[tamathumper]

Is this one of those - no test, just visually inspect and/or replace them and see how it goes - kind of things? The test for the CPS seems "involved" - e.g. it requires an oscilloscope to do it right!

Partial Post: Please Login or Register to read the full post.

[banditsc]

Exactly if you have a oscilloscope hanging around you can test the sensor. I replaced mine mainly due to age and not wanting to be stranded when it does finally give out.

Partial Post: Please Login or Register to read the full post.

[tamathumper]

My first test of the hall sender was to reach for the cable and give it a wiggle. I just pulled into the garage so the engine bay is max temperature. While it was OK last fall when I checked it, this time it basically disintegrated as my fingers touched it. As for the crank sensor, I can just barely see it down behind the oil fill tube, and with the engine bay at stupid degrees I didn't reach for it,... I'll go with fixing that hall sender for now.



Now I need to find that thread on how to remake the end of this cable, or is there an easier way to replace that end?! Off to EagleDay.com at the very least?

Partial Post: Please Login or Register to read the full post.

[banditsc]

I would just replace the sensor.

Partial Post: Please Login or Register to read the full post.

[tamathumper]

Ah, you're right. At first, I thought the harness-end connector was broken (the one I'm holding), but that's just the remnants of the hall sender's connector still wedged inside it! So, apparently a new hall sender it is, but I do wish there were a kit for just the end - I don't like pulling the valve cover if I don't have to.

Partial Post: Please Login or Register to read the full post.

[tamathumper]

Would this not work if the pins could somehow be inserted through from the back?



http://www.944online.com/cgi-bin/ASI_Sto...1298060689

Partial Post: Please Login or Register to read the full post.

[banditsc]

It probably would but sensors don't live forever. You don't have to remove the cover completely, just lift up the front.

Partial Post: Please Login or Register to read the full post.

[tamathumper]

Past threads seem to recommend removing the fuel lines, removing the valve cover,... and then there's the "while you're in there" of inspecting the variocam pads,... is 53,000 miles really as far as a Hall Sensor will go?

Partial Post: Please Login or Register to read the full post.

[flash]

it's more of a heat thing than mileage. that's why i came up with the heat shield. unfortunately it is often not in time to save those that have already been torched.

Partial Post: Please Login or Register to read the full post.

[banditsc]

I've replaced mine a couple times, first Bosch one died in less then a year. You really don't need to remove everything thing, the only reason you have to get the cam cover out of the way is for one allen bolt that is in the way. So if you just pull the bolts on the cover and lift of the front you will be fine, no need unbolt the fuel lines.

Partial Post: Please Login or Register to read the full post.

[MB968]

OK, going against the grain again. Let me first say that you do need to fix the sensor connector, or at some point it will likely give you issues. But if I were facing your other issues I wouldn't put too much energy to this sensor right now.



When I began my engine rebuild about 18 mos. ago I noticed the same issue. The connector on the sensor was disintegrated. My hall sensor is still in that condition. I should say my vision of an electrical connector may be different than the norm. It's just a means to get electrons from one wire to another while supporting ease of maintenance/assembly/disassembly and protection from the elements for reliability. On my disintegrated connector, there was still a good friction fit between the blades and the female members. I just reinserted the proper blade into the proper female side and carefully insullated everything and wrapped it with some of the 3M rubberized tape that does a great job of conforming to unusual shapes while doing a good job of sealing against moisture. I will repair it at some point.



Also, and it may just be because I'm tooo german, I would put a new connector on the sensor rather than to replace it. Sometimes the old sensors are better manufactured than new ones and can literally last a lifetime.

Partial Post: Please Login or Register to read the full post.

[MB968]

[quote name='tamathumper' timestamp='1367871652' post='142406']

Is this one of those - no test, just visually inspect and/or replace them and see how it goes - kind of things? The test for the CPS seems "involved" - e.g. it requires an oscilloscope to do it right!

[/quote]



I'm pretty sure you don't need a scope to test the crank pos sensor. You should be able to just use a VOM. I'll see if I have something in my Mazda manual. If so I'll post a copy here. I know I've tested wheel sensors with a VOM, and I think they are virtually identical sensors, just a magnet and a coil.



