So, the 8s marking on the switch really indicates its maximum interval time based on cranking time; if you crank less, you get less, is that it? Or, does the cranking energize the circuit for the eight seconds? That's never been fully explained in any of the Bosch FI stuff I read. Thank you.No, it would not run all the time because the CSV/TTS only gets power when the key is in the crank position, not the run position.
It's a maximum of 8 seconds if the conditions are cold enough. If you're in 20 below, it's 8 seconds. If you're at 70F, it might be a second or two. If you're in Phoenix in the summer it probably never comes on. But if you crank for a while, give it a brief rest, then crank again it's not supposed to come on again, it's supposed to stay hot so to speak.BRRV wrote: So, the 8s marking on the switch really indicates its maximum interval time based on cranking time; if you crank less, you get less, is that it? Or, does the cranking energize the circuit for the eight seconds? That's never been fully explained in any of the Bosch FI stuff I read. Thank you.
I've got too many parts...How do you have three of these switches?? Never mind, hang onto them, they've gotten expensive!
I'm a building electrician with considerable experience in electronics down to component level too. So it just kind of comes natural to me."Heater" - I wasn't sure what you and others were talking about when you were referencing heater, now I know, I'd never seen that symbol before and I couldn't find it on any automotive symbols either.
Now that does not make sense. Unless your readings are bad. I used small alligator clip jumper leads and roughed up the probe to try to get a good connection. I then let the meter settle down to get a good reading while not touching any of it, just using the spring pressure on the leads.I'm going to update the cold readings on the TTS in the morning, and then post the op temp I get after driving it. I still don't understand how W would be infinite ohms when the engine is hot and still be energizing the CSV.
Didn't make sense to me either, so, I may take readings from not just the base, as called for in Bentley, but actual negative ground, from the braids or the battery. In any event, I'm leaving it disconnected.Now that does not make sense. Unless your readings are bad. I used small alligator clip jumper leads and roughed up the probe to try to get a good connection. I then let the meter settle down to get a good reading while not touching any of it, just using the spring pressure on the leads.
And the cut sheet even says,BRRV wrote:Really, it boils down to this switch, doesn't it? Here's the exact switch from Bosch Classic:
http://www.bosch-classic.com/en/interne ... er_1.html#
As you can see, this switch is markedly different from the switch installed on the E28, originally. The two P/Ns listed for this TTS in realoem, 13 62 1 362 599, which supersedes 13 61 1 274 630, both cross reference to Bosch F026 T03 100, listed on the Bosch site.
Now, I did find my old switch: it was in the new Bosch box in my spares; I never throw anything away either. I('ve verified that the P/N on the Bosch box matches the cross reference shown in the Bosch site.)
I reinstalled the old (OE) switch and took readings:
G 131 ohms (.131 kohms) W 63.5 ohms, not cold, coolant a little warm, not hot (temp in the blue zone)
Old switch showed continuity out of the (new) box.
so I guess that clarifies things somewhat.wear-resistant electronics
Your modern TTS probably just needs a firmware update to be compatible with some other modern replacement part you have installed, provided you are paid up on software subscription fees. 
Right, I completely agree. However, what if the switch is so changed internally that it bears little resemblance to the originally specified switch? I looked at the spec sheet on the cars this is fitted to: virtually every L-Jet equipped vehicle ever made. Maybe, I just got a bad one?Your cold measurements say the TTS is out of spec and your hot measurements do not explain/correspond to the hot start problem
I'm usually pretty good about overall cleanliness - I don't see anything here that would lead to think I have an issue. This is a pretty clean engine bay, original connectors, no disturbance, harness checks out okay at the ECU end. I don't say it's impossible though.If an electrical part is bad from dirty contacts, it does not have to have a defined fixed resistance just so you can neatly mentally categorize it. If a contact was dirty inside the TTS, it does not have to present the same fixed number of ohms to several volts applied as it presents when 12 volts is applied by the CSV circuit. Also, the connector places some forces on the TTS spades and housing non-identical to test leads, if one of those connection spades is mechanically intermittent it could read one way and perform another. If the TTS case is cracked on the coolant side the insides could be reacting to coolant and cranking vibrations.
I do not know how to do this. The first part, I mean. And CSI = cold start valve, yes?Another thing that would be interesting to try is make the connection between the switch side and the wire harness CTS lead with meter looking at amps and see if there is any significant current flow. If you know how to do that properly. That should match the current draw of the CSI.
I guess I'm assume everyone in the discussion realizes the CSI/TTS is ONLY active and has power while there is power to the starter solenoid. Both leads come from same point. So another quick test of your wiring would be to just measure each lead on the harness while you give the starter a bump. It should go to 12vDC but unplug the CSi and there should be 0 at the connector on the CSI side.
