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No boost below 2,500rpm, no warning lights or fault codes

M

mutley

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Location
Wiltshire
Car
2005 Accord i-CTDi
Hi Guys

I'm now well over a year in to trying to fix the faults on my 2005 i-CTDi tourer. I know there are similar threads on this subject but nothing close enough to convince me to spend yet more money on going down a particular route.

The problem started out as an occasional power loss, usually a few minutes after start up after the car had been stood for a day the engine would fail to give power when trying to pull away from a junction.

Things have now progressed (or is it a different problem?) so that now there is no turbo boost until about 2,200rpm, and from about 2,500rpm the boost kicks in and the power comes in. As a result the car is a complete dog to drive - to accelerate from 30mph you need to be in 2nd gear, from 50mph you need to be in 3rd gear, and if you don't have loads of revs in when you let the clutch up to pull away they you won't go anywhere.

When the power finally does come in then all the cars that had to slow down for you disappear in a massive cloud of black smoke - though whether that is a symptom or just a result of having to accelerate at high rpm with your foot flat on the floor is hard to know.

The car has never shown any fault codes. It passes all of the test on the diagnostics.

The following has been tried to date:

Replaced the IMRC solenoid (failed a diagnostics test)
Fuel filter changed
Freed up the turbo actuator arm
Refitted the air inlet cover
Replaced all of the vacuum hoses
Had an "EGR-off" remap and full diagnostics run
Cleaned out the induction system, EGR valve, MAF sensor etc
Turbo has been removed and de-carbonised
Still nothing on fault codes or on diagnostics when they are run

So about £900 spent so far and it's still not working.

Any bright ideas where to look next? The engine is as smooth as anything, but its either not getting enough air or not getting enough fuel - but which of those things it is and what is causing it is a complete mystery.
 
Steve - I think it's probably your turbo in all honesty.
 
Turbo boost control valve?... http://typeaccord.co.uk/forum/topic/12281-manifold-replacement-control-valve-problem/page__p__136914__hl__boost__fromsearch__1#entry136914
 
Jon_G said:
Turbo boost control valve?... http://typeaccord.co.uk/forum/topic/12281-manifold-replacement-control-valve-problem/page__p__136914__hl__boost__fromsearch__1#entry136914
Click to expand...

Thanks Jon - interesting link. It sounds like it might be possible to swap the IMRC solenoid with the turbo control solenoid to see if it is working - I'll take a look under the bonnet tomorrow and see if that is the case!

Noriced another possible symptom on the drive home this evening - crusing at 60mph in 4th (it won't do it in 5th!) with the cruise control on - every couple of minutes there would be a very slight hesitation from the engine. No idea whether it is related or not.
 
mutley said:
Thanks Jon - interesting link. It sounds like it might be possible to swap the IMRC solenoid with the turbo control solenoid to see if it is working - I'll take a look under the bonnet tomorrow and see if that is the case!
Click to expand...
Good luck with the swap... please do report back on what you find.

mutley said:
Noriced another possible symptom on the drive home this evening - crusing at 60mph in 4th (it won't do it in 5th!) with the cruise control on - every couple of minutes there would be a very slight hesitation from the engine. No idea whether it is related or not.
Click to expand...
I can't suggest anything that you haven't already tried!

When you had the fuel filter replaced, was the replacement definitely the Honda OEM (actually Bosch) unit?

You mentioned a diagnostic check... was this simply an OBD2 scan, a garage Snap-On machine or was it checked using a Honda Diagnostic System (HDS)?
 
Replace the EGR VALVE, I had the same problem like yours! Nearly had I accident when I in the roundabout because of the lack of power, if you done EGR off remap, I don't know about that as my car is srardard now.I suggest you let Honda deal diagnose the problem , don't waste money and time test yourself anymore

Ray
 
1st thing you need to do is get the cars ECU back to stock, that way it will be able to produce all the fault codes it was designed to do. Then you'll stand a better chance of the car picking up the relevant fault code to indicate the problem.
 
I ran a full HDS test and every available engine functional test on it. It passed all tests, which doesn't mean there isn't a problem but it does mean that at the time of testing all the components were operating within threshold set by Honda.

The EGR OFF stage 1 will not affect anybody's ability to run diagnostics on the car. The EGR valve should work when commanded to (we do not erase any errors in our EGR OFF).

It's worth trying the valve, but my money is now on a sticky turbo.
 
