300 Mack, only starts if plugged in

[sedgehammer]

this is for a friend of mine. he doesn't have internet, so i am asking for him.

2001 300 mack turned up to 350.

complete engine overhaul last year

injectors 3 months later

new primer pump

the truck under load at higher rpm's makes a bit of a surging noise

will not start no matter the temp if not plugged in, but will fire right back up if just shut off only a short time.

current temps are 70's days and nights 40-50 range.

thanx

Edited October 21, 2013 by sedgehammer

[fxfymn]

Plugged in as in engine block heater or battery booster?

[sedgehammer]

Plugged in as in engine block heater or battery booster?

Good point.

Engine block heater.

She cranks over easy and fires right up with a shot of either if not plugged in and she fires right off if plugged in. But if she is not plugged in, will not start without the ether

thanx.

[rsb502]

Sounds like ya got sum bad spark plugs!lol, sounds like too much fuel at start up, possibly low injector pop pressure, does it have a lot of fuel smoke cold or just on initial start up. I dunno would be interesting to figure out though.

[sedgehammer]

Sounds like ya got sum bad spark plugs!lol, sounds like too much fuel at start up, possibly low injector pop pressure, does it have a lot of fuel smoke cold or just on initial start up. I dunno would be interesting to figure out though.

Yup, hate them diesel spark plugs.....lol

just some smoke at startup

on the pop pressure, why would that make a difference if it was plugged in (warm) or not?

[theakerstwo]

Let me run this by you. I work with a Russian friend that has a 01 350 that was doing same thing. He did not ask for any help or advice from anyone cause don't know English so good but took it to many independent shops hear for repairs. About six shop over a 8 month time and some could tell him what it need like we do here over the phone and he invested about 7500 dollars in it from injectors to unit pumps and sensors but no help. He took it to the dealer and they replaced the ecm and no help. I think he told me they put his old one back on.They told him that was all that had not been replaced and that had to be the problem. He and his son one day said if they plug the header in even in the summer it will start and start all day after that.So he got the ideal that it may be low voltage to the ecm so he replaced batterys. first with no help and then the starter next. its started ever since after that.And some call him stupid at work. I feel ashame that I didn't take time to help but cause if it had been a cat cummins or DD I would have checked that first and should have had a low volt code.I do not know mack electronics but they shuld have a low volt code also.check it out.

[gearhead204]

on the other end of this topic I know the thing was rebuilt a year ago, but what does the draft tube say ? ive seen botched overhauls that last about that long if johnny either was under the hood

[sedgehammer]

Let me run this by you. I work with a Russian friend that has a 01 350 that was doing same thing. He did not ask for any help or advice from anyone cause don't know English so good but took it to many independent shops hear for repairs. About six shop over a 8 month time and some could tell him what it need like we do here over the phone and he invested about 7500 dollars in it from injectors to unit pumps and sensors but no help. He took it to the dealer and they replaced the ecm and no help. I think he told me they put his old one back on.They told him that was all that had not been replaced and that had to be the problem. He and his son one day said if they plug the header in even in the summer it will start and start all day after that.So he got the ideal that it may be low voltage to the ecm so he replaced batterys. first with no help and then the starter next. its started ever since after that.And some call him stupid at work. I feel ashame that I didn't take time to help but cause if it had been a cat cummins or DD I would have checked that first and should have had a low volt code.I do not know mack electronics but they shuld have a low volt code also.check it out.

hmm, question. why does the low voltage only show when it's cold. i mean, why does that allow it to start when it is warm, but not when it is cold?

thanx

[sedgehammer]

on the other end of this topic I know the thing was rebuilt a year ago, but what does the draft tube say ? ive seen botched overhauls that last about that long if johnny either was under the hood

rebuild was done by the local mack dealer. draft tube good.

johnny didn't show up till after problem started. personally i have used ether for years on some motors, no adverse effects.

[thomastractorsvc]

will it start with the battery charger on it? How is the compression? if it was me that's what I would do next if you don't think it is low voltage. Easy test is put the charger on it for half hour or so and see if that works

[theakerstwo]

hmm, question. why does the low voltage only show when it's cold. i mean, why does that allow it to start when it is warm, but not when it is cold?

thanx

When a engine is cold the oil is thicker and the drag is greater on the pistons and brgs.So the starter draws more current and if the starter is drawing too much current due to worn out the the voltage could get below the range the ecm needs.

