CSI and TTS Baloney

[Oski_Bear]

So my CSI does not function. I've taken resistance readings of the TTS and CTS. Results showed the CTS was normal and the TTS was abnormal. At room temperature my TTS read 30 ohms instead of zero.

I've read on other forums that people have encountered the same issue with their TTS and replacing it often resolved the issue with the CSI not firing when the engine is cold.

I tested the CSI by removing it from the intake plenum and trying to start the engine with CTS and TTS connected. Nothing came out of the CSI.

I then decided to order a new TTS from IAP. Unfortunately the new one also reads 30 ohms at room temperature (65 F) out of the box. ah!

I am debating whether or not to put the new TTS in. I feel like my old one is just fine and that the problem may be another electrical relay or fuse. Someone suggested that I check my main relay in the luggage compartment area. Anyone have any ideas where the electrical signal to the CSI is getting lost?

Thanks!
-Oski

P.S. Please enjoy the charts I made since I had nothing else to do.

[Oski_Bear]

Anyone have input for this thread?

[ghnl]

Well, the charts are nice.

Beyond that I don't have much to add, sorry. Try a PM to PapaJam.

[BattleBug]

What is your source of determining "abnormal" operation? I too am having TTS issues. And I'm not sure the ad hoc Bosch L-Jet Troubleshooting guide is correct WRT the TTS. Betwixt the two [G &W] terminals, it should not read zero resistance when cool. According to my manual, it should read 25-40 Ohms (<30C) and 50-80 Ohms (>30C).
Furthermore, Terminal 'G' to ground and terminal 'W' to ground both have different hot & cold values as well..Borrow your spousal unit's (wife's) blow dryer to check these also.
W-ground= 0 Ohms <30C and 100-160 Ohm >40C
G-ground=25-40 Ohms <30C and 50-80 Ohm >40C
Now, If your CSI is getting proper voltage & you have appropriate fuel pressure but no fuel squirting, it sounds to me like your CSI is bad. Resistance at the CSI means diddly if its clogged up. Not unusual. Had the same issue with my VW. Send the TTS back, replace/clean your CSI.
Cheers!

[ghnl]

The TTS is just a switch. Below a certain temp the contacts are closed (to allow electrons to flow to the CSI), above a certain temp the contacts are open (to prevent the CSI from squirting). The complicating factor in the TTS is its bi-metal strip that is designed to heat up and open those contacts after a few seconds (to limit how long the CSI squirts after a cold start).

Try measuring the resistance (using your ohm meter) across the two terminals when the TTS is cold (put it in a pan of ice water). Then, leaving the ohm meter connected, place the TTS into a pan of boiling water. The reading should change as the contacts open. I suspect the reason it does not switch from zero (no resistance) to infinate (no contact) is because of the presence of the bi-metal strip. But you should be able to see the meter's reading change as the TTS warms up/cools off.

PapaJam's replies in this thread are helpful in trying to understand the TTS & CSI.