Non-BMW Stuff on a BMW Forum
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...one thing has crept up that I've noticed. Everyone once in a while when I'm driving, it is usually just cruising along, the car seems to cut out for half a second and jolts. It feels almost as if the throttle body snapped shut and then opened back up. Then the car keeps going as if nothing happened. The cluster doesn't change, the needles don't zero out, no lights come on. I've read that the main relay and ECU can eventually start going bad and cause little blips like this. I would assume if the main relay was bad, there would be a loss of electrical power, not just "mechanical" power.
My e34 had similar symptoms. Eventually started getting worse. Finally stopped working long enough for me to do some troubleshooting (a nice way of saying it died and left me on the side of the road...). After trying a couple other things with no success, I jumpered the fuel pump relay and it fired right up.
After that, I changed out both the fuel pump and main relay, but it still kept happening. I never actually fixed it, but the problem was assumed to be the ECU at that point. I just wired in a switch to bypass the fuel pump relay because the car was a POS and it was funny. I daily drove it for months after that and never had any problems.
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Check your ECU number and let me know, I've got a spare ECU for an M20 laying about as well.
^HipMF did some amusing fixes for that issue and it was interesting to see the failure.
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Does the cutout happen when you hit small bumps/road imperfections? If so maybe something is a little loose and gets jostled. If you haven't done so already make sure your battery connections are tight, also the connections to the power block under the hood. Are the three relays new and do they fit tightly in the carrier (main, fuel, 02), track folks often ziptie them down into the carrier to keep them from moving. Could be the electrical disruption is so slight that it doesn't show up in the cluster or by the time you look it's already passed.
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Check your ECU number and let me know, I've got a spare ECU for an M20 laying about as well.
^HipMF did some amusing fixes for that issue and it was interesting to see the failure.
Will do! I've read that as a possible cause. I'll message you that info and maybe if it's the same, we can group it with the carpets.
Does the cutout happen when you hit small bumps/road imperfections? If so maybe something is a little loose and gets jostled. If you haven't done so already make sure your battery connections are tight, also the connections to the power block under the hood. Are the three relays new and do they fit tightly in the carrier (main, fuel, 02), track folks often ziptie them down into the carrier to keep them from moving. Could be the electrical disruption is so slight that it doesn't show up in the cluster or by the time you look it's already passed.
No, road imperfections make no difference. This has happened wot in 1st gear and it has happened while cruising in 5th on a smooth road. There is zero consistency to it.
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Interesting and frustrating. Your R3v thread mentions PO had the same issue?
Just a random list of a few more things: Plugs and wires tight, no oil in tps plug connector, any issue with air flow meter (try swapping), stomp test or code reader to see if any stored fault codes since you noted cel flashed, fuel related (does fuel level matter, something that is intermittently affecting flow: fuel pump wiring, crap in tank clogging screen, water in tank, fuel pump, etc)
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Interesting and frustrating. Your R3v thread mentions PO had the same issue?
Just a random list of a few more things: Plugs and wires tight, no oil in tps plug connector, any issue with air flow meter (try swapping), stomp test or code reader to see if any stored fault codes since you noted cel flashed, fuel related (does fuel level matter, something that is intermittently affecting flow: fuel pump wiring, crap in tank clogging screen, water in tank, fuel pump, etc)
Yeah, the PO said he experienced it too every once in a while. New plug wire and they are all tight, spark plugs were torqued down to their recommended torque settings. Stomp test was not useful because the ECU doesn't store codes; only active codes. Crank position sensor bracket being out of alignment might explain this. I replaced the crank sensor and it still happened, so if it was a hardware issue, and not sensor issue it would make sense.
It really doesn't feel fuel related, but I may replace the ignition coil and fuel pump this winter just for good measure since they're both original. Unfortunately I parked the car for the winter to address some things, so I'll just be refreshing some of the parts and then come Spring, we'll test it again! lol
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Switching gears here:
To those with e30s who drive theirs pretty frequently with the occasional spirited driving session and maybe some autocross: what engine and transmission mounts do you have?
I currently have the condor solid engine mounts and poly 80a transmission mounts and the vibrations/noise they transmit is too much for what I want the car to be - a comfortable spirited daily driver for the summer with an occasional autocross. I would like to go back to stock engine & transmission mounts but hoping to get some input on that.
