Perkins Diesel - Starting / Running Issue

[V8RX7]

Hi

I'm hoping someone can help, I have a '93 Manitou telehandler with a 4cyl Perkins diesel that I've owned for years without issue - it always starts immediately.

The other day it died whilst idling.

I found it had lots of air in the diesel system.

I cleaned & tightened everything and there is no more air albeit I didn't find an obvious problem

However it simply will not start unless I squirt some diesel into the intake manifold - then it starts immediately.

It will also randomly stall on idle and is clearly down on power - try to use the ram and drive and it will stall.

I have cleaned and checked the filters, cracked the injectors multiple times and bled it for hours.

I've cleaned the gauze filter in the lift pump and the fuel / fuel filter are clean, I've even cleaned out the tank (hardly dirty) and blown the lines through

What have I missed ?

Thanks

Am I correct that the 5th injector mounted on the inlet is for cold starting only ?

[andyiley]

I suspect you are on the right track with air in the fuel system.

I had one of these in an old motorhome a few years ago & had the same problem after doing a service.

I bled & better bled the system, for hours & only when I added the back up of a fast idling car & jump leads could I get it to turn over long & fast enough to start.

When it did, I ran it at a very fast idle for a few minutes until it smoothed out & after that it was fine.

[powerstroke]

V8RX7 said:

Hi

I'm hoping someone can help, I have a '93 Manitou telehandler with a 4cyl Perkins diesel that I've owned for years without issue - it always starts immediately.

The other day it died whilst idling.

I found it had lots of air in the diesel system.

I cleaned & tightened everything and there is no more air albeit I didn't find an obvious problem

However it simply will not start unless I squirt some diesel into the intake manifold - then it starts immediately.

It will also randomly stall on idle and is clearly down on power - try to use the ram and drive and it will stall.

I have cleaned and checked the filters, cracked the injectors multiple times and bled it for hours.

I've cleaned the gauze filter in the lift pump and the fuel / fuel filter are clean, I've even cleaned out the tank (hardly dirty) and blown the lines through

What have I missed ?

Thanks

Am I correct that the 5th injector mounted on the inlet is for cold starting only ?

Split pipe filter seal or primer pump ? something is letting air in !! best bet is steam clean with degreaser and check pipework starting at the tank , yes the thing on the inlet is a cold start it has an element that burns diesel to heat the incoming air..

[V8RX7]

But that's the thing - there is no air in there (that I can see)

Above the filter there is a distribution block.

It was bubbling out every time I loosened the input nut - it doesn't now (nor at any of the other points)

I ran the machine for 8 hrs yesterday - just I had to restart it using diesel - about 50 times

I've cracked the injectors when it's running and all cylinders are firing.

I have a mechanic coming out but I've already waited a week for him

[one eyed mick]

Possible cracked stack pipe in the tank ,brim fill tank ,it might help also as said cracked pipe to pump /filter

[powerstroke]

V8RX7 said:

Bout that's the thing - there is no air in there (that I can see)

Above the filter there is a distribution block.

It was bubbling out every time I loosened the input nut - it doesn't now (nor at any of the other points)

I ran the machine for 8 hrs yesterday - just I had to restart it using diesel - about 50 times

I've cracked the injectors when it's running and all cylinders are firing.

I have a mechanic coming out but I've already waited a week for him

,
Maybe worth rigging up a temporary fuel tank that feeds the pump directly make sure you use a inline filter !!! if that cures it then you can work back ,but I would also try taking the return off the pump to see you have a good flow of fuel first, if you are SURE its not sucking air then something is blocked or the lift pump or main injector pump is U/S ...

[stevieturbo]

You mentioned a lift pump ?

Do you mean an electric pump local to the fuel tank ? If so, surely if it is working, that would rule out potential air in the line issues normally associated with engine pumps that have to suck all the time ?

[powerstroke]

stevieturbo said:

You mentioned a lift pump ?

Do you mean an electric pump local to the fuel tank ? If so, surely if it is working, that would rule out potential air in the line issues normally associated with engine pumps that have to suck all the time ?

That sort of old school engine uses a lift pump like a 50s car ie a diaphragm pump worked of the camshaft!!with lever to prime manually..

[V8RX7]

I had thought about a temporary tank but after (apparently) fixing the air in the supply line I moved on.

There is certainly return fuel at idle - I guess there should be even at full throttle - if not then either a filter is blocked (they aren't) or the pump is duff - is that right ?

Annoyingly I had a similar problem when I bought it - no power. That turned out to be 2" of crap in the bottom of the tank - I cleaned the tank and changed all the filters and it's never had an issue since.

[C Lee Farquar]

You've done the obvious so, assuming you haven't made an error, I would change the lift pump next. Or rig up a temporary electric one to see if that makes a difference.

[V8RX7]

C Lee Farquar said:

You've done the obvious so, assuming you haven't made an error, I would change the lift pump next. Or rig up a temporary electric one to see if that makes a difference.

Would you ? (serious question as I know nothing about diesels)

The lift pump draws through a water trap - that is full of diesel and then supplies the filter - that is full of diesel so unless either is emptied at full throttle surely it must be ok - or doesn't it work like that ?

[stevieturbo]

I think the fitting of an electric pump...even temporary, is to eliminate the suction side of things.

If it makes no difference, then I think it would be safe to say there is no issue between main pump and the fuel tank.

If it fixes it and the engine runs...whilst not a normal solution...if it works, it works.

[C Lee Farquar]

From my experience of working with old tractors it's surprising how often replacing a lift pump will overcome problems.

It's extremely rare to have a fuel pump problem that will stop the engine running.

And as Mick says, run it with a full tank of fuel.

Edited by C Lee Farquar on Monday 9th June 06:13

[dbfan]

Being a DB fanatic doesn't necessarily mean that I'm right about Perkins engines, but the common cause is the valves in the lift pump failing - or getting dirt stuck in them. If it has a CAV rotary pump, there is usually a gauze filter where the fuel line goes in that can also get blocked.

It shouldn't need it, but the "fifth injector" in the inlet manifold is a "thermostart", which heats fuel from "header tank" that is filled with fuel from the leak-off pipe. If the thermostart fails, it would be difficult to start in cold weather - but I suspect it should be OK without it in June! Whatever you do, don't just pull the thermostart out and try the "Heat" position on the ignition switch - if it works, you'll get a nice long flame from the thermostart!!

As an aside, there should be an engine number (or model) on the engine somewhere that that goes something like AD4/238 or A4/238 (assuming it's an agricultural 4 cylinder engine). The 238 is capacity in cubic inches. This might help a Perkins expert (but not me!!)

[mark-ypqhs]

I have a perkins engine in a jcb 520-40. It starts fine, idles fine and revs hard at standstill but as soon as you pull away it dies and loses power. It has an electric pump that seems to run continuously and I have changed the in line plastic gauze filter along with the main filter. It still does exactly the same. While at standstill it revs fine and you can even keep your foot flat to the floor and it doesn't even splutter but as soon as you drive it loses power and almost dies??? Lift pump not supplying enough diesel??

[V8RX7]

I found the issue with mine was there was a final filter in the fuel pump (after the incoming fuel line, within the pump).

Only a little bit of crap in it - but enough to cause an issue.

Cleaned it out and all good.