Just had new magnecor wires installed via the leaving the intake plenum alone method. Now running very rough and throwing the p1300 code, as well as p301/ p306/p304 codes. Has my mechanic screwed up the firing order? He's a good Porsche mechanic but unfamiliar with LR's. He looked at my wires and noticed the little ceramic? doughnut in the wire boot (of the old stock wires) isn't a part of the new Magnecor wires, and sugg. I may have order the wrong wires but me thinks thats just a design difference.

 

also just replaced plugs with new NGK Iridiums

 

First thing I would do is change out your plugs. I also tried the NCG Iridiums and my truck ran like ***. I went back to +4 Platinums and that cured it. I know a lot of folks that have had success with the iridiums, but I wasn't one of them. If you are throwing that many codes, your firing order is probably incorrect. Try switching the plugs first and see if that helps. If not, trace out your wires.

One more thing...make sure that all the plugs by the intake are connected. Not the spark plugs, but the electrical plugs. Your mechanic may have had to remove some plugs and maybe forgot to plug them back in.

 

I just went out and checked my engine. There is a gray plug that plugs into Bosch silver cylinder thing to the right of the intake...right on top. Yeah, I know that it has a name, but you can't miss it. There are 2 black hoses that connect to it...one hose goes to the intake and the other goes to the intake pipe before the throttle body. The gray plug goes in the back. When I replaced my head gaskets, I forgot to hook that back up and had the same symptoms.

 

Magnecor wires say SS25 200T. Mechanic says they're fitting very tight and may be the wrong ones. Anyone know if this is the proper part # for my '04?

 

UPDATE! Either the wiring diagram in my factory manual is wrong- or completley misleading!! The diagram provided in post #53 in the sticky "replacing your wires without removing IM" is VERY helpful in comparison to the small manual diagram. Will know shortly if the new wiring paths work...

 

Here is a picture of a the Wiring diagram.

That silver cylinder you are describing is the Idler Air Control valve. A silver multi plug does plug into the back of it.
- Dido on the NGK Iridium plugs. I put them in and they ran crappy. Sold them on eBay with less than 25 miles on them.
I have used Bosch Plat +4's which works for most people on here. And they give some extra ponies right after install.
Now I have installed the E'3 plugs which are advertised on the side bar.
I found the best price @ Summit Racing $5.99 each + I get them next day from Ohio.
http://www.summitracing.com/parts/ETP-E3-48/
I will see not with new O2 sesnors and new plugs within 4500 miles if my fuel economy increase slightly.




Here is the Idler Air control Valve.

http://cgi.ebay.com/ebaymotors/ws/eB...e=STRK:MESE:IT

Dave

 

I dont know if this helps but just because you use 8mm magnacore wires doeent mean all your problems will be solved. I have a 2004 that just blew up..yea 2004...i am not suprised as i have owned these LR's for over 10 years and know they are POS... But back to your problem... i have a 2005 volvo s40 with 48,000 miles we got. i started using premium and with in 1 month i got a misfire cylinder 3 code ...was pretty stumped and was going to replace the plugs. i went to my local dealer and explained the problem and he said super? use regular 87 octaine as described in the manual. Sure enough , yes it says requires 87 octaine petrol. I switched to 89 octain and my check engine misfire was gone within a week... i agree in principle with the theroy of quality 8mm wires but remember you are putting them on something thats already a POS....

 

Allright now I'm really confused. Re-routed wires using the good wiring diagram posted on these forums (not that dang user manual guide!) and am now absolutley sure the wires are correctly routed, and the NGK iridium plugs correctly seated with the wire boots pressed on correctly- and everything seemed fine for a few minutes of idling, no codes and smooth idle, but then- turned her off, waited a little while, then re-started to take her for a test run and BAM- blinking CEL light, rough idle, etc. I still drove her for about a mile, power seemed to be all there but still ran rough and that blinking light...
I'm certain all the wires and hoses are back in their correct places. What does that blinking light mean, and any guesses? One earlier was the NGK iridium plugs are no good, but could that really be it? Would they cause the blinking CEL light?

 

Misfire. Get a scanner and figure out what cylinder(s) its on.