Suspicious sporadic start

[Coleman El]

Hello guys. I'm new here and this is my first post. I just bought a 2003 4.6is. And it needed a little work, according to the seller. He stated that all it needs is a throttle body and maf sensor. I scanned the vehicle with my INSTA software, and sure nuff, it came back with the codes for the throttle and maf sensor and also the pedal potentiometer. I changed the tb and sensor but couldn't get it to start. Mind you, last week, it was the samething. I tried starting it bit it wouldn't start. Went out a few days later, it started right up. Along with the bad idle he told me about. I let it idle for a while to see if it would clear up but it didn't. Turned it off and I couldn't start it again. Fast forward to now, this is where I'm at. Cranks but no start with the TB and sensor newly installed. I checked for fuel in the rails, has fuel. Checked for spark. No spark
I don't know why it would start one time and not the next. Is it possible that it being immobilized? I don't know at this point. Can I get some of yous to help? I would really appreciate it. Thanks. And I have videos of it idling and pictures of the codes I pulled if that would help ya.

[andrewwynn]

Crank fuel no spark hints at EWS so scan for EWS.

No start intermittent suggests crank position sensor. (and may also inhibit spark).

[Coleman El]

Can you clarify what EWS is? And with CPS? It never showed up on the scan. Could it still be a possible culprit? And which CPS should I change or check? There's two of them.

[andrewwynn]

CPS is cam position sensor and I'm not sure that will prevent a start, the car I think has a workaround for the CPS not working.

Crank sensor is CPK for some reason. I'm pretty sure the car won't allow spark until it knows where the crank is.

EWS stands for D rive A way P rotection.

(Whatever the three words in German). Aka immobilizer.

The "catch22" is that you won't get a code until you get a start from my understanding. But look into immobilizer, because it comes up on the forum regularly the EWS gets out of sync and allows crank but no start (why allows crank the world may never know)

[Clavurion]

Originally Posted by andrewwynn

EWS stands for D rive A way P rotection.

(Whatever the three words in German). Aka immobilizer.

The "catch22" is that you won't get a code until you get a start from my understanding. But look into immobilizer, because it comes up on the forum regularly the EWS gets out of sync and allows crank but no start (why allows crank the world may never know)

EWS = Elektronische WegfahrSperre

If the rolling code sync between EWS and DME is lost it's lost permanently until initialised again with diagnostics. This can't explain temporary non start symptoms (cranks but won't allow fuel injection).

(If we were talking about temporary symptoms where the engine is not even cranking a problem on EWS module key recognition and start motor activation is a different thing.)

EWS 3.3 bedtime reading.
http://www.e38.org/EWS.pdf

[Coleman El]

Okay. Will do.

[X5chemist]

Can we check fuel pressure? How many miles on it? How much fuel is in the tank?
No spark is a biggie. Remove and clean the cam position sensors. Check the wiring harness. Wiggle the harness while someone cranks it.

[Coleman El]

Which is the cam sensor and which is the crank sensor?

[Coleman El]

Originally Posted by X5chemist

Can we check fuel pressure? How many miles on it? How much fuel is in the tank?
No spark is a biggie. Remove and clean the cam position sensors. Check the wiring harness. Wiggle the harness while someone cranks it.

Yes there's fuel in the tank. I have 15X,XXX miles on it. I just replaced the tb and maf sensor.

[andrewwynn]

Cam sensors are right on the front of the engine. The crank sensor is usually near the bell housing for the transmission. I've never changed on M62 not sure exactly where it is.