OK, well this morning I disconnected and blanked off the vacuum connection to the EVR valve (item 5 on this picture http://www.lingshondaparts.com/honda_car_parts_selection_pfk.php?block_01=17SED01&block_02=E__3200&block_03=608 ). Unfortunately mine is a pre-facelift model so it doesn't have a pair of matching valves which I can swap around.

The car ran similarly to before with the exception that the turbo didn't kick in at all (no surprises there). As before there were no DTC codes generated, so this appears to be a part of the engine which isn't covered by any of the on-board sensors / diagnostics.

Based on what I did this morning things seem to point to either a malfunctioning EVR valve or a dodgy turbo. Both are unpleasantly expensive to swap on a trial-and-error basis (£195 for an EVR valve, fitting is a DIY job; used turbo about £250 to £400 off ebay plus about 4.5 hours at the garage to fit).

:(
 
.... just to answer some of the other questions - Fahad ran the full honda diags on it (on two separate occasions - first time found an IMRC faulty which i fixed) before the EGR-off tune went on it. I've got a code reader so I have been looking out for anything on that. The garage it has been to for the last couple of attempts at fixing have a full generic diagnostic rig which can exercise the components.

I've found an EVR valve on ebay for £40, so I may give that a go ..........
 
There is actually a Manifold Absolute Pressure (MAP) sensor that, in effect, monitors the performance of the turbo. I am surprised that you are not getting a DTC for this reading being too low.

It would be great if a fellow member near you could swop over their EVR with yours! Can't you get a secondhand one from a breakers or eBay? I understand your reluctance to throw big money at the problem, but I don't know what else to suggest! If you took it to a garage, they might also struggle to diagnose the exact problem (I'm bearing in mind here that apparently Fahad has already used HDS to look for the fault).

***uming you have spent a decent amount of time searching TypeAccord for clues to your problem, then maybe also search here as well... http://www.civinfo.com/forum/engines-transmission/ - the version of the i-CTDi fitted to Civics is practically the same as in the facelift (not pre-facelift, unfortunately) 7th gen Accord.

EDIT - I was writting so slowly our posts crossed! I think it's worth spending the £40!
 
By way of an expirement I tried bypassing the EVR valve and attaching the turbo actuator line direct to the vacuum system. The actuator arm moved to full deflection, it didin't make a lot of difference to how the car drove (though I didn't push too hard as I didin't know what the effect would be).

Does anyone know what the actuator arm on the turbo controls? Is it a wastegate or does it control something else?
 
Interesting test result! It's a variable-geometry turbo... http://en.wikipedia.org/wiki/Variable-geometry_turbocharger ...the vacuum line controls the internal turbo vanes to allow the optimum operation for the required boost.

Using your OBD2 reader, are you able to read real time MAP info (I can on mine). This will obviously show how much boost is being generated in the inlet manifold. Maybe the turbo is working and your intercooler or pipework is leaking?
 
Jon_G said:
Interesting test result! It's a variable-geometry turbo... http://en.wikipedia.org/wiki/Variable-geometry_turbocharger ...the vacuum line controls the internal turbo vanes to allow the optimum operation for the required boost.

Using your OBD2 reader, are you able to read real time MAP info (I can on mine). This will obviously show how much boost is being generated in the inlet manifold. Maybe the turbo is working and your intercooler or pipework is leaking?
Click to expand...

In that case the test probably didn't demonstrate anything useful as all it would have done is held the turbine blades in the wrong position - so its no surprise that things weren't better. Had it been a waste gate then I would have expected to see some failry significant boost pressures (hence my gentle driving!).

Unfortunately I have the nastiest, cheapest OBD2 reader known to man, so nothing as fancy as real time data available.
 
mutley said:
In that case the test probably didn't demonstrate anything useful as all it would have done is held the turbine blades in the wrong position - so its no surprise that things weren't better. Had it been a waste gate then I would have expected to see some failry significant boost pressures (hence my gentle driving!).

Unfortunately I have the nastiest, cheapest OBD2 reader known to man, so nothing as fancy as real time data available.
Click to expand...
I'm not sure what vane position applying vacuum causes... it could be high boost, or it could be low boost? Maybe you need to also try it with the pipe blocked off?

I've read a few threads where owners have removed the turbo to clean up and free the vane mechanism with some success - this would obviously also allow the turbo to be examined to see if the bearings are either worn or jammed. Reconditioned turbos are available (and I've seen them on EuroCarParts), but - as you mentioned earlier - are a bit pricey.
 
You can't really clean VNT turbo's as it's a totally sealed unit. And the fact that you can move the arm completely and it makes no difference suggests to me that it's a sticky turbo.

