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2004 i-CTDI low MPG

H Peasource said:
That said I too don't believe that the vibration is the cause of the fuel consumption issue. It could contribute a bit but not that much. I'm still struggling with why this engine is not producing a huge smokescreen.
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On a partuclar make of French N/A diesel from the 80s/90s, it was not unusual for people to replace the head gasket, and put the timing belt back one tooth out. The engine would run but without any serious symptoms, apart from vibration, loss of power, and reduced mpg. I believe that the valves would not be damaged on that engine, and redoing the timing belt properly would correct the problem.

***uming that if someone has previously worked on Natasha's diesel and put the camshaft one tooth out on the chain, is it also possible for the engine to run without damaging the valves ?

Also, if any 4-cylinder engine runs on only 3-cylinders, you would also get vibration, loss of power, and reduced mpg.

As the Accord engine is a bigger diesel turbo, if the camshaft is a tooth out, or one cylinder is not running properly (poor valve seal) then maybe loss of power may not be so apparent ?
 
Well I don't think chain is one tooth out I think it's just stretched badly, same was on my 2005 Accord but I also had noise and slight loss of power but no reduction in mpg.

But I now I start to think that I can actually have loss of power I just did not realized that from the start as I was driving 2.0 automatic Passat.

Thanks for explanation, I just did not realized that it's a flywheel.

Jon_G Thanks for proposal, let me think about that till next week.
 
Jon_G said:
H Peasource said:
I'm still struggling with why this engine is not producing a huge smokescreen.
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That's what I don't get either
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This link is very informative for diagnosis re different kinds of smoke from a diesel, though it doesn't give possible problems such as faulty valve timing or a bent/stuck valve in a cylinder.

If the valve timing is out, then I'd say that one would more likely get white smoke from the incomplete combustion. Possibly no smoke.

If an exhaust valve was not closing for some reason (bent?) then unburnt diesel will be going down the exhaust pipe, and again one would more likely expect white smoke, but maybe no smoke.

If it's a combustion/fuel issue causing such an extremely low diesel mpg, then excess diesel has to be coming down the exhaust, either as black smoke, or white smoke, or maybe as an imperceptible mist. Other than combustion/fuel issues, if such a low mpg was due to brakes or engine bearings etc, then something would be well and truly melted by now.
 
^and there's also the possibility of an incorrectly remapped ECU (as Natasha said in the beginning). If I'm not mistaken, these engines give multiple (2 or 3) squirts from the injector at the top of the compression stroke. If those squirts are too long, too many, timed wrong, then depending on which it is, you may not get any smoke.

Try flooring the accelerator in 2nd gear all the way to max rpm, see how it feels, look in the mirror for smoke.

If there is definitely no black smoke, then look for white smoke, and if there's no white smoke either, and the engine is vibrating, then it's either faulty valve timing on all cylinders, faulty valve closure on one cylinder, or faulty injector timing (ECU). Any of those would also give a lack of power.

As before, If it is a combustion/fuel issue causing such an extremely low diesel mpg, then excess diesel has to be coming down the exhaust, either as black smoke, or white smoke, or maybe as an imperceptible mist.
 
Although the exhaust could be emitting white smoke, i.e. unburnt diesel, I hope this would have been mentioned. Even if the smoke itself had not been noticed the appalling stench of diesel fumes is very hard to miss.

The real trouble we have here is the lack of hard data. Ideally I'd like to see the results of a compression test, confirmation that the injectors have been put on a test rig and their spray patterns confirmed as OK, injection correction figures from a good scanner and a cam/crank synchronistion oscilloscope trace.
I am beginning to wonder if this engine has mechanical damage, for example worn bores, a bent conrod ,valve troubles or worn cam lobe.
 
^ yep, 100% comvergent thinking there Alan.

And, one quick way to find out if it's just one cylinder causing the problem, try disconnecting the electrical connector to each injector, one-at-a-time. If it is properly running on only 3 cylinders, when you disconnect the injector pulses from the faulty cylinder, you won't notice much difference, but you will on any of the other 3.
 
