• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

D24t rough idle

I think more than one of the nozzles are worn. I am going to get 6 reman injectors and heat shields for it. I can't get the rebuild kit or nozzles from Volvo anymore. I think getting 6 injectors should be part of the stage 0 for this car.
 
How can I service the injectors without any special tools? I don't suppose there's a way to check spray pattern without a bench type injector tester?

Friend and I rebuild our own injectors. It is super easy to do, we take part the injectors clean inside the body with solvent. Once we clean the injectors, I had my friend lap the injectors inside the sealing surfaces. He uses a diamond stone to lap them til the surface is flat. I heard some people just put new nozzle in without lapping the injectors, but I think that is not the correct way of doing them.

You can buy new Bosch nozzles from any place that does diesel fuel injection systems. We build our own pop tester out of a bottle jack its simple easy to used.
 
Don't buy bosch. They are made in India. Find a set of monarch nozzles for like $150 for all 6......either that or rebuild yours......but I went monarch on the Benz. All the Benz diesels are switching to monarchs when they are in stock....they are better suited to atomize bio as well.
 
How can I service the injectors without any special tools? I don't suppose there's a way to check spray pattern without a bench type injector tester?
Here you go:
HOW-TO: Rebuild Diesel IDI Injectors
http://vincewaldon.com/index.php?option=com_content&task=view&id=20&Itemid=28

Careful when removing the injectors from the head-- orient the ratchet handle so you are only pushing (or pulling) towards the head. Otherwise you run the risk of snapping the injector boss off the head.

BUT::::
Just a couple days ago the engine started running rough at idle, above 1000rpm everything is normal and power delivery is good.
If it were me, I would set the idle at 1000 RPM and drive it rather than go thru all that trouble. Might not even be the injector(s)...

v8volvo is the go-to guy for these engines. Take advantage of that, save yourself some thrashing around in the dark and get ahead by starting with his questions and suggestions::nod:
"Do you notice the issue hot, cold, or both?"
"Any air in the translucent line from the fuel filter head to the IP inlet? "
"Check the valve clearances."
 
^^^ sorry, the issue happens weather hot or cold, there isn't any air in the fuel line, I checked that first and the valve clearances are within spec.
 
What are the chances that a perfectly working injection pump just randomly starts acting up without any tinkering?

I thought once those pumps are set, timed and right, that they stay running right unless you mess with something.

Don't you all think it's more likely an injector issue or should I be looking for another pump if rebuilding the injectors doesn't remedy the issue?
 
IP can malfunction from unnecessary tinkering (as you say), improper fuel, dirty fuel, clogged fuel filter (cavitating IP internal vane pump grinds itself up and distributes metal shavings throughout IP), overly tight IP belt.

What were the results of this test:
Isolating the miss works the same way as a gasser, hold a steady fast idle and crack open fuel line unions one by one, see which one causes largest RPM change.
(Let's correct v8volvo a bit here: The bad injector will exhibit less difference to idle quality when disabled by cutting fuel pressure). This process bleeds off the fuel pressure spike from reaching that injector, temporarily rendering it inoperative. To clarify, crack the fuel line unions on top of each injector one by one and verify its effect on idle quality. Similar to unplugging each spark plug on a gasser. Don't let fuel drip down onto the coolant hoses. Don't overtorque the nuts when retightening. Just enough to stop any leaking fuel.

If this test leads you to suspect a faulty injector, you can swap it to another hole and see if the problem follows the injector. NOTE: Heat shields (the special "crush washers" between injector and head) are NOT reusable so have some new ones on hand.

No need to jump to rebuilding the injectors until you can verify faulty injector(s).

What idle RPM are you shooting for?
 
I'd like it to idle at factory spec, 750rpm I think is correct.

What about the overly tight IP belt, how tight is too tight? I installed the IP belt to the same tightness it was before I took out the injection pump to replace seals.

I did not use a belt gauge, I used my fingers to twist the belt a little and see how much give it had and used the same method to put it back making sure it had the same give.

