Engine & Gearbox No turbo and limp mode above 2.5k revs

Discussion in 'Honda N-Series' started by skip_1, Saturday 11th Jul, 2015.

  1. skip_1 Junior Member ☆ ☆ ☆ ☆ ☆

    Hi all, I am new on here after lurking for a few months.

    I own a 2.2 ICTDI Accord tourer. One day whilst accelerating hard on the motorway the car suddenly went into limp mode.
    I got code P1237 - Low boost pressure.

    Upon clearing the code and re-setting limp mode the car was running fine for about two weeks. However it then let go again (whilst overtaking on an A road!).
    Upon clearing the fault code the car hesitates and won't provide boost after about 2.5k revs. You can hear and feel the turbo prior to this.

    My local Honda specialist checked all the pipes for leaks etc. and other checks and reckons either IMRC solenoids or sticking turbo vanes.
    I have had to keep hold of the car for a couple of weeks, but it will be going back in and having the solenoids swapped with two know working valves to see if it is that or the turbo vanes.

    My question is whether there is anything else that we should be looking at?

    Further info: Car was serviced with genuine Honda fuel filter about 5-6k miles ago.
    On driving home on Thurs the car appears to now be fine and revving at least up to 3.5k without hesitation or limp mode coming on!?

  2. Zebster Guest

    It's hugely disappointing that the Honda dealer couldn't even tell whether it was the IMRC or turbo causing the problem... the Honda Diagnostic System (HDS) has separate test routines for IMRC positioning and incremental boost performance (and a EGR valve test routine, and fuel pressure tests, etc...)!

    It's not clear whether you have a facelift (6-speed) model? I think on that model you can swap the EVR actuators for the boost control and IMRC positioning? This might be a useful diagnostic, but not as clear as replacing parts with known good ones.
  3. skip_1 Junior Member ☆ ☆ ☆ ☆ ☆

    My car is the pre-facelift 5 speed. The garage is an independent specialist (ex-Honda tech) so no access to the HDS. He suggested swapping the IMRC's with known good ones in a couple of weeks time in order to avoid spending if not necessary. It seems to be a decent garage, they don't charge if they cannot diagnose etc.

    It may be worth sticking the car through a Honda dealer HDS. I assume this would be an hours labour?
  4. Zebster Guest

    I'm surprised a Honda specialist wouldn't at least have a 'cloned' HDS... they are available from eBay for around £100 (or less). In my opinion, it would certainly be worth asking a Honda dealer to investigate the problem, or at least someone with an HDS.

    But swapping parts should also find the culprit, but could be very time-consuming.
    SpeedyGee likes this.
  5. skip_1 Junior Member ☆ ☆ ☆ ☆ ☆

    Bit of an update. Honda dealer put it through HDS. Followed all the trouble shooting and couldn't find the issue. They apparently phoned Honda UK who said to take the cat off and do something with it. This would cost another £75 and may mean due to the age and condition new exhaust bits needed. Aren't new cats extortionate?

    What could the CAT be causing? Error code was low boost pressure? If the Cat was bunged up surely that would be higher pressure through the turbo?
  6. Zebster Guest

    If the cat was bunged-up then the exhaust gas flow would be impaired, so the turbo would spin less fast.
  7. Ichiban Founder Staff Team

    England CJ Leeds
    Not a specalist then are they? What worrying is there are do many of these so called specalist who just work on Honda's ,by working only on Honda does give you the specalist crown.

    It's biggest con going aroun
  8. Zebster Guest

    Did their diagnostics prove that there was a problem achieving the higher boost targets? If they suggested it could be a blocked cat, then hopefully it is. Maybe letting them do further investigations for only £75 is the best course of action?

    I'm not sure what causes the cat to become blocked though. Do you only ever do short journeys?
  9. skip_1 Junior Member ☆ ☆ ☆ ☆ ☆

    Apparently the vacuum test pressures were wildly out, but the tech didn't think it was the vacuum pump as didn't match the symptoms.
    Tech doesn't think it is sticking vanes as the turbo sounds OK. I'm going to try swapping both IMRC valves with known good ones as the HDS may not have picked up any intermittent faults.

    The tech also mentioned that the car feels slightly sluggish even at lower revs than it maybe should do.

    The Cat being bunged up is what Honda UK suggested once the HDS troubleshooting drew a blank. We do undertake some short journeys, but normally my commute is mixed motorway and fast B roads over 18 miles each way. Didn't think short journeys could be an issue without DPF!
  10. Zebster Guest

    No, not normally. I'm just trying to find a reason why your cat may be blocked, when it's quite a rare problem on these engines. If it is blocked, then I guess it must be due to soot?
  11. skip_1 Junior Member ☆ ☆ ☆ ☆ ☆

    I guess so. The tech did say that if Honda UK tech are saying to do this then they must have come across a similar problem before.
  12. Zebster Guest

  13. blackbeard Club Member ★ ☆ ☆ ☆ ☆

    England England Kent
    As you have recently had a fuel filter change it is one item to rule out. I would de-gunk the EGR valve, the swirl valve ,along with the inlet manifold itself, you will be shocked to see how much gunk the inlet manifold contains, and wonder how it managed to perform at all .The lower section of mine was completely solid.
    You can hurt nothing at all by cleaning these items, which will help restore restricted air flow to help the car " breath " better.

    These cars chuck up code faults not necessarily relevant to the actual fault. Mine showed an Glowplug relay or glow plug coded fault for example , yet all tested out perfectly ok in reality it was a non OEM fuel filter that was the cause.

    As for the cataclean I can say that you will see it working via the exhaust pipe , does injectors and cat at the same time if your fault is cat related this at least may address some of your symptoms, certainly cheaper than an unneeded cat.

    You may just have had a bad batch of fuel if as you say at the end of your post the car is behaving itself.
  14. skip_1 Junior Member ☆ ☆ ☆ ☆ ☆

    Will go for the CAT check at 75. I will try a cleaner for the whole fuel system too before a new CAT if needed.

    The car went for MOT yesterday and passed. On its way the power came back again.
  15. Zebster Guest

    That isn't what I'd expect of a blocked cat!
  16. skip_1 Junior Member ☆ ☆ ☆ ☆ ☆

    I suppose not if it can't blow itself clean occasionally. Not sure where to turn next, Honda were the ones suggesting the CAT.

    The HDS did throw up the vacuum pump which the technician dismissed.
  17. Zebster Guest

    Was it thought to be generating insufficient vacuum? That could be a leak somewhere. The EGR and IMRC would be affected by this, as well as the boost control.
  18. skip_1 Junior Member ☆ ☆ ☆ ☆ ☆

    Dealer said the vacuum results were all over the place. They had checked the pipework though supposedly. I have asked for the technician to call me, as you said above the power coming back may discount the CAT.
  19. Zebster Guest

    I'm not sure how HDS measures the vacuum pump performance. The vacuum pump is driven by the camchain, so I'd expect it to be time-consuming to replace. Hopefully it isn't that!
  20. skip_1 Junior Member ☆ ☆ ☆ ☆ ☆

    Yeah they said 4 hrs or so just to check it.