Rough idle and feels sluggish

[Jaybee325is]

Hey all,
So I've got my 88 325ic manual all back together (blown block). That's the good news.
The bad news is that I have 3 primary issues.
- there's a chatter in neutral with the clutch in the engaged position
- I'm experiencing not so much a rough idle as much as a rev surging at idle. Not a huge one; just 6-900/1000 rpms. Sounds like a light revving. Gets worse as the car warms up.
- gas smell
- I feel like I'm pushing the car harder than I used to. Tach works intermittently so I'm not sure on rpms but I'm in 4th gear at 40mph. I'm basing shifting on engine noise and not wanting to push it too hard at the moment.

What I've done.
-afm I leaned it out a bit thinking it's getting too much gas, but I'm thinking that was the wrong choice.
- valve adjustment. Fairly tight 10. Medium touching on feeler gauge.
- tps is clicking in (about) the right place.

Any suggestions on what I've done? I'm thinking I'm looking at an O2 sensor next. Praying it's not the cat.

[supermansocks95]

My first one surged like that. After I had the O2 sensor replaced, it went away.

[Gregs///M]

Adjusting a 30 year old AFM without having it replace with new or having it refurbished, will not help you much. The signal output to the DME will still be weak leaving you with rough idle, sluggish running, and sudden/brief misfire type symptom at certain speeds.

[ahlem]

Double check to see that you aren't one notch off on your timing marks?
Did you replace the O rings at the injectors?

[Jaybee325is]

Adjusting a 30 year old AFM without having it replace with new or having it refurbished, will not help you much. The signal output to the DME will still be weak leaving you with rough idle, sluggish running, and sudden/brief misfire type symptom at certain speeds.

Well I did clean it a bit. I have another that I'll do a full refurb on. And try that.

[Jaybee325is]

Double check to see that you aren't one notch off on your timing marks?
Did you replace the O rings at the injectors?

I'm 99.9% sure timing is dead on. It's (and an obvious oil starvation) is what blew it up in the first place.
Didn't replace o rings. Thinking fuel pressure?

As I was driving it today it felt very wound up. Like torkier. In a bad way. Wondering if valves are too loose.

[Jaybee325is]

Oh. And it's ticking.

[estoguy]

Well, there is always a tick to a M20... properly adjusted, it should sound like a sewing machine at idle.

[Jaybee325is]

Pretty damn close to a sewing machine. I thought that meant it was a little out. I'm trying to dial this thing in. Maybe I'm a little gun shy having blown up the last.

[estoguy]

Another possible fix for the idle could be adjusting your spark plug gap. When I got my E30, the spark plugs in it were set to the narrow end of the spec. I put in new NGK ZGR5As, and their out of the box adjustment were closer to the wide end. There was an old article from the now defunct E30World that suggested a smoother idle with a wider gap.

" Gapping spark plugs on the higher end of specifications makes for stabler idle speed. "

FYI, The gap for the i engine is .028"- .032" (0.7 - 0.8 mm). I think the NGKs came out of the box at .031", if memory serves. And I never readjust them while in service and change them every 60K km or so.

[Chris Spiegl]

Another thing could be the fuel pump connector.

"- I'm experiencing not so much a rough idle as much as a rev surging at idle. Not a huge one; just 6-900/1000 rpms. Sounds like a light revving. Gets worse as the car warms up.
- gas smell
- I feel like I'm pushing the car harder than I used to. Tach works intermittently so I'm not sure on rpms but I'm in 4th gear at 40mph. I'm basing shifting on engine noise and not wanting to push it too hard at the moment."

All of that my car had. I fixed it by removing the fuel pump and replacing the oring (part #16111744369 , ordered from ecstuning) the oring stopped the gas smell. I replaced the connector with a new plastic plastic connector that I pulled at a pull a part and now it works great.

[Jaybee325is]

Ok. Well I did another valve adjustment and it's much better. Idle has smoothed out a bit, but now I'm showing low oil pressure. Changed oil (20w50) and filter. I'm hoping it's my pump and not bearings.
I gues my main question at this point is: how do I know when my AFM is correct?