Sensor stupidity

[todwic]

I am feeling deepening ire for bosch sensors. This still involves my TDC and RPM sensors. Here's the sit:

• Properly adjusted bracket at start up. Starts fine, idles ok, anything above idle it starts getting choppy, worse as more throttle is applied.
• Move the sensor bracket away from the flywheel, and engine performs better.
• The farther away you move it, the better the engine runs.
• Kill the engine, it will not start untill you move bracket to original position, where it will start right up.

What the hell's going on around here????

[88_944]

The farther away you move it, the better the engine runs.

WTF? LOL!! What kind of engine rebuild you did? Did you take out the DME relay for some reason?


Here, this is why I ask.

Thanks to SoCal Driver, I learn how to oil prime the engine. I had zero oil pressure. I just did a bottom half engine work. My engine needed new con-rods bearings so you know how that goes.

Anyway, I was cranking the engine without the plugs in when getting oil pressure up and then I could smell lots of gas coming from the plug holes. SoCal Driver said to pull my DME relay out so it will stop the fuel smell. As soon I got 4 bar oil pressure, I put back the DME relay and the engine ran but it was holding the idling but when I push the gas, the engine would want to die. I said WTF, the vacuums?

So I took out the air box to look to see if any was out but nothing was. I then said, maybe I reset the DME since it was reading inputs without the relay in. So I took off the positive side of the battery and putting it back on did the trick. The engine ran like new!

[FLA944]

Tod,

Sounds like DME or AFM. But, I think you have a vacuum concern going
on as it starts and idles great and then increase throttle and your'e in the dumper.

AF and FR are more experienced than I on this but I think that the sensors are working against the vacuum causing a retard (not you) and/or advanced (again, not you) condition.

Get a squirt bottle with distilled water and as wifey increases throttle spray around and see if you hear any changes. Cap off the vac to the AFM and see if you have a change.

Rick

[todwic]

I did change the relay, but I've had the batt. out of vehicle since then, but I'll file that one away iin the memory banks.
I checked all my vacuum thingies with propane, I have no leaks that are detectable. I also sprayed all the con. and hoses with WD-40 so that it would be easily sucked in, and nothing (yes I did disc. my Lambda).
My sensor is slightly damaged at the end where whe got a little too close to the spinny things, could that be it? I would think as long as it sends a pulse, it should be good, but this isn't Todd's world. Anyone else care to opine a solution?

[carsontc]

Sounds like a 'possessed' reference sensor.

I had a 'hot start' problem a few weeks back. It would start fine when below normal running temp.

And would run fine all day unless I shut it off...then, no spark!

Sensor resistance measured OK & I always could see a pulse w/multimeter but still no spark.

Removed sensor 'hold down' bolt and twist the reference sensor 45 deg. & it would start (I left it like this for a week). So I though sensor was bent. It wasn't.

Put in different sensor and problem solved.!

Never touched the bracket and so I didn't reset .8 mil adjustment.

btw...I knew when it wasn't gonna start cuz the tach didn't pulse a little when cranking...yet at the sensor I could see a pulse while cranking.

I think that DME wants to see the pulse with a certain rise/fall time and amplitude...

or it was just possessed...dunno!

[todwic]

I've already touched everything, Mr. Wilk. I think I will replace the sensor, I have twisted it like carson did with varied results. It's had a rough go of it, those 20 yr old sensors just can't handle my hamfisted excuse of finese. Is there a generic Bosch sensor? Who has the cheapest TDC sensor? My batt. is fully charged, btw.

[todwic]

Oh yeah! I swapped sensors around, and violá she runs like a dream. I just need a couple new ones and I believe she'll be top notch. I had her up to 100mph on the 605 tonight and she still had a LOT of pedal left. I'm not gonna push her too hard untill she gets to 2k and broken in nice n tite, or as the germans say:"goodentite". Man I'm soooo relieved, I thought I forgot something in the rebuild or did something wrong, or that corona bottle I misplaced is in a bad spot. I was in the yard doing a jig today. I can't wait to see what it does with Wilk's chiped DME!@

[carsontc]

another possessed sensor?

btw...lot's of inexpensive used sensors out there

and doing the jig in your yard is actually part of an old exerosim rite performed next to many Porsches usually with excellent results

[COLDBASS]

100 mph on the 605? Use discretion near the 405/605 junction, 605/210 junction, and 605 and Telegraph off ramp...

[coupe]

Welldone Todwic. Isn't it a great feeling when it all works out?!!
Regarding the sensors, do they have 3 wires each? 0 volt, positive and output?

[todwic]

Originally posted by carsontc
another possessed sensor?

btw...lot's of inexpensive used sensors out there

and doing the jig in your yard is actually part of an old exerosim rite performed next to many Porsches usually with excellent results

LMAO it worked for me.
I got on at Del Amo went thru the 605/405 on to the 22, turned around on Westminster and cam back. I live right under the catwalk that goes over the 605, on the SB side. I seldom go north to joyride, but I do love the 105w onramp from the 605n. Long gracefull curve that really lets you ease into the g's. Course, I do most of this after 10pm when traffic is light.
Yes coupe, it does have 3 wires. 1 is a ground, I think one sends a ~2V signal, and the other does some kind of Ohmish thing, with the beard amd the furniture.

[88_944]

Congrats!

and the other does some kind of Ohmish thing,

The ohm should range from 700-1,000 if it's good.

[carsontc]

or if it isn't good !