new injector, now can't fire up

[tyssniffen]

So, after messing up my injector and creating a leak, I finally put in a new one.  Sounds great, with a nice tight squeak every squirt.

BUT, after a good crank, I can only get a couple of fires; it doesn't actually keep up.   Sounds a bit like low fuel, but it's definitely squirting...  so, somehow, the compression is messed up?    I had this experience maybe 5 times - crank, pull the lifter, fire, fire... die. 

How did it start up and run for hours with a leaky injector, but now, with a shiny new one, it won't?  I feel the new injector is definitely seated properly.  The top of my exhaust valve pin is definitely worn - could there be slack in the valves that somehow the leaky injector was covering for?

Anyway, any advice on what to do would be welcome.

[ajaffa1]

Sorry to hear the new injector did not solve your problems. There are several things that will stop a diesel engine from running:
1. fuel injector/injector pump issues causing insufficient fuel to be injected. Perhaps there is still air in the fuel injector lines or the element in the injector pump is worn, also check that the rack on the injector pump is fully open, the older Bryce injector pumps had a starting pawl that over fueled the engine for easier starting, the later Bosch Mico pumps don`t have this facility.
2. Compression or lack of it, worn piston rings or poorly fitting inlet or exhaust valves can cause loss of compression as can wear in the big and little end bearings.
3. Dirty air filters can restrict the amount of air available for combustion
4. Blocked exhaust system preventing expulsion of waste gases.

My best guess is that there is still air in the injector line or you have a sticking exhaust valve. Try giving the exhaust valve a couple of taps with hammer.

Let us know how you go.

Bob

[38ac]

Doubtfull that it is compression related. I assume you can hear the injector creak when hand cranking it? Start it and let it fire twice and quickly throw the decompression lever and listen for the injector to creak as it coasts down. I had a 3/1 Lister here with very similar issues that had been in 3 shops and they couldn't figure it out. The pintle wasn't seating in the tip and when that happens and the engine fires it pushes air into the injector and engine dies.

[tyssniffen]

1. fuel injector/injector pump issues causing insufficient fuel to be injected. Perhaps there is still air in the fuel injector lines or the element in the injector pump is worn, also check that the rack on the injector pump is fully open, the older Bryce injector pumps had a starting pawl that over fueled the engine for easier starting, the later Bosch Mico pumps don`t have this facility.
2. Compression or lack of it
3. Dirty air filters can restrict the amount of air available for combustion
4. Blocked exhaust system preventing expulsion of waste gases.
My best guess is that there is still air in the injector line or you have a sticking exhaust valve. Try giving the exhaust valve a couple of taps with hammer.

thanks for this reply. quick responses:
1. this actually seems like a real issue. messing around today, I put a spoonful of one of those 'injector cleaners' down into the chamber (by removing the injector for a moment) and cranked it and it fired a few more times than before, but then coasted down again, as though it wasn't getting fuel.

2. Nothing has changed except the injector swap - I do worry about my system being dirty/old/loose, but the thing was firing up no problem with the leaky old injector, so while I wonder if something about the proper amount of fuel (rather than an over-abundance from the old injector) is somehow revealing the lack of perfect compression??

3. I've had the intake filter off for a few days... while I'm sure there's build up of carbon everywhere, I don't think it's an air-in problem.

4. my exhaust system is a funky one, I have to admit... but again, it was working last week with the old injector. I did in fact take out my 4 foot horizontal run exhaust pipe as I was concerned about blockage, and the thing was just fine.  I then hooked it back into the rest of my muffler-ing system... perhaps I'll give it a try with just 4 ft of straight pipe tomorrow, just to see... but again, seems odd to suddenly develop this issue.

I love the idea of a hammer being the solution... and you mean, take the rockers off and smack it?  but isn't the rocker arm moving it up and down already (I see it moving) so how could it be stuck?

about air - I've cranked this thing to no start at least 20 times by now, and don't even pull the holder until I'm hearing the squeak of the injector... I've had air troubles in my time, but it seems crazy that it would be that.

[tyssniffen]

Doubtful that it is compression related. I assume you can hear the injector creak when hand cranking it?

I am hopeful it isn't compression related.  yes, I can hear a tight creak while cranking.

Start it and let it fire twice and quickly throw the decompression lever and listen for the injector to creak as it coasts down. I had a 3/1 Lister here with very similar issues that had been in 3 shops and they couldn't figure it out. The pintle wasn't seating in the tip and when that happens and the engine fires it pushes air into the injector and engine dies.

I hear the injector creak as it coasts down yes, but IT DOES seem like it skips one creak when it's already slowing down. Is that similar to what you're talking about?

what does one do about a pintle not moving correctly??

and, of course, I should (confess?) that I bought this injector off eBay from India, thinking there couldn't be much difference between them.   I see now that the thing might be able to be adjusted for different 'ats'?  could there be something I need to do to this injector to have it do more or less spray?

a quote from the eBay page:

"A direct equivalent of the CAV injector used for Lister CS & JP Engines. CAV Holder Type BKB50S507B. Nozzle BDL30S46. Set at 90 ats. for engine types: CS 5-1, 6-1, 8-1, 10-2, 12-2 and 16-2 engines but also suitable for use with the 3-1, 3.5-1, 10-1 and 20-2 engine types when set at the correct pressure."

