Engine stalled... Crank Position Sensor??

[cossie]

My 93' 500E started fine this morning, drove for about 5kms then the engine hesitated for a couple of seconds then died. The engine only cranks and the exhaust was backfiring everytime I attempted to re-start it. After about 30 minutes of trying, decided to have it towed. When the car got to the shop, without touching anything, the car fired up right away with no ill symptoms - it was running very smooth like nothing happened.

Prior to this, I just replaced the Fuel Pressure Regulator last month after experiencing hard starting. The symptoms that time were the same except that the hard starting occurred after 30 minutes of leaving it parked. It cranked and backfired, but after 10mins it finally started and idle was smooth.

I thought the FPR solved the problem since my car was running and starting well for a month before it stalled again. Can it be the Crank Position Sensor? Is it possible that the CPS can cause intermittent hard starting - in my case it failed again after a month approx after 250kms since the last stalling. OR what other parts should I look at that can cause this?

 

[gsxr]

You have to pull all codes, clear them, and see which ones return. Trying to diagnose this without codes is a waste of time (sorry).

 

[T-500]

What condition is your wiring harness in?
I had a similar issue after my harness was "disturbed". Magnets varying the cam timing were not operating correctly.

 

[gsxr]

The CPS can cause intermittent hard starting, but it doesn't necessarily mean the sensor is bad. I had this problem on both of my 500's, but on the 94 it was a missing flywheel magnet, and on the '92 adding a 0.5mm shim under the sensor (as mentioned in the WIS) cured the problem. Both cars had EZL (DI) code #18 which would return consistently. After the fixes, code 18 has not returned. Which is why I say you have to pull codes, clear them, and see which codes re-appear quickly and/or consistently. New CPS's would have been a waste of money on both my cars and would not have solved the problem!

 

[cossie]

No error codes popped up... from what I've read, it is possible that there are no error codes when the CPS fails. Hence, the reason why I suspect it's the CPS.

Regarding the wiring harness, I know its due for replacement since its still original with only 80K kms. A visual inspection, however, shows no damage yet - wires have no cuts or peeling .

 

[gsxr]

When you say no error codes... how exactly are you checking them? Only via the built-in blinker in front of the CAN box, via digital scanner (SDS / Snap-On / etc), or hand-held LED blinker connected to the six different engine management systems one at a time (EZL/DI, LH, E-GAS, BM, ASR, DM)?

I'd expect a code or two on the EZL/DI if there was a bad or intermittent CPS issue.

 

[T-500]

Regarding the wiring harness, I know its due for replacement since its still original with only 80K kms. A visual inspection, however, shows no damage yet - wires have no cuts or peeling .

My harness failed at 100K km. That was just 4 months ago. There were no visible outward signs.
Some very experienced people on the forum here, had told me I needed to cut back the insulation a bit, to see what was the true condition of the wires.
They were right.
I wish I'd checked. I got caught a long way from home and paid double $$$ to have someone else fix it.

 

[cossie]

@gsxr the codes were checked by the dealer using a Star computer. I just visited the shop to check for myself and there is really no error codes. Currently, the car is on idle for about more than an hour already hoping to replicate the issue but no stalling yet - idle is still very smooth. Just to double check other possible causes, fuel pressure & MAF airflow are both within spec.

@t500 just purchased both upper and lower harness a couple of minutes ago

 

[T-500]

I hope that's it.
They needed to be changed anyway.

Good luck!

 

[cossie]

Seems like the stalling/hard starting issue is caused by a dying Crank Position Sensor. When I removed the CKS the wire already has cracks on both ends. Since I'm at it, decided to replace the Cam Position Sensor as well for my peace of mind.

My question is, when replacing the Cam Position Sensor do I need to make adjustments to the gap between the sensor and the cam sprocket segment (which in the manual states it should be between .4-.6 mm) assuming I use the old shim? Is this done during replacement or only applicable when only doing a top engine rebuild?

 

[gsxr]

I would replace the cam sensor using the existing shim, and I would not bother trying to measure the gap unless you start getting codes indicating a problem. Pulling the valve cover isn't any fun on these cars, I wouldn't do it unless I had to. I'd say you have a 99% chance of replacing the sensor (with original shim) and having it work fine. The old sensor may break upon removal, btw...

 

[cossie]

With regard to the crank position sensor I've already replaced the one at the back of the engine, the one that connects to the EZL.

Do I need to replace the one mounted in front too? Does it cause the same hard starting and stalling issues similar as the one at the rear?

Here is a link to the part being sold in ebay http://cgi.ebay.com/ebaymotors/Merc...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

 

[gsxr]

With regard to the crank position sensor I've already replaced the one at the back of the engine, the one that connects to the EZL. Do I need to replace the one mounted in front too? Does it cause the same hard starting and stalling issues similar as the one at the rear?

No. The front sensor only connects to the diagnostic port near the EZL. It is for easy connection of diagnostic equipment only and has zero effect on engine operation. The front sensor was deleted starting somewhere in 1993 production, IIRC. Definitely no need to replace it though. The one in the back, near the transmission, is the important one.

 

[cossie]

Thanks for all the info...

 

[cossie]

My car just stalled again today after a week since I replaced the CKS and CPS, cranks but no start. After around 30 minutes of attempting to start the car to no avail, I decided to check the distributor caps while waiting to get towed. Both caps had a minimal amount of moisture and the contacts were corroded with white stuff just like in battery terminals. Cleaning the contacts made the car start with 1 crank. I went straight to the dealer and got a pair of new Bosch distributor caps and rotors with high hopes of solving my stalling issue.