So, my heater side, old switch, G, 131 ohms, W, ground.. 63.5 ohms. What do you think, good?My heater side measures 64 ohms. Seems high based on the spec but still OK for a small heater. The switch side was about 128 ohms though !! That means I don't remember just what I was talking about above and the switch itself is more of a solid state device that still has some conductivity when hot. But realize 128 ohms resistance is high enough the CSI will not active.
I'm a novice remember? Walk me through that, gently. In a few words. I can pick up on it easily, I just want to make sure I understand exactly what you mean so that I don't wind up scerwing up a component or frying an ECU.I agree, if you can measure current, that would be a far more definitive way of determining what's going on.
I'll check this in a few. I'm stuck waiting for a package all day, might as well be useful..I 'll be back.But back to TTS... if your TTS W lead is at the 120-130 ohm range it should have NO Effect when you plug it back in on a hot restart unless there is some other thing going on. What happens if you start it hot unplugged and plug it back in once running. Does that make it stumble momentarily? If so is there power on either TTS lead once the car is running? They should also be 0.
See page 1: full list of all diagnostics/maintenance/repairs done to date.gadget73 wrote:Not being at all familiar with the system used on these cars, I may be way off base here but have you ever done a fuel pressure test on this when its acting up? I'm wondering if maybe you have an injector that leaks down when hot, or maybe the fuel pump gets lazy when its hot and it takes an overly long time to build up fuel pressure. I've seen both of those issues on other things, but I can't say I've seen it temperature dependent.
Just a random thought from someone who knows nothing about what you're working on.
Pressure was tested both running and not running by bypassing the relay; residual pressure was corrected; both fuel pumps are new, CSV new, dampers new, filter new, she holds pressure past the twenty minute mark. Hoses are new, clamps are new. FPR is new-ish and passes all tests. I've ruled out fuel pressure issues because any issues were resolved on the first go around, I also thought fuel pressure issues since it's hard to test the in-tank fuel pump and a hot re-start is a common symptom of a failing in-tank pump. I replaced all of these components with Genuine BMW or Bosch. The in-tank pump was a genuine NOS BMW unit.gadget73 wrote:Just wasn't clear if the pressure was tested when its not wanting to start or only when its cold and acting normally.
Dear God make this go away.. I keep saying that while scratching my head and trying to just find The Cure.Or make our heads explode if we think about this much longer...
I would think the exact same thing. Having owned this car since 1995, and having done nothing to this that would create an issue that I can think of (no re-wiring, no add-ons, nothing untoward: anything I've done wiring or electrical-wise has post-dated the appearance of this issue, such as new Bosch fuel injector connectors) I can't image what a wiring issue could be. The harness connector only connects to the TTS one way; Bosch's cure for swapping wires. I am going to use a test light to verify that the G lead is actually delivering power when cranking, here shortly. The switch cold shows continuity. No one could have switched the pins in the connector, or at the ECU. We'd be in The Twilight Zone if that happened without my knowledge.Reading that posted G=2 ohms W=35.7 ohms: I am wondering, G and W identification error or wiring error causing identification error or part really performed swapped pinout function? I know you wrote bad part per Bentley but I am also thinking something is reversed and could damage other stuff like wiring and/or replacement part.
Now THAT is food for thought. I had thought for decades that S110/D11 dropped IMMEDIATELY when key left start. But until the starter motor RPM spin down, the back EMF of the starter now operating as a generator is being dumped back into the S110 node maybe? And during those seconds if the timer in the TTS has not expired, CSV fuel spray can continue if TTS temperature warrants? Starter motor model inertial dependent enrichment?BRRV wrote:...On the loom to the TTS, using a test light, G lights ONLY in start, and goes out within seconds of the car running...
Don't you mean comes from the CSV? When I look at the schematic, I show power to both wires, BK/YL and BK/RD, from S110. W is the switch and closes, completing the circuit, when G is active below 35C. Doesn't the CSV always have power to it, but is only energized when the heater closes the switch W, thereby allowing current to flow and completing the circuit?So have you verified by ohms which is really G and which goes to the CSV?
I'll try this tomorrow and report back. I updated everything else in the previous post. Thank you!But back to TTS... if your TTS W lead is at the 120-130 ohm range it should have NO Effect when you plug it back in on a hot restart unless there is some other thing going on. What happens if you start it hot unplugged and plug it back in once running. Does that make it stumble momentarily? If so is there power on either TTS lead once the car is running? They should also be 0.
