535I engine missing after tune up

[athflying79]

I used Bosch Platinum's with the 4 prongs...don't remember what they are called. Anyway, my car was idling like crap and hesitated when cold. I did the plugs, rotor, and cap....it runs much better now. Since I did it all at once, I can't contribute it to one thing or the other, but I haven't had any problem with the plugs. Next time around, I will go with regular plugs simply for the price difference.

[Robert K]

If I remember correctly, Bruno's site says the the 3.5 liter motor also likes the plug gaps opened up to .034 - .036. It has been found that the slightly wider gap promotes a better idle. If you decide to adjust the valves, I believe a slight change to a wider clearance has also been found to help idle. If memory serves me well, the stock clearance is .012 cold. The advice is to set them at .013. Hope someone can back me up on this because it wasn't listed on Bruno's site.

Grace and peace,

Robert K
1991 535i

[GS535i]

Do Bosch actually supply a silver electrode version of the W8LCR ( ie W8LSR, if they follow the same nomenclature)? I have used the 'silber' with superior results in both 16v and 32v 928s ( the 16v ones have 12 years on them! - and are still perfect).
I do have the Bosch +4s in the 535i, and they are fine - the M30 never hesitates idle to redline..... but a single silver electrode would be the first choice.

[1990535IM]

OK - I replaced the Bosch Platinium 2's with

W8LPR part # 6234 - not the W8LCR as posted - any spark plug experts out there know the difference??

Gapped at .030

I got my car back - No more miss!!! Plus the off idle hestiation is gone - rotor and cap were in bad shape.

Live and learn!!!!

Thanks all for the responses.

PS - Martin and Scott quit your bickering - !!!

[Kalevera]

Idle might be a little rough at .030; I run them around.

LPRs are platinum, versus the copper LCRs.

best, whit

[genphreak]

Its always nice to hear more than one opinion, even if they are the same. The PO installed platinum plugs in my car, and now with two people saying that the m30 doesnt like them, I will buy regular bocsh plugs.

Platiunums are supposed to last for ages... (according to Bosch) , I had to get mine, its all the shop had. My M30 has done 5k with them and runs fine (but I believe my consumption is high)... I only get 16mpg (15l/100km) around town, 23.5mpg (10l/100km) [that's US gallons, not English btw] on the highway. (cries) C'est la vie!

[Paul in NZ]

I only get 16mpg (15l/100km) around town, 23.5mpg (10l/100km) [that's US gallons, not English btw] on the highway. (cries) C'est la vie!

sounds about right to me