[Jon NZ]

Just bought a 94 4m40 2.8TD, 50,000km, which is a fresh Jap import
We live in the lower half of the south island
It has a real bad miss on cold start up.
If let to idle on cold start up, it has a miss for 30 sec and exhausts clouds of pale blue
smoke, for the period of the missing
If I give it 1500 revs on cold start up, it will clear itself within 10 sec
No problems with warm start up.
We had the glow plugs tested, timing checked and timing reset. It was advanced
by 8 deg !. Pump was checked by a second diesel service workshop, one of the pump
seals was replaced & K dimension checked out.
No difference.
The dealer (Canterbury), and his nominated local workshop (Southland based) said this is quite normal
I beg to differ. We have friends with the same type vehicle. No miss on cold start up for them !
It had got the pros beat at this point
Any suggestions
Jon NZ

 

[Trev O]

mine misses like yours and I think it's a sticky valve, but I'm keen on a second opinion!
As a first attempt at a remedy, I'm putting injector cleaner through the system (into the tank when filling) as it's suppose to lubricate the valve stems.
I've done that twice already and it seems a little better, there's about 5 tankfuls in the bottle (called Morley's from Repco at $10), so if it hasn't done it by then I'll be thinking of taking the head off and cleaning the valves.
Sticky valves lead to dropped valves which wrecks the engine and I'm told it's a Paj problem around 300Km's

 

[ramdamoadr]

I had the same problem with my '95 2.8 TD , finally fixed it by removing the Injectors,and re calibrating them,new nozzles also fitted.

 

[Trev O]

your probably right about the injectors ramdamoadr as my paj is pretty much back to normal after the injector cleaner.
Did you notice any carbon build up on the injector tips when you took them out? I hope I don't have to do any more than the rest of the cleaner fluid, but either way it all sounds a lot simpler than doing a valve grind & stem clean etc!

I guess cleaning and calibrating is not a job I can do myself at home anyway, or is it...?

 

[ramdamoadr]

Yes it is possible to clean out the Fuel injectors yourself . You will have to remove the intercooler and the air filter assembly to gain access, then disconnect the diesel return hose,and the return tube,(be careful here, and do not let the stationary part rotate, or you'll kink the tube),using a tube spanner, or a extra deep socket, unscrew the injectors,lightly hold injector in a vise and dis assemble .Do not use any metal items to clean the nozzle and holder, (I use a piece of soft wood)After you separate the bottom nut from the body,clean all the items carefully and reassemble.If you do not wish to dis assemble the unit, then just do a careful clean up of the tip and re fit

 

[Trev O]

thanks ramdamoadr, that all sound too easy! I'll give it a go when I get the chance.
I hope jon nz is gleaning info too...

 

[Jon NZ]

Just had injectors serviced and cold idle adjusted up to 900rpm. Still no difference on a cold start
Will try new glow plugs next week

 

[Jon NZ]

Fitted new glow plugs yesterday.
Still a huge missing on cold start-up this morning
All possible items now addressed
Where to now, who knows.

 

[Trev O]

bad luck Jon. My miss now has moved a bit to about 30 secs after initially starting up, as opposed to as soon as it's started. So I'm not much closer either and I haven't had time to take the injectors out yet to do a proper clean...
I've had to focus on the hand brake as it failed the warrent last week!

 

[Benckj]

Not sure if this is an answer or not as it seems you have looked at all the obvious problems but have you thought about the fuel? They have reduced the sulfur levels in the diesel from 3000ppm to 500 and are now reducing to 50. This will cause the rubber components which swelled with the sulfur to shrink back slightly and possibly crack. What was the condition of the seal you replaced in the pump?

It seems to me that you are not getting the correct fuel pressure into the cylinder at start-up which lowers the compression then and after it is running and heats up it is not as noticiable. Do you notice any fuel leaks and do you get black smoke from the tail pipe after it is running at temp?