When we ran the diags and tuned it, the car drove faultlessly.. so the problem is intermittent. I really don't want it to be the turbo.. but I think it is that.
 
Some possibly useful info here... http://www.civinfo.com/forum/engines-transmission/57729-2-2-ctdi-actuator-movement-s-how-much.html and - ***uming it's not an unlikely coincidence - ebod is also a TypeAccord member, so you could PM him to see how he got on (and if he did ever manage to do a strip and clean)... http://typeaccord.co.uk/forum/user/1935-ebod/ I've discussed stuff with him before and he's a helpful guy so maybe ask him to contribute to this thread to add to its potential usefulness?

As Fahad said, hope it doesn't need a replacement turbo... they are horribly expensive.
 
Well, the new EVR valve was on within 30 minutes of it coming through the door .... and it made no difference at all :( .

No real surprise, but it would have been nice if it had worked!

Am now waiting a call back from the garage I've been using to discuss what to do next.
 
Sorry to hear that Steve.. but as you say. probably not a big surprise.. more and more likely to be the turbo from what you're describing.
 
Same as faddy, sorry to hear that the egr valve won't work with the problem, you have to have it diagnosed professionally, making sure the where is the problem, save you time and hassle, hope to see your update with the problem being sorted..good luck
 
mutley said:
Well, the new EVR valve was on within 30 minutes of it coming through the door .... and it made no difference at all :( .

No real surprise, but it would have been nice if it had worked!

Am now waiting a call back from the garage I've been using to discuss what to do next.
Click to expand...
Did you manage to contact ebod?
 
Have been driving the car for the last few days and it has got much better - not perfect, but much, much better. It now has some pull from about 1,500rpm and is relatively driveable compared to how it was before.

Don't know whether the improvement is due to the turbo vanes freeing-up post-clean, the impact of the new solenoid, or a combination of the two. Whatever the cause of the improvement, it is good news as the car is no longer the cause of a crisis and is usable for the foreseeable.
 
It's most likely your turbo then Steve - hopefully it will free itself up properly. Give it some high rev running when it's safe to do so.
 
Another good excuse i can use with the missus now - especially after she's had the car for a week.

"It's OK dear - Uncle Faddy says we need to keep the vanes free of face a £1500 repair" :lol:

Top-TA-Tip :D
 
Well it's running kind of OK now, which is good news. The bad news is that its "old" problem of conking out when you try to pull away is back.

Just to recap - it had a habit of refusing to rev when pulling away from a junction - normally happened about a couple of minutes after a start from cold when the car had been sat for a day or more - it would start up and drive normally then after a couple of minutes (usually when pulling out on to a main road!) the engine wouldn't respond to the throttle and would remain at or close to idle - not good when you have just started to pull out in to traffic.

Things have changed slightly - because now it does it immediately after start up. Start the engine, car ticks over - but revs won't rise off tickover. Pump the throttle - nothing. Shut down, restart, and its the same. Pump the throttle for a while and nothing happens. Eventually (after a couple of minutes) revs pick up and we're off - with the car driving normally (or at least as normally as it does these days).

I will squirt some switch cleaner around the Throttle Position Sensor later to see if that helps.
 
Latest update on my car:

Turbo is now working fine and the car is back to its old self in that regard. Whether it was the turbo taking a week or two to free up after it was de-coked, the install of the replacement solenoid or the ECU taking a while to "re-learn" or a combination of all three I guess I will never know.

The power-loss while warming-up is still there though, and worse than ever. It only seems to happen when the car is stone-cold, seems to happen more often when it is damp, but that may be coincidence. The car typically starts and drives OK initially, but after a few minutes it suddenly loses all power and I end up stuck at the roadside trying to coax the engine back in to life (it doesn't stop, but won't rev much past tickover). After a few minutes of cursing it comes back to life and then we're off again with everything working perfectly.

I've recounted these symptoms a few times before, but my question to anyone who knows is - what processes does the engine go through as it warms up? It seems to me that when the engine is stone cold all is fine, as it warms up something changes (possibly the engine management system changing some parameter to reflect the new engine temperature) which causes a problem, and then once the engine is past that temperature something changes again and all is OK. What I'm trying to identify is what is changing - that way I might be able to identify the problem.

Needless to say there are no fault codes coming up.

Any thoughts / comments / suggestions?

Thanks

Steve
 
Are you tryed disconect imrc valve?I saw,that you changed.Are you put new valve?
 
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