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New DME and Fuel Pump relays are never a bad idea. I kept spares with me at all times as a cheap easy thing to keep me going if i ever found myself dead on the roadside. They have been known to cause similar issues. The other item is the injection harness corrosion and crank sensor alignment. I had powdercoated my bracket along with all my other engine parts and that thin film of plastic was enough to cause the car to cut out at 4500rpm. new uncoated bracket fixed it
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New DME and Fuel Pump relays are never a bad idea. I kept spares with me at all times as a cheap easy thing to keep me going if i ever found myself dead on the roadside. They have been known to cause similar issues. The other item is the injection harness corrosion and crank sensor alignment. I had powdercoated my bracket along with all my other engine parts and that thin film of plastic was enough to cause the car to cut out at 4500rpm. new uncoated bracket fixed it
That's right. The relays were another thing I read to replace. I will replace those as well. I had also powdercoated my CPS bracket, it might have made the issue worse, but I believe the bracket was still a little messed up before powder coating. I am ordering a new bracket.
As for transmission mounts. use E21 mounts with reinforcement cups. Anything stiffer than original rubber becomes a NVH issue. Condor UHMW/poly Engine mounts are just fine in the NVH department.
Now please excuse me while I go back into hibernation
The e21 transmission mounts and e24 engine mounts appear to be the go-to HD stock engine mount substitute. Probably best to go that route.
Goodnight.
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When the 1990 was still streetable I had the e21 transmission mounts (w/o cups) and the BW engine mounts (probably same as the e24 in terms of hardness)
https://www.bimmerworld.com/Engine/Engine-Mounts/Heavy-Duty-E30-325-Engine-Mount-Set_2.html
If you go with the e21/e24 combo watch for Garagistic's Black Friday sale coming up later this month, here's the current listing but they usually have some good BF deals. If you sign up with them you get early notification of deals
https://store.garagistic.com/E30-hd-mounts-23711175424-11811132322
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To those with e30s who drive theirs pretty frequently with the occasional spirited driving session and maybe some autocross: what engine and transmission mounts do you have?
I think you're on the wrong forum for this question.....
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When the 1990 was still streetable I had the e21 transmission mounts (w/o cups) and the BW engine mounts (probably same as the e24 in terms of hardness)
https://www.bimmerworld.com/Engine/Engine-Mounts/Heavy-Duty-E30-325-Engine-Mount-Set_2.html
If you go with the e21/e24 combo watch for Garagistic's Black Friday sale coming up later this month, here's the current listing but they usually have some good BF deals. If you sign up with them you get early notification of deals
https://store.garagistic.com/E30-hd-mounts-23711175424-11811132322
Garagistic does offer a ton of sales, so that's a good idea. I saw their kit and was going to get that, but found the same mounts (searching part numbers) on RM European for $8ea.
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I think you're on the wrong forum for this question.....
lol. I have noticed that many of the cars here are on jack stands.
I should rephrase that question:
To those who have driven their car at some point while in their ownership...
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To those who have driven their car at some point while in their ownership...
Still wrong forum.
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Still wrong forum.
To those who have installed engine mounts: did the poly engine mounts or rubber engine mounts feel better in your hands?
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To those who have installed engine mounts: did the poly engine mounts or rubber engine mounts feel better in your hands?
Just my two cents, but for a street car I’d go for the HD OEM stuff if I were you. Usually not very expensive, it should last a long time, it’ll make the car more pleasant to drive, and you really don’t have to worry about fitment or quality like with some aftermarket stuff. Obviously, if it’s gonna see track time that doesn’t apply and I’m of absolutely no help, but for what it’s worth I’ve been nothing but pleased with every OEM bushing I’ve put onto my car (except for rear shock mounts, the stockers suck wiener). Other people will be better sources for info for autox stuff, but this is my recommendation for a car capable of spirited driving.
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I ordered the e21 and e24 mounts. I think they'll do the job. I would like to get into some autocross next year, but I'm guessing it will be fine.
I intend to almost daily this next summer, so I would like it to be as comfortable and quiet as it can be while still being great for a spirited cruise.
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