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121

Omega General Help / Re: Error codes 0170 & 0173

« on: 09 November 2008, 17:36:28 »

OK fuel filter will be changed on Monday and codes cleared again.

I just checked the top panel of the fuel pump, cleaned it off, cleaned all the contacts with cleaner and checked that there were no leaks at the junction between the flat plate and the metal 90^o elbow bends. There was a little surface rust, but I cleaned that off and all looks good.

I'll post again with reports after another thrashing with a new fuel filter. What I need to try to achive now is a code 0420 and/or 0430, but no 0170 or 0173 over a period of a few days.

Once I can do that then I can start thinking about moving the secondary O2 sensors back to behind the main cats and clearing the codes.

Then it is another re-test.

Is there anywhere under the bonnet that I should be looking for fuel / air leaks?

JamesV6CDX and I had the plenum off and he re-sealed my cam-covers for me and replaced the cam-belt, water pump and rollers, whilst I cleaned out the plenum and breather pipes. All rubber seals were replaced and were checked for quality before use. The MAF/Plenum gasket was replaced as were both the big (arms thickness) rubber hose elbows which are jubilee clipped to the front of the throttle body /  plenum.
We also changed the plugs (the dealer gave me those 4 point plugs). We changed the HT leads too.

Air filter is less than 500 miles old and the box is perectly sealed. Oil and oil filter less than 1000 miles.

122

Omega General Help / Re: Error codes 0170 & 0173

« on: 09 November 2008, 08:10:54 »

I would say change the fuel filter if it's not been done recently.

Oh, and I reckon the cat codes will be back in a day or two.

At least it looks like the fix will work. Just got to find out why the fuel trim problems now. I would say fuel pressure won't be a problem at idle because it was winding up the fuel trim under load. Measuring the flow rate from the return from the rail would be a useful diagnostic step if the filter doesn't help.

Kevin

Is this what you were talking about when you were here (i.e. a garage can check the pressure) or is this something different?

How can I measure this accurately?

EDIT: Kevin, would a damaged secondary 02 sensor on ONE side possibly cause a fuel trim error on both sides simulataneously? I ask becasue when I was moving the sensors back to the original position yesterday I noticed that the sensor on the near-side bank was a bit scratched just inside the thread (slight flaw in the o2 sensor boss on the new SS exhaust which is now fixed with a round file). The end point where the actual sensor hole is was fine, but I am just checking. I suspect that it is unlikely and we should be looking or something that is common to both sides, and "pre-combustion", due to the symetry of the errors.

123

Omega General Help / SHOCK HORRER!!!

« on: 08 November 2008, 17:55:40 »

Now here's what I was not expecting.

Sensors in the standard postition and all codes cleared. I take the car out for a good thrash and keep the foot down and ...

wahey the EML light re-appears...

0420, 0430 you're thinking?

Nope :-/

Bloody 0170 and 0173 again.

Now that points me back to low fuel pressure, dirty filter, lazy fuel pump or air leak.

On the other hand, that still leaves the distinct prossibility (probability) that moving the sensors did work, because I haven't had a single 0420 or 0430 whilst they were back there.

So I need to solve these 0170 & 0173 fuel trim issues on both sides 1^st then once I have that settled then I need to start looking at moving the O2 sensors back again.

Or is there some possibility that after having the codes cleared (Cheapo TechII) that there was some residual effect of the "long term fuel trim" readings left in the system that has caused the recurrence of the fault code? All he did was "CLEAR ALL DTS CODES".

Any ideas on where to start? I suppose it is the same answer(s) of "change the fuel filter" and then "get the fuel pressure checked" isn't it?

124

Omega General Help / Re: Error codes 0170 & 0173

« on: 08 November 2008, 12:31:42 »

Sensors now moved back and codes cleared.


Let's see where we go from here...

 

Any bets? Ill have a pound on...
 No fuel codes, back to cat codes.

No bet from my end I'm afraid as I'm pretty damn sure that's what'll happen too. I know this is resolvable though and I will come up with the final solution.

