DT466 Bosch MW low idle at start up

[Wes J]

I've got an old International truck with a DT466 engine. I think it's a Bosch MW pump, but I'm not positive.

The engine runs good, but when you first start it, when the engine is cold, the idle is very low, maybe 400 RPM. You have to hold the pedal down a bit to get it to start. I'd say within 2 minutes the RPMs will come up to 700 or so and idle fine. It seems to have plenty of power and does not smoke.

I have not done anything yet, just wondering if there is something that might be sticky or that needs to be checked.

 

[Tenwheeler]

Does it have a mechanical fuel supply pump on the side of it? Remove the hand primer and plug on top on the other side of the pump. There are plastic check valves and springs under them. Are they clean and in good condition? Lap the seats on emery cloth or replace them. If the hand pump is leaking fuel replace it. That is where I would start.

 

[thepumpguysc]

Your SUPPOSED TO hold the pedal down when starting.. Tyr it & see what THAT does..
When it starts, take your foot off the pedal.. does it idle correctly??

 

[Wes J]

No. It will start but if it's really cold (below freezing) it will die. If it's warmer (say 55F), it will idle around 400 rpm for maybe a minute then it will come up to 700.

 

[Birken Vogt]

I sort of remember that in the 80s something like that was common behavior on a 466. Not like other diesels where you would just crank and have it start and idle, you had to fool with the pedal a little to keep it running. I think somebody explained why somewhere but I don't remember any more.

 

[Wes J]

If it's normal, I'm fine with that. It's been a long time since I worked on a mechanical DT466. I don't remember how they acted.

 

[DMiller]

Corn Queens, always a little 'Different'.

 

[Spud_Monkey]

Sounds about how mine starts when it hits below 50 degrees or around in the 30's except I have a high idle knob as I call it I can pull and lock it. I do that while it sits at a 1000 rpm and when I hear it creep up I go and set it around 750 to warm up.

 

[Welder Dave]

I had a Hino with a rebuilt engine. When cold you had to cycle the glow plugs about 3 times and hold the throttle wide open. It had so much white smoke you couldn't see 5 feet and you had to keep it full throttle till the RPM came up to about 11-1200 RM. After that it idled fine at about 700 RPM but had a hand throttle so you could speed it up. At idle it could run all day and not warm up. Once warm, no smoke at all and didn't use any oil. Just warm blooded.

 

[thepumpguysc]

This complaint is a 1st for me.. I've been rebuilding those pumps for 30 years & have never heard of that complaint..Hmm.
Probably because I've ALWAYS found serious wear in the gov. & just replaced the components.{guide block & fulcrum lever} AND... I'm in SC where it doesn't get "that" cold..
You guys ever think it could be your engine oil.?? {thick}

 

[DMiller]

I had a Hino with a rebuilt engine. When cold you had to cycle the glow plugs about 3 times and hold the throttle wide open. It had so much white smoke you couldn't see 5 feet and you had to keep it full throttle till the RPM came up to about 11-1200 RM. After that it idled fine at about 700 RPM but had a hand throttle so you could speed it up. At idle it could run all day and not warm up. Once warm, no smoke at all and didn't use any oil. Just warm blooded.

My ancient Allis farm tractor is so weak that is how it starts, can tell it needs nozzles gone thru but along same lines needs a overhaul, just biding time til get time I don't need it. White smokes like on fire clears right up as gain any heat burns little oil but blow by is horrible.

 

[Spud_Monkey]

This complaint is a 1st for me.. I've been rebuilding those pumps for 30 years & have never heard of that complaint..Hmm.
Probably because I've ALWAYS found serious wear in the gov. & just replaced the components.{guide block & fulcrum lever} AND... I'm in SC where it doesn't get "that" cold..
You guys ever think it could be your engine oil.?? {thick}

I know it is thick oil though when traversing country side to warm weather not cheap to change oil out per the climate. Gets too bad I will put a tarp over the hood and stick a Buddy Heater under the oil pan or dig a hole and make small camp fire.

 

[Wes J]

I don't know if there is internal wear in the pump. The engine only has 200,000 miles.

 

[thepumpguysc]

IDK either... just talking from experience.