Hi folks

i'm a mexican guy i have a doubt about the AWD system.

In mexico the smog test is done on a dyno with only the rear wheels.

My question is

How the AWD system will be act if detect the front tires without move and the rear axle running on the dyno?

Thanks

Gabo

 

It'll probably try and engage the front axle, hence why it's all wheel drive.

I believe you can pull a fuse or something that basically pull power to the system. My answer should only be a quick response and something for you to search the forums for.

Don't go pulling the fuse because of my response, <-- my disclaimer.

Call up your Ford/Lincoln dealership too and ask them. Maybe they have an idea.

-rockstate

 

I would say first ask the inspection place, I doubt you're the first one with this issue. What do they do about vehicles that have all time 4WD?

 

Here in St. louis they use a dyno that has rollers for all 4 wheels for use by vehicles with full time 4x4 or awd. You may want to inquire about that.

 

Your front tires should not engage on a dyno. They only lock in if the system sences some slipping. Its not an all time AWD system. Unless your is totally different than mine.

I copy & paisted this for you.


The only available transmission, regardless of engine, is an automatic 4-speed, but you can order the Expedition with either 2wd or awd. Ford's Control Trac has a dashboard switch that allows you to select 2wd, awd, 4wd High or 4wd Low. In the awd setting, Control Trac selects 2wd for normal driving, but automatically engages 4wd when it senses the rear wheels slipping. This makes for better traction on wet, loose or icy surfaces. Four-wheel antilock disc brakes, dual airbags and an antitheft system are standard. A locking center differential and a skidplate are available optionally, as are front/rear air conditioning plus two types of air suspension systems (one for 2wd and one for 4wd).

 

In CT they put AWD drive vehicles on dynos that have two sets of rollers, but as 99 said you don't have full time AWD, you have A4WD which only kicks in when it slips.

 

Um sorry you two but I have to point out the obvious. If the rear wheels are on the dyno rollers and are turning, while the front wheels are on the floor and are not turning, to the A4WD system this will appear to be rear wheel spin. The system will engage the front axle and the vehicle will lurch forward.

 

I have to do smog every year. It a pain because my swampers have to come off and I have to roll there on the stock rubber. I have had it for 5 years now and everytime they do it. Only the rears spin. I don't think the system on a dyno conciders it slipping. I belive it kicks AWD when one wheel starts to spin faster that the other. Not front to rear but from right to left in the rear. slipping.

 

Big expo, you should post a pic of your Expy. I wanna see what she looks like.

-rockstate

 

I'm new to this forum. And also glad I found it. You guys seem like a great group. I can't figure out how to add info on my signiture line???

 

Alloro you are correct as always. I didn't think enough, no coffee. In any event it won't matter, he'll be on rollers in the front.

 

BigExpy, you might have to have a certain amount of posts before you can put something in your sig - I'm not sure.

However you can upload pics to a photobucket account and post 'em up. I think to put 'em in your gallery you have to have like 25 posts. Probably the same with adding to sig.

-rockstate

 

In any event, go to User CP on the top left, then look down like an inch and click on "Edit Signature"

-rockstate

 

The PCM reads the front wheel speed sensors and compares them to the rear wheel speed sensor located inside the rear diff. If it determines that the rear wheels are turning faster than the front wheels it will activate the clutch inside the transfer case, which applies power to the front wheels, IF, your selctor switch is in the AWD position. Some early vehicle years (I don't remember which years - '98 and '99?) had a 2WD position on the selector switch, which prevents the front wheels from engaging. Maybe your vehicle has the 2WD position?

 

Im stumped on this one. Mine def doesn't have 2wd. In any case they have to have a way to test more than just rear wheel and front wheel drive cars. There are so many AWD vehicles out there.