You need to be careful disconnecting injector wiring on a running CR diesel for two reasons. Firstly, on many systems the ECU will detect the open circuit condition and shut down the engine. The other issue is that these injectors don't operate at battery voltage but typically at around 80 volts. Both issues can be got around but it is not as straightforward as disconnecting injectors on a petrol engine.

The ugly thought going through my mind is that the engine may have ingested some water, suffered a hydraulic lock and bent a conrod or two.
 
I guess you're correct, I've only ever done it on petrol engines.

A bent conrod would explain everything
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Some news but they are not great. Chain replacement did not solve a problem. And we are sick if trying...

So we bought a crashed Accord with good engine and are going to change the whole engine with gearbox, flywheel, turbo, rail, car converter etc. hopefully that will sort a problem. If not it will be only ecu problem. And does anybody ever changed ecu on accord? Do you really gave to go to dealer to code that?

Oh yes, just to note. Car has much more power now and vibration is gone. Still no smoke, so all other signed have dissapeared, we are left with pure high fuel consumption.

Just one more thing to say. This morning started cold and was driving hard car lost power and glow plug light came on. Diagnostic read P1237 fault, after clearing error no problem at all.
 
If there is no smoke from the exhaust, is there any sign of diesel coming out of the exhaust (excess diesel has to be going somewhere).

Also, compression tests on the cyclinders should be easier than replacing the engine.

The ECU can be recoded for a different key, but if you have both the ECU and the key from the crashed car, why not try both those in your car before swapping engine, although to use the key from the crashed car is not straightforward for obvious reasons. I've never taken the stearing lock off an Accord, but I have on other cars. It might not be difficult, but its an added complication that might not be a good idea ....anyone got a better idea ?
 
Natasha, you did suggest that maybe the fuel rail pressure sensor might be worth changing. Maybe you should try the one from the crashed car?

Sorry it's still not working better after all this effort.
 
Sorry to hear that the chain didn't solve the problem. I was hoping it will, because also my accord has a little chain noise and I thought that by changing it, will resolve my low fuel consumption as well.
I also suggest It worth to try to change the MAP and MAF from the crashed Accord. I still believe that since the car has power and runs ok the problem comes from some sensors or something related.
An engine that is damage with bent conrods or valve issues will not have power and will heavily smoking and also oil usage would be very high.

Though I have a new suggestion that I need to do it also on my Accord, is to verify the fuel pipelines that takes back the fuel into the tank, maybe they are clogged.
Is it possible ? And how can those be checked ?
 
baxy said:
Though I have a new suggestion that I need to do it also on my Accord, is to verify the fuel pipelines that takes back the fuel into the tank, maybe they are clogged.
Is it possible ? And how can those be checked ?
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It is unlikely that these return lines could be clogged, as they are fed from injectors and the relief valve which are connected to the fuel rail which runs at over 20,000 PSI. A blockage would therefore result in pressure building up towards a very high figure, which would either shift the blockage or result in a leak, which would become obvious (given the volume of fuel that you are looking to account for).
 
The point that's being missed is that if fuel consumption is low, then engine efficiency is low, which means either:

1. fuel is being burned as normal, but a lesser amount of heat energy is going into pushing the piston down, because more heat energy is being lost into the walls of the cylinders (usually engine running too cool)

2. fuel is being burned as normal, but a lesser amount of heat energy is going into pushing the piston down, because more heat energy is being lost into the exhaust (e.g. exhaust valves opening too soon)

3. fuel is being burned as normal, but energy is being lost between pushing the piston down and getting to the wheel (e.g. crankshaft issue, or brakes issue, but these would have melted by now).

4. fuel is not being burned as normal, so unburned fuel is coming out of the exhaust either as smoke or mist (e.g. faulty injector timing, valve issue in one cylinder).

It can only be one of those four things causing excessive fuel consumption.
 
This is a guess but I would imagine there is a timing issue on the exhaust cam as others have suggested.. low power / high fuel consumption means loss of compression somewhere ...

