Tii fifth injector help wanted!

[Stein-man]

Hi, All -

I have a small quandary I need some help with.  My car is a fresh disassemble/assemble restoration job.  Recently, I have been starting up the new engine and just observing.  I noticed that it ran great with the fifth injector disconnected.  I took the fifth injector out and stuck it into a graduated cylinder to verify a 2.25 mL output before the cold start relay dials it back to nothing.  It squirts full-on, full-time, and filled up my graduated cylinder in a jiffy.  I verified the ground on the connector goes to ground, and the other lead is 12V full-time.  I have a "new" cold start circuit board this bright dude here on FAQ developed as a guts-replacement for the 49 year-old cold start relay.  It also did the same thing: full-bore, full-time.  My thermo-time switch in the water divider is a new part ($).  Does anyone have any ideas for me?  Thank you in advance!

- Rob

[Son of Marty]

Does it stop passing fuel when unplugged? 

[Stein-man]

Hi, Marty -

It stops pumping when disconnected.  I just discovered that my thermo-time switch, which should show rapidly decreasing voltage when 12v is applied to the other lead, doesn't decrease the voltage at all.  I just bought this thermo-time switch, and paid a pretty penny for it!  ?  So, it appears to be not working, at least if the BMW fuel injection system instructions are to be believed.  If true, this would make it just pump fuel endlessly.  

- Rob

[Son of Marty]

Bummer Rob no one makes parts like they used to, but at least you know what the problem is.

[PaulTWinterton]

That module relies on the sensor in the water splitter at the front of the engine.  If the sensor doesn't cut out I don't think the module or injector will stop either.

 

Have you tested that sensor?

[Stein-man]

Hi, Paul -

 

The thermo-time switch?  Yes, I did.  There is a pretty basic test in the MFI supplement.  It's test of the bi-metallic strip in there.  It didn't work for me, so I think I have a bad (new) one!  ?

 

- Rob

[PaulTWinterton]

Sorry, misunderstood the name.  Mistaken for the other  "switch".  Get your money  back or a replacement?

[0257]

Try switching the leads on the thermo-time switch.  The brown is power, not ground, on that harness.

[Stein-man]

0257 -

Good tip, thanks - I will check it out tomorrow, during daylight.  However, the plug only goes on one way, so I'm not optimistic. 

- Rob

[dlacey]

That system of start valve, zeitschalter and thermo-time switch has its own separate wiring loom. I also had a problem of the valve staying 'on', it was a bad connection in that loom...re-seated all plugs and checked the earth connection & now all OK.

[Stein-man]

D - 

Which earth connections did you check?  Where are they on the wiring diagram?   Thanks!

- Rob

[dlacey]

The wiring diagram is in this doc:

 

The earth point is the screw for the blanking plate on the bulkhead:

That's the air cleaner horn across the bottom of the pic

[Stein-man]

Hi, D -

I have good ground there!

- Rob