84 3.2 flywheel sensor connections - better way?

[scarceller]

Any decent shop or electronics person can change that connector. And the pin crimp-er tool is nice but not required. The pins can be crimped carefully with needle noose pliers and then soldered and shrink tubed. Again, decent electronic skills needed here.

You don't need a pin extractor tool if you plan to replace the pins and the connector, you should replace both. Just cut the old connector off and install new pins then seat them into the new connector. Also worth mention is that those wire harnesses have a shielded braid that MUST be also connected to a pin.

[Quasimoto]

I could have sworn I found the harness side connectors here on the host, but can’t locate now?

[HaroldMHedge]

Originally Posted by Quasimoto

I could have sworn I found the harness side connectors here on the host, but can’t locate now?

I believe you are searching for 022-906-233-B Electrical Terminal Housing (3-pole).

[Quasimoto]

Originally Posted by HaroldMHedge

I believe you are searching for.

Thank you! My Pelican-Fu is improving, but I still get lost in the weeds occasionally...

[scarceller]

These connectors are called 'Junior Power Timer' or 'JPT' and the one you need is 3 pole.

Search for "junior power timer connector 3 way" you will find them.

[famoroso]

Originally Posted by KTL

We had a no-start issue with an '86 BMW 325e that uses a similar Motronic engine management system. The set screw in the flywheel was installed loosely and the gap was not proper. Thus the sensor couldn't detect the screw and it wouldn't start. Ironically the guy we bought it from traced the same no start problem when he bought it to a missing set screw. He "fixed" the issue with a new screw that eventually came loose again!!!

Jae Lee built a 3.4 for my 1987 nine months ago and ever since the rebuild, I've been having a hot start issue. For around ten minutes post a full operating temp shutdown, the engine will crank, but will not fire. If I try to start the car immediately after shutdown, it just cranks. One minute later, it just cranks. Five minutes later, it just cranks. Ten minutes later... It starts.

Car runs GREAT otherwise.

We tried a new two wire CHT sensor, but that didn't solve the problem (switched back to the previous two wire CHT) and I've been casually troubleshooting the issue, including unplugging the CHT sensor and jumping the CHT sensor (no change in either case).

The motor has an @salcarceller MAF / injector / ECU setup, but that was on pre-rebuild and the hot start problem started with the rebuild.

@KTL your BMW flywheel set screw issue is interesting. We did replace both flywheel sensors, but we also installed an Aase lightweight flywheel as part of the build.

I wonder if my issue is heat related with the set screw or set screw sensor. Could the gap grow enough at full operating temp to cause the no-start, but 10 minutes later shrink enough to allow starts?

I believe I need an oscilloscope to test the flywheel sensor outputs? Alas, I don't have one and I wouldn't know how to use it if I did.

Apologies for the tangent here.

[911obgyn]

You can test the sensors with a multimeter for resistance any open shows bad, i heard you can check with the ac function and crank the engine should show some AC voltage

[scarceller]

Do you have spark during the no start? Just remove center wire from Dizzy and put a test plug on it, does it spark during cranking?

If you have spark then your Flywheel Sensors are fine.

If you have spark, then spray 2 shots of starter fluid into the intake and try starting. If she catches you have a fuel issue!

Originally Posted by famoroso

Jae Lee built a 3.4 for my 1987 nine months ago and ever since the rebuild, I've been having a hot start issue. For around ten minutes post a full operating temp shutdown, the engine will crank, but will not fire. If I try to start the car immediately after shutdown, it just cranks. One minute later, it just cranks. Five minutes later, it just cranks. Ten minutes later... It starts.

Car runs GREAT otherwise.

We tried a new two wire CHT sensor, but that didn't solve the problem (switched back to the previous two wire CHT) and I've been casually troubleshooting the issue, including unplugging the CHT sensor and jumping the CHT sensor (no change in either case).

The motor has an @salcarceller MAF / injector / ECU setup, but that was on pre-rebuild and the hot start problem started with the rebuild.

@KTL your BMW flywheel set screw issue is interesting. We did replace both flywheel sensors, but we also installed an Aase lightweight flywheel as part of the build.

I wonder if my issue is heat related with the set screw or set screw sensor. Could the gap grow enough at full operating temp to cause the no-start, but 10 minutes later shrink enough to allow starts?

I believe I need an oscilloscope to test the flywheel sensor outputs? Alas, I don't have one and I wouldn't know how to use it if I did.

Apologies for the tangent here.

[famoroso]

Originally Posted by scarceller

Do you have spark during the no start? Just remove center wire from Dizzy and put a test plug on it, does it spark during cranking?

If you have spark then your Flywheel Sensors are fine.

If you have spark, then spray 2 shots of starter fluid into the intake and try starting. If she catches you have a fuel issue!

On my to do list (after I find a test plug and purchase some starter fluid).

Like I said, I've been *casually* troubleshooting! It hasn't been a huge issue, save for fueling up on the back end of a drive. On the front end, I can start the car, drive a few miles to the gas station, shut it off, fuel up and it starts right up again, no problemo.

I am extra diligent about not stalling the car in traffic though. That would SUCK!

