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106

Omega General Help / Re: Error codes 0170 & 0173

« on: 15 November 2008, 10:46:07 »

I've just had a long chat with a chap from a specialist garage that deals with this sort of thing here in Bedford.

He says that he thinks:

• It is unlikely to be a fuel pressure issue
• More likely a MAF issue
• The exhaust change will not be a cause
• The secondary sensors definitley do NOT affect trim, but only measure the pre-cat efficiency.

As far as he is concerned I need to bring the car down to him and leave it with him for the day to scan it. He wants to check the MAF sensor voltage and the grams per hour rate of the air flow too.

He's quoted me £50 for the initial scanning etc.


I had another chat with a mobile engine tuning chap and the first thing he said was have you checked the fuel pressure?

Any thoughts? (Kevin et al.)

Do you think that it is worthwhile to start to go down the road of investing in the 1st garage's time and investigations?

107

Omega General Help / Re: Error codes 0170 & 0173

« on: 14 November 2008, 18:50:01 »

so, as you (Kevin) where saying about the exhaust, if it is more free flowing, fuel trim would increase to get the mixture correct again...?

Well, not in an ideal world. :-/ In theory the MAF measures all the air that gets into the engine, so the ECU knows how much air is going in and knows how much fuel to add. A freer exhaust would result in more air, but the ECU would know about it so it shoudn't be corrected by fuel trim. It shouldn't have an effect on fuel trim but the fact remains that the fuel trim problem co-incided with the exhaust change.


EDIT: Abatross' exhaust does have a centre box (although I think just a single large box rather than two boxes?). It looked about as close to a standard system as you could get, TBH

Kevin

I've been offline at a customer site for much of this week so have missed out on these debates. Very interesting too.

As Kevin says, my exhaust has a pretty standard set up. The "single large box" that Kevin refers to is a single box with two seperate segments one for each bank. It is a 2 in 2 out box. The 2 banks' exhaust flows never actually meet as both through the centre box and the back box the pipes (flows) are through their own discrete flows.

I'm a bit stuck now, as I don't know what to look out for next. All air pipes are good.

If I want to get the fuel pressure checked, what do I need to do? Should a good mechanic / garage know what to do? What should the pressure be?

108

Omega General Help / Re: Error codes 0170 & 0173

« on: 12 November 2008, 19:23:03 »

http://www.obd-codes.com/trouble_codes/
The above link, which you may have seen on here before, from Entwood, gives seperate codes for lean and rich. So, are we "assumeing" your "fuel trim malfunction" is giving a rich mixture? Do your codes encompas lean and rich? Or does 0170 and 0173 mean something else. Yes the "trim" is out of limits but if its rich why is there not a rich code? or whatever.

On the Maf subject, i dont mean to be rude, but do you have a cone/oiled filter? They can oil up the maf (as you probably know tbh), is it worth cleaning the maf anyway just to eliminate it?

You will see also in the link, the site has its own forum. Might be worth a go...

And you probably mean coil packs in your list above rather than ht leads? A very minor, rather picky point...

No cone filter, just a new standard air filter. I think cone filters are $hite because they draw warm air (Put an oiled sports panel filter in if you must). Yes I do mean coil packs and they weren't changed; I just got away with myself a bit on the list.

As for :http://www.obd-codes.com/trouble_codes/

P0170 Fuel Trim Malfunction (Bank 1)
P0173 Fuel Trim Malfunction (Bank 2)

Come up simultaneously and Kevin has answered most of your questions above^^

Thanks for all your thoughts and input though, they are appreciated and will only add value.

109

Omega General Help / Re: Error codes 0170 & 0173

« on: 12 November 2008, 19:20:36 »

Is the vac pipe to the fuel pressure regulator on and ok?

Front end of it certainly is. Might well be worth lifting the plenum and checking the back end.

Kevin

I'll have to have a look to make sure when I get back from Newcastle. I suspect it will be this weekend. I won't need to replace any of the 'O' Rings etc will I as these were done when the cam-belt was done recently.

