I noticed that one of the exhaust pipes where darker than the other (have centre box replayced by staight pipes), smelled the exhaust from car at operating temp and on RH pipe no smell, just hot vapour. LH (darker one) smell of gas. Changed all plugs and noticed that LH banks plugs where a lot darker than RH. Especially the secound from firewall, but as said all alot darker.
Sadly enough, the smell is still there.
When at it I did check intake pipe for leakage, looked all right, also poured a injector clearner in and only 20l of gas...
No to the strange part. Car feels ok to drive? Maybe little higher consumption though. No check eng light! I will check breather on both banks as well as clean MAF, but that would affect both banks right?
Could it be that I have faultcodes but still no check eng? If so, it is time to buy an obd II reader! Thanks!
Cheers!
/Per

PS
I did search the forum but did not really feel I got an answer on the question.

 

Could it be faulty lambda sensor on the LH side? That could make the LH side run rich and leave RH side unaffected. It can run pretty rich (+20%) before you get a fault code. You could check the fuel trims on both banks with an obd2 reader.

BTW, how does the exhaust sound with straight pipes instead of the centre box?

 

+1 pn the need to do OBD logging ... and the sound bite

 

OK, just need to open the wallet for an OBD II device than.

Regarding exhaust system. Well just for info, the system is no set up, starting from Cat's: Straight SS pipes 2" instead of big box, org silencers going over the rearaxel and than full flow aftermarket before SS endpipes.
The car had only the rear axel ones when I bought it and that gave therible resonance at 60 mpa, and really odd noise. THan added the full flows before endpipe and this took away the resonance and gave a more clean noise/sound.
Vertict is that you can here exhaust note on full throttle between 2000 and 3500, strangly enaugh as I think the exhaust note gets lost in engine sound above 3500rpm . No haul or tiger roar as I want. Not even sounding powerfull. It's almost as if the car runs out of cam when you rev it (but it pulls hard ), it's the oposite of how my Alfa V6 2,5 sounded during full he he. However, for most normal running, 1500rpm-2500rpm cruising with window down, you can enjoy the V8 burble, but more bada-bada-bada than thud-thud-thud from a American V8.
Hope that gave you an idea? Thanks for the help all!!
Cheers!
/Pelle

 

Try adding a H or X pipe where the original big box used to be as close to the cats as you can get.

 

Sorry for the OT, but what exactly is the logic in putting the X (or H) as up front as possible? Most seem to recommend it just because they've heard someone recommend it back in the day. Some say the location does not matter, some prefer the crayon or paint method (put it where the paint on the pipe does not burn off anymore). Some say the crayon/paint method is actually used to determine collector length.

 

Hello again!
Looked at a lokal supplier for OBD II loggers, checked an iteam out but did not read anything about it being able to read fuel balance or how much correction the ecu have done itself for each bank? Is it only some of the OBD II that can give you advanced input such as that or is it something that all OBD II can? Could you maybe recomend any, preferably sold in EU . Would be really sad if I bought one wich does not show more than fault code... Maybe there is an add on to JTIS, laptop interface maybe? Please do enlighten me he he.

Just a comment regarding exhaust, is the x or H there to gain power or to make sound more cool. I have a hard time thinking that it would do any good for power as exhaust temp have droped much to that point. Theoretically, crosssection area will be twice for each exhaust pulse from x and out, but as there are so many cylinders firing really close, I would guess that the biggset power thief in these exhausts are header or lack of it with it's dodgy looking marin style exhaust thingy... Why didn't JAG do this right in the first place....
Cheers!
/Per

 

I have one of these and it will show long and short fuel trim -
UltraGauge Automotive Information Center and OBDII Scan Tool

 

LOL! because the chassis was designed for a long thin straight 6. They then squeezed the V8 in, with it's marine diesel manifolds

OBDII I can recommend a memoscan for fuel trims.
U581 Diagnostic Fault Code Reader Scanner Memoscan CAN OBD2 | eBay

 

Perfer further from the cat as possible, if not using the crayon/paint melt method

X-Pipe balances exhaust pressure between our engines left and right cylinder banks. The result is better flow compared to "true duals.

That is why the crayon/paint method is so important, its melts at the point where both banks pulse are balanced. Which is the hottest point of the exhaust after the Cats.

Also it is quietier and more of a suble tone than a low roar roar roar roar.

A good example of this is to remove the exhaust at the cats, you will hear each back pulsing unbalance.

You can keep adding extention pipes to each bank until you hear a nice balance tone and thats where you intall the x-pipe.

SGB.

 

That sounds like the best approach of all.

 

Hello and good morning to EU, night to US .

Back to topic!
Well, I bought an OBDII reader from a local car retailer, it was stated to be prof type . It did show a lot of different data streaming... Anyway. No faultcodes at first, enigine at ideal, but than when streaming all gauges went funny. Looked at lambda volt, both showed fluctating voltage and as said no codes connected to that. Turned ign off. Unplugged OBDII, started up, no codes, but when out on way I noticed the never felt before, restricted power. Turned in, ign off, hocked up, turned on, got P1642, erased, run again. FUll power again! Puuh. But, still the exhaust smells like gas from LH bank...
So, basicly no idea. Will need to check the fuel trim data and see if I can find it and just continue.... . Could it be that lambda sond is broken but still shows values, I basically, it must be an upstream problem, as plugs are black. I was thinking about cat, but than plugs would not be black...
As said before, any help/xperience would be appriciated!
Have a splendid Saturday all!
Cheers
/Pelle

 

Think I found it now!
I had a deeper look and filtered viewed signals, looking only on fueltrim and lambda volt. bank 2 showed that voltage was stuck on 0.30-40, fuel trim on stead 19.5%+. Going to change the sensor now and see if it fixes the problem. Will write to inform of outcome!

Little of topic, but tested to unplug the CATS on one of the fwd dampers, to push ECU into fault/firm setting. Wow, now this is how the car should feel. Frim on highway at about 70mph and none of that bouncing around (which I hate). Definatly going to build some kind of "breake connection to susp and warning signal to cluster" switch. ´Maybe throw in the steeing rack dynamic servo assistance also, to go from softy to stiffy .
Cheers!
/Per

 

There are two basic sensors controling fuel trim, that is the O2 and MAF. Each of the sensors tell the ECU to add more (rich) or less (lean) fuel. This is caused by a vaccum leak or bad sensor/s.

In your case, running rich, the value of air is to high on one back.

Make sure your airbox and tubing is on securely. When I had a fuel trim issue, founded out the air tube connecting to the top of the throttle body, the gasket wasn't on correctly.

Check the secondary air pump (comes on during cold startups). You can check that by ear, if you hear a load fan/sucking noise at cold start up, either the hose is off or broken.

Also, remove the throttle body, clean it while its off, but thats not what I'm getting to. Remove and clean the EGR valve, it is right below the TB. When I removed my, it was TOTALLY clogged closed with carbon. It is easy to remove and clean, make sure you don't damage the gasket, if it needs replacing do it. If not, you can reuse it. I had to use a flat head screw driver to chisle at it.

Check them and you find your running rich issue.

 

Hello! Changed the oxygen sensor yesterday and now the exhaust smell is gone and checked with OBD2 and it cycles as it should, with fueltrim at a much lower value. Good, that will improve my mpg values he he.
Thanks for the help!
Best regards
/Per