Here's my edit:

First I'd check the crank sensor by measuring the resistence across the black and yellow pins. If the coil part of the sensor is compromised the resistence shouldn't be in it's normal range. I don't know what exactly that range should be, but when I measured mine when the engine was out, I read approx. 980 ohms across the male pins for the yellow and black wire. It this reading is in range, it is very unusual for the sensor to me bad; it's a really simple device.



You can try this next test, but I don't think you can test it with the sensor mounted in the engine. The frequency will be too high for the meter to respond to. But, if you want to go further, you can use the toothed wheel that is part of the ABS sustem to test the crank sensor. You'll measure AC volts on the VOM across these same two wires. If you had a scope you'd see a signwave at the tooth pass frequency of the flywheel sensor teeth. On the VOM, measuring AC volts, you will see the voltage go from zero (as the signwave passes zero) climbing to a max. voltage at the peak of the signwave. You'll have to somehow clamp the sensor by the toothed wheel whit a similar gap to the mounting at the flywheel. Then as you rotate the front tire you will see the VOM reading fluctuate as mentioned above. Don't have any info on exactly what the voltage should be on the 968. Based on my Mazda experience the voltage will be in the range of .5 - 3 volts or so. The key is to see the meter needle go up and down as the wheel is rotating.

Partial Post: Please Login or Register to read the full post.

[tamathumper]

Flash, yes I just put the heat shield on there last fall and apparently it was too late to protect the plastic bits above the exhaust manifold. I will plan on doing the heater control valve at the same time as the thermostat as a result. I've had a spare in the cubby for a while now.



MB, are you saying I will need to do the female side of the connector as well? It would seem very hard to put anything on the end of that cable as it might require cutting the wire and soldering a new connector to the end? I haven't traced it all the way back yet as it goes down into the front of the engine and I think disappears behind the belt covers, so I don't know if there's a connector on the far end of that thing or not?

Partial Post: Please Login or Register to read the full post.

[Lear35A]

No, the Hall sensor connector is part of the main engine wiring harness (as is every other sensor). This makes it tough to change out the wiring for one sensor. OTOH, it makes assembly of the whole thing quite easy.

Partial Post: Please Login or Register to read the full post.

[Cloud9...68]

Tama,



I've read through this whole thread, and maybe I read too fast and missed it, but have you done a blink test yet? That will tell you if you have a bad hall sensor. However, my understanding is that the symptoms of a bad hall sensor are more manifest at high rpms, so the opposite of what you're experiencing. I agree with MB968 - I would clean up and repair the connector for the hall sensor, and, especially if the blink test indicates it's OK, leave the sensor itself alone for now.



As far as the CPS, that sounds like a more likely cause of your problem. Here's a "quick and dirty" test of the CPS: Remove you DME relay, and crank the engine about a ahlf dozen times. The tach needle should bounce pretty wildly from zero to about 4000 rpm (iirc) while you're cranking (but not firing, since the engine won't get any fuel with the DME relay disconnected). If not, you probably have a bad, or incorrectly gapped, CPS.

Partial Post: Please Login or Register to read the full post.

[banditsc]

Hall sensors don't always show up on the blink test. Mine went bad about 500 miles into a 2000 mile trip, started with the down on power and stumbling and some missing. It never triggered a code until about 100 miles from home when it triggered a intermittent hall sensor code.

Partial Post: Please Login or Register to read the full post.

[MB968]

[quote name='tamathumper' timestamp='1367926886' post='142434']

MB, are you saying I will need to do the female side of the connector as well? It would seem very hard to put anything on the end of that cable as it might require cutting the wire and soldering a new connector to the end? I haven't traced it all the way back yet as it goes down into the front of the engine and I think disappears behind the belt covers, so I don't know if there's a connector on the far end of that thing or not?