Get a compression test done as lets see what the results are :)
 
freddofrog said:
The point that's being missed is that if fuel consumption is low, then engine efficiency is low, which means either:

1. fuel is being burned as normal, but a lesser amount of heat energy is going into pushing the piston down, because more heat energy is being lost into the walls of the cylinders (usually engine running too cool)

2. fuel is being burned as normal, but a lesser amount of heat energy is going into pushing the piston down, because more heat energy is being lost into the exhaust (e.g. exhaust valves opening too soon)

3. fuel is being burned as normal, but energy is being lost between pushing the piston down and getting to the wheel (e.g. crankshaft issue, or brakes issue, but these would have melted by now).

4. fuel is not being burned as normal, so unburned fuel is coming out of the exhaust either as smoke or mist (e.g. faulty injector timing, valve issue in one cylinder).

It can only be one of those four things causing excessive fuel consumption.
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I agree. The trouble is there are so many possible causes and without the data we can only guess. Let's see the results of a compression test and have confirmation that the injector spray patterns have been properly checked.

Changing things in the hope that it will cure a problem usually turns out to be a slow and expensive solution.
 
baxy said:
Though I have a new suggestion that I need to do it also on my Accord, is to verify the fuel pipelines that takes back the fuel into the tank, maybe they are clogged.
Is it possible ? And how can those be checked ?
Click to expand...

As Jon has said this is unlikely. Even if they were the result would be an engine producing more power than it should for a given accelerator position rather than poor fuel consumption.

By the way, I've seen a couple of diesel engines that suffered bent conrods as a result of hydraulic lock. Neither burnt oil. The only symptoms were a degree of vibration, white smoke (unburnt diesel) from the exhaust and poor performance/fuel consumption.
 
Any pics of this car? just so as we know we're all not jumping on the "mystery bandwagon" :huh:
 
I had a problem like this many yrs ago on a volvo i had. turned out i was loosing fuel no patches on drive only found out when car was on idle one day when left phone in house. Fuel only leaked when car running. Im also with mr Honda here any pictures as this must be costing a small fortune :unsure:
 
FUN!!! I will post pictures tomorrow or day after tomorrow will do mine and the crashed one as well.

Some update:

P1237 came up again when flooring pedal and glow plug light is flashing. Car goes into limp mode and has no power. The highest speed I can get then is 60 miles. But after resetting errors on computer everything goes back to normal.

The possible cause is:
1. that we broke EVR sensor on top of the engine when was removing injectors.
OR
2. we noticed that flap on turbo is not moving when you accelerate.

We will change EVR tomorrow when crashed car will arrive, so will see.

If it's not I'm afraid that we will never find out the problem as we are going to replace the whole engine with everything (turbo, evr, map, maf etc) as we are sick of guessing and trying.
 
P1237 might relate to boost pressure lower than expected... http://www.micro-tronik.com/faultcodes/obdiifaultcode_p1237.html
 
As some of you recommended the compression test, I've just been at the local Honda Dealer for one.
On all cylinders the compression was between 29 and 30 bars. The test was done while the engine was cold. They told me the engine compression is very good.
I still think to believe that my high fuel consumption is sensor problem or something related.

The quest continues...
 
I've been watching this post with keen interest. I too own the 2.2 i-ctdi Sport version, and my MPG ranges anything from 33-42 MPG. (I routinely get about 370miles to 42Litres, but this has been declining recently)
I'm not clued up on cars like most of you on here, but it has been giving me ideas to check out on my own vehicle (which has 167k miles on the clock).

Just wondering if any of you use apps such as Torque or droidscan, and how useful they would be to give further clues as to whats going on? Whats expected ranges for MAF/Boost etc at say 2000 revs?- I know that Honda would be a better bet for their diagnostics etc, but with Xmas coming up, can't afford to be robbed blind (out of curiosity, for those that have used the dealers services, what £££'s are we looking at for Compression testing etc?)

Thanks
 
I think its ridiculous to expect 60 mpg from this car.

The absolute highest I've seen on the trip computer is around 55 mpg and that is factoring in the fact that mine is off about 10 mpg.

I average about 30-35 mpg around town and 40-45 around the highway depending on how I drive.

This is confirmed by data from spritmonitor.de and it seems like its what other i-ctdi owners are also getting.

Not sure why anyone would expect 60 mpg over any kind of normal journey.
 
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