Fitted R520s and misfire?

Hi All

Today a friend fitted R520 5-hole injectors to his car (11mm pump, previously had 0.280s running great, BV43 etc) it's running my remap

They were set up by one of the main places in the UK who do this, and they set the pop pressures etc. (They also did his 0.280s which are great)

It's misfiring on one cylinder under full load.

Static timing fine, idle IQ is fine, group 13 shows the injectors to be very well balanced.

No faults with VCDS.

The timing is erratic, which I presume is effect and not cause.

We threw the 0.280s back in and great again

No obvious damage to injector #3 wiring, and again no faults.
Copper washers were new.

I presume one injector is clogged? Any thoughts please?
Currently we plan to return them to the place that calibrated them.

Did the calibration come with any reports? Would seem strange if they check pop pressures to have an issue...

Had a set of R783 nozzles set up and calibrated by a UK shop. They did however report that one injector was out of balance with the rest. After a weeks running on the motor the missing stopped, which they said might happen. So maybe the injectors on your friends car will settle down or bed in after a bit of use.

As above, usually injectors need a bit of bedding in, they usualy stop clattering after a 100 miles or so !

Does he have any clutch upgrade ? 11mm pump/race 520 and bv43 usualy slips stock clutches right away !

Many thanks

Yes upgraded clutch, FMIC, 3 bar MAP sensor etc - all the normal stuff. There was a lot more torque when we put the 0.280's back in (as I hadn't yet re-done the map for the smaller nozzles, but couldn't with the issue we had)

Otherwise its running 200bhp without issue.

Maybe he should refit and run for a while, but he'd already done 100 miles on them when he'd got to me.

Ive never seen that before with about 10 sets of new injectors? United Diesel did them, and did he previous ones (and I believe Darkside send all theirs there too)
Surely that shows something isn't right?
I presume during calibration they're checking spray pattern and pop pressures as opposed to anything timing-wise?

In principle though, I guess it could be a dirty injector/some debris in it?

adamss24 said:

As above, usually injectors need a bit of bedding in, they usualy stop clattering after a 100 miles or so !

Click to expand...

Hi Adam,

What is there to bed in in an injector? I thought these were extremely precise instruments with little or no tolerances or play in their construction.

I don't see why a brand new set of nozzles balanced and pop tested, (with no advisories) need to be bedded in, I mean, what is there that can, or needs time to settle down?

The previous sets of brand new nozzles worked fine from day one without issue, as have every other set of new ones I have previously installed in the car.

A need to blow the cobwebs away in second hand injectors, I can fully accept but not in a totally new installation.

Also the car is being run on the 'Super' Diesel so should have a better calorific value and I would have thought a smoother operation...

Are my thoughts wrong??

The needles are tight in the nozzles so they make more noise on a brand new set of injectors. Also springs will be harder so they need to “soften” a little hence the noise reduction after a few miles on them. Where the nozzles fine on idle and part load ? If yes then I suspect your pump is not playing ball and pump voltage is off.... I had same sort of mods on a 2001 Audi A4 FWD with AHH 90 Bhp engine, it comes stock with 11mm pump and VNT turbo. After fitting race nozzles and a gt1749va I ripped the flywheel to pieces. Swapping to a new bv43 made it a bit more compliant, not as pokey but with loads more headroom ! It was a really fun car to drive, up to 100 Mph it would humiliate many sports petrol cars !

The car was silky smooth with the power delivery on the .280 nozzles and has been for the last 15,000 miles.

I installed the R520's in the car and it ran like a bag of nails with a poor tick over and power delivery all over the place... Re install the .280's and everything is back to silky smooth immediately with no misfire anywhere in the rev range.

And as Ben mentioned, Set up by UD.



Reminded me of my old Morris Cooper S of 1969 vintage following driving through heavy water... It was trying to run and clear the 'issue' but all it would do is misfire like a pig, until everything dried out and the moisture had disappeared.

bhodgkiss,

We also will raise the rpm to about 1450 and see if the deviation in injectors changes. We know Keith and think he's a good guy, but I would be wary of large injectors that misfire, as it might just as well melt a piston in a few kilometers. I suppose you can't tell which cylinder is causing the misfire..

