Hey all,

 

Have previously posted regarding misfires and rough running / poor acceleration on a 1.4 tsi (122 caxa) octavia. We ordered a new injector, and whilst fitting it elected to clean out as much as possible of the carbon buildup in the intake. The car had done 86k miles at that point, and the state of the intake valves was pretty horrific. I've attached a few photos, which aren't the clearest but came from a cheap endoscope camera - it may tempt some of you to check yours! Whilst we couldn't reach all of the valves due to the fixed runners, the valves had significantly less build up afterwards. The car since has accelerated significantly better, fuel economy seems to have improved and it's just generally a nicer drive.... or it was.

 

Now there is a loud ticking injector like noise when on the throttle, which vanishes once you take your foot off the accelerator and the ecu cuts fuel due to overrun. What I can't fathom is, where the noise is coming from, whether it's a new injector that's decided it has had enough or if there is some other issue. If anyone has any ideas I'd really appreciate it, unfortunately I have a feeling I'll need to replace the other three injectors which a friend insisted, but at £130 each they aren't a cheap outlay to potentially fix the issue. Maybe worth noting, when I used the screwdriver-stethoscope on the hpfp it's very noisy but I don't think that's the ticking noise that has appeared. Car has done 2000 miles since injector replacement without issue before this ticking started.

 

Any help would be much appreciated,

 

Thank you. 

 

 

I'm not familiar with the engine in your car but it reminds me of a Corsa with a similar problem, turned out to be a mis-installed o-ring on an injector.

I don't think it's a seal issue, all were replaced as were the gaskets interfered with during the swap. Unfortunately it looks like I may have to order those overpriced things again!

Can't you disconnect each injector in turn to troubleshoot?

I don't think there's access to them that easily with the lower inlet manifold installed (also has built in fuel rail)... I am happy to be corrected though if someone knows!

You can get injectors cleaned and tested including spray pattern on an ansu machine. That's what I did when I removed and cleaned the intake manifold. It's not cheap cheap, around £100 for four but that usually incl new seals and gives piece of mind you are not putting anything back faulty. 

 

I don't know for sure what your issue is. Obviously there is a suspicion it is related to the remedial work but could be just co-incidence.  Thinking about your explanation maybe the sounds is the pressure regulator in the hpfp if noticeable when fuel is not being supplied.

 

Did it do this ticking immediately or has it taken some time?

 

It seems most likely you are going to have to reprove the installation  and test the other injectors and replace.  After that I suppose the hpfp maybe a go to for focus. 

 

18 hours ago, TheClient said:

You can get injectors cleaned and tested including spray pattern on an ansu machine. That's what I did when I removed and cleaned the intake manifold. It's not cheap cheap, around £100 for four but that usually incl new seals and gives piece of mind you are not putting anything back faulty. 

 

I don't know for sure what your issue is. Obviously there is a suspicion it is related to the remedial work but could be just co-incidence.  Thinking about your explanation maybe the sounds is the pressure regulator in the hpfp if noticeable when fuel is not being supplied.

 

Did it do this ticking immediately or has it taken some time?

 

It seems most likely you are going to have to reprove the installation  and test the other injectors and replace.  After that I suppose the hpfp maybe a go to for focus. 

 

The noise has taken a few thousand miles to appear, car still pulls really well with no hesitation through the rev range but it's noisy and a tad lumpy at idle. The noise goes away when you're off the throttle and the injectors are no longer firing (down hill for example). I'm quite comfortable with the bkd diesel lump (in my car) but this caxa thing is a curse so far! Thanks so much for your reply

I wanted to update this topic to let you know the fault was rectified finally by replacing the cam follower for the fuel pump for the noise, and the Lambda sensor had decided to quit on us - which fixed the lumpy idle. Someone drove into the side of her last week, after we'd invested far too much money into the car and it has since been written off.