125

Omega General Help / Re: Error codes 0170 & 0173

« on: 08 November 2008, 11:08:58 »

Sensors now moved back and codes cleared.


Let's see where we go from here...

 

126

Omega General Help / Re: Error codes 0170 & 0173

« on: 08 November 2008, 09:18:13 »

will you change the fuel filter first? Or after. I suppose if you move the sensors and you have fuel trim AND pre cat codes then... You have a fuel issue? If just a the cat code then the position is relevent to fuel trim...

I'm going to move the sensors 1st, so as to isolate each change. That way I won't muddy the waters at all whilst trying to analyse the root cause.

Like you say, if the 0420/0430 & the 0170/0173 all occur when I hve moved them I can then look at fuel filter.

I also need to get the fuel pressure checked, but I'm very confident that that is good and also that there are no air leaks. Reading Kevin's posts above I think that we have eliminated those anyway in a process of his logical reasoning.

127

Omega General Help / Re: Error codes 0170 & 0173

« on: 08 November 2008, 08:26:52 »

watching with interest gents...

can the ecu be re-mapped/hacked to give the correct fuel trim with the 02s in the current(behind big cat) position? Is it a set value or does it "learn"?

As said, interesting to see if problem swaps when 02s returned to original location.

As stated I will be "testing" as of later this morning, but if it transpires to be that the movement back to behind the main cat causes the fuel trim issue then I am considering two options:

• An ECU remap / hack as suggested, but I consider this to be a bit over complex and perhaps expensive.

So, working on the principle of Okham's razor...

• On reading the link that Kevin Wood posted (Click Here) it seems to me that the fuel trim acts based on the voltage sent back by the secondary O2 sensor. I have an idea which might counteract this: If I were to add a peice of electrickery (I can't remember what they are called, I know it isn't a resistor because that would constantly reduce the voltage, but there is such a thing that "clips" the voltage to a certain amount), this should, in theory, then allow me to stop the higher voltage being sent back to the ECU from the O2 sensor. If the O2 sensor sends more voltage back on higher emmissions then this should work against the 0420/0430 issue with the sensors in the original position, if it is the other way round and voltage sent from the O2 sensor increases as the air in the exhaust is cleaner then this should work agaisnt the fuel trim issue 0170/0173 when the sensors are moved behind the main cat.

I hope that makes sense. I just need to test 1^st by moving the sensors back today to be sure about where we're at at the moment and then take it from there with an electronics wizard when I can find one.

128

Omega General Help / Re: Error codes 0170 & 0173

« on: 08 November 2008, 07:01:39 »

I am moving my sensors back to their original position this morning to establish root cause. I'll be clearing tthe codes and will be able to confirm whether my current 0170 & 0173 problem is then replaced by 0420 & 0430 again in the next few days.

I am building up quite a case of evidence on sorting this 0420 pre-cat isue and I WILL FIX IT, but the movement of the secondary O2 sensors has co-incided perfectly with no further 0420 codes and the start of the 0170 codes.

129

Omega General Help / Re: Error codes 0170 & 0173

« on: 04 November 2008, 19:25:40 »

Rather worryingly, I have just found this:

http://newsgroups.derkeiler.com/Archive/Rec/rec.autos.makers.honda/2005-12/msg00732.html

It suggests post-cat Lambda sensors can have an influence on fuel trim on certain engine management systems whereas previously we assumed they were only to monitor cat efficiency. I wonder if relocating them has upset something? :-/

Have you noticed any change in fuel consumption since relocating the Lambda sensors?

Kevin

Yes fuel consumption is Sh!t now :-/

I used 2/3 of a tank going from Bedford to Worcester and back again!

I reckon it looks like the secondary O2S may have to go backto where they were again. What other optons are there? Can the ECU system be remapped so that the O2S sensors are less sensitive and therefore stop complaining 0430 stylee that the pre-cats are tired?

Do you reckon I should consider replacing the pre-cats?

