E30 Zone

Hello,

Need some advice as I have try to find the problem but failed.

Idle at 600rpm and now car has run at 150 kilometers since rebuilt.

Compression tes is good 130,120,120,120,120,140.

Power while acceleration is good and solid, Cruise at 1500 rpm to up is good and solid.

No air leak. Icv good, afm good, camshaft and rockers is new.

Used old injectors but I have test is good.

New spark plugs and have change sparkplug cable and no change.

The problem is only while idle at 600rpm it is rough and body shake, but while I press the accelerate pedal shake is reduce a lot still feel vibration but very very little.

My friend suggest me to change the valve seal and re seating the valve because he think it is the suspect or may be valve guide is not good.

Does is it true and can I diagnose it with leak down tester? Before I disassembly my Cyl head again?

Or what caused the shake?

Any advise very appreciate.

Thank you
Markus

Note. I have also problem with e30zone system, I can make new thread but the system prevent me to send reply or quote and I don't know how to fix it. So I will respond your advice at my first thread.


Response to speedtouch
May be because I use cheap compression tester so it it no represent the real value, I will re check again.

And while I made test the engine haven't break in yet and not warm enough. I file the piston ring so the gap is 0.3mm

Idle is steady at 600rpm but the idle is erratic, I mean not have good rhythm and too much shake.

Engine mount is good

Another development
I just made leak down test and at Cyl 1 and a few otherI found that a significant air leak through intake valve so the tester can not hold air it drop soo fast.

I think this is the problem why my engine idle is so erratic and the compression test number not is low.

I will change my valve guide but I don't know which should I buy as there is a standart and +3 diameter.

Any info about this? And any advice to support my development?

Thank you

The compression readings on the centre four cylinders look a bit on the low side.

Alldata says a new m20 should have 142-156psi with a maximum of 60% variance (lowest cylinder should be 60% or more of highest cylinder), engine warm, throttle open.

Try pouring a teaspoon of engine oil through the spark plug holes and see if the readings increase...

Also, what state are the engine mounts in?

Did you increase the lift of the cam?

Check ignition timing and clean tracks on MAF with paper.