[sedgehammer]

will it start with the battery charger on it? How is the compression? if it was me that's what I would do next if you don't think it is low voltage. Easy test is put the charger on it for half hour or so and see if that works

dunno.

good.

good idea.

thanx

[fullfuel01]

Bad timing?

[rsb502]

Sounds like low compression, slobbery injector nozzles, low injection pressure or low amperage/ slow crank. If it had low injection pressures or slobbery injectors it would have a lot of them smoke cold, if it was low compression it could have some fuel smoke also, low amperage to the starter or ecm would show up as a no start as described above. Remember after that first start your building your batteries up for more amps the rest of the day and as above the starter draws fewer amps on a hot start than it does cold.

[Mack Doctor Jr.]

I have kinda of experienced this a little. My situation is a little different cause mine was an all mechanical E6 350. The only thing I can think of that may have the same similarity is the fuel.

What I have figured is the fuel may have been turned up and the timing of the engine being left the stock may effect the ability to start on cooler days.

The valueliner I drove had the fuel cranked to the max and when the weather turned cold you could not touch the pedal to start it like the visor said per Mack instruction ( basically mat the pedal till the engine is hitting on all cylinders).

If you tried to give it any extra fuel on a cold fire up it would just die. The only thing I could ever figure was that the timing just wasnt right for the amount of fuel at that temp. The truck still does it to this day.......

[thomastractorsvc]

I have kinda of experienced this a little. My situation is a little different cause mine was an all mechanical E6 350. The only thing I can think of that may have the same similarity is the fuel.

What I have figured is the fuel may have been turned up and the timing of the engine being left the stock may effect the ability to start on cooler days.

The valueliner I drove had the fuel cranked to the max and when the weather turned cold you could not touch the pedal to start it like the visor said per Mack instruction ( basically mat the pedal till the engine is hitting on all cylinders).

If you tried to give it any extra fuel on a cold fire up it would just die. The only thing I could ever figure was that the timing just wasnt right for the amount of fuel at that temp. The truck still does it to this day.......

In my opinion I would say that is probably a correct diagnosis for your truck, based off what you said, do you still run it? If so next time its down for a service have them check the timing to know for sure.

[fxfymn]

Troubleshooting 101; look for something simple. Chances are the timing did not suddenly change and the injectors didn't crap out (and if they did it would run like crap when it did start). The battery can, and often does, deteriorate quickly, so low starting voltage resulting in low crank speeds is a possibility.

The other thing I would look at is the fuel since pre-heating the fuel solves the issue. Did you buy fuel just before this began? Did the vendor change to cold weather formulation when this started? If so, low crank speed could be the culprit again due to the fuels lower volatility. Is the fuel or the filter waxed up? Did someone put high viscosity oil in the crankcase?

A quick check might be to try starting it on WD-40 to see if it will run on a alternate fuel. If it starts I'd suspect a fuel issue; no start= low crank speed.

The bottom line is to look at what changed from when it ran right to where it is now.

[sedgehammer]

it's a brand new rebuild 9 months ago from the local mack dealer and has had really good power.

yesterday it was blowing a litle blue/white smoke, so i think there is a bad injector.

fuel was turned up last winter right after the rebuild and it started fine last winter.

no cold weather formulation here yet and fuel is purchased at several vendors.

didn't change anything since the rebuild and this just started to happen.

[fjh]

how's the fuel pressure ? if it has unit pumps it needs 70 psi to run decent, if it has vmac 2 it needs 15 psi min to run right

low fuel pressure fuel transfer pump failing or sum bad fuel lines coming to and from the pump also fuel drainback valve issue

[gearhead204]

can you separate the ecm power supply from the starting batteries? if so supply with a good batt and giver a try. after reading the previous posts I to think its a fuel issue a fresh eng.shouldnt be smoken. but getting a second power supply to the ecm at startup would help conform this

[thomastractorsvc]

So what did you find out?