fuel systen cleaner

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martyb
Joined: Thu 10 Jan, 2013 16:53
Posts: 308

  Z3 roadster 1.9

fuel systen cleaner

Post by martyb »

After having a couple bottles of stp fuel system cleaner, I wonder how regularly should you treat your system?

The thing is I have a sticky sender gauge and each bottle about a thousand miles apart when added has increased the level the gauge reads but it's not quite fully clear yet. I'm wondering if there's a length of time or distance travelled to wait before adding another bottle.

Any thoughts gents?
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BonBon
Joined: Tue 08 Jan, 2008 21:10
Posts: 1227

  Z3 roadster 1.9

Re: fuel systen cleaner

Post by BonBon »

I recall that it should only be done once a year.
Have you tried a full tank of the highest octane available (say 98)?
martyb
Joined: Thu 10 Jan, 2013 16:53
Posts: 308

  Z3 roadster 1.9

Re: fuel systen cleaner

Post by martyb »

Yeah I run it on shell v-power which is slowly but surely showing results but the biggest difference was with a bottle of stp petrol cleaner I'm only 1/8 of a tank off having it sit on full when the tank is. If I got same result from another bottle I'd be there.
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Southernboy
Joined: Thu 07 Oct, 2010 12:39
Posts: 6436

  Z3 roadster 3.0i
Location: Johannesburg

Re: fuel systen cleaner

Post by Southernboy »

The problem won't go away...The problem is inside the tank. There is a curved coil of very fine wire, and a copper or brass finger which is meant to stay in touch with that coil, and dependent on the fuel level, it relates a current to the guage which is indicated as a degree of fullness.... That finger, is the culprit as it is attached to a wire arm with a plastic float at the end of it. It hinges in a plastic hole, and over time the hinge point has a little wear...this results in the finger losing touch with the coil...the solution is to remove the pump, and clean up the coil and finger, as well as very slightly bend it so that it is again always in touch with the coil....
I had this issue with my last Z3, and in spite of using injector and fuel system cleaner, I eventually had to do the deed.... A real PITA but the pain is soon forgotten as the years go by...and a guage that works as it should. I recall at the time considering the replacement of the entire sender etc, but at the price decided to have a closer look at it's workings... A toothbrush and some decent metal polish, about an hour of manual labour and you're good to go - permanently sorted - well for years anyhow... If you search eBay or google for a Z3 fuel sender assembly, you may be lucky enough to find a close-up pic of the offending coil / finger aspects.... The removal of the said item is done via a cut-out panel in the floor carpet against the back wall behind the driver side seat. The tank should be as near as dammit to empty before doing this job... if not you'll have a car full of petrol soaking into the carpet when you remove the huge screw on plastic holder.... I'm sure the task has been covered on the forum by others who have been through the removal / repair / replacement of this item... :wink:
"Normal is overrated"
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BonBon
Joined: Tue 08 Jan, 2008 21:10
Posts: 1227

  Z3 roadster 1.9

Re: fuel system cleaner / level gauge

Post by BonBon »

My luck... :head:
Mine just got stuck again on empty...
98 Octane which worked for me a couple of years ago only worked marginally now.
When did you add the STP petrol cleaner? to a full tank, half tank or close to empty tank?
Here is the follow up: http://www.zroadster.net/forum/viewtopi ... =5&t=41826
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