Could VANOS be guilty?

[coolbear1]

Hey Guys,

Have a problem with my wife's 93 e36.
The car has 250,000 miles and has been fairly trouble free for a long time, but recently It has been missing and loosing power from 1500 to 3500 rpm. The car idles fine and smooths out after 3500 rpm.
The compression is 185 lbs. (+/- 5 lbs.) on all six cylinders. The fuel pressure is 44 lbs. at the fuel rail. I installed new Bosch Platnum +4 Plugs and torqued them to specs. There are no vacuum leaks.

I am begining to suspect the VANOS unit.

Any thoughts or sugestions would be appreciated.

[dfrost]

I'd suspect the Platinum +4 plugs. There are many reports of problems with those plugs in E36 motors. I liked the factory spec NGK plugs.

[coolbear1]

Thanks for the reply David!
I'm sure you are right on.
I had no idea the Bosch +4 plugs had such a bad reputation. After your responce I searched the thread for Bosch +4.
Why in the world would a company with such a good reputation put such a product on the market, and worse yet allow it to continue.
I am pretty upset with Bosch.
I Just this morning purchased a set of NGK plugs.
I will definatly send Bosch a nastygram with a link to my thread (with Pelican Parts OK).

David, Thanks again.
I will post an update on the plug replacement, and any (if any) response I get from Bosch.

Randy B.

[Jeron]

I've had two very bad experiences with Bosch, one I posted about in this forum. But I'd be surprised if installing a new set of Bosch+4's would cause the problem you described.

Were you having any problems before the new plugs? Did you make sure to replace the ground wires on the coils? How certain are you you have no vacuum leaks?

[coolbear1]

Jeron,

If I had not done the repair today myself, and driven the car after I was finished, I would have a hard time believing that a brand new set of platnum spark plugs, designed for my car, could have such an adverse effect on the performance of an engine.

BUT NOW THE CAR RUNS GREAT, with the NGK plugs!!!!

The Bosch plugs I removed were burned and fouled.

By the way, the plugs I replaced today turned out to be +2s, with maybe 500 miles on them.

I bought them to replace +4s that had around 10,000 miles on them.

This all came about because I was inspecting the head looking for vacuum leaks that might be causing the problem I mentioned in my first thread.

When I removed the coils, I found a small amount of oil on the spark plug boots, so I decided to change the gaskets for good measure.

As I removed the +4 plugs I found them to be in poor condition. They where fouled and burnt. I just atributed it to the oil on the boots, and bought another set of Bosch plugs.

Won't happen again.

Thank you for the reply and the good advice.
Also thanks again to David.

Because of you guys I didn't go to alot of needless trouble and expense.

Even more important, I don't have to listen to my wife complain every day about her car running bad.

Randy B.

[Jeron]

Wow fouled plugs in 500mi is quick.

The story I never posted here was in my old 93 Sentra SE-R. I put Bosch Plat in back in 98-ish and they fouled in 3 months. I never figured it out it cost me about $100 for tow, diagnostic fee and plugs.

The other story is:
Sparkplug electrodes GONE

[coolbear1]

Jeron,

Your bad experiences that long ago, even though in a racing application, should have sent up a red flag to Bosch.

After all, many car technoligies are proven on the race track.

It puzzles me why they continue to manufacture the plug, they have to know how marginal it is. They must be making a lot of money off of that big hunk of platnum they put into the plug.

I'm going to drop Bosch a little note, and maybe since they don't recomend it for racing, I will suggest to them they not recomend it for highway use also!

By chance did you get some level of satisfaction out of them?

Randy B.

[Jeron]

No satisfaction, but I didn't bother asking.

The trouble I had back in 98 was not racing, just street.

The thread above was this summer. I just posted an update in that thread.