E30 all new- won’t rev past 3-4-5k depending on CKP adjustments

[Rutech13]

Hi everyone.
I got 88 325e with 325i engine/harness/ecu/dash in it .
I got this car in barely running condition but after a full ending rebuild,new head was also installed .
im fighting ,what seems to be a simple problem at first ,a nightmare if my days .
Car will not rev past 3000 rpm,no matter at WOT or half throttle or even driving. All kinds of test and swaps and new parts done to it-nothing.
But here is a catch that stomps me . If I go and adjust CKP bracket all the way out and put few shims under sensor ,it brings me way out of recommended specs,but-car will rave up to 4000-4300 now-if I mess with it more I can achieve 5000-5300 but in that condition it takes more that 5 seconds of cranking to start it .
With that said-least start a discussion so I know what info y’all would want me to provide .

[Rutech13]

I’ll throw out here what have been replaced:
4 ecu’s(all kid of numbers)
4 CKP sensors (2oem ,1hella,1chinise)
FPR (oem was good but I still put hella I believe )
3 fuel pumps ,all tested good (bosh oem in it now)
2 TPS (oem and hella) both tested as they should
3 AFM -all tested perfect but still swapped it
Harmonic balancer
CKP sensor braket
Coolant temp sensor ECM side
plugs
3 engine coils
vlaves adjusted
fuel drained and refiled before pump replacement
Bosh fuel filter
ICV was good but still cleaned it just to make sure .
Grounds and powers are secured
alternator puts out 13.5 at idle
fuel pressure 38-42 psi at idle,45 ish at WOT
Fuel delivery 30sec/30oz

Got no stomp test on any of those ecu’s but connected the scanner and got no codes .

[It's Soda Not Pop]

Which DME's did you use? (meaning 173, 525, etc.) Stock chips in the DME's? Did you replace the cap and rotor? Does it break up at 3k rpms and then keep trying to rev past that? Or does it stop there like it is the limiter?

I was having issues awhile ago with my car. It would buck and misfire bad underload around 3k-4k. I went with a standalone with LS coils from ClassicDaily. All my problems went away. I replaced everything similar to you and I kept having the same problem. I believe it was in the ignition somewhere. Either way I went standalone and didn't look back.

Check you plug wires and make sure that the crimp hasn't come loose. I had bad wire one time that looked fine at a glance. But the crimp on the inside was bad.

[tomstin]

Have you tested all the circuits back to the ECU (continuity)? There is a connector under the intake on the "I" engines that is notorious for corrosion, make sure all those connections in that connector are clean.

[Rutech13]

It’s Soda Not Pop, ecm’s two 380 ,173 with chip .
i got donor car that runs only while cranking but even that thing would rev up to the sky.
Yes,just like a rev limiter-half throttle it nice and smooth but full throttle it goes “ratatatatata” but only at 3k unless I mess with CKP sensor
cap and rotor are new Berim and coil bosh .
if I set CKP sensor by Bentley book 1mm -/+.3 than I left with 3k rpm and periodically poop from exhaust ,but when I put spacers to bring it further away from h.balancer I achieve 4k and a little worth starting and idling conditions. And when I put it twice further away (2ish mm) from balancer I can achieve 5k+ but in this condition car will not start unless I bring sensor closer.



What stand-alone did you go with?

[Rutech13]

tomstin, I’ve check a few at ecu-yes. What exactly should I have check ?
Also it seems that I have early version of the i harness as I don’t have a circle injector harness plug and my injectors connect separately one by one .
car or connectors got no rust or corrosion
I’ve check relays fuses and 101 connector
🤷

[digger]

If it runs then the circuits obviously work. to get the the bottom of this from a root cause you need to scope out the VR crank signal when it runs and then when it plays up and see if that is the cause whether this be loss of signal fully, in part, excessive noise etc (most likely is as the change of air gap affects the result) and if not then also repeat on the same but on control side of the coil as IMO these are the two (2) most likely culprits.

for the case where the standalone ECU swap fixed things it is possible that a different ecu will have much better signal conditioning than the 1980s tech so can deal with a degraded signal without necessarily fixing the root cause

[Rutech13]

By “scoping” you mean oscilloscope?

[digger]

By “scoping” you mean oscilloscope?

yes here is an example from m42 but should be similar for m20

https://www.r3vlimited.com/board/forum/e30-technical-forums/engine-drivetrain/alternative-tuning-w-a-r-megasquirt-etc/341864-the-definitive-m42-crank-and-cam-angle-info-thread

[zaq123]

when you gap CKP too much, you loose sync hence your rpms go up, normal behaviour. You have probably some mechanical issue with TB plate/ cable etc or your ECU ids acting up.