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I'm in the 'Valley Of Death'...
#1
Should I replace the thermo time switch and Idle
speed thermistor while I’m in there?

I haven't diagnosed any problems directly associated with these, but would it be sensible? I'm just thinking because it's not easily accessible.

I'm in there because I'm replacing my vacuum hoses (hopefully sorting my idle issues out).

Is there anyway to test either of these switches just by running a multimeter across them?

I'm an idiot because I should have check before removing the intake and meter head... :? Cry
-------------------------
- Dave Smith

VIN: #00944 DOC: #535
VIN: #03193
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#2
Thermistor - Bosch 0 280 130 028

- 10 deg c - 32,000 to 53,000 ohms
+20 deg c - 8500 to 11500 ohms
+80 deg c - 770 to 1320 ohms
Pins 9 and 11 of idle speed ecu
i.e. between black/yellow & black/slate cable on the 4 cable block

Lambda switch

< 15 deg c - 0 ohms (i.e. closed switch)
> 15 deg c - infinite (i.e. open switch)
Test wiring to pin 7 on fuel computer (shares same pin with wide open throttle switch so make sure this is not short)

Thermo Vac Switch (for standard Delorean setup with stock engine)
Look in parts manual section 2/4/0 for vacuum pipe routing.
On the thermo vac switch:

Thickest end "2" to vac advance solenoid CENTRE pipe stud.
Middle size "D" to Inlet manifold
Thinnest size "1" to CPR T-Piece

When cold you should be able to blow between D and 1 and 2 blocked.
i.e. vacuum is applied from the inlet manifold to the CPR ONLY

When >50 deg c you should be able to blow between D and 2 and 1 blocked i.e. vaccuum is from the inlet manifold to the distributor solenoid ONLY.

Use silicone if you can but if you have standard vac hose warm the hose in boiling water first to make it slide on easier.

When removing the old hose use a stanley blade to cut the pipe off so you don't break the plastic stubbs.

The distributor solenoid blocks vacuum to the distributor vacuum advance when the engine is idling and should have 12v across the pins with the throttle closed ONLY.
The piping on the solenid is handed and should be the correct way round.

If you PM me your email address I can send you a diagram.

Hope this helps.

NickT.
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#3
Hi Nick

Thanks for the info.

i take it to mean that the LAMBDA switch when closed will deliver current (at temps less than 15deg c)?



Yes, I've got Silicone tubing.

cheers
Dave.
-------------------------
- Dave Smith

VIN: #00944 DOC: #535
VIN: #03193
Reply
#4
it's just a switch to signal the ecu to run the frequency valve at 60% when the engine is cold
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