[/quote]



I can't quite tell from the pic above if I'd ever do anything with the female connector. Depends on how badly it mates up with the male connector and if it would still be functional or not. I assumed the male side of the hall sensor is also destroyed, and my comments referred to replacing that side if it too was disintegrated. Either way, to me fixing the connector is something to put on your long term list, just so it never creates an issue. That being said, before splicing in a new wire and connector, I'd try to just replace the plastic part of the connector. There are tools made to allow easy removal of wires/pins from the plastic connector. However, if the old connector is that brittle, you can probably crush the plastic piece, and with a little care, end up removing all the old plastic from the wires. If this works, you will end up with the end of the old wires with the connectors still crimped onto them. With the right new connector pieces, then it is just a matter of inserting the old wire/connector into the new plastic connector peice. These plastic parts should be redily available, possibly from the source you mentioned. I know I've seen kits from some of our 944/968 parts houses. You'll pay quite a bit more, but this is another source.



If all else fails, most factory repair kits just use crimp connectors to splice in a wire. I much prefer these not only because it is easier than soldering, but the built in wire strain relief makes the connection superior to a soldered connection and less likely to fail long term. Don't shy away from crimp connectors to splice in wires. They are the norm for industrial use; just make sure you get a good crimp, using a quality crimp tool.

Partial Post: Please Login or Register to read the full post.

[flash]

before anybody else starts making suggestions without actually playing with the parts first, let me tell you that there is not enough length in the harness to start cutting and pasting, and where it runs disallows crimp connectors. also, the gauge of the wire is extremely small, and very difficult to work with.



changing the connector may or may not be an option. many of the connectors on this car are no longer available. you may have to source a used one. i don't have the part number on that connector, but 5 years ago, when i tried to fix this by cutting and splicing, i had a very hard time finding one. unfortunately i no longer have the information on it.



changing the Hall (or pulse) Sender (not sensor) is pretty straight forward. while you don't actually have to remove the valve cover to do it, unless you are extremely lucky, and it comes up completely clean, you'll be removing it just to reseal it. i have yet to be able to pull one off and be able to put it back down without a leak of some sort. i gave up trying. i hate the design they used. the fuel lines have to come off, and you have to use schmootz in the corners, as well as replace the 4 doughnut seals at the bottom. half the time you pop a hold down bolt too.



i'd just do the complete fix. change the connector if you can find it, remove the valve cover, and change the gasket and rings (plugs if you haven't recently) and install the new Sender. take care not to let the wires slip under the cover and crimp the wires on installation. it's a bitch when you do (ask me how i know)



lol - this would be a great chance to do some powdercoating.

Partial Post: Please Login or Register to read the full post.

[tamathumper]

@Cloud, Thanks for the reminder - I realized last night I should probably try to fit the pins back together and do a blink test, but with the lower male connector completely gone, it would be a bit of a cobb-job. At this point, I'm inclined to replace the male connector, if possible, and not mess with the valve cover. I don't want to create more problems.



Tonight I will put the pins back in and run the blink test, as well as turn the engine over and observe the tach. If I can find a 3V diode, I'll also test the crank position sensor.



@MB, It's hard to tell from the picture, but the female (harness) side of the connector is OK (at the moment). I had to use a dental pick to fish out the broken remains of the male connector from the female half, and the male side has just completely crumbled away so only a little bit of it is left clinging to the cable. I assume the female half is crispy, too, but I don't want to crush it just to prove it's crispy, and I'm going to focus on fixing the male half first.



I can't seem to find a good picture of how these Amp Jr connectors hold the wires in. I was assuming the wires had to be passed through the connector, then the pins were crimped on and then seated into the plug, and if that's correct, I'm not quite sure how I'll get the original wires/pins into a new connector?



@flash, it's for exactly all those reasons that I'm leery of lifting the valve cover - my 944S had the same thing, and the bolts are very prone to breaking off, and on that car I even had a broken bolt hole in the rear corner which leaked oil the whole time I owned the car. I've just learned to try to stay away from that thing if I can.



I seem to think 944online.com has the parts I need, I just can't figure out if the original wires will poke nicely into the connector or not.



http://www.944online.com/cgi-bin/ASI_Sto...1298060689

Partial Post: Please Login or Register to read the full post.

[MB968]

If you look at the male pins, you should be able to tell which side the insert from depending on which way the tang (that holds it in) goes. I thought they went in from the rear, but could be wrong.

Partial Post: Please Login or Register to read the full post.