Jim
Alex

 

[prashanth]

Hi,

You might want to check the glow plug relay, apparently the glow plugs have a dual circuitry, One that supplies the plugs full voltage before starting and the other which supplies a lower voltage for a few more seconds after the engine has fired up.

Let me know if it works

 

[Trev O]

I was thinking of that for my problem but as I can hear the second solenoid clicking, I was just assuming everything was OK there. But maybe I should be checking that voltage is actually getting to the glowplugs when It's clicking in, thanks for the prompt Prashanth

 

[Flemming Mortensen]

your problem could be diesel drainage from or to the diesel tank or maybe on the diesel pump on any of the axels conneting the outside of the pump to the inside of the pump, I once had a leak on the diesel pipes inside of the dieseltank.

 

[Trev O]

the trouble for me is, if it is anything thats going to cost heaps, like the pump as Benckj suggested or something that'll be difficult to find such as a leak in the tank!, i'm probably not going to do it, as it does still run well and only has a slight miss when warming up and idleing
I may have to put up with it

I wonder if Jon has nailed it down yet...?

 

[prashanth]

Trev0,

did you finally figure out what was the problem here,

Last week my car suddenly developed poor cold start.
i takes a few cranks to fire away and the running is rough with some missing for a few minutes till it warms up.
Checked the glow plugs, they are working fine, the voltage coming to the glow plugs is good, around 11 volts under load.

Not sure if there is an issue with the fuel supply, the priming pump on the fuel filter takes about 10 to 10 strokes before becoming hard.

Once the engine is warm, running is faultless

Any thoughts.

 

[Trev O]

Hi Prashanth,
no sorry I've forgotten all about it. I did have a fuel pump leak, which I fixed with silicon.. Broken injectors has always been the biggest culprit for slow start up for me, after that, If the fuel filter is OK then next there's a little gause filter on the pump fuel inlet that could get clogged.
Soon after my starting problems I swapped engine to one with less mileage... which is sweet!

sorry and good luck!

Trev

 

[Trev O]

Hi again.. I remembered it was the top seal on the fuel pump, which released the pressure from the fuel inlet allowing air in.
It's a pig to take the top of the injector pump off and as I remember is easier if it doesn't come right off. Then either get a new seal (prefered) or as I did use silicon.
The new Lead free diesel caused the fault here by shrinking the rubber seal. Also there's a couple of other O rings that may as well be changed at the same time..

cheers

 

[prashanth]

Trev,

Thanks for the info.
The problem seems to have vanished by itself. me thinks it has something to do with the fuel, because the first time this occurred was when I filled the tank with 50 litres of diesel. (i normally dont put in that much as my daily commute has drastically reduced)
I filled 50 again this week and i had the same symptom for one cold start.
maybe it is time to drain and clean the tank and fuel lines.

cheers,

 

[prashanth]

<div class='quotetop'>QUOTE (prashanth @ Sep 7 2008, 07:22 AM) <{POST_SNAPBACK}></div>

Trev,

Thanks for the info.
The problem seems to have vanished by itself. me thinks it has something to do with the fuel, because the first time this occurred was when I filled the tank with 50 litres of diesel. (i normally dont put in that much as my daily commute has drastically reduced)
I filled 50 again this week and i had the same symptom for one cold start.
maybe it is time to drain and clean the tank and fuel lines.

cheers,[/b]

Finally found all the culprits.

1, The power supply cable from the relay to the plugs had a loose contact. This took care of the poor cold start.

2, To take care of the cold start miss, I advanced the fuel timing a bit and next morning when I checked, the miss had vanished. :banana:

 

[colinley]

<div class='quotetop'>QUOTE (prashanth @ Jan 31 2009, 06:46 AM) <{POST_SNAPBACK}></div>

Finally found all the culprits.

1, The power supply cable from the relay to the plugs had a loose contact. This took care of the poor cold start.

2, To take care of the cold start miss, I advanced the fuel timing a bit and next morning when I checked, the miss had vanished. :banana:[/b]

hi just wanted to know if any one new where the relay for the glow plugs is on my 1996 2.8TD mitsubishi challenger