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Accord iDTEC "misfires" and cuts off.

Acco_idtec

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Accord tourer iDTEC
Hi guys.

This is my first post here, though I've been browsing here for a while when troubleshooting things. Sorry for my english, I'm a finnish dude so its defo not fluent!

So, I'm having some nasty problems with '09 tourer 2.2 iDtec. The car has 233 000km on it's clock.

Symptoms:
- The fault is continuos and has been present for about a week now.
- When idling, the engine "misfires" randomly at 1-20 sec intervals.
- When driving, the car stumbles at same intervals.
- When reaching normal coolant temperature, car tends to cut out. There has been couple of occasions, when I had to wait for approx 30min after the cutout to get the car started.
- Otherwise the engine starts easily and there's no excess smoke to be seen.
- NO check engine etc. lights flashing.

Notes:
- No fuel leaks.
- NO DTC:s to be found. I've read the log with Auto-Com & launch pro -testers. (No access to HDS yet).
- The car is re-mapped with dpf & egr elimination.
- The fuel filter has been changed ~2000km ago. Oem part.
- We were able to do a rail pressure test with launch pro. Result 1800bar.
- When idling, the rail pressure is around 260-280bar. The MAF-voltage is ~1,8V.
- Dunno the right term in english, but theres a slight difference in the injectors "correction amount" Cyl. 2 is -1,7 while the other ones are at +0,6.
- Most interesting thing is, that the crankshaft pulse sensor gives the values of either "63220" or "0". Revving the engine doesn't affect the values. Still, the RPM-signal is correct at the tester.

If theres any hints or ideas where to begin, I'd be glad to hear those! Taking the car to the dealer service is the last call, as its gonna cost some serious money..
 
Hi and welcome
That's for sure a fuel cut off for some reason.
The most common check up you already did...good work
All the parameters you mentioned are OK so the fault is not where you are searching, even the injector correction per cycle.
If i would be you i will take the injectors out and send them to an good company for check up, and check the cylinder compression.
 
Jan Accord said:
Hi and welcome
That's for sure a fuel cut off for some reason.
The most common check up you already did...good work
All the parameters you mentioned are OK so the fault is not where you are searching, even the injector correction per cycle.
If i would be you i will take the injectors out and send them to an good company for check up, and check the cylinder compression.
Thank you for your quick reply.
I also guess that it's a fuel cut for some mysterious reason. When the car "dies" properly, first it cranks after the cutoff, but doesn't run for more than just a second. A bit later, it starts and idles but doesn't rev. So It takes totally about 30min for the car again to work as well as it does in this condition.

Does the ECU cut off the fuel supply, if, for example just 1 injector is faulty?

I was also wondering, could a dodgy inertia switch cause these symptoms as there is no check engine-lights or fault codes to be seen?

That injector test totally should be done, I just don't have a decent diesel specialist nearby, so its gonna take some time to find a proper garage who could test em.

Can I get a clue about the injectors condition for example, by making some resistance measurements?
 
If your ECU does not recognise any fault than somewhere must be a mechanical fault... where the "check" sensor is not mounted as already mentioned injectors.
The resistance measured on the injector will show you only the state of the electromagnetic valve which opens and closes the injector when needed.
Search for some decent BOSCH service around there with good reputation of the company.
If you don't have any around there take them out your own and sent them.
Belive me...it's better that the injector service takes few days more with postage included and costs a bit more, than you take the injector to some "specialist"...
If the injectors are not prepared as they should, the can cause problems bigger than you expect, and you will still have in mind that " the injectors are rebuilded" and point the problem solving in some other way
 
Hi Simo,
if you think it is injector trouble you could try this :-

Open the diesel filter top and remove the diesel filter.

Remove the fuel from the chamber and refit the filter.

Fill the chamber body with a good quality diesel injector cleaner.

Refit the filter top and and run the engine for about 30 seconds.

Switch off and leave over night for the diesel injector cleaner the do its job.

Next day give the car a good run out and use the revs to the full once or twice.

This method has been known to improve/clean up diesel injectors.

Cheers, Pete.

P.S. let us know the outcome.
 
TourerFan said:
Hi Simo,
if you think it is injector trouble you could try this :-

Open the diesel filter top and remove the diesel filter.

Remove the fuel from the chamber and refit the filter.

Fill the chamber body with a good quality diesel injector cleaner.

Refit the filter top and and run the engine for about 30 seconds.

Switch off and leave over night for the diesel injector cleaner the do its job.

Next day give the car a good run out and use the revs to the full once or twice.

This method has been known to improve/clean up diesel injectors.

Cheers, Pete.

P.S. let us know the outcome.
This could be also a solution...but you need to be careful what you put in.
Strongly avoid any aditive with alcohol or any other aggresive solvent.
It must be based on parafin oil like Antigrippante 25.
 
Thx for these additions, I'll try to get my hands on that stuff and have a go on that treatment first!
 