I think I want to locate a spare injection pump for this car just in case. I mean it can only be the one/multiple injectors or the pump.

I also switched the injectors around and the way it idles looks a little different. When I first started, it was shaking as if the uneven firing was towards the back of the engine, like I could see it by the way it was shaking the mounts and trans. Now that I moved the injectors around, it appears to have centered itself so that the rocking is more even from front to back.
 
here, quick cell phone video, maybe seeing it will help, also you can see how tight the belt is and let me know if it's too much..

<iframe width="840" height="630" src="//www.youtube.com/embed/5iSVkrOpZdE" frameborder="0" allowfullscreen></iframe>
 
I might be getting somewhere because spraying parts cleaner around the #6 injector causes the idle speed to smooth out and noticeably increase.

What could this indicate?
most likely an intake gasket leak.

A little gunk in a delivery valve will keep one injector from doing its job too.

Raising the idle when doing the line crack check helps lessen the idle governor confusing you.

Any tractor shop should be able to pop test your nozzles, but I made a tester out of an old port a power.

AutohausAZ has Bosch $12 nozzles IIRC

Poke around with a stethoscope.

Run at high idle for awhile, and you may see an exhaust manifold flange at a different heat.

Any chance the wire fell off the temp compensator or switch? that makes em sound like a bag of rocks.
 
...you can see how tight the belt is and let me know if it's too much..
Could not tell from the video but you should be able to easily (light fingertips) twist the belt 45*, and with some force get near to 90*.

Too much tension will prematurely wear the mainshaft bushing. The resulting slop causes the seal to quickly fail, allowing air ingress. Main symptom: Hard starting after sitting some time, poor running at lower RPMs.

This is not the cause of your current problem, as you said clear fuel supply line was free of bubbles.
 
narrowed it down to #4 cylinder missing at idle, compression results are very good. 450ish psi all around.

cranking the engine over with #4 injector pointed into a plastic bottle showed little to no fuel being injected. swapped injectors with no difference.

ran the engine with #4 injector pointed into the bottle and only after 1500rpm did it start spraying.

there seems to be fuel feed to the injector but not enough pressure to pop the nozzle. i have new nozzles on all the injectors.

i tried decreasing shim thickness on the spring inside that injector with no luck.

i'm no diesel genie but i did take the pump apart to get a look and saw nothing amiss. at that point i sent the pump off to someone who knows more. we're just going to get the pump rebuilt.

it's silly to continue dicking around because the guy wants to daily drive this thing so we'll just get the pump rebuilt. i couldn't find a good used one.
 
I *think* you can still get that pump brand new, since they used in the lt van, 9 series volvo up to 98?, and various other junk.

But if someone can be found to do a bosch ve pump right, great!
 
Pretty unusual for a pump problem to make a symptom in only on one cylinder -- the injection itself is all based around that one hi pressure piston in the pump head that shoots to each cylinder depending on engine rotation position, like a gasser dizzy; if there's a problem there then nothing's gonna happen anywhere more or less, or at least I have never heard of a way for those bits to go wrong in a way that is isolated to one hole. Only parts in the pump that really have any clear ability to affect individual cylinders are the cam plate and the delivery valves. I don't think the cam plate could get a flat lobe that quickly, plus if that happened you would have seen it on inspection. A stuck delivery valve (check valve) might cause this, did you try moving those around to see what would happen?

You had the pump off to reseal it, right? Contaminated injector sounds like maybe a possibility too, especially if they were opened up; did that injector do anything at all under 1500 RPM? Did the needle move freely in the nozzle in that injector?

Sounds like maybe it's moot now if the pump is already sent away, but I kinda would suspect it sounds like a delivery valve or an injector, for lack of any other good explanation inside the pump that seems to make sense... will be interested to hear what happens with the pump refreshed.
 
Sometimes idle problems on these are due to air getting sucked into the fuel delivery system due to bad hoses/seals. I'd test run it with an electric fuel pump, or gravity feed off a diesel can to see if it fixes the idle.
 
Back
Top