cold start valve csv not getting power?

[body_infinity]

Hi all and thanks for all the help so far..i am currently working thru my ignition system on the 71 280se m116 3.5 engine…the problem I am getting is that I am getting no power going to the cold start valve (CSV). I have checked other posts here and on other sites but no real answers to my problem...

I have done all the tests as per manual
(ie) have grounded the csv “w” terminal which should trigger the csv but again no power, checked the terminal on the TTS all good I am getting power to the TTS "G" terminal while cranking which as per the manual is the heating element so looks good. so I am thinking of a relay problem that sends the power to the csv?? my question is where the relay is for the CSV or how the csv work? I think I read that it gets ground from the TTS (w) terminal but as I have grounded this it continues not to have power

I did see two silver cylinder relays attached near the ecu in the engine bay (2x 30a and part number 000 542 9719 they are dated 1971 wow original relays) I know one is for the csv but what is the other one for??? info /diagram would be great..thanks heaps ;-)

[GaryF]

Not 100% familar with the relay locations on your model but you should be able to compare the wire colour coding on the Thermo Time Switch with the relay to identify which one it is. The other one may be the fuel pump relay.
Once you've identified it try swapping the relays over to see if you get power to the CSV, if its anything like mine there's nothing else involved in operating the CSV just the TTS and Relay so its either the relay itself or the wiring.

[Tomguy]

Those are what your relays are for

If you are getting power to the TTS, your relay is functioning properly (from my understanding of the grainy diagrams I have).

[SootyPast]

As I recall, this circuit has to be energized by the starter switch mode on the ignition switch (cranking). I also seem to recall that it is controlled by the ecu to some degree. The relays can be swapped out for diagnostics. poll #30 is power as I recall. Been a long time... Thermo time switch should provide continuity when cold. They are easy to test as you can simply drop them in almost boiling water, test, then place in the freezer, do same. You are testing for continuity between the two posts when cold. You can test jump 1 wire into both little slots at the connector which would act like a good working tts with cold indication. Those
old relays are very suspect. I think they were all 4 pole. They are nice to have around for spares on that system. They are in tons of cars at the wrecking yards. Pretty much anything with an older bosch system will have em. You can use either the silver aluminum ones or the later black plastic covered ones. If you are in a pinch you can un-crimp the little crimps at the bottom of the relay and slide the cover off. Sometimes you can clean them up and reuse them for a short period of time to get you bye.

[Arthur Dalton]

Power to TTS simply means the relay is getting power to the coil/primary side of the relay..it does not mean the relay contacts that activate the CSV are closing/conducting. Jumper terminals #87 and #30 at relay connector and see if you have 12v at CSV..if so, replace relay. If not , check fuses.

Also, jumpering terminals at TTS does not verify TTS ..grounding the W terminal activates the relay coil circuit. The G wire just holds the TTS heater circuit in for required Time/Temp. It is a Switched Ground circuit.

[body_infinity]

Hi guys and must say thanks for the diagram of the fuses, whish my manual was as easy to understand ..anyway had some spare time today so had a look at the relay (and I know some think these are very average) but I must say they are made very solid ...!

I did some checking and the winding and contact looked good then checked the resistor it was out of spec so replaced it with a similar resistor (90 ohm big boy) put her back in and wow we have power to the CSV ... I also checked the other relay it was good and according to the diagram it controls the thermo fan? My fan fails to turn on even around 215 f so I guess will check the switch in the coolant any tips here would be good? Again thanks for the help guys!

[SootyPast]

Congradulations! The fan switches are notoriously famous for failure. Buy the good one. Not an aftermarket.