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Old 10-14-2011, 11:16 AM
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bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
Join Date: Mar 2008
Posts: 25,236
Mein Auto: 02 BMW 525i M54 auto 130K
Originally Posted by doru View Post
I can bet a few dollars you will not find anything.

I don't disagree with you on the fuel system testing ... but ... at the very least, we'll get a nice simple DIY for testing the fuel pressure ... since I don't like to replace things (like the fuel pump and fuel filter) until/unless I've diagnosed them as being bad.

Bearing in mind I use the cheapest gas I can find (at the lowest octane I can get away with), my injectors may very well be clogged!
- What is the cost differential between 87 & 91 octane AKI (1)

The main thing I don't like about getting injectors serviced is I'd like to 'know' they're bad before sending them out. So I'd want to test them first. Somehow.

Plus, you don't even get 'your' fuel injectors back when you send them out.

I researched testing (thanks to Franka) and it's pretty complicated:
- Decent Techron thread

Originally Posted by bluebee View Post
BTW, one thing that came to me loudly and clearly after reading the Witchhunter site was that cleaning a fuel injector is a lot more than just dumping a can of snake oil into the fuel tank every 3,000 miles!

The site says that "effective" cleaning can not be done while on the car, which I would tend to believe.
... stuff deleted ...
Here's what the FAQ says, verbatim, on exchanges:
Why doesn't WitchHunter Performance offer an injector exchange service?

We only clean our customers injectors, that way you know what you are getting. Some companies buy old used injectors by the truckload, use minimum wage labor to clean the injectors that work and throw the rest away. So you may be getting one with 30K miles and some with 400K on them in the same set. It is common practice for these places to grind off the original part number and give you an injector that flows "close" to your injector.

So, what I gather from this is the following assumption:

- You give them YOUR injectors
- So does another customer, and another, and another
- They clean and test YOUR injectors (and that of the other customers)
- If any of yours need to be "replaced"; they take them from the other customers' injectors

I guess what they do not do is buy injectors in bulk and use them for the matching - but apparently they do use other customers' injectors to substitute when the need for matching arises.

Do I have the basics of "matching" understood yet?

Originally Posted by doru View Post
carb cleaner around the fuel rail. If the rpm climb, you have bad injector O-rings
Great idea! I love TEST procedures (I hate to replace anything, willy nilly!).

Originally Posted by doru View Post
inspect carefully the boots of the coils for each sparkplug.
When I recently replaced my spark plugs, all looked good.

Plus, I have 'lean conditions"; not misfire conditions, per se.

Last edited by bluebee; 10-14-2011 at 11:21 AM.
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