1991 325i m20 help, madison
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These engines can be finicky on plugs, everyone seems to prefer the NGK but it also depends on the type of plug.
I'm basically doing the same thing as you, throwing parts at the 325i because its that time anyways. I would be willing to swap around parts if you wanted to meet at my shop sometime. I'll keep what I take off the car this weekend in case I run into similar issues but I don't think mine could run any worse
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The plug issue was on my m50 and I had a noticeable power and mpg improvement when I switched to the NGK. I didn't realize at the time that NGK was OE and just used them from previous good experiences. I found a set in an m52 with 210k on it that had NGK on one side and BMW on the other side of the spark plug.
The vacuum gauge can be helpful to diagnose leaks, spark issues, a sticking valve. Somewhat more application on even older engines where you could adjust the timing by turning the distributor, old mechanics can set the timing with a vacuum gauge. The one I am sending is a cheap one and reads a little low but the main thing is how the needle moves rather than the actual measurements. I took a couple videos that I will post later.
The dropping tach needle could be a CPS issue. I noticed that when driving with the cruise on it would feel like a misfire when the needle dropped. The CPS tells the ecu where the crankshaft is so it knows when to send the spark. If the CPS isn't pulsing you won't get spark at all. Here are some pics from mine. http://www.wibimmers.com/board/index.php?/topic/2215-new-ride-89-e30-vert/page-6
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These engines can be finicky on plugs, everyone seems to prefer the NGK but it also depends on the type of plug.
I'm basically doing the same thing as you, throwing parts at the 325i because its that time anyways. I would be willing to swap around parts if you wanted to meet at my shop sometime. I'll keep what I take off the car this weekend in case I run into similar issues but I don't think mine could run any worse
thanks cyoung. yeah id love to swap plugs / wires to start there and see if thats the issue before getting to more expensive things. visversa if i have some parts you need to try. where's your shop?
JC43098 - i could have what you're describing. i'll try to drive and post a video of whats happening
i think i have the timing ok after the change? i hand cranked everything a few times through and it all lined up as it was supposed to.
Andrew
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All items replaced:
timing belt, timing belt tensioner, all belts, distributor cap, water pump, thermostat, valve cover gasket, plugs, wires, air filter. All the tune-up things since i didn't know when they were last done.
I would look at the fuel filter and fuel pump if you haven't yet. I am in Cottage Grove and am more than willing to help you diagnose the problem. I am around almost every night after 5pm.
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Thanks Jd, I'll probably take you up on that. I haven't had a chance to get it out again and the weather didn't help last night! I'm also waiting on my plates to arrive, so I don't want to drive it on the street too often. After I can get it out I'll shoot you a PM.
JC - I got your vacuum gauge. Can you help me figure out how to use it by any chance? Never done a vacuum test before.
Thanks again,
Andrew
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did the vacuum test, at idle it was at about 11ish PSI. Pushing the gas in neutral it would jump up to 17-18. All lines and hoses seem seem intact. Anyone ever try the cigar smoke test on these cars? Where would i introduce the smoke into the system?
Changing fuel filter tomorrow. Cleaned ICV
Every time i start the car it seems to get worse. I'm stumped as problems only arose after doing routine maintenance and I haven't driven the car more than 20 miles from swapping parts. I don't think I will make it to anyone's shop who's offered to help me (thanks again by the way you guys!) without breaking down as bad as its running. Don't suppose anyone is around the westside that could help for a beer?
Andrew
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did the vacuum test, at idle it was at about 11ish PSI. Pushing the gas in neutral it would jump up to 17-18. All lines and hoses seem seem intact. Anyone ever try the cigar smoke test on these cars? Where would i introduce the smoke into the system?
Changing fuel filter tomorrow. Cleaned ICV
Every time i start the car it seems to get worse. I'm stumped as problems only arose after doing routine maintenance and I haven't driven the car more than 20 miles from swapping parts. I don't think I will make it to anyone's shop who's offered to help me (thanks again by the way you guys!) without breaking down as bad as its running. Don't suppose anyone is around the westside that could help for a beer?
Andrew
The idle vacuum is too low. Is it steady, fluttering, or wandering? That is an ok reading when at higher RPM on that particular gauge, 17-18 is actually around 21-22 inHg. (inches of mercury, a smaller measure of pressure).
You are sure the cam timing lined up right? You should try removing each spark plug wire one at a time and see if there is one that does not make a difference. There could be a bad wire even though they are new. You will see the result immediately if the cylinder was working properly. This would rule out a spark issue that is possibly one cylinder only. Maybe a wire didn't get crimped right or the cap is deformed.
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Thanks guys, I'll try both tonight and report back. I'm 99% sure that timing is right. I did the timing belt in December and drove it back and forth from rimrock road to verona a couple times without issue before performing the plug and were changed. I did those in February.
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Did the plug check over lunch. That checked out fine. Unpluged each one, the engine would change sound a bit, then as I got the wire close to the plug you could hear each one spark. After connecting the engine sounded normal. So, I don't think there's a misfire issue.
When I do the smoke test tonight I think this is the correct brake booster line to disconnect? There are two in this area, one right on top of the other.
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I could use the ICV but then won't I be missing if there's a leak from that a point forward through the airbox? Is there a better part in the system to blow into to capture everything? At the fuel pressure regulator hose? If so, should I blow from point 1 or 2 attached? Thanks, never done this before, should be fun.
Yeah, just using some old cigars. Gonna have to be sure not to inhale too much or I'll get a mad buzz. Wait, or maybe I should?
Andrew
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I could use the ICV but then won't I be missing if there's a leak from that a point forward through the airbox? Is there a better part in the system to blow into to capture everything? At the fuel pressure regulator hose? If so, should I blow from point 1 or 2 attached? Thanks, never done this before, should be fun.
Yeah, just using some old cigars. Gonna have to be sure not to inhale too much or I'll get a mad buzz. Wait, or maybe I should?
Andrew
The pressure drop happens across the ICV and throttle body plate so any leaks on the airbox side of those 2 things is not as much of an issue. It will only let a slight amount of air through that did not get metered by the air flow meter (flapper thing in the intake). The pressure on the airbox side of the throttle plate and ICV will be very close to atmospheric.
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well, i didn't do the vacuum test yet. Changed the fuel filter and went for a drive around the neighbor hood. While compression could be better I don't think it's really a major vacuum leak. Here's why. While driving it starts out running pretty good, strong acceleration, reasonably smooth. A little rough, but drive able. The problem gets REALLY bad after the car warms up. I'll try to attach a video. (video didn't work, ugh) You can't hear sound all that well, but the engine is about to cut out. Probably would if I let it keep going it sounds BAD. You can see the temp gauge flicker, mpg, etc. Again, only gets terrible after it warms up.
So, I think I can rule out bad plugs and wires cause it goes fine for a bit.
I noticed while jacking the car up to change the filter I have a bad gasket after my catalytic converter. There was A LOT of water/exhaust liquid dripping out. Not gas though, didn't smell. just vapor. Could mean nothing, could mean something, i don't know. Not sure how the problem only happening when up to operating temp might play into all that.
Thanks again for all your help. Sure would be nice to get her running for spring.
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idle is fine until it's warm. it starting surging real bad while driving. i limped it back to the garage, put in neutral and it would still surge badly. i shut it down then and came on here.
been doing lots of searching online. Does the fuel pressure regulator make any sense that it'd fail when engine is warm? I gotta find some westsiders that I can swap parts with.
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