tii fuel pressure regulator help

[hiebertm]

I'm trying to sort out variable idle and misfire issues on my tii. These problems had become much worse since my electric FP died recently and was replaced w/ a rebuilt unit from Mesa Performance.

- So first check was fuel return back to the tank, it was much lower than expected (~100ml/30 seconds).

- Next was pressure, 70psi before and after filter instead of the expected regulated ~28psi.

- I pulled the regulator valve off the back of the kfish and it doesn't look obviously gummed up.

- The screen at the kfish inlet is clear, the reutrn line to the tank after the regulator didn't seem to have any blockages

Conclusion: the regulator valve is not opening... and therefore there is no recirculation and unreasonably high pressure in my fuel lines. I recently had a leak develop at the filter inlet, so I think that the regulator failed recently.

How do I test the regulator? Can I just use compressed air to check how many PSI it needs to open, and maybe blow out any garbage that's stuck in there?

The blue binders vaguely state that the "pressure maintenance valve may be stripped and cleaned" if pressure is exceeding 28psi, anyone have any insight into what that means or who I send it to? I've only unscrewed the valve from the kfish, I didn't pop out the clip and see what's inside there yet.

Mark

[JerryC]

I've never heard of anyone disassembling the pressure regulator so I think you're creating new knowledge for the shade tree types here if you do so. If you're choice is to get a new one anyway, what have you got to lose?

Wear a safety shield, there's springs in there. Aim it into a rag-lined box to catch flying parts, too.

[hiebertm]

I'm all for learning about the internals of parts of my tii, except that this particular part is NLA, as far as I know. So I'll wait a couple days to see if anyone here has any tips, and then I'll bug a professional tii guru to see if a used regulator can be found or better yet see if the professionals have any tips on reviving a bad regulator before I go crazy and pop out the internals of mine.

Rob @2002Haus should have a 1-900 number so I could call him w/ questions w/o worrying about wasting his time.

Regardless I'll post the outcome here once I get this figured out.

[jgerock]

I took mine apart and cleaned it using an Ultrasonic Jewelry cleaner. Make sure to cover the valve with a rag or paper towel to keep from losing the tiny clip that holds the piston and spring inside the fitting. Take your time and use (2) pocket screwdrivers to R&R the valve components. The valve components are pictured on page 137 of Mike Macartney's Restoration Guide book.

The Ultrasonic unit worked great for my injectors and the inlet screen fitting.

[2002haus]

I'm all for learning about the internals of parts of my tii, except that this particular part is NLA, as far as I know. So I'll wait a couple days to see if anyone here has any tips, and then I'll bug a professional tii guru to see if a used regulator can be found or better yet see if the professionals have any tips on reviving a bad regulator before I go crazy and pop out the internals of mine.

Rob @2002Haus should have a 1-900 number so I could call him w/ questions w/o worrying about wasting his time.

Regardless I'll post the outcome here once I get this figured out.

Thanks man! Jim Gerock has done some good work with his Tii. One of the new guys that has a clue as to whats going on and how to deal. Thanks Jim!

[jgerock]

Thanks for the kind comments Rob. Glad to be of help to others. For me, there's no better way to apply my Engineering background than to cars.

[2002haus]

Thanks for the kind comments Rob. Glad to be of help to others. For me, there's no better way to apply my Engineering background than to cars.

Same here Jim - my engineering background proves a solid foundation from which to make a difference in the world or '02s! We appreciate your support and your kind words as well. Keep it up! Remember - another day, another fine cigar

[hiebertm]

Well, I popped out the internals of the valve after Jim's pics gave me some confidence... cleaned everything and put it back together exactly the way I found it, but still 70psi line pressure(valve didn't open at all).

Then I spent a month painting the house while the summer wasted away and the tii sat in the garage. When the house was painted, I looked into the cost of a replacement of the NLA part, and it was quite high, so I decided I'd pop the valve apart one more time before I shipped it down to Rob@2002Haus hoping he could fix it or sell me a replacement.

When I popped it open this time, I took a closer look at the components and I realized that the valve had been assembled with a piece in backwards all along (it was like that when I got the car, I swear). So that's a pretty obscure thing to be done by a PO, but I put it back together correctly and now fuel supply rate and pressure is correct.

[jgerock]

Bravo! Always great news when something is fixed without spending any $. Almost every article/book I've read about the tii advises to check the settings, linkages and components (if it doesn't run well). Start from scratch to make sure you know it's supposed to be that way.

[Marty]

That's so funny I bought my 74 Tii not running from the original owner for $1200 with the same problem, took the pressure regulator apart about 10 times with no improvement then I saw that the relief cut into the piston body fit inside the spring perfectly and thought there's no way a German would make that cut and not have the spring fit the notch so I turned it around and viola, on the road again.

[jgerock]

Congrats!

The diagram in Mike Macartney's Restoration book was very handy to me while taking it apart. I too worried about the spring-to-poppet valve location.

[hiebertm]

thanks guys,

I own Haynes and Chiltons, but not the blue binders or McCartney. If McCartney has tii details like internals of the pressure regulator valve, it sounds like I need to get my hands on a copy of that too.

[jgerock]

Mike's BMW 2002 Restoration Book is very handy (to me) with lots of illustrations, pictures and reference info. The pressure valve reference I gave above is an illustration that shows the components in the correct order.

You can probably find it either on Amazon.com or Motorbooks.com.

Since Mike is the owner of Jaymic (in the UK), visit their website for more good 02 information.