Can the distributor caps cause the intermittent stalling problem? The old caps I had were BREMI and based on what I read from other forums they are no good and some have caused similar stalling problems. Is this true for the M119 engines too?

 

[emerydc8]

The CPS can cause intermittent hard starting, but it doesn't necessarily mean the sensor is bad. I had this problem on both of my 500's, but on the 94 it was a missing flywheel magnet, and on the '92 adding a 0.5mm shim under the sensor (as mentioned in the WIS) cured the problem. Both cars had EZL (DI) code #18 which would return consistently. After the fixes, code 18 has not returned. Which is why I say you have to pull codes, clear them, and see which codes re-appear quickly and/or consistently. New CPS's would have been a waste of money on both my cars and would not have solved the problem!

Hi Dave. Where did you find the .5mm shim? Do you have to pull the sensor out to shim it? Since I got the random DTC 18 on the EZL, I'm just getting a head start in case it reappears. The EPC shows two different part numbers for my E420 but doesn't describe how to determine the correct part for my vehicle. Is the second part number (003 153 50 28) the CPS with the non-corrosive material? If the DTC comes back, I'd like to try to shim it first, but if the CPS has to come out and there is a good chance that it will break, I may just bite the bullet and order a new one. They are up to $200.40 at parts.com.

 

[500ESpain]

My car just stalled again today after a week since I replaced the CKS and CPS, cranks but no start. After around 30 minutes of attempting to start the car to no avail, I decided to check the distributor caps while waiting to get towed. Both caps had a minimal amount of moisture and the contacts were corroded with white stuff just like in battery terminals. Cleaning the contacts made the car start with 1 crank. I went straight to the dealer and got a pair of new Bosch distributor caps and rotors with high hopes of solving my stalling issue.

Can the distributor caps cause the intermittent stalling problem? The old caps I had were BREMI and based on what I read from other forums they are no good and some have caused similar stalling problems. Is this true for the M119 engines too?

I had very similar synthoms and finally the problem was moisture inside the caps. They were BREMI. I replaced them with Bosch and everything is fine so far.

 

[gsxr]

Hi Dave. Where did you find the .5mm shim? Do you have to pull the sensor out to shim it? Since I got the random DTC 18 on the EZL, I'm just getting a head start in case it reappears. The EPC shows two different part numbers for my E420 but doesn't describe how to determine the correct part for my vehicle. Is the second part number (003 153 50 28) the CPS with the non-corrosive material? If the DTC comes back, I'd like to try to shim it first, but if the CPS has to come out and there is a good chance that it will break, I may just bite the bullet and order a new one. They are up to $200.40 at parts.com.

Jon, I used bulk paper gasket material to fabricate a shim. You do need to pull the CPS to add the shim, which isn't a fun job given the location. And if the old CPS is stuck in there, ugh. I am not sure if one part number is for metal body and the other for plastic body. If you use a metal body sensor, I think a thin coat of anti-seize on the barrel would be a good idea.

 

[emerydc8]

Thanks, Dave. Do you happen to have a copy of the WIS on this shim?

When I run either part number through the autohausaz website, it comes back with the earlier part number CPS (003 153 49 28) and a picture of what looks like the plastic sensor for $126.72 (picture). It states that it is the OE supplier, but it doesn't say who makes it. The alternate part (Bosch) is on back order.

 

[gsxr]

Here you go, Jon!

http://www.w124performance.com/docs/mb/M119/M119_crank_sensor_TSB.pdf

 

[emerydc8]

Awesome, as usual. Thanks Dave!

 

[clarkz71]

Not to nit pick, but the correct acronym for a crank position sensor is CKP

For the Camshaft position sensor CMP

Reason being both share the same letters Crank/Cam position sensor

So the automotive industry decided to use the last letters of each

cranK cKp
caM cMp

 

[gerryvz]

Not to nit pick, but the correct acronym for a crank position sensor is CKP

For the Camshaft position sensor CMP

Reason being both share the same letters Crank/Cam position sensor

So the automotive industry decided to use the last letters of each

cranK cKp
caM cMp

Good clarification, thanks Clark !

I tried to provide these definitions in this document in the Wiki, but it does not seem to have received much traffic (only ~150 hits).

 

[clarkz71]

Good clarification, thanks Clark !

I tried to provide these definitions in this document in the Wiki, but it does not seem to have received much traffic (only ~150 hits).

I know Gerry, I posted a complete list over on BenzWorld.org and nobody uses it either.

Oh well.

I'm thinking if we keep pointing it out, maybe it will catch on.

 

[gerryvz]

The intelligence level is pretty low at Banzworld, so that's not too much surprise. Luckily the knowledge levels are far higher here....


Sent from my iPhone using Tapatalk

 

[clarkz71]

The intelligence level is pretty low at Banzworld, so that's not too much surprise. Luckily the knowledge levels are far higher here....


Sent from my iPhone using Tapatalk

Ugh, you have no idea.

I really need to spend more time over here.

 

[gerryvz]

I understand from Zeitgeist and GSXR that the 124 board at Banzworld isn't nearly as bad as the 126 board, but that it is slowly devolving.

 

[clarkz71]

I understand from Zeitgeist and GSXR that the 124 board at Banzworld isn't nearly as bad as the 126 board, but that it is slowly devolving.

You understand correctly.

Sent from my SPH-M930BST using Tapatalk 2

 

[400Eric]

The front sensor was deleted starting somewhere in 1993 production, IIRC.

This would explain why I wasn't able to find the one on my 95!
Thanks Dave!

I'm still researching, learning, and figuring things out, so that when I bring Benzer4 back home, I will hopefully be able to get him running right away. I can't bring him home unless he's running or close to it! (I have too many crybaby neighbors!)

Regards,
Eric