[Need Engine Help!] 2.7i varying compression issues

[_kanon]

Hi R3V

I'd like to ask you guys some quick questions (okay maybe not so quick) about getting a chip for my car. I'm new to engine work (car work in general really) and my E30 is my way of learning and getting know automotives more. Please bear with me if I seem to ask too many questions hah. Also I've been reading through the sticky on 2.7i engines. So down to business.

I bought a grey market 323i sedan from Florida this past month. The engine, however, has been reworked and there is not a lot of documentation on it. Here's what I know about it (little details from the previous owner and from driving it). The quotes are from the previous owner.

- 325e bottom end
- 325i top end
- "injectors are larger than stock"
- "as is cam"
- "The ECU might need to be reprogrammed to match"
- compression testing shows now shows:
1. 170
2. 170
3. 150
4. 100
5. 90
6. 125
- MAF, headers, a few other things have been upgraded to match the 325i top end as well
-dog leg transmission (I'm not sure if this will matter)

from driving it
- rough idle (400-600 rpm). it will bounce up and down that range before settling on around 500rpms - could be due to having e pistons
-edit* fixed the misfiring.

My goal at the moment is to gain reliability and gas mileage and fix that engine is fire. I'm not looking for any serious power gains any time in the near future. That said, do you think

1) Using a chip like this one:

http://sssquid.com/v2/shop/e30/e30-327i-conversion-chip-2/

would help me solve some of my problems (i.e. low gas mileage, low idling speeds)

2) IF so, what would else would I need to know about my engine in order to run the chip? I.E should I try to figure out what pistons, crank, cam and rods and ECU I actually have?

Just thinking about it, seems like figuring out what exactly is in my car seems like a good place to start, for myself and for others to help me.

I apologize if this is rather long but thank you for help!
Thanks and cheers!
Kelly

[digger]

sounds like you have other general maintenance issues besides the chip. it should run ok on a stock chip if everything is functioning

first thing is verify the injectors have flowrate in the right ballpark, the PO could have been some genius who though that 30lb injectors would flow more and hence make more power. whats the bosch part number on them?

[_kanon]

sounds like you have other general maintenance issues besides the chip. it should run ok on a stock chip if everything is functioning

first thing is verify the injectors have flowrate in the right ballpark, the PO could have been some genius who though that 30lb injectors would flow more and hence make more power. whats the bosch part number on them?

Digger,

Thanks for your help. The Part number reads as 0 280 150 716. Here's a picture:



My research tells me that it's a stock 325e injector @ 12.75lb/hr (correct me if I'm wrong!).

So my friend helped me out with a compression test. The readings are all over the place!

1. 170
2. 170
3. 150
4. 100
5. 90
6. 125

Also the reason for the misfire was a spark plug fouled with oily dirt. I think the rough idling is due to the compression being all over the place. My friend who helped me out suggests i just swap in a regular working m20b25 and don't mess with the 2.7i 'frankenstein' engine anymore.

[digger]

yeah not healthy

[_kanon]

yeah not healthy

Tell me about it :(

Any ideas on what it could be? I did a little research and this thread: http://www.e30tech.com/forum/showthread.php?t=93639

makes me believe I could possibly have bad rings (from that site: supposedly leading to fouling the spark plugs) or valves (the rough idling).

How accurate is this test (on that same link): squirt oil in cylinders #2 and #6 to see if compression rises. If yes, you have bad rings.

Hook up a vacuum gauge to your fuel pressure regulator vacuum line. If the needle vibrates like crazy at idle but gets steady if you raise the rpm's then you got bad valve(s).

I might do that to test it out.

[digger]

leakdown test also can help diagnose