E30 Zone

My m52b28 is having issues where it has no power and does not pull at all across the entire rev range.

When cold it will pull quite strong, but higher in the rpm it feels like it is hesitating. It runs alot better when colder though.

It idles perfectly, though blipping the throttle it sometimes drops the revs slowly. Also it back fires alot when downshifting (or rolling down hill in gear it will cough and splutter back firing). And also between gearshifts.


I have bought a range of new things I will be swapping in all at once, VANOS seals, IAT sensor, Camshaft sensor, water temp sensor and new bosch O2 sensors. (I have a strong suspicion it has something to do with these as I got it scanned and it threw codes for the O2 heating? - We cleared them and it ran quite well for a while but has eventually gone crap).


Any one have ideas? I have replaced the MAF with a new one and also coils from another M52 but both made no difference.

Had same on mine was a leak on the inlet to head! New rubber gaskets and it run sweet might be worth a shot parts are cheap and easy to fit good luck jim

fooking hell you spend some on it. Check the rocker cover they do crack and sends all of them faults O2,MAF faults to the ECU

I have replaced the O2 sensors now, the last ones were pretty fouled. It runs alot better, but still flat above 4000rpm.

I am going to change the intake as I am thinking I have am strangling it by having a smaller intake than the MAF on there, but it has a carbon intake box around the air filter - Which probably needs to be changed too.

Still issues;
Idles perfectly, Though it is quite rich when warming up. So much so when rev'd cold there is moisture spat out the back, also a tad smokey. But very faint. It has not lost any coolant since I filled it months ago and did over 500kms so doubt it's coolant.

Flat sport above 4000rpm.

Doing either this weekend or next:
Replace Intake air temp sensor,
ECU Coolant temp sensor,
Cam Angle sensor,
Vanos seal replacement (though I think this would only help an idle / low rpm issue which I still think it is lacking in low end torque)
And if I get the larger intake piping / new air filter I will install this. I have read that POD filter added directly to the MAF can cause turbulence and confuse the MAF, But who knows. I will extend it further with pipe and close it off as a cold air intake since I will lose the carbon intake and old air filter.