Acco_idtec said:
...Dunno the right term in english, but theres a slight difference in the injectors "correction amount" Cyl. 2 is -1,7 while the other ones are at +0,6.
That's normal... the ECU will always ***ess one 'mid-range' injector to be the baseline then reference the other three injectors to it. Logically then two injectors will be either plus or minus in relation, while the fourth will be the opposite. Your results are completely normal and so do not indicate an injector problem. I'm not dismissing the suggestion, but I would therefore be wary of running practically neat cleaner through the injectors (or particularly the pump) in case the lack of lubrication causes excess wear, at least until I had ruled out other things.

If this was an i-CTDi diesel (with the previous 3rd generation Bosch injection system) then I would focus on either the rail over-pressure valve intermittently releasing rail pressure (by channelling the return into a container and blocking the loose pipe) or the M-Prop (pressure regulator solenoid) on the fuel pump being a bit sticky. I've suffered both these faults!

You appear top have access to advanced diagnostic equipment, so why not log engine parameters whilst driving around?
 
Jon_G said:
That's normal... the ECU will always ***ess one 'mid-range' injector to be the baseline then reference the other three injectors to it. Logically then two injectors will be either plus or minus in relation, while the fourth will be the opposite. Your results are completely normal and so do not indicate an injector problem. I'm not dismissing the suggestion, but I would therefore be wary of running practically neat cleaner through the injectors (or particularly the pump) in case the lack of lubrication causes excess wear, at least until I had ruled out other things.

If this was an i-CTDi diesel (with the previous 3rd generation Bosch injection system) then I would focus on either the rail over-pressure valve intermittently releasing rail pressure (by channelling the return into a container and blocking the loose pipe) or the M-Prop (pressure regulator solenoid) on the fuel pump being a bit sticky. I've suffered both these faults!

You appear top have access to advanced diagnostic equipment, so why not log engine parameters whilst driving around?
Thank you very much for sharing knowledge about the injector correction amounts! That's certainly new info for me.

I found a topic about the relief valve diagnosis on a i-ctdi. This: http://www.civinfo.com/forum/how-guides-only/111264-how-diagnose-replace-faulty-over-pressure-relief-valve-2006-2-2-i-ctdi.html#/topics/111264

Does this apply to iDTEC also, or are there major differences in that area? Shame that the pictures in this topic do not show anymore.

About the diagnostics, I do have the Autocom software, but at the moment its in a laptop with a ****ty battery, so I can only use it stationary.

The LaunchPro that I mentioned is owned by a guy I know, so I don't have everyday access to it.

We did a drive with LaunchPro connected, and we monitored The actual fuel rail pressure and it's target pressure. They seemed to go pretty much together, even when the engine was stumbling.
 
Jon any ideas ?

Sent from my C6603 using Tapatalk
 
I'm sorry the most obvious culprit here is the remap.

It's not possible for such a major malfunction to take place where you engine is actually cutting out and no DTC is being logged. Your tuner has most likely deleted either a bank or an entire table of DTC's because they didn't know how to remove a DPF regen cycle or switch off an egr.

I see this stuff day in day out now.

Was this happening before it went to them?

Have your ecu flashed back to stock and then test it.
 
F6HAD said:
I'm sorry the most obvious culprit here is the remap.

It's not possible for such a major malfunction to take place where you engine is actually cutting out and no DTC is being logged. Your tuner has most likely deleted either a bank or an entire table of DTC's because they didn't know how to remove a DPF regen cycle or switch off an egr.

I see this stuff day in day out now.

Was this happening before it went to them?

Have your ecu flashed back to stock and then test it.
Ok, that's also one of the scenarios I was afraid of. The remap was done during the previous owner, so I don't know if there was symptoms like this before the remap.

But I do know the company who made the remap, so I have to give them a call next monday.

About a year ago, I had a couple of cutoffs after a full throttle acceleration, but back then I was able to find a MAF-related DTC with Autocom and everything fixed by cleaning the air sensor.

But if it's possible to remove just a bank of DTC's (like EGR-related) then that might be the case.

Which makes me wonder, could I track a faulty EGR-valve by monitoring the target & the actual intake air amounts going into the engine?
 
Hi Simo,
Below is a list of MAF readings taken using "Torque" app. with an android phone. This was taken with the car stationary and from it you may be able to check for a faulty EGR valve.

Engine temperature 80 degree C


Revs Grams/stroke

820 (idle) 7.3
1000 9.7
1500 15.1
2000 18.5
2500 32.4
3000 58.00

Hope this helps, Pete
 
F6HAD said:
I'm sorry the most obvious culprit here is the remap.

It's not possible for such a major malfunction to take place where you engine is actually cutting out and no DTC is being logged. Your tuner has most likely deleted either a bank or an entire table of DTC's because they didn't know how to remove a DPF regen cycle or switch off an egr.

I see this stuff day in day out now.

Was this happening before it went to them?

Have your ecu flashed back to stock and then test it.
Is that really possible?? To delete the DTC's?
 
Absolutely yes, and more and more so called tuners are doing it because it's very easy to do, and it's far easier than taking the time to understand individual mapping structures to correctly close egr maps and DPF cycles. They just delete errors permanently and hand the car back with a horror of problems brewing in the background.

