BHW Injector Install Issue

[caffeine]

Looking for advice on how to proceed with this issue I'm having. I sent off my injectors to MecEvo in Quebec to be rebuilt with new Firad nozzles. Before removing the injectors, I could feel strong compression on every cylinder turning over the engine by hand (replaced timing belt and camshaft before I removed the injectors).

After installing the injectors, I now seem to be losing compression in every cylinder, but most noticeably on 3/4 (one still has noticable compression but not as much as before). I used new bolts, made sure the holes were completely clean, and turned the engine over with the glow plugs out to make sure there was no excess fuel in the cylinders. I then gave each injector a few good whacks with a rubber mallet and installed new hold down bolts hoping they would seat better, but it's still the same as the first try. It's bad enough that I can hear quite a bit of air leaking out as I turn the engine over by hand.

Any tips on how to get these to seal properly?

 

[MEgearhead]

Are you certain all the seals were installed properly?

 

[caffeine]

Are you certain all the seals were installed properly?

Not exactly. The injectors came shipped with new seals already on the injectors. The o-rings were all in their grooves and the copper washer was in place on the nozzle end. I just installed the whole assemblies as shipped into the head.

 

[MEgearhead]

Injector hold down bolts torqued to 12 Nm plus an additional 270 deg. (3/4 of a turn)?

 

[caffeine]

Injector hold down bolts torqued to 12 Nm plus an additional 270 deg. (3/4 of a turn)?

Yes

 

[caffeine]

I took the injectors out today to see if any o rings got snagged etc, but couldn't find anything. Only thing that makes sense to me right now is that maybe the sealing washers that were shipped with the injectors are wrong.

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Here's also a video where you can hear the compression escaping.

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[MEgearhead]

Do the copper rings look like they were slightly compressed. They are what seal compression. They are supplied somewhat soft and compress when the injector hold down bolt is torqued. This usually also work hardens them slightly so they hold the seal. If the don't show evidence like the old ones do something is wrong with their dimension.

 

[MEgearhead]

It looks like there's something in the hold-down bolt hole. Maybe the bolts are bottoming out before the injector is tight.

 

[caffeine]

It looks like there's something in the hold-down bolt hole. Maybe the bolts are bottoming out before the injector is tight.

I don't think there's anything in the bolt hole, just bad lighting. Certainly not in all 4. When I initially installed the injectors, they torqued nicely, not like a bolt that's bottomed out.

I'll pull the injectors again tomorrow night or Wednesday and check the copper washer. I wouldn't say I thoroughly checked them today, but I don't remember seeing any obvious signs that they were compressed. Do you know what the thickness is supposed to be compressed vs new?

 

[caffeine]

I contacted MecEvo and they basically just told me that this is normal and to start the engine. Has anyone here replaced injectors in a PD engine? Is it normal to be losing compression like this after replacement??

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[zzdiesel]

I replaced the seals in one with no problem.

 

[Windex]

I've replaced mine before, successfully...

Two thing I do on any injector:
1) ensure the sealing surface for the copper washer is pristine (clean, clean, clean and clean again. Q-tips are your friend)
2) give the injector, once installed down in the bore, a decent tap downward to "seat" the copper washer onto the land on which it sits.

These PD injectors are tight in the bore, and you want to ensure the injector is fully seated down before tightening the hold-down bolt finally.

 

[caffeine]

I've replaced mine before, successfully...

Two thing I do on any injector:
1) ensure the sealing surface for the copper washer is pristine (clean, clean, clean and clean again. Q-tips are your friend)
2) give the injector, once installed down in the bore, a decent tap downward to "seat" the copper washer onto the land on which it sits.

These PD injectors are tight in the bore, and you want to ensure the injector is fully seated down before tightening the hold-down bolt finally.

Yeah I've been cleaning and cleaning and tapping them in pretty heavily with a mallet. I think that maybe the fact that the fuel rail is empty may somehow be playing a role.

As a test, I went to the local pick n pull and grabbed some BEW injectors, then went home and installed them in the engine after annealing the washers. Same thing. MecEvo may be on to something when they say I just need to start the engine and get fluids flowing before they will seal fully.

 

[d0u8l3m]

I swapped mine with their m50 nozzles and didn't have any of the issues you are describing. Make sure you prime the fuel system first by unplugging the injector harness and cranking the engine over a bit before plugging it back in and trying to start it.

 

[caffeine]

I swapped mine with their m50 nozzles and didn't have any of the issues you are describing. Make sure you prime the fuel system first by unplugging the injector harness and cranking the engine over a bit before plugging it back in and trying to start it.

Yeah in my case the engine won't be started for a bit. It's getting swapped into an Allroad and has been sitting on an engine stand for over a year.