it could be from a couple bad plugs.