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        General >> Problems >> Hello and 1 DTC P0420
        
(Message started by: Kanary on Jan 3^rd, 2008, 11:31am)

Title: Hello and 1 DTC P0420
Post by Kanary on Jan 3^rd, 2008, 11:31am

Hello all
I visit your website for a long time because there is a lot of very interesting thinks about odb ;) Congratulations for the job []
I am Christophe, i leave in France ... and don't have a Scorpio :-X But i hope you will help me.
I own a Opel speedster atomsphéric 2.2L ecotec.

So i explain my problem.
My MIL appears one more time. At idle. No problem when the MIL lighted ... All was fine as each time.
Scanmaster and ODBKey tell P0420 DTC ! With is about the catalytic. But all is ok with engine management.

But few kilometers later, waiting at the Macdrive for a long time, the idle became bad. At the same time, the short fuel trim change to -14/-17%. Before it was around 0%. So it became too rich... It stay at these values and bad idle, but after pushing the throttle many times, it came back around 0%.
This appened similar last week and each time after stop at idle for a long time or when i started the engine after a 10 or 30minutes stop. So only when hot engine. Water coulant around 91°c minimum or plus.

My car is a little modificated.
I have no cat for 2 years and 1 O² simulator. The couple worked fine since.
I have no EGR valve.
I have changed my inlet manifold (not exhaust) 2.2L by the 2.4 inlet. Bigger volume and much power at high revs :P
But the DTC codes and trouble idle arrived just after changing the inlet manifold.

- My second catalytic lambda sensor is always below 0,3volt at idle or when runing so too lean.
- My first lmabda sensor turn around 0.4V to 0.8V. So seems ok.
- Usualy Short fuel trim at idle around -2 and 3% when hot. But it came back to -17% many times as i have explain to you :(
When running, it is always 0% or a little positive.
- Long fuell trim always around +10/20% when running but -6% at idle
Is anybody anderstand something !!

So need help please ??? ??? I don't anderstand why i have idle troubles and why i have P0420 DTC code :'(

Thanks in advance
Hope that Snoppy won't delete my post :-/ :)
Christophe

Title: Re: Hello and 1 DTC P0420
Post by Kanary on Jan 5^th, 2008, 11:44am

Hello
I am surprised. Nobody can help me ???

Christophe

Title: Re: Hello and 1 DTC P0420
Post by peteHull on Jan 6^th, 2008, 11:40am

Hi, This maybe a usefull suggestion as it seems to be a GM issue, Here is the link to the Vecra forum, they may be able to pinpoint your problem....

http://www.cavweb-forums.co.uk/

Hth

Pete

Title: Re: Hello and 1 DTC P0420
Post by Kanary on Jan 7^th, 2008, 5:59pm

Ok thanks for the answer Pete ;) I thought that nobody wanted to help me ::) ::)
I will try on the forum.
I have found about my DTC code. But not the idle problem.

Christophe

Title: Re: Hello and 1 DTC P0420
Post by TiberiuS on Jan 7^th, 2008, 6:07pm

It's not that nobody wants to help but Ford - GM are like chalk and cheese ;D. Pretty much everything is different, fault codes for Ford probably have completely different meaning to the GM ones.

Completely wild stab, as you have no cat, if it's OBD 2 and has both upstream and downstream lambda sensors, it'll probably trigger a 'catalytic converter efficiency' code, the ECU thinking the cat's dead. Sounds like the parts you've replaced have upset the balance and the ECU can't work out what's going on.

Good luck.

Title: Re: Hello and 1 DTC P0420
Post by Kanary on Jan 7^th, 2008, 6:54pm

I have found that my simulator is out of order.
I have almays the good 12V bifore but the simulator gives 0 to 0,3V only.

But for trouble idle is du to injection syteme. I think all ecu works with short and long fuel trim. A reach trim at idle is a pb which could happen on all cars i suppose and so my trouble idle.
Someone told me that it could be a leak in the exhaust system ...

Christophe