[KTL]

I don't think the heat is great enough to cause the air gap issue with the reference sensor. We've run our Carreras on the track on very hot days and never encountered any hot no-start conditions

When you guys did the rebuild, did you install new reference sensors or reuse the old? I'm just wondering if they are old enough to have some issue with the wiring itself. Try messing with the two black connector wires where they lead out to the actual sensors on the back of the engine?

How old is the fuel pump? They can be pesky with age as well.

[famoroso]

Originally Posted by KTL

I don't think the heat is great enough to cause the air gap issue with the reference sensor. We've run our Carreras on the track on very hot days and never encountered any hot no-start conditions

When you guys did the rebuild, did you install new reference sensors or reuse the old? I'm just wondering if they are old enough to have some issue with the wiring itself. Try messing with the two black connector wires where they lead out to the actual sensors on the back of the engine?

How old is the fuel pump? They can be pesky with age as well.

We did replace both flywheel sensors with new Porsche parts.

As far as I know, fuel pump is original.

I've got some troubleshooting to do. I've just been having so much damn fun driving the car.

Thanks for the ideas!

[scarceller]

Revised diag steps:
- During no start event
1. Turn key to RUN but do not start engine, then verify that the idle control valve is vibrating and humming.

2. Test for spark

3. Spray starter fluid into intake

Do them in that order, if one of those steps fails do not move on to the next step.

Originally Posted by famoroso

We did replace both flywheel sensors with new Porsche parts.

As far as I know, fuel pump is original.

I've got some troubleshooting to do. I've just been having so much damn fun driving the car.

Thanks for the ideas!

[911pcars]

To reduce possible pin corrosion in this often-times wet environment, apply dielectric grease to those contacts.

Sherwood

[GH85Carrera]

I had one pair of sensors that only lasted a few years. After those few years it was like the car was haunted. The sensors would read fine with a ohm meter when cold. Once they warmed up they would on occasion get flaky. I finally replaced them after every other test and that solved my problems.

Once removed it was easy to test them hot and one of them would cut out. It was weird. I was happy to throw them out.

[famoroso]

Originally Posted by GH85Carrera

I had one pair of sensors that only lasted a few years. After those few years it was like the car was haunted. The sensors would read fine with a ohm meter when cold. Once they warmed up they would on occasion get flaky. I finally replaced them after every other test and that solved my problems.

Once removed it was easy to test them hot and one of them would cut out. It was weird. I was happy to throw them out.

Thanks Glen. When I wondered earlier in this thread if I had a heat related reference sensor issue, I was thinking more along the lines of intermittent sensor issue vs sensor gap growing beyond 0.8mm spec.

FWIW, I replicated the issue yesterday and was able to ascertain the following... 1) thanks to Sal's fuel pump prime feature in his ECU, I could at least hear the pump running during every subsequent restart attempt and 2) I connected my Fluke up to cylinder 3 spark plug lead, to check RPMs, and it showed ~300 RPM during no-start / cranking. I assume the latter qualifies as "having spark."

Will confirm IAC valve operation and attempt starter fluid test next time.

FWIW, here's another thing, while the car is failing starting attempts and when it eventually starts, I smell something difficult to describe and, more importantly, something I've never smelled before in 30 years of being around cars. It isn't unburned fuel. IDK what it is. It's pretty pungent tho. After the car finally starts, the smell quickly disappears.

Anyone have an ECU breakout box I can borrow? OTC 3226, or the like? I'd love to take reference sensor measurements.

[gomezoneill]

https://www.pelicanparts.com/cgi-bin/ksearch/pel_search_2016.cgi?command=DWsearch&LastVisited_input=0804&make=POR&description=022906233B

Wow 15 dollars for a 5 cent piece of plastic!

[ian c2]

Frank
Does it smell a little like rotten eggs ?

[Quasimoto]

Originally Posted by gomezoneill

https://www.pelicanparts.com/cgi-bin/ksearch/pel_search_2016.cgi?command=DWsearch&LastVisited_input=0804&make=POR&description=022906233B

Wow 15 dollars for a 5 cent piece of plastic!

That came out of a mold that cost 100k+, then was packaged, distributed and made available to users in low volume market.

It’s a bit dear, but not when you account for all the factors.

I hear you though, the tally adds up as you start fixing things!!! Eye watering at times...

[famoroso]

Originally Posted by ian c2

Frank
Does it smell a little like rotten eggs ?

Not particularly. It has more of an acrid quality.

Also, currently running a pre-muffler, so not a cat issue.

[scarceller]

The BMW crank sensors work in the 84-89 3.2L and they are Bosch OEM sensors at reduced price. The part number for the BMW sensors is:
Bosch # 0.261.210.002 about $80

Pelican has them:
https://www.pelicanparts.com/More_Info/12141708619.htm?pn=12-14-1-708-619-M14&bc=c&q=0.261.210.002

The Porsche Bosch sensor # is
0.261.210.005 about $150

The only slight difference is that the BMW sensor harness is a tad longer. I've used the BMW sensors in the past with no issues other than a few dollars saved.