I drove 6 miles but odometer shows 10

[Netboy]

Oct 1: FIXED! See post #14 of this thread for the details.

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Hi, I recently bought an '89 325is which has had an s50 engine swap. The car runs pretty nice, but it has a number of issues I am trying to resolve.

The other day I noticed that the odometer is WAY off -- it records 10 miles for every 6 actually traveled (verified by freeway mile markers and GPS). The speedometer is off a little (when traveling 60, speedo shows 65), but the odometer reading is wacked. It almost seems like it is displaying kilometers. However, the gauge cluster appears to be a US model (says Miles above odometer).

I know the speedo and odometer both get their input from a single sender on the differential, so I don't understand how one can be fairly accurate and the other off so far. I don't think an incorrect coding chip would cause this (?).

If anyone has a clue, please give a shout -- thanks!

[Rascal2pt0]

First thing to check is tire diameters. If your tires are smaller than stock then the reading will be off.

[KennyT]

Reading 5mph fast will give you 6.5 miles for every 6. Its possible that your odo gears are skipping and needing replacement, also possible the speedo is mis reading and your odometer is working correctly. I would try another cluster to figure out which is the problem.

[Netboy]

First thing to check is tire diameters. If your tires are smaller than stock then the reading will be off.

Tire size variations could account for some error (say plus or minus 10%), but NOT the roughly 40% the odometer reads too high.

What I hate is that the odometer is running up miles that are not really on the car (every 6 miles I drive registers as 10 miles on the odometer).

[jlevie]

With the speedometer being fairly close to correct and the odometer being way off, I'd suspect the speedometer/odometer first. Swap in a different unit and see what happens. If that doesn't help saw out the speed sensor

[xxx-Lost-Soul-xxx]

I had a US cluster i got out of the junkyard. everything was fine,till i had the same issue you had. Went back to the junk yard,and found out the car was from canada,and only the face had been swaped. Also know someone whos E24 had the same thing.

[Jaxx_]

often times gears can miss teeth and jump, watch the odometer while driving(maybe someone else should watch...) if it jumps and isn't smooth, there's something wrong with the gear mechanism.

[b*saint]

Just unplug it so many miles.

[FredK]

I had a US cluster i got out of the junkyard. everything was fine,till i had the same issue you had. Went back to the junk yard,and found out the car was from canada,and only the face had been swaped. Also know someone whos E24 had the same thing.

This is the most likely scenario.

The symptoms of odometer gears going bad is underreporting mileage. Just the way the odometer gears mesh together, it would be extremely difficult to make them read 40% high.

I'd suggest finding a used cluster somewhere, removing the speedometer, setting the mileage (this can be tricky, but patience is key when setting it), then dropping it back into your car. Finding one without stripped gears can be challenging, but there are a few people that refurbish clusters and do a good job.

"Jean" knows the ins and outs of them and might have a couple on hand.

[Netboy]

Hey everyone, thanks for the ideas and comments.

This is the most likely scenario. The symptoms of odometer gears going bad is underreporting mileage. Just the way the odometer gears mesh together, it would be extremely difficult to make them read 40% high.

I totally agree. In the absence of some kind of electronic glitch that I don't know about, it seems to me the odometer problem almost certainly has to be caused by kilometer gears rather than mile gears (something along the line of what xxx-Lost-Soul-xxx said: Canadian or European odometer guts). It is frustrating to not know the history of the car. The PO generally did a decent job on the swap but there were a lot of little short-cuts taken, such as lots of stuff held together with cable ties (the radiator for example), lose wires here and there, and components not connected (ABS, backup lights, cruise). So who knows what they did with the odometer.

I'd suggest finding a used cluster somewhere, removing the speedometer, setting the mileage (this can be tricky, but patience is key when setting it), then dropping it back into your car. Finding one without stripped gears can be challenging, but there are a few people that refurbish clusters and do a good job.

I have my eye on a cluster on ebay that is from an '88 325is, and it has about the same mileage as mine (150k). If I win that auction, I should have the components to compare and swap. Also, pulling out my cluster will give me a chance to update the SI board batteries. I'm not too worried about the trickyness of adjusting the odometer of a new cluster to match my mileage -- when I was a teen I had a lot of odometers apart for adjustments. LOL


I will post a followup if I get this problem solved....

[Netboy]

Just unplug it so many miles.

LOL! Maybe I could install a switch on the dash so I can turn the odometer off one week a month!

[sonnyqm3]

On a e30 m3 we change the coding plug from a 5 series. is that something that might fix the problem for the OP.

[Pac1373]

the 6/10 ratio would put that at nearly the exact Miles/KM ratio. I suspect as mentioned earlier that you have a Metric cluster with a US Standard guage face.

[Netboy]

the 6/10 ratio would put that at nearly the exact Miles/KM ratio. I suspect as mentioned earlier that you have a Metric cluster with a US Standard guage face.

I think almost certainly that was the problem. I bought another instrument cluster on ebay out of an '88 325is, and got it today. I just slipped it in to my rig, and drove 9.6 miles -- and my GPS said I had gone 9.6 miles! Yahoo.

The old cluster had been replaced or at least opened up -- screws and nuts were missing. I understand that the guy that did the engine swap dealt in used BMW parts, so I'd say they slapped the guts from a Canadian (kilometer) car into the cluster. Anyway, this all means that the real mileage on the car is unknown, but it doesn't matter because ALL the running gear and suspension has been replaced and everything is tight.

I fixed up the new gauge cluster with a carbon fiber face and chrome gauge rings -- it looks great.

[Pac1373]

nice, glad you got it fixed, looks great.