110

Omega General Help / Re: Error codes 0170 & 0173

« on: 12 November 2008, 04:46:21 »

My car runs sweet as a nut even straight after resetting the codes. :-/

I wish I could find out the root cause of this. Someone said to me the other day that "MAF units are always going on Omegas", but I never see anyone complain about it on here, so I don't know whether to takke that with a pinch of salt or not.

Genreal opinion on here,
Maf very rarely fails.
Im sure Jamie will agree when he sees this. And you have no Maf code?
Have the simple things been eliminated? have to say fuel filter would be one of them?(sorry, a bit of a low blow) air filter plugs usual service stuff. Just thinking if the fuel filter hash made a difference, have any other service items been over looked?

Fair question. I can't remember if I have missed something from this list:

• air filter
• plugs
• oil
• oil filter
• HT Leads
• plugs
• breathers cleaned thoroughly
• cam-cover gaskets
• plunum 'O' rings
• water pump
• timing belt
• coolant

All changed recently. Most of the big (timing belt related) stuff was done by JamesV6CDX.

111

Omega General Help / Re: Error codes 0170 & 0173

« on: 11 November 2008, 20:21:22 »

My car runs sweet as a nut even straight after resetting the codes. :-/

I wish I could find out the root cause of this. Someone said to me the other day that "MAF units are always going on Omegas", but I never see anyone complain about it on here, so I don't know whether to takke that with a pinch of salt or not.

112

Omega General Help / Re: Error codes 0170 & 0173

« on: 11 November 2008, 19:25:55 »

Bugger!  

0170 & 0173 on the way to work this morning. It's only a 4 mile journey and the EML light came on about half way there. After I pulled into the car park I switched the ignition off and then on again for the pedal trick...0170 and 0173 only.

I reckon this could be a combination of things. The fuel filter definitely made a difference.

What do you reckon next?  :-/

113

Omega General Help / Re: Error codes 0170 & 0173

« on: 10 November 2008, 20:44:29 »

I couldn't wait in all evening and not try, so I just went for a "pushing it" drive for 25 miles each way up the A1 and back.

No codes, not even an 0420 or 0430 as yet.

Considering that I got the 0173 and 0170 come up within 3 or 4 miles every time I had them cleared lately this is certainly an massive improvement so far.

I'll still stick to the plan.

114

Omega General Help / Re: Error codes 0170 & 0173

« on: 10 November 2008, 18:38:15 »

Ok, filter changed and codes cleared.

I drove it like a nutter for an extra long detour home of about 8 miles altogether. No codes recurring just yet, but I won't trust it until I've driven it a bit further.

I don't know if it's my imagination, but the car seemed about 20% more powerful today after the filter was changed. I booted it when I was driving at 30mph in the wet and the back wheels just kept spinning and jumping on and off the TC for about 200yds. It was great fun. The car seems to launch much more than it did.

As I said I have to drive to Gateshead this week so that is a good test. I fully suspect that I will get 0420 and 0430 again, but that doesn't bother me. If anything it is good because I am currently back where I started with regard to sensor positions etc. What I really want is not to get the 0170 and 0173 again.

I had a damn good look at all the various air pipes etc. and with the exception of the one which dissapears under the plenum, because I can't see it, and as far as I can make out all are confirmed as fine at the moment.

As for the suggestion to move the 1st sensors to behind the pre-cats, I agree with Kevin, there is very little point as it won't prove anything and won't reflect what a 3.0 cat section would be like anyway.

My intended sequence of next steps are:

• Carry on for now until I can confirm either way whether the 0170 and 0173 are fixed.
• Act further on 0170 and 0173 if necessary until fixed.
• Move secondary sensors to behind the main cats again and drive for a test period of 2 weeks or 500 miles whichever is sooner. This will test the 0420 and 0430.
• Then finally check out the resistance of the pre-cat to see if it is worth moving to a stainless steel set up with sports cats in the place of main cats only.

