Help me troubleshoot an M20b29 replacing an M20B27.

[Tinkerer007]

what tune are you running?

Just the stock ECU.

I think I want a W.A.R. chip to be able to keep the OBC functional. But I don't understand how I would tune it. What tools can I use, and what inputs do I need to track?
CPS (TDC)
AFM (Is this engine load?)
Temp (Operating tempature)
TPS ( Idle / normal / WOT)
Is there a signal for the #1 spark plug wire? (Would this show timing?)
O2 (Feedback on fueling)
AC (Show additional load on the engine for increased idle speed)

Are there any other inputs that drive the ECU?

[ForcedFirebird]

Do some research before purchasing WAR, we have removed a few of them at work to replace with MS. It's nothing more than a preloaded emulator which you can get from Moates.net for $175.

[Tinkerer007]

I got an exhaust gas analyzer today.
The AFR is good on the freeway.




If I accelerate hard it goes very lean (over 20). (I guess I have to stop that until I can figure out how to address.)

I also have a ping on hard acceleration or acceleration from less than 2K RPM. I think retarding the timing would help?
I installed another computer with a Dinan chip, and it pinged worse. (I assume they advance the timing to take advantage of higher octane fuel.)

How long does it take for a computer to learn when you change it? At what point does it not learn any more?
(Edit: E30wiki says -- 11.Go for a drive, the car will run a bit “rough” for about an hour while the ECU learns the new chips settings.)

I have a Nuke adjustable cam gear. Does this adjust both cam timing and ignition timing? How much should I try retarding it? I was thinking 3 degrees would be a good start.

I will order an Ostrich 2.0, and see what I can do with that. (Thanks for the pointer ForcedFirebird.)

[bmwman91]

Assuming that there are TDC marks on the cam, set it to TDC (or whatever is indicated on the cam, it is not intended to me manually advanced or retarded since the tune in the ECU will only be optimal for one position of it). Ignition timing is controlled by the ECU.

If the thing is pinging, it is probably because of the hotter cam and increased compression. I assume you are running 91 octane gas? Pinging with a stock set of ignition timing values is a red flag for sure.

As far as "learning", the M1.x ECUs are very limited. The main thing they do is take O2 sensor feedback and store basic adjustments based on that. The "short term" adaptation occurs nearly constantly once the engine is warm, and ends up looking like ~1Hz oscillation in AFR. It is an additive correction. The other one, which is "learned" is the "long term" adaptation. That one basically determines an "average" deviation from stoichiometric, so if you put in larger injectors it would determine that there is a global rich condition. It is a multiplicative term, meaning it will serve to scale all fuel calcs by the reciprocal of the determined deviation. In my experience logging AFR, this "long term" correction takes maybe 15-20 minutes to fully settle when driving with the engine fully warmed up. You want to disable both the short and long term corrections when trying to tune fuel.

There are some other adaptations pertaining to idle control as well, which do seem to take a little longer to settle, probably because most of the time spent running is not at idle.

Are you still experiencing any intermittent power loss or other abrupt changes to behavior while driving, or is the issue now just pinging and general lousy running? If it is just poor running with no major hiccups, then it is probably the case that this non-stock engine plus a stock tune is not a great combination. Digger and ForcedFirebird have way more experience with built M20's, so they would know how well it should run (or not) on a stock tune. Assuming there are no other red flags form them that indicate electrical or mechanical issues, I am standing by my recommendation in your thread in the tuning subforum...Sssquid tuning.

[Tinkerer007]

bmwman91 Thanks for the comments.

It is still lean. And cuts out ~3800 RPM at WOT. If I accelerate with moderation, it will pull well to 6k RPM.

I have reached out to SSSquid.

[Tinkerer007]

So, I have replaced the engine with a stock I engine.
My boys have been learning to drive and one of them got his drivers license.

I have the stroker engine in the garage, and measured the valve lift with a degree wheel and dial indicator (.001").

Intake open @ .020" 347 Intake open @ .050" 3
Intake peak of .433" @ 113
Intake close @ .050" 223
Intake close @ .020" 235
Max lift .433"

Exhaust open @ .020" 133
Exhaust open @ .050" 146
Exhaust peak of .419" @ 249
Exhaust close @ .050" 2
Exhaust close @ .020" 15
Max lift .419"

Advertised duration 274/274
Lobe separation: 136 (?)

Any other measurements I should get? .005"?
I didn't measure valve clearance (seems like this could affect numbers).

[digger]

I usually set zero lash measure open and close at

(0+cl = 0.25)
(0.1 +cl = 0.35)
(1+cl= 1.25)
(0.050”+cl = 1.52)
(0.200”+cl = 5.33)

or put another way set clearance at 0.25 and measure open and close at fhe following lift points

seat
0.1mm
1.00mm
1.27mm
5.08mm

[Tinkerer007]

So, my son was sporting around in the E30 with the "stock" engine, and it "stopped working".
Found a broken rocker arm.

I need to get the car to pass a smog test
, so I put the stroker engine back in.

After chasing miscellaneous leaks, loose hose clamps, unseated throttle cable (high idle), new battery, I got to go for a drive today.

Wow, the car drives great, and pulls hard to redline at full throttle (originally would cut out at 4K RPM).

I did buy a rebuilt set of M50 injectors.

And this was on a stock chip.

Pretty exciting. Now, fingers are crossed it will pass smog.

[hasa]

If you found a broken rocker it likely needs proper valve springs.

[Tinkerer007]

So, the M20B29 still had the cut out after re-installing it.

Last week my son gapped the plugs, and that seems to have resolved the cut out. He set them to .28, not sure what they were before... :-( Boy do I feel silly.

[3seriersD]

By chance, do you still have the old harness for the b27?

[Tinkerer007]

I don't. I gave them away with the engines, I think.