Camshaft position sensor problem

[Mikael Sundelin]

Hello!
First of all, I don’t have a E500, I have a 1992 W140 with the M119 engine. A barnfind that i bought for a few hundred dollars when the owner was going to send it to the scrapyard because the engine was running bad. Turned out to be the engine harness, so I made a new engine harness by my self. Drove the car for a year or so after that but sometimes it was hard to start when engine was warm. The car stood still for 5-6 years after that and now it hardly starts and the engine runs really rough, driving it is not an alternative.

Made my self a fault code reader and got 4 codes that concerns me:

• Camshaft position sensor faulty
• Magnets for crankshaft position sensor not recognized.
• Voltage at mass air sensor with hot wire circuit. Open or short circuit.
• Injectors open or short circuit.

Decided to tackle the Camshaft & Crankshaft sensor problems first. Ohm measurement and Voltage measurement(when cranking)on both sensors didn’t indicate any problem with the sensors, so my best guess then was a bad EZL. Replaced the EZL with a used one I bought, but it did not solve the problem. Replaced both the sensors with new ones after that, but the trouble codes stays on.

Magnets falling off the crankshaft seems unlikely but could of course be the problem with that sensor, but does anyone have any idea what could cause my ”Camshaft position sensor faulty” code on my M119???




Regards Mikael

 

[gsxr]

After clearing those codes, do all of them return quickly after driving? Or is the car not currently starting / driving?

The crank magnets can be checked visually by rotating the crank and looking through the grille at the bottom of the bellhousing. There are 2 in different locations, if both are present, try shimming the CKP (crank sensor) with a 0.5mm paper gasket. If the crank sensor was defective, the usual failure is the engine dying after reaching operating temp (and, the CKP will measure very high ohms when in 'failure mode'... when it cools, resistance goes back to normal, 800-1000 ohms).

EZL's almost never fail, and when they do, you lose either 1 distributor (runs on 4 cyl), or you lose both and it won't start at all. Cam sensor fault COULD be due to the camshaft timing out of synch... need to pull the valve covers and check cam timing.

If the current problem is the engine running very rough, you either have a bad injector or two, OR there's a secondary ignition problem. Neither of these issues will trigger a fault code. You'll need to do additional diagnostics.

BTW - welcome to the forum!

 

[Mikael Sundelin]

Thanks gsxr for your good advice on the next steps in my troubleshooting, really appreciate it
I’m gonna pull up the car and check if the magnets are visible and also pull the valve covers to check the timing. I’ll be back with more info when I’ve done that.

Got good spark on all 8 spark plugs so probably not the EZL then. All 8 injectors gets an impulse(tested with a lamp) and clicks/open when I hit them with 12v, but getting them to a professional for testing the spray pattern and rebuild them is on my mind if I don’t find anything else that is wrong.

Never been able to clear the codes, they just stays on. The engine starts(sometimes) but runs rough for like 1-10 second and then dies.

Thanks, nice to be here

 

[gsxr]

Strange you cannot clear the codes on any module. Definitely need to clear the codes and see which ones return. Codes are not self-clearing, and some can be stored from many, many years ago. Any time someone buys a car and checks codes the result can be what I refer to as "code diarrhea" where a dozen or two codes show up, because they have not been checked/cleared in a decade or longer. The only ones which matter are current / recurring codes.

Anyway: Make sure you are using the correct process to clear codes. After counting the blinks, hold the button for 6-8 seconds to clear the code. Each code must be cleared separately, one at a time (painfully slow). Some modules require turning the ignition off/on again.

In the meantime, also check fuel pressure at the rail during the startup and rough running. Normal pressure should be 45-55psi.

 

[Mikael Sundelin]

Definitely had a ”code diarrhea” cleared about 25 trouble codes on the other modules so my clearing process worked in that case, but i’m gonna try with ignition off/on and see if that helps clearing the codes in this module.

Fuel pressure is probably ok. Got 2 new pumps and when I disconnected the fuel hose going to the fuel rail I had a flow (liters/minute) that was comparable with the capacity of the pump.

 

[Markus-MD]

Your wiring harnes is ok?

 

[TerryA]

@Mikael Sundelin,
Your problem sounds interesting with gsxr’s knowledgeable advise you should be back on the road soon.

Again, Welcome Aboard

Terry

 

[Mikael Sundelin]

Your wiring harnes is ok?

Think so, haven’t found any damages or loose connections. Replaced the harness about 7 years ago.