115

Omega General Help / Re: Error codes 0170 & 0173

« on: 10 November 2008, 08:14:28 »

Watching this thread with interest as I have exactly the same problem with fuel trim issues on both banks, and EML on, I changed the fuel filter a few weeks ago, interestingly I do appear to get the fuel reading from the MID eg range is giving me what is states around town. I have a GS 500 maxscan which I can reset and read the codes, but last time I reset the codes the engine does not like it at all, ad sounds like a pil of poo for a little while until it then eventually settles down, some folks may recall this from the Newent meet. May reset them again today and see what happens, and let you know.

Hi Mike,

What engine size do you have?

When you say you're getting the same codes, do you mean that you get 0170 & 0173 together?

I don't fully understand some parts of your post there. When you say that "interestingly I do appear to get the fuel reading from the MID eg range is giving me what is states around town." I'm unsure.

Could you clarify this bit for me please?

I'll be changing my fuel filter today, assuming they have one on the shelf at the Vx stealers of course, and clearing the codes.

116

Omega General Help / Re: Error codes 0170 & 0173

« on: 10 November 2008, 00:13:09 »

Will it matter if I have the fuel filter changed during this measuring/reconciliation process?

I think I might try to get the fuel filter done first, codes cleared and then go down to the petrol station.

Would that be the best approach?

117

Omega General Help / Re: Error codes 0170 & 0173

« on: 10 November 2008, 00:06:10 »

Thanks for all of that, I'll have a look in daylight tomorrow.

One thing might be interesting: Is average fuel consumption being accurately calculated by the display in the car or does it differ from what you're putting into the tank?

Kevin

Christ on a bike, now you're asking. I never take note of that; I can do now though.

I'll start soon. I'll run her nearly dry and then fill up with Super Unleaded, it should be in the next couple of days. I'll take note of the amount of litres put in, reset all the clocks etc. and then run her for a while, what say 3 or 4 days? I have to nip up to Gateshead this week, so that will give me the opportunity to fill up at least once or twice. :-/.

Then I'll take note of how many litres it is to fill her up again each time and a reading from the odometer and all the clock readings on the CID.

118

Omega General Help / Re: Error codes 0170 & 0173

« on: 09 November 2008, 23:48:38 »

Thanks Kevin,

Not sure I understand all that, but I'll have a go. I'm not sure what the throttle looks like for starters. :-/

What does the fuel pressure regulator look like and where will I find it?

After consideraton, do you still think that it can't be the increased flow (reduced restriction) of the new stainless cat-back exhaust?

119

Omega General Help / Re: Error codes 0170 & 0173

« on: 09 November 2008, 23:37:28 »

Received by PM...

Thanks as always Kevin.

Hi Nathan,
 
Hmm. Interesting thought. I guess you could. Only thing that might be an issue is that the single large cat might not get up to temperature as quick as the small pre-cat so if there is any monitoring of the warmup cycle it could raise a cat efficiency code. Given that the pre-cats are probably not working well if at all it might not be any different. There is always going to be a bit of "suck it and see" involved in this type of thing, but I'd say it might be worth a try. I'd certainly try a pair of 3.0 cats if my cats failed, put it that way.
 
Failing that, take out both cats and make up a pipe with a little sports cat each side. I wonder how much more restrictive the twin cat pipes are, if at all?
 
Kevin

120

Omega General Help / Re: Error codes 0170 & 0173

« on: 09 November 2008, 23:30:36 »

Kevin,

I've just PM'd you with this same question, but it seems to make sense to post it here as it is somewhat related:


First two assumptions:

Assumption 1:

• I get to the bottom of this fuel trim issue of the codes 0170 and 0173.

Assumption 2:

• Once I have done the above I have reverted to having the secondary 02 sensors behind the main cats and that this solves the original problem of 0420 and 0430 pre-cat deficiency issues.

Question:

• Would I be mad for thinking that I could actually fit 3.0 standard cat sections into my 3.2 exhaust system?

The reason I ask is three-fold:

The first two are Economy & Availability as the single cat sections are both cheaper and more readily available second hand.

The third is increased air-flow out through the exhaust system as I would only have a single cat on each side to contend with.