Has anyone used a universal CPS?

[tspangle88]

Since it appears I need to replace both the CPS and the vehicle speed sensor in my early 85 325e, I'm trying to do it as cheaply as possible. The usual places like Pelican, BMA, and RM European all want around $70-75 for these things, and a search on Rock Auto shows those, but also this universal one: http://www.rockauto.com/catalog/moreinfo.php?pk=443693

And it's only $28. Rock Auto part # is 12521279695. It'd be easy enough to connect the wires to my existing plug, the question is can you get that sensor into the factory bracket that attaches to the bellhousing? Anyone tried it?

[Gregs///M]

It will probably work, granted you wire it correctly. However, I never cheap out on parts that affect the running condition of your motor so much.

To save some money, try a used CPS from a low mile car or newer car. Same with the speed sensor. These parts are pretty robust and don't go bad often.

[tspangle88]

It will probably work, granted you wire it correctly. However, I never cheap out on parts that affect the running condition of your motor so much.

My impression is that the sensors themselves are universal, what you are paying for is the proper plug and bracket for the E30 application. If I can reuse those things and the sensor is just is good, then why not?

To save some money, try a used CPS from a low mile car or newer car. Same with the speed sensor. These parts are pretty robust and don't go bad often.

If I had one handy, I would.

Here's another question: Are the crank position and vehicle speed sensors the same sensor? They sure look the same.

[ForcedFirebird]

Not even close. The eta sensors reach far into the bell housing, about 2x as far as the iS or wheel sensors.

And no, not all sensors are equal. If you buy one from Autozone etc, made in China they will have a 1000ohm resistance and won't run your car, the stock sensor should read 580ohms - I have seen them run a car at 650-700ohms, but not well, if they read open, they are junk.

The wheel speed sensors might work in the iS engine, but they are 2 wire and don't have the shielded ground, it may cause interference with the more sensitive DME as I have had break up issues when that ground is broken.

Email Steve at Blunttech.com and ask for a quote for the sensors. He lists them for $42 (crank), but may have less expensive brands. Mention my name and he will even throw in some funny antics about me. We do a lot of business with him at the shop, emails from us daily. The wheel sensors are expensive, but they have a nicer wiring setup that should be fine pulling from another car.

While the magnetic part doesn't go bad, it's the soft plastic sheathing on the CPS that turns hard and brittle over the years and when it breaks near the sensor, it often shears the wires right at the epoxy and renders them useless and non-repairable. So, getting a used sensor might work fine for a bit, that plastic will still be brittle.

[tspangle88]

Not even close. The eta sensors reach far into the bell housing, about 2x as far as the iS or wheel sensors.

Maybe I'm using the wrong term. On my car (early eta), there are no wheel sensors (that I know of, I don't have ABS), there are two sensors that go into the bellhousing. The Bentley refers to them as the "reference sensor" (what I'm calling crankshaft position) and "speed sensor". My understanding is that the reference sensor detects the teeth on the flywheel and the speed sensor detects a post that sticks out of the flywheel. Both terminate on the back part of the intake manifold and have identical plugs, one is gray, one is black. I'm asking if *those* two sensors are interchangeable.

And no, not all sensors are equal. If you buy one from Autozone etc, made in China they will have a 1000ohm resistance and won't run your car, the stock sensor should read 580ohms - I have seen them run a car at 650-700ohms, but not well, if they read open, they are junk.

Again, going by Bentley, it says that my resistance should be 960 +- 96 ohms.

Email Steve at Blunttech.com and ask for a quote for the sensors. He lists them for $42 (crank), but may have less expensive brands. Mention my name and he will even throw in some funny antics about me. We do a lot of business with him at the shop, emails from us daily. The wheel sensors are expensive, but they have a nicer wiring setup that should be fine pulling from another car.

Will do, thanks!

While the magnetic part doesn't go bad, it's the soft plastic sheathing on the CPS that turns hard and brittle over the years and when it breaks near the sensor, it often shears the wires right at the epoxy and renders them useless and non-repairable. So, getting a used sensor might work fine for a bit, that plastic will still be brittle.

Yeah, I'm really not interested in used electronic parts like sensors. If I had some sitting around to try, I would, but I'm not going to pay for them.

Thanks!

[ForcedFirebird]

The Bentley has a typo and that's why the Chinese sensors read wrong, they based it off Bentley to make the windings and your car will not run of the sensor with a resistance that high. The sensors need to read 540-580ohms.

I currently own 5 e30's and work on them for a living, I have dealt with bad sensors many many times - even had cars come in for not running after putting a new sensor in, swapped it out for a known good brand with the proper resistance and they fire right up.

While you have the sensor pulled that goes to the flywheel pin, use a light to shine in there and rotate the engine until you can see it to make sure the pin didn't become dislodged, that is also a common problem.

[tspangle88]

The Bentley has a typo and that's why the Chinese sensors read wrong, they based it off Bentley to make the windings and your car will not run of the sensor with a resistance that high. The sensors need to read 540-580ohms.

No kidding? Wow, that's good to know. That's why it's good to ask!

I currently own 5 e30's and work on them for a living, I have dealt with bad sensors many many times - even had cars come in for not running after putting a new sensor in, swapped it out for a known good brand with the proper resistance and they fire right up.

That makes me think I should go OEM/Bosch. The $42 one at Blunttech is an "FAE" brand, have you used those?

While you have the sensor pulled that goes to the flywheel pin, use a light to shine in there and rotate the engine until you can see it to make sure the pin didn't become dislodged, that is also a common problem.

So I've heard. I will check it.

Thanks again!!

[ForcedFirebird]

When you email Blunttech, he will guide you on the quality of the stuff.

[rodpaine]

Snip... Not even close. The eta sensors reach far into the bell housing, about 2x as far as the iS or wheel sensors.

And no, not all sensors are equal. If you buy one from Autozone etc, made in China they will have a 1000ohm resistance and won't run your car, the stock sensor should read 580ohms - I have seen them run a car at 650-700ohms, but not well, if they read open, they are junk.

John is correct! I've replaced several eta sensors on early 528es that were way out of spec, purchased from some odd ball source. Stick with Blunttech and save yourself a lot of potential grief.
-Rod

[tspangle88]

Just as an FYI, I ended up buying Bosch sensors from BMA, both tested out at 980 ohms, and my car fired right up after installation. YMMV, of course.