Kevin in Atlanta

The connector has crumbled. The CPS is OK - I used it in another car and it started. I will repair the connector and pocket the savings.

Landseer

Whoever plans make the car reliable will need to replace all the sensors.

They've simply all exceeded their service life.

If you replace them, then start replacing a second time, that's parts changing.

Kevin in Atlanta

The parts changers I am referring to all the dealerships that are too lazy to perform tests to isolate the causation. I could change all the sensors and maybe that fixes it or maybe not. What will I have learned? I was lucky? What I want is to learn more about my cars and each time I acquire a non-runner I learn a bit more. The wonderful thing about this forum is that we get to debug these cars and share what we know.

outbackgeorgia

How does a passive sensor like the CPS "Wear Out". Not speaking about the wiring, that can be replaced, but the sensor itself.
Dave

rnixon

These are in the engine bay, subject to large temperature cycles and some vibration. They'll crack and rust eventually.

Kevin in Atlanta

So, with some annual preventive maintenance that includes looking at the connector, adding some heat wrap insulation to the connector, removing the CPS itself, cleaning it and applying some dielectric or anti seize grease the CPS will live on only to expire eventually.

Mrmerlin

What happens to the CPS the knock sensors and the Hall sensor is something thats not easily seen.

BUT the obvious thing that can be seen is the crumbling connector.

This is your hint thats its time to swap in a new part.

Infact all of the parts mentioned will be suffering the same fate.

What you cant see is the corrosion that's infiltrating the wires of these parts.

Sometimes you will see the whole length of wire insulation peeling off,
thus exposing a sheathed set of wires,
other times the connector will be crumbling.

This lets moisture into the wires and like the ground strap that is in the back of the car,
it may look new but inside its full of corrosion.

This will change the signal its sending to the computers.

Now you may get lucky and have a car thats been in a dry climate maybe it doesnt have the corrosion inside the insulation.

BUT really if your going to try to make a machine like this run perfectly why would you try to count your pennies when all your doing is adding a bandaid,

How much would a flat bed ride cost on a Sunday night when your 300 miles from home.
Because you saved some cash by installing a connector.

If your going to own one of these machines, fix it properly the first time.


The proper repair is to replace the CPS the knock sensors and the hall sensor as well install a fresh MAF ,O2 sensor and temp 2 sensor.

NOTE adding all of these parts should restore the engine electronics to top running condition.

Goodluck with your project,
Keep em flying!

Chalkboss

I agree with Merlin. I think a Band-Aid approach works just fine in some scenarios but I have read too many horror stories here where folks chase these electrical problems down into a rabbit hole. When I did my intake refresh I just bore down and replaced everything, cause I really did not want to have these sorts of doubts and issues, and man did I find some bombs lurking in there. I kept most of the old stuff, and some of it "looked" good, but I plan on keeping the car for some time and, again, I just don't those types of problems to worry about.

Kevin in Atlanta

So, if your car won't start the first thing you will do is replace the CPS, all 4 relays and the hall sensor?

Hilton

I'm with you - better to diagnose the problem than throw money at it.

However, most people here don't have an oscilloscope, wideband O2 sensor, shark tuner, spare MAF, spare LH etc. So they go with a most-to-least-likely (or expensive) replacement strategy. Having said which, the CPS are known to fail, and reasonably cheap. IMO its one of those "go ahead and make sure you've got a new one for your ownership" things in order to make the car more reliable.

BTW Kevin - if you have a reasonably small laptop, I recommend you get a dual-channel USB oscilloscope instead of the one you linked. being able to easily take screenshots/log is handy, as is the ability to monitor two different signals.

Chalkboss

Throwing parts at a problem without knowing the cause of failure is not what I advocate. What I am saying here is replacing obviously worn, crumbling, disintegrating 27 year old electrical parts/connectors that may still be working while you're in there might be a prudent path to save you a lot of grief later. That's all.
My car was garaged it's whole life in So Cal and in overall very good condition, but these Bosch connectors and the wiring just do not hold up after so long, even in near ideal conditions.

Landseer

We've determined where the weaknesses emerge on these.
Basic stuff
Trying to "troubleshoot" before working through that known list of known troubles is a bit of nonsense.

Mrmerlin

Its a good idea to use fresh parts when going after a bad running engine

Kevin in Atlanta

Getting back on track... Connected the chewed up ground to the block and am testing per Electronik Repair Inc's write up.

Ohms from connector's pin 17 to the grounds above the CE board ~3 ohms - should be zero. That is in line with my and other's theory that the ground is insufficient to trigger the injectors but good enough to trigger the noid.

I will repair the ground wires and re-test. Damn cold in ATL today.

Mark R.

The forecasted high for tomorrow is only 26-F.
But don't worry. It's gonna be back up in the 60's on Sunday.
Gotta love the manic nature of Atlanta weather...
But overall, we definitely can't complain...