Even with some very basic knowledge any novice can download a flash and use some online software to delete a DTC table. It's an extremely dangerous thing to do.

I had an Accord just this week from a forum member here who had lost hope in it. It was cutting out and throwing bags of smoke and losing power but no garage or the RAC could diagnose it because their machines were showing no DTC codes.

I had solve it by rebuilding the software and reinstating all the error codes. Turns out his egr was sticking open so it was solved with our egr off solution.
 
Omg. You never know what you buy and then even when you pay for something when upgrading the car.

The only hope are you guys, specialized in what you do.
 
Ran the Autocom test again, stationary as always. This is what I got:

Maf-values
Idle (720rpm) 12,3g/s
1500 rpm 29.5g/s
2000 rpm 43g/s
2500 rpm 53,4g/s
3000 rpm 62,5g/s
These are indeed higher than the reference values TourerFan shared.

Air mass/stroke @3000rpm
Target 540mg
Actual 630mg

Egr position devation between -2% & 0%
Egr valve status continuously OPEN
EGR cooler bypass 100% when idling, when revving 0%

Tomorrow I'm gonna give a call to the tuner company, and ask did they blank the egr at all or did they do the removal only software-wise.

Also going to ask about deleting the DTC-banks. Just hoping they'd give me a honest answer.
 
Hope you get sorted soon

Sent from my C6603 using Tapatalk
 
Instead of looking for honest answers just ask them to reflash it to the original factory setting file and then drive it to see what DTC codes appear. You should get p2002 for the DPF but anything additional will be what's causing your issue.
 
So, I gave a call to the tuner company. They would charge me a good few hundred € for flashing it stock, so I thought I'd try everything else before that manouver.

They said, yes, the EGR-valve position is locked only software-wise and the EGR-related DTC library is removed. So I ***embled a blanking plate between the exhaust manifold & EGR-pipe. It made no difference..

Still wondering why the actual airmass/stroke is a lot higher than the target.
Also had a drive with maf-sensor disconnected. The car went to limp-mode as it should. But on limp mode there was no hesitation or stumbling to be noticed. Trying to get my hands on a maf-sensor which for sure works properly and have a go with that.

Otherwise I'm running out of ideas, so better start saving money for some re-flash/visiting the dealer garage..
 
Drop me a line, I can probably help if you can manage without your ecu for a few days.
 
F6HAD said:
Drop me a line, I can probably help if you can manage without your ecu for a few days.
Thx, I really appreciate your offer but I guess now it's a bit too late for that, as the car died properly this time while I was trying to perform a test drive. Afterwards I got the engine running (but very roughly), so the car got carried away by a local towing company, and is now taken to a Honda dealer service.

Now I'll just have to wait for the outcome of their tests. I'll keep you posted once I know something new.
 
I had a similar problem.

Turned out to be a poor electrical connection to the in-tank primary pump. Once this connection was re-made, everything was fine.

you have to remove the rear seat squab to get at the connections at the pump, but its easy enough.

Honda tried to renew the fuel filter and also the high pressure pump (they were fixated on this being the problem). Only when I intervened and asked them to start at the beginning of the fuel delivery chain was the problem then immediately spotted. Sometimes the simplest possibility is worth trying.

Cheers, Terry
 
Got a call from Honda today. They weren't able to get out any DTC's either. But when they did the fuel pressure test with HDS, the engine didn't reach the target pressure and stalled. So after all, the main suspect is the high pressure pump.

It's worth serious money.. completely new unit from Honda costs about 2200€. But they also think it's a very hairy price, so they are now seeking for a rebuilt one from Bosch via their contacts. The price should settle around ~1000€.

I know I could find one from Ebay or Japan for a cheaper price, but as it's not 100% sure that the pump is the cause, I'll hand the part purchasing process to them.

Just have to wait and see.
 
I've had an idtec in with a failing fuel pressure relief valve that had similar symptoms. I would suspect that first. We changed the whole fuel rail from another donor car.
 
F6HAD said:
I've had an idtec in with a failing fuel pressure relief valve that had similar symptoms. I would suspect that first. We changed the whole fuel rail from another donor car.
Actually, I also mentioned them about the relief valve, but they seem to be fixated on the hp-pump, just like in scotsgent's case.
 
Some update. So, first they changed the high-pressure pump. It made no difference. Next they changed the in-tank pump, which also has somekind of "rough filter" built in.

After this, the problems with low fuel pressure were fixed, but the engine was still misfiring and hesitating. Now they've spotted that the injector of cyl. 2 drops out of range when the engine is misfiring.

So it has been pretty complicated. Now we are waiting for a new injector. Hopefully the engine will finally run correctly after they change it..
 
freddofrog said:
Surely they should have found that the first time they connected their HDS :eek:
That's what I'm thinking too.. I Guess at the beginning they were just concentrated on the pressure test, rather than having a decent test drive with live data.

Though, I think that one faulty injector doesn't "kill" the engine for 30mins like in this case. So, the reason could be both, the injector and the primary in-tank pump.
 
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