[ajaffa1]

Looks to me like it is an injector problem, Once again 38ac has diagnosed the problem. A sticking pintle could well be the problem, probably caused by dirt ingress during reassembly. The pop pressure on these injectors is set on the top of the injector so dismantling and cleaning the injector nozzle end  shouldn`t effect anything. Strip it and clean it and see what happens. Try not to bend anything during reassembly

Bob

[38ac]

This is one of those deals where if the engine was in front of me we could have it going quickly. Very hard to diagnose from a distance. The 3/1 I spoke of was fixed here in 20 minutes after having been on the phone 10 times and probably 4 hours total.
Its not impossible that carbon is finding its way under a valve and your losing compression, its just very improbable that it happens every time after firing 2-3 times. If so you should be getting a cloud of white smoke when it quits firing. Also an engine that has compression issues will run decently but be very hard to start cold, not the situation you have.   Im going to stand on fuel supply issues for now. Injectors frim India are not all equal. If MICO they are good. If unbranded some good, some not so good.
Back to the pintle deal. If totally stuck the injector will not creak. However it is possible for a small leak to allow it to creak yet combustion pressure will push air back into the line. Doesnt take much, but as it coasts down. the air is purged and it will start again. Sounds far fetched but exactly what was going on with the 3/1. I would remove the injector and the nozzle, pull the pintle with your fingers it should move easy and smooth with absolutely no perceptable side to side slop. Then examine the tip of the pintle and the seat in the nozzle for imperfections.  Another running check is to quickly loossen the line nut at the injector after it quits firing and look for foam.

Thanks Bob, the admiration of knowledge is mutual

[dieselspanner]

Hi All

I had the same problem, air 'pushing back' into the injector. I lapped the pintle in with jewellers rouge, problem solved

A fivers worth off eBay will be lifetime supply.

Cheers
Stef

[dieselspanner]

Hi All

I had the same problem, air 'pushing back' into the injector. I lapped the pintle in with jewellers rouge, problem solved

A fivers worth off eBay will be lifetime supply.

Cheers

Stef

[tyssniffen]

Its not impossible that carbon is finding its way under a valve and your losing compression, its just very improbable that it happens every time after firing 2-3 times. If so you should be getting a cloud of white smoke when it quits firing. Also an engine that has compression issues will run decently but be very hard to start cold, not the situation you have. 

Well, now you've got me wondering.  I will disassemble the injector and check the pintle movement, but I have to say I *have* seen white smoke as the thing fails to fully start.  you know how the flywheel goes backwards when fail-to-start; I see white smoke coming out the air INtake, as well as some smoke out the exhaust. (that's why I pulled the exhaust pipe, I was worried it was blocked)

[tyssniffen]

Update going I got it started. I did all the things. I checked the injector pintle and it seemed to move okay, I hit the exhaust valve with a hammer numerous times, I also spun it a bit within a hope that it would seat it again, and when I got it cranking, it started off running extremely slow for 2 minutes, and then slowly built up speed to regular run speed. I put a load on it and ran it for 30 minutes.  I should have tried to start it again right then, but I'll let it cool off and try tonight.

[ajaffa1]

White smoke indicates unburned fuel, try not to breath it in, very unhealthy. I note that you have been running this on WVO which tends to produce more soot during combustion. I would be having a good look at the exhaust valve and valve guide, wear mixed with carbon build up could be causing it to stick part open, if you try starting it with the rocker cover off you might be able to see the exhaust valve sticking open. If you can get it to run, a long run on regular diesel will probably clear the problem.
There has been a lot of talk about running water injection when using WVO it helps reduce carbon build up.

Bob

[tyssniffen]

yeah, I've followed the water injection conversation for the whole thread, and have set up a water drip for when I run WVO.
And I've cut down on my veg oil use due to supply issues.  I've probably been on regular 'store bought' diesel for 30-50 hours. 

But you're absolutely right, I've got soot problems.

[tyssniffen]

update to the update - It started again this morning, cold, with normal behavior.   Running 'store bought' diesel.

Soot build up question: best way to try and deal with it without breaking things down?
- 100ml water down the air intake when it's real hot?
- regular drip into air intake over time?
- fancy store-bought chemical, like 'Sea Foam' ... into the fuel tank, or into injector housing?

[ajaffa1]

The best thing for diesel engines is a long run under full load. The real question is why is it producing soot? A poor spray pattern from the fuel injector is the most likely cause. You have just fitted a new injector so this problem should go away. A second possibility is that the engine is burning some sump oil, is there a blueish tinge to the exhaust fumes and do you have to top up the sump oil regularly? Could be you have wear in the cylinder and piston rings but much more likely the piston rings are stuck in their grooves due to carbon deposits from running WVO.
Give it a good run on regular diesel and see what happens.

Bob