Leon, adams and FlyingFin,

Depending on the manufacturer of the nozzle, there can be quite a difference in the needle 'seating'. In the Bosch nozzles, there is a very good 'two angle' cut on the needle seat, and those nozzles are very close at the initial startup and stay that way.

Others are cut with an interference angle and they do seat in. I know that given 10,000 miles, the nozzles will change, hopefully just a minor bit. That is not something I would depend on this set accomplishing, as nozzles that are not working right can ruin an engine, especially if they have excessive flow.

bhodgkiss,

Our single biggest problem with mailing out injectors is returns that we clean out a bit of dirt from the nozzle and it goes back to working as it should. But that normally is something that shows up in the deviation of the nozzle in the VCDS idle balance. I would worry that these may be a sticking needle or a nozzle seat area that is bad.

When it comes to knowing which injector is acting up, I can't think of a single time that we were not able to determine which injector was bad. I bet Keith will take care of the issue. Not all nozzles are good, just because they are new.

Adamss24 quoted, "The needles are tight in the nozzles so they make more noise on a brand new set of injectors. Also springs will be harder so they need to “soften” a little hence the noise reduction after a few miles on them.

I hope the hell NOT! We expect the needle to bore distance to remain very precise over the life of the injector. We also expect that the pressures we set in the injectors to remain at or near the 220/ 300 bar we set them to for an equally long time.

As for springs 'softening', I will agree, the value of a brand-new spring, no matter what application, will lose 5% of it's initial tension in the first 6 months. After that, it should be stable for years. We rarely replace the springs in a nozzle, unless we can see they are damaged. So, I think I'd dispense with the idea injector springs 'soften'.

The only other thing is, we are no fans of the Race 520's and regularly had troubles with them. They are prone to leaking.

It must be noted that the larger the hole size, and the fact that DSLA style nozzles injector holes are patterned in an elipse, that the holes ride high and low against the needle seat. Any error in needle seating location or tagged seat can cause leakage. That is our least favorite thing to deal with in injectors, as an overheating cylinder and melting out pistons is the usual symptom.

I've always used Keith for injectors fitting and testing....so far great customer support.

Regards bedding in of nozzles Keith did say to me that one of my R783s was slightly out but that this would settle down after some running time. In my book this is bedding the injector in.

Frank...


The nozzles are Fratelli Bosio Race 520.

Many thanks, that's great info.

The idle deviation (group 13) was around 0.05/0.25/0.40mg when warm
I believe this to be fairly normal?

I have R520s which have been fine for 50k miles (and four other people I know) but that's just my experience

I still have bosio 520 race nozzles in a ported AFN engine and they run just fine, the nozzles must be 8-9 year old but with low mileage 3000 miles or so. They are running fine although on the stock AFN they kangarooed a little ! I suspect pump voltage is a bit out hence the slight misfire !

Franko, I bought Bosio race nozzles from reputable uk vendors before and had absolutely no trouble with them for years however in a few instances I bought nozzles from a Portuguese popular vendor and the quality was low. One guy I know cracked a piston when a nozzle went bad and the injectors were set by dieselbob in uk.
Maybe Bosio QC went down in the last few years or maybe they were knock offs ! I remember comparing boxes a few years ago, there were differences in fonts, paper and ink color between 2 sets of race 683 nozzles I tried ! I must have pictures somewhere on my photobucket !

How bad does the pump voltage map have to be for misfires?
I've never had that.

I saw a case recently of an AFN ecu on an AHU with ahu injectors causing a "missfire" at idle. As the idle controller couldn't cope with the AHU injectors, which peversely deliver more fuel at idle according to the pump voltage map than the larger afn injectors.

Putting in the AHU pump voltage fixed the poor idling problems. The owner didn't run the car much with the AFN pump voltage map though..

Get a stock AHH pump map and graft that into your tune... if it doesnt fix the Issue then the pump might need to be rebuilt...
Also check the pump case valve, the collar is known to fall over time and the pump is cavitation although it’s doing it mostly on idle and part load. Make sure your fuel filter is clean, big nozzles and 11mm pump always warrant a clean, good quality fuel filter !

Many thanks
I'll try the map that works well on my identical setup - that was the plan before we got the misfire