Author Topic: Unable to rev past 3k... (Read 17174 times)

318iEric · « **Reply #30 on:** December 13, 2012, 07:41:10 AM »

All good advice keflaman; and to answer your question, I toyed around with mine a little when I was leaving work yesterday and it did its' usual cut-out at around 2250 in gear, but to my surprise, when clutched it would run up to ~3000 before hitting the cut. But, again, the longer I drove, the better it got. Even hit the actual limiter on the interstate once it was up to temp. So I don't know!

I've got a week off coming up so hopefully I'll get in and poke around some more.

Hunsbergring · « **Reply #31 on:** December 13, 2012, 05:17:33 PM »

Hunsbergring · « **Reply #32 on:** December 13, 2012, 05:18:29 PM »

Hey, Eric, just saw this and your PM--haven't been on here in a few weeks.

I haven't thrown any more time at my issue since my last post. I've been focusing on my 325e and my new winter beater, which is a nice, rusty, dented, boring, '99 Civic hatch. Pretty easy to justify 800 bucks on something you know will run through the winter without giving you any guff. Too bad about the complete lack of steering feel, but whatcha gonna do?

I fired up the 318i today for the first time in a few weeks. Got it up to temp and took it for a drive. Didn't misbehave at all, but these days it's going for 30mins or more before acting up.

Next job is going to be grounds. Gonna find every one I can and clean it up. Battery connections are good, so I'll go for the alternator next and proceed from there.

It's hilarious that yours and mine are doing the same thing but under opposite conditions! Mine runs fine cold but sputters when warm, yours sputters when cold but runs fine when warm. I expect we're chasing the same gremlin, here.

Hunsbergring · « **Reply #33 on:** December 13, 2012, 05:30:52 PM »

...sorry for that blank post. It won't seem to let me delete it...

keflaman · « **Reply #34 on:** December 13, 2012, 08:26:24 PM »

Quote from: jtrenary;116818

I have a new fuel pump; pressure & flow check per Chilton manual. Also new:
camshaft sensor
vacuum hoses (replaced as they were when I purchased car)
O2 sensor
fuel filter
injectors
spark plugs
plug wires

Coils check ok and am getting spark on all four.
Exhaust has been checked for blockage.
Replaced ECM with another used one.

Nothing has helped. Still suspect hoses and need an accurate diagram for my 1991 318 I.

Hope you all don't mind my adding my problem. (first time user)

The M42 Holy Grail for "The Mess Under The Intake". Refer to page 14, post #321 for an excellent picture reference.

keflaman · « **Reply #35 on:** December 13, 2012, 08:57:33 PM »

Quote from: Hunsbergring;117529

Does anyone have a quick link for DME pin tests? I've just been through that on my Eta but haven't been able to find a list of tests for an M42. Figure it'd be easier to do that and test a bunch of sensors all in one go rather than yanking stuff out one at a time...

I'm not sure if you're going to be able to download this, but I just tried and it appears to be working: http://bmw.ctcms.net/BMW/Software/E30%20CD%20Repair/Cd%20Repair%20Bmw%20e30.rar

Page 202, section 12-111/4. It's a read only PDF document and a great (if not better IMHO) companion to the Bentley.

keflaman · « **Reply #36 on:** December 13, 2012, 10:26:22 PM »

Quote from: Hunsbergring;118327

I fired up the 318i today for the first time in a few weeks. Got it up to temp and took it for a drive. Didn't misbehave at all, but these days it's going for 30mins or more before acting up.

Next job is going to be grounds. Gonna find every one I can and clean it up. Battery connections are good, so I'll go for the alternator next and proceed from there.

It's hilarious that yours and mine are doing the same thing but under opposite conditions! Mine runs fine cold but sputters when warm, yours sputters when cold but runs fine when warm. I expect we're chasing the same gremlin, here.

Here's an idea: Cool down what's hot and heat up what's cool.:cool:

Your problem actually sounds like a coil and I know you swapped them around, but typically when a coil has a cracked case or is breaking down internally it will operate fine when cool but exhibit exactly what is happening as you describe it. So, drive the car until it starts to sputter and then immediately swap out the coils (or another component you suspect) and see what happens. If you don't have a spare, throw that component in the freezer (or snow bank:eek:) for ten or fifteen minutes and reinstall.

318ieric - you could try doing the same thing in reverse: hit a component with a hair dryer or heat gun and see if you can duplicate your problem while the engine is cold.

Hunsbergring · « **Reply #37 on:** December 14, 2012, 09:20:19 AM »

Keflaman--I've actually tried that exactly! It was one of the first things I did when the problem appeared.

For my own peace of mind, I think I've comfortably exhausted all ignition/fuel delivery/DME/sensor possibilities and need to move on to grounds. Since the DME was throwing codes for two completely unrelated components (cam sensor and diff speed sensor), that sounds to me like a bad ground that's causing problems for a few different systems. Will start with alternator ground.

romkasponka · « **Reply #38 on:** December 14, 2012, 11:02:19 AM »

Cam sensor is related to that problem. I was not able to rev past 3k. After sensor replacement problem was solved... Quite important is to have correct gap, my friend had missing O-ring and after he installed O-ring fault of the cam sensor was gone.

keflaman · « **Reply #39 on:** December 14, 2012, 07:58:53 PM »

Quote from: romkasponka;118339

Cam sensor is related to that problem. I was not able to rev past 3k. After sensor replacement problem was solved... Quite important is to have correct gap, my friend had missing O-ring and after he installed O-ring fault of the cam sensor was gone.

