Problems If I Remove ABS Completely (DII)?

[Greg Davis]

A friend of mine has a 97 Defender, and was told that there is a tone ring which feeds info back to the ECU to determine if the vehicle is in motion or not. He doesn't have ABS, but if that ring is not there, the engine will think the vehicle is stationary and it will not go above idle. He found this out when he went to aftermarket CV's and shafts. I had never heard of this before so it got me thinking.

So here's my question. Is there something similar on my DII? If I remove the ABS pump, sensors, etc. when I do my axle conversion, will it affect anything else? Is the ABS system somehow integrated into other areas of my vehicle so that it won't run properly if I remove it?

[madcowdungbeetle]

Originally Posted by Greg Davis

He doesn't have ABS, but if that ring is not there, the engine will think the vehicle is stationary and it will not go above idle. He found this out when he went to aftermarket CV's and shafts.

I don't know that I quite understand this. I mean, if you put your foot on the gas, the engine revs, and if you put it in gear, the vehicle goes. The ABS ring is just for the ABS sensors/computer (I think) and I would think should have no bearing on the function of the rest of the vehicle, especially the engine.

[Greg Davis]

That was my thinking as well. But my friend actually spoke w/ the Master Tech and was told that even though he doesn't have ABS, the computer reads whether or not the vehicle is in motion, and this helps control engine functions such as air/fuel ratio, etc. If he had left the rings off of his new CV/shafts, the engine would have been on permanent idle.

While this doesn't seem logical to me, I just want to make sure before I find something out the hard way.

PT, you ever hear of anything like this?

[Dave_Lucas]

I know he is a master tech and all… But that sounds like BS to me.

What about people that have upgraded to CV’s without tone rings that have discos and RRC’s? I guess you could always just try unplugging all 4 connectors and see if it will still move .

If that were true it would be a great trick to play on someone crawl under and unplug all 4 lines and watch them just sit there

[lwg]

I'm kind of with Dave on this one. I had ABS on my 1990 RRC, and I cut all of the sensors. The only negative effect was the dang dash light for ABS was always on, the positive effect was I didn't have ABS. Everything else was the same. I would think the '97 D would work the same because I think it has the exact same computers (14CUX, can't remember what type ABS computer).

On a DII it might be different. Since it has 4-wheel traction control, HDC, and other gadgets it might disable. I have heard of ABS failures on the trail stranding DII because there is no CDL though. With Traction control only one wheel will spin, kind of difficult to off-road with that.

[ROVER JUNKIE]

the rover will still move but you will a check eng. light. eng ecu uses abs ecu for speed input

above info not not for 14 cux ecu

[lwg]

Originally Posted by Dave_Lucas

If that were true it would be a great trick to play on someone crawl under and unplug all 4 lines and watch them just sit there

Maybe we can test this theory on some unsuspecting soul in Leadville next week!

[Discosaurus]

Originally Posted by Greg Davis

That was my thinking as well. But my friend actually spoke w/ the Master Tech and was told that even though he doesn't have ABS, the computer reads whether or not the vehicle is in motion, and this helps control engine functions such as air/fuel ratio, etc. If he had left the rings off of his new CV/shafts, the engine would have been on permanent idle.

Maybe what he means is that the ECU will think the truck is stationary and run a different set of defaults then it would if it was running down the road at 100KPH.

Since there is no electronic throttle control on these engines, it wouldn't be possible to hold the engine at idle.

[Greg Davis]

Like I said, it didn't make any sense to me, but I've been wrong about stupid things before.

Anyway, I guess I'll just pull all my sensors, fuses, etc. and see what happens. Thanks for the input.

[mongosDII]

Hey Greg,
it doesn't make a difference, I haven't had the ABS hooked up in my DII for the last year (pulled the sensor wiring harness because of the lift)...only thing is the abs/tc/hdc lights stays on. I don't think you could fool the ecu with a resistor or something else because it a not a constant. But mine's been fine..are u really putting d60's on that thing?

Frank

[Keith Armstrong]

Now wait a minute....isn't the only thing the CV tone ring and accompanying ABS sensor on a '97 Defender (NAS) used for is that stinky "rough road" sensor?

[Discosaurus]

No, I think there is an independent sensor for that rough road BS.
At least THAT input makes SOME sense on a electronic controlled engine...

[PTSchram]

Originally Posted by Keith Armstrong

Now wait a minute....isn't the only thing the CV tone ring and accompanying ABS sensor on a '97 Defender (NAS) used for is that stinky "rough road" sensor?

Bingo! It MAY result in an error code due to "Rough Road" errors. OTOH, it may result in the absence of the rough road codes.
The engine will rev above idle, but it may also result in retardation of spark and illumination of the CEL.

I hate ABS!!!

[Old Scout]

So no VSS in a '97 Defender?

[Greg Davis]

Frank, thanks for the info. And yeah, one of these years I'll get it done.

[SeaRover]

>> So no VSS in a '97 Defender?

I know there's no VSS on the DII, at least not like D1's and RRC's. I had to swap the rear output housing on my DII case i installed on the rangie to make the electronics happy

dunno about the DII's and ABS - mine is happy without the tone rings; gone from every wheel finally

[darkstar]

You guys are talking about the "rough road sensor" on the 97 D90s. The purpose of it is the following: if the computer senses that the truck is off-road, it will igonore minor engine misfires, assuming that the cause is the the engine (and the rest of the truck) is being bounced around.

ABS discos 96 to 99 have this also--when I first started having ABS problems I pulled only the ABS fuse in the under dash fuse panel, and I was getting constant check engine lights. There was absolutely no difference in performance or fueld mileage when these codes were set, so I doubt that a different fueling program was used. Pulling two more fuses in the engine compartment (along with the abs light bulb in the dash) got rid of that pesky annoyance.

I would ASSume that the same fix can be applied to the 90. Does it really use the wheel speed sensors for other stuff? I don't know for sure but I would be surprised if it didn't have the transfer case mounted VSS like a Disco of the same vintage.

[PTSchram]

Originally Posted by Old Scout

So no VSS in a '97 Defender?

I can't speak directly to the '97, but the earlier defenders (93 110s, 94 & 95 90s) used a similar setup to those found on early Rangies (pre-95)-ie: there is a VSS, but the speedo is mechanically driven with an in-line VSS on the inner frame rail, right side.

[red90rover]

As I recall, the VSS was as PT states (a box in the speedo cable). All it did was turn off the high idle control once you were moving.

[JPGUY]

Originally Posted by Greg Davis

A friend of mine has a 97 Defender, and was told that there is a tone ring which feeds info back to the ECU to determine if the vehicle is in motion or not. He doesn't have ABS, but if that ring is not there, the engine will think the vehicle is stationary and it will not go above idle. He found this out when he went to aftermarket CV's and shafts. I had never heard of this before so it got me thinking.

So here's my question. Is there something similar on my DII? If I remove the ABS pump, sensors, etc. when I do my axle conversion, will it affect anything else? Is the ABS system somehow integrated into other areas of my vehicle so that it won't run properly if I remove it?

The anwser is no. Now was that so hard people?

[ROVER JUNKIE]

from rave on disco 2

[ROVER JUNKIE]

i don't know what happens to anything if you unplug the abs, but the abs sends road speed to a couple of ecus

[Greg Davis]

RJ, that's good info!

Welcome.