TBH, where I'd really like to get to is to de-cat the car completely and then only refit the main cats on MOT day once a year, but not at the expense of fuel consumption.

What sort of place does this sort of bespoke remapping on a OBDII DBW engine?

130

Omega General Help / Re: Error codes 0170 & 0173

« on: 04 November 2008, 07:41:20 »

Thanks Kevin,

I'll change the fuel filter this weekend and try to use some motivational management techniques on the pump.

If the fuel filter change doesn't work, what's the next step? How can I diagnose the fuel pump before going to the lengths of replacing it?

I'll get the fuel pressure checked at a garage like you suggested, but I'll wait now until I've changed the filter.

I've seen the maintenance guide on changing the fuel filter, but that's on a 3.2 estate. Is it pretty much the same with a saloon? Do I need to do the "remove the fuse whilst the engine is running" bit that it mentions to drain the fuel lines 1st?

Fuel filter change (Estate) http://www.omegaowners.com/forum/YaBB.pl?num=1177279323


Fuel pump plate renewal http://www.omegaowners.com/forum/YaBB.pl?num=1186065848

131

Omega General Help / Re: Error codes 0170 & 0173

« on: 03 November 2008, 20:44:30 »

No problem. Was nice to meet you earlier.

Hmm. :-/ Thinking about it, more flow through the exhaust should mean more flow through the MAF which would mean the ECU would give you more fuel anyway, without extra fuel trim.

Long term trim for both banks seemed to be pegged out at +24% and at times under load it was adding another 10% short term. At idle the total trim was only a few percent. Makes me think it might be an air leak or a fuel delivery problem.

I think I will compare live data from my car to that snapshot. See if anything jumps out as being different.

Kevin

I don't suppose you had a chance to check your readings on your car did you?

I was wondering; do you think that it could even be a very dirty fuel filter?

132

Omega General Help / Re: Error codes 0170 & 0173

« on: 02 November 2008, 18:09:36 »

Right; post rejuvenation:

TB helped me to clear the codes and replace the EML bulb this morning and then Kevin Wood just popped round with a Tech2 this afternoon.

I had some "Intermittent Trim" (0170 & 0173) codes in the 45 mile run home from Jaime's, but the EML light hadn't been triggered.

On a run we checked the live feed with the Tech2 and Kevin Wood. My immediate trims seemed to be running in balance accross either side of the engine at around the 7 - 10% rich i.e. having to compensate by putting extra fuel through. The "long term" trims were up by 24% on both sides.

This seems to be the engine feeling the need to pump more fuel in than the normal trim level.

Possible diagnosis:

Too much air:

• Air leak (as this is consistent from side to side it would need to be quite close to the plenum)
• Better flow through the new stainless free flow exhaust

Not enough fuel:

• Dirty injectors (I'll try some cleaner fliud in the fuel, but I am quite frequent with this)
• Low fuel pressure (I'll get this checked at a garage)

Kevin and I realised that it could be that the free flow exhaust is giving improved air flow and therefore the 3-bar air flow regulator might simply not be man anough to keep with the improved air flow up as standard. Taking that further we felt that it might be worth (after checking for air leaks and cleaning the injectors) that it might be worthwhile considering a 4-bar fuel pressure guage to up the pressure in line with the increased air flow created by the upgraded exhaust.

Car is running like a dream though.

I'll keep the post posted as it were.

Once again, many thanks again to Jaime and Kevin for your help today; much appreciated.

133

Omega General Help / Re: Error codes 0170 & 0173

« on: 05 September 2008, 19:21:56 »

Thanks blokes.

What is my best next course of action? (apart from the EML bulb)

134

Omega General Help / Re: Error codes 0170 & 0173

« on: 01 September 2008, 16:53:31 »

That graph looks great, but what software would I need to be able to read the file and turn it into a graph.

And what does the graph actually mean?

135

Omega General Help / Re: Error codes 0170 & 0173

« on: 31 August 2008, 22:31:49 »

Thanks TB; pleasure as always.

Nathan