And my theory about the coils doesn't stand because it wouldn't be RPM specific.:mad: Sorry about that.

I disregarded the cam sensor because two of the cars swapped a total of three sensors (two of them were new) and the problem persisted.

As an act of penance for my misdirection I will pull my cam sensor and remove the O-ring. Standby for results.

Edit: Going back to the basics, have you guys tried pulling your sparkplug wires one at a time while it's running rough to see if there's a difference?

Hunsbergring · « **Reply #40 on:** December 15, 2012, 10:05:09 AM »

I haven't pulled the wires one at a time since it's clear that the ignition (or fuel) cut is complete--it's not just one or two cylinders not firing, it's definitely all of them.

keflaman · « **Reply #41 on:** December 16, 2012, 07:56:23 AM »

I hope you don't see my contributions to solving your problem as little more than spamming the thread. Solving the mystery is a bit of a personal issue for me: http://www.m42club.com/forums/showthread.php?t=8981

I never figured out my problem and as I stated in the thread, it occurred only when I drove the vehicle. I even tried several different driving styles; I lived in Italy at the time and it was an '89 Euro-spec car, non-cat.

I looked into the O-ring issue as suggested by romkasponka and I don't see how it could affect the sensor except in regards to a wiring issue.

318iEric · « **Reply #42 on:** December 17, 2012, 12:15:37 PM »

Got a bit of an update; I was able to pin down a buddy of mine who works at an indy Benz shop, but they had a scanner for BMW's so we hooked it up and were able to see a few things the stomp test didn't reveal. The only fault code stored was for the No. 2 knock sensor (replaced both knock sensors w/ new Bosch units earlier this past year, while chasing another issue which turned out to be a dead injector), were able to see the intake temperature reading and it seemed reasonable considering the ambient temperature and the fact that the engine was hot when we scanned it. Coolant temperature readout seemed right as well. Wish I'd written the exact numbers down, but the scanner honestly wasn't the best one around so I was really just looking for a major red flag here.

He reset the knock sensor code, and we need to scan it again now that I've driven it a while to see if it came back. My thoughts at this point are:

-something's causing it to knock when cold (failing plug/wire/coil/fuel injector) and the DME is retarding/advancing timing to try to fix the knock, hence in effect "limiting" the revs

OR

-the knock is due to the "misfire" triggered by the DME when the engine is being "limited"

Since I know the knock sensors are new and I in no way touched them (or anything to do with them) while repairing the seals I mentioned earlier, I'm operating under the assumption that they're working correctly. To me, it's a question of which came first- the knock or the DME reacting to the knock..if that makes sense.

In regards to my first suspicion about a failing component, the plugs have probably less than 10k miles on them, although they aren't the copper plugs I've read so many places that our engines seem to prefer; they're Bosch dual-tipped platinums, whichever ones are outlined in the owner's manual. I checked resistance on the coils back this summer (when the plugs were replaced) and they all checked out just fine, and one injector has been rebuilt; no. 3 I believe.

jtrenary · « **Reply #43 on:** December 30, 2012, 03:52:03 PM »

I got mine back from the shop with no resolution and no charge. FYI, my fuel pump has been replaced and my speed sensor, CAE, has been replaced. The car was running hot, so I replaced the thermostat with a cooler one. Now it runs too cool (154 deg. F.) Could the O2 sensor cause this problem because the engine is not actually at operating temp? My reading of the literature indicates that it would simply run in open loop, but it should run.
At one point I thought I had it fixed. The literature indicates that the ABS could throw a code to the ecm if the wheels were slipping. Two of my wheel sensors were bad. Replaced them and it seemed to run fine on short trips, about six miles; just enough to get heated up to operating temp. Then, it started cutting out again at 3500 rpm. on the same six mile test run. I have checked continuity of the sensors and replaced the DME twice. Any new thoughts?

318iEric · « **Reply #44 on:** January 07, 2013, 07:37:23 AM »

Well guys- I can't say w/ 100% certainty that it was any one thing, but something I did last night fixed my rev problem. As I believe I'd mentioned before, my harmonic balancer had a slight crack in the rubber which caused it to "wobble" as it rotated. Well, last night I installed another balancer from a junkyard car and cleaned the crank position sensor and wallah! No more rev problems

I discovered, once I removed the old balancer, that it appeared as though perhaps (somehow) the balancer had shifted from center. I'm not sure how this could happen because the woodruff key was intact, and I don't recall having to put any effort at all into installing it when I had it off the first time. Perhaps torquing it down with the crank bolt caused it to rotate?? Still doesn't make sense, though, if the key wasn't broken. So I don't know, but I'm just happy to report that it appears to be back to normal.

Thanks for all the head scratching guys- if not for you guys, I probably would have spent countless hours and money replacing things that didn't need replacing.