Still wont start

[max77713]

changed the fuel filter but engine still wont start. good hot batteries turns over good. newmar 350 cummins will start on starting fluid but wont run long few seconds. some folks mentioned the fuel sensor, where is it on the engine changed the large fuel filter is there a smaller one and where is it located one the unit. cant think of another filter that could keep it from running ??????

[jacwjames]

You probably have the 8.3 ISC 350 HP.

My engine manual says not to fill filter with diesel when changing and I had done that for ~6 years but the last time I changed my fuel filer I did the primary first and I could not get the coach to start.

I ended up having to put compressed air on the tank and finally got the filter to prime and the engine to start.

When I changed the secondary filter I went ahead and filled the filter with diesel, I used a plastic PVC plug in the enter hole to prevent contamination, I think it was a 3/4" plug. The engine fired right up.

You may have to resort to compressed air to force fuel to the transfer pump.

BTW, can you hear the transfer pump run when you first turn the key on, it should run for ~30 seconds. If you don't hear it run that may be your problem. The pump is located on the passenger side of the engine toward the transmission mounted up high. Make sure it is not leaking.

Avoid continued use of the starting fluid as if the engine tries to run for an extended period without fuel you could ruin your CAPS fuel pump as it needs fuel for lubrication.

[twinboat]

Ok I'm going to guess that it didn't start before you changed the filters.

Loosen the filter, turn the key on for 10 seconds and off 5 times.

If fuel is spilling out the plumbing from the tank and lift pump are ok.

If not, look back before the pump for another filter, bad pump, loose or cracked hose, empty tank.

Just so you know, in 35 years I have never seen a filter bad enough to not start, unless it had jelled fuel or ice in it. ( is it freezing where you are ? )

The common issue of bad filters is low power.

Use WD40 instead of starting fluid. Better for the engine.

[twinboat]

Originally Posted by jacwjames

You probably have the 8.3 ISC 350 HP.

My engine manual says not to fill filter with diesel when changing and I had done that for ~6 years but the last time I changed my fuel filer I did the primary first and I could not get the coach to start.

I ended up having to put compressed air on the tank and finally got the filter to prime and the engine to start.

When I changed the secondary filter I went ahead and filled the filter with diesel, I used a plastic PVC plug in the enter hole to prevent contamination, I think it was a 3/4" plug. The engine fired right up.

You may have to resort to compressed air to force fuel to the transfer pump.

BTW, can you hear the transfer pump run when you first turn the key on, it should run for ~30 seconds. If you don't hear it run that may be your problem. The pump is located on the passenger side of the engine toward the transmission mounted up high. Make sure it is not leaking.

Avoid continued use of the starting fluid as if the engine tries to run for an extended period without fuel you could ruin your CAPS fuel pump as it needs fuel for lubrication.

If your lift pump can not pull fuel to itself, something is wrong.

Blowing in the tank is not a fix but a cover-up of another problem.

Something as minor as a loose clamp.

I have read on a Cummins site that your CAPS pump will pull fuel to it, even with a bad lift pump but it will fail from the reduced fuel flow.

[znt1186]

I would never use starting fluid in my Cummins 350. The air preheater could result in an unpleasant explosion.

[twinboat]

Originally Posted by znt1186

I would never use starting fluid in my Cummins 350. The air preheater could result in an unpleasant explosion.

It's not really an explosion. Since there is no compression in the manifold its more like a woosh of flame.

[HoleInOne]

Probably a bad fuel pump. My brother just recently had one go bad and found out it was pretty common.

[stuhly]

Prefill the filters. Save your self a lot of grief. The book telling you not to do it is a cover their rear thing.

[Mr_D]

Originally Posted by twinboat

It's not really an explosion. Since there is no compression in the manifold its more like a whoosh of flame.

Actually it can be an explosion if the "whoosh" is big enough.

I have never prefilled my filters and never had a problem. But then I've followed the directions to the letter too.

[twinboat]

He did not say that it won't start after changing the fuel filters.

He said " changed filters but ENGINE STILL WONT START "

That tells me it did not start before he changed them.

Everyone telling him to fill the filters that he may have changed for no reason, because something else could be wrong, may not help.

[twinboat]

Originally Posted by stuhly

Prefill the filters. Save your self a lot of grief. The book telling you not to do it is a cover their rear thing.

Having the lift pump fill the filters is to protect the expensive injection pump from backyard mechanics who could be dumping fuel in from an old beer can that was laying in the dirt.

If the elecrtric lift pump can't fill a fuel filter, it certainly won't supply enough fuel to keep the injection pump cool and lubricated.

For weekenders a fuel starved injection pump could last years.

I would want mine working properly.

[stuhly]

Fill the filters.

[Piledrive]

I'm not sure I should even be entering into this, (see my ID) but many years using stationary deisel engines, Cats, Cummins, Detroits etc. I remember that on those engines when you turned on the switch, it activated a solonoid that allowed the fuel to travel through. Many times over the years we had to screw that unit down in order to start the engine, and then reset it to stop, until our Mechanic could get a replacement installed.
Like I said, don't know if these engines use the same fuel cut-off system or not. However, since it is not fired with spark, some means must be used to allow you to start and stop it.
Very seldom did we have filter problems. Primary filter had see through globe with drain cock and good fuel along with proper maint. kept us running.
Only problem we had with the Detroit was when the Operator stuck the drill and caused the darned engine to run backwards. (what fun).
(If i"m wrong be kind, I've been retired over 15 years )

[Ray,IN]

Originally Posted by twinboat

It's not really an explosion. Since there is no compression in the manifold its more like a woosh of flame.

Sematics; it can still cause engine damage according to Cummins.