S52 Swap Hard Start Issues...

[HyperMikeD]

So Ive been trying to work out the little bugs on my S52 swapped Ti and here is one I'm having a hard time figuring out. Ive read lots of posts/threads about it possibly being a ECM problem, FPR problem, a leaking injector problem, or a CPS problem. All sensors are Brand New, New CPS, New Cam Sensor, New Knocks, New O2, New 255LPH fuel pump. No check engine light and yes it works. I swapped 413 ECUs with a friends. No change. I installed a known good set of injectors with new seals. No change. I swapped the stock fuel pump back in place of the 255lph unit. No change. I installed a known good stock OBD1 fuel rail w/ FPR. No change. I installed an OBD2 fuel rail w/ aftermarket FPR set to 51psi per Bentley. I assume this deletes the anti-drain back function of the factory FPR so the internets say to wait 3 seconds for the fuel pump to prime. No change. The fuel pump doesn't initially prime but does pulse when cranking. So I wired it to a relay switched on with the ignition. Then it loads up and when it finally hits there's usually a loud bang followed by a 4 foot flame that shoots out the exhaust. So I don't think its a fuel problem ...

What are the odds that I got a bad CPS out of the box and how do you check that ??

Any suggestions ??

TIA.
MikeD.

[Platanos]

Mike, are your new sensors oem bmw? or are they autozone brand? I bought some autozone crap (cps) and it was bad from the box. It was also a little shorter (1 or 2 mm) than the oem one.

I think the CPS is supposed to see a 5v signal. I don't know why, but that sounds familiar...

[HyperMikeD]

I bought them from Pelican...I dont think it was OEM but another.

Ill have to find my receipt to confirm.

Guess I can swap in a known good used OEM CPS and see if there's any change.

Thanks !
MikeD.

[BMW_Hatchback]

Sounds like EWS

[slow_ti]

Yeah. Go to the dealer and get the EWS realigned. Oh I think there is a member on here that does it


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[HyperMikeD]

Not EWS cause I am driving it....

[BoostLee]

how does it run once it's started? that 4 foot flame is the clue

[HyperMikeD]

Update...I ohm'd out the new cps and it was way out of spec.

I installed a known good BMW cps and it cranked much better but was backfiring worse than before.

Ultimately it was the EWS...Cut pin 7 and it now fires right up like its supposed to.

Thanks guys for help !

Cheers !
MikeD.

[BoostLee]

That seems really strange, EWS is usually crank and no start at all.

[HyperMikeD]

Yeh thats what I thought...This isnt my first swap and usually they wont start at all.

[BMW_Hatchback]

Originally Posted by BMW_Hatchback

Sounds like EWS

Originally Posted by slow_ti

Yeah. Go to the dealer and get the EWS realigned. Oh I think there is a member on here that does it


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Originally Posted by HyperMikeD

Not EWS cause I am driving it....

Originally Posted by HyperMikeD

Update...I ohm'd out the new cps and it was way out of spec.

I installed a known good BMW cps and it cranked much better but was backfiring worse than before.

Ultimately it was the EWS...Cut pin 7 and it now fires right up like its supposed to.

Thanks guys for help !

Cheers !
MikeD.

Originally Posted by HyperMikeD

Yeh thats what I thought...This isnt my first swap and usually they wont start at all.

Glad the info worked for you. Usually EWS will crank and the fuel pump will prime, but it shouldn't turn over. I've never heard of clipping EWS II though

[HyperMikeD]

Yeh its a bastard child of about 5 different cars...The EWS wire wasn't even green/white it was a violet/grey on the engine harness side but on the car side it was correct. Really weird.