AWD Delay

NoName · #1 01-25-2007, 02:30 PM

This started a couple months ago before i did not have this issue. When i am in the snow, my front wheels will spin then anywhere from 1 - 5 seconds later my back wheels will kick in. If i am giving it lots gas it will make a big clunking sound when the back wheels kick in. I had the car in a transmission shop for some work(replacing torque converter) I mentioned the awd delay issue to them. They said they looked it over and said that it had to be an electrical problem that everything checked out ok when it was apart. What electrical stuff should i look for and how should I test. Or what other things can i check to try to clear up this issue.
Any suggestions would be great.
I searched the forums to look for some info but didn't find any clear answers or ways i can check electircal components.

oab_au · #2 01-25-2007, 03:18 PM

Quote:

Originally Posted by NoName

This started a couple months ago before i did not have this issue. When i am in the snow, my front wheels will spin then anywhere from 1 - 5 seconds later my back wheels will kick in. If i am giving it lots gas it will make a big clunking sound when the back wheels kick in. I had the car in a transmission shop for some work(replacing torque converter) I mentioned the awd delay issue to them. They said they looked it over and said that it had to be an electrical problem that everything checked out ok when it was apart. What electrical stuff should i look for and how should I test. Or what other things can i check to try to clear up this issue.
Any suggestions would be great.
I searched the forums to look for some info but didn't find any clear answers or ways i can check electircal components.

Hi NoName, you should put some info about your car in your locker. Makes it easier to troubleshoot, if I know the model, and any previous work.

The delay in driving the rear wheels is not an electrical problem, it is caused by a delay in the transfer valve, sending line pressure to the transfer clutch.

When the front wheels spin, the TCU detects the difference and sends a signal to the C solenoid to apply pressure to the transfer clutch. Yours is letting the front wheels spin too fast, by the time the clutch engages. That is where the CLUNK comes from. If this is allowed to continue, it will break the transfer clutch drum off the transfer gear.

There are as number of faults that can do this.
1. The transfer valve spool is sticking to delay.
2. The transfer valve reducer holes are blocked.
3. The oil sealing rings that seal the transfer oil, from the case to the clutch are worn and leaking.

The fix is to pull the rear of the box and replace the C solenoid/transfer valve, check the sealing rings for the clutch and the clutch plates.

A search of "C Solenoid/transfer valve replacement", should tell you all you need.

Harvey.

Trevor · #3 01-25-2007, 03:18 PM

Quote:

Originally Posted by NoName

This started a couple months ago before i did not have this issue. When i am in the snow, my front wheels will spin then anywhere from 1 - 5 seconds later my back wheels will kick in. If i am giving it lots gas it will make a big clunking sound when the back wheels kick in. I had the car in a transmission shop for some work(replacing torque converter) I mentioned the awd delay issue to them. They said they looked it over and said that it had to be an electrical problem that everything checked out ok when it was apart. What electrical stuff should i look for and how should I test. Or what other things can i check to try to clear up this issue.
Any suggestions would be great.
I searched the forums to look for some info but didn't find any clear answers or ways i can check electircal components.

Not a definitive reply as there are several possible answers. I would start by checking the TPS as per my instructions within the how too stuff. This will cost you nothing and you can move on from there, towards the C solenoid and other reasons for delay in the center clutch operation.

NoName · #4 01-25-2007, 04:10 PM

I can't find your how to on the tps sensor. I am wondering if you can post a direct link to it please.

oab_au · #5 01-25-2007, 04:57 PM

Quote:

Originally Posted by NoName

I can't find your how to on the tps sensor. I am wondering if you can post a direct link to it please.

I would not worry about the Throttle Position sensor. It won't affect the delay.

Harvey.

Trevor · #6 01-25-2007, 06:30 PM

Quote:

Originally Posted by oab_au

I would not worry about the Throttle Position sensor. It won't affect the delay.

Harvey.

The TPS is exactly involved in respect the initiation or start time of signals. N.B. no reason is given or fact stated within the instruction.

Trevor · #7 01-25-2007, 07:17 PM

Quote:

Originally Posted by NoName

I can't find your how to on the tps sensor. I am wondering if you can post a direct link to it please.

Here are the instructions:-

ADJUSTING AND CLEANING THE THROTTLE POSITION SENSOR.

In order to adjust the TPS the manual says to measure voltage at the TPS by inserting meter probes into the plug at the ECU plug connection. Nice and easy that is ! In order to accomplish the feat at the TPS itself, therefore without tying yourself in a knot under the dash, you will require, best of all one of those dress making pins with a nice thin shank and a knob on the end, or a thin needle. Also a meter to measure 0.5 volts d.c..

The TPS comprises a potentiometer, presumably used in a voltage divider configuration, as three wires come from it. There is a plug and socket close to the unit so that it can be easily removed for servicing. At this plug the wires are --- black ground and one end of the resistance element, red the other end and white the wiping contact.

Stick your pin right through the white insulated wire, so that you can clip your meter lead onto it to make measurements. A fine pin will not damage the conductors as they will spread and there will be no significant damage to the insulation. Measure between the wiper, i.e. white wire and ground by connecting to engine, chassis, battery negative, or whatever.

If you remove the unit, stick the pin in before replacing it, as it is much easier to do on the bench. Don't forget to pull it out when you have done the deed.

Now from the book :-- 1. Connect all connectors. 2. loosen TPS fixing screws. 3. Turn ignition on. 4. Adjust TPS position while throttle valve is confirmed FULLY closed, to specified voltage, using a volt meter. 5. tighten fixing screws.

The voltage is specified as within a tolerance of from 0.45 to 0.55 volts. You should have no trouble in setting things at exactly half a volt.

Before removing the TPS or altering the original setting it is a good idea to mark the mating castings with a scratch so that one can check on the adjustment, before and after, as a matter of interest. It is always nice to know if the effort expended has in fact improved things.

CLEANING AND CHECKING.

After removal the unit it is easily checked with an ohm meter for smooth operation or otherwise. Evan without dismantling the unit a spray with CRC or similar cleaner and a work out will do wonders. The resistance end to end ( black to red ) should measure very close to 5000 ohms. Measuring between white and red or black should show a smooooooth change in resistance when moving the control shaft over full distance.

A voltage check on the output as the mechanism is operated while connected and energised, will also give an indication of possible intermittent contact. Again using a needle or pin to make contact can be helpful.

A meter with a bar graph or a scope, will show up short duration faults much better than a normal instrument, digital or analogue, as both have an inherent time delay before indication is registered. This factor should be taken into account.

NoName · #8 01-26-2007, 09:18 AM

Thanks for the info Trevor i will check that out as soon as i have some time to mess around with it.
This morning on my way to work I decided i wanted to test out the AWD again. I found an empty ice parking lot. I have found the AWD never takes longer than 1 second to kick in. Also, when all the wheels are spinning, if i give it full throttle and the rpms hit about 5000 i hear a sqeaking sound coming from the back of the car. Anyone of any input on that? Could the rear diff cause delay or anything around there. Or is the sound a 2nd issue that may be seperate that i have to deal with?

NoName · #9 01-27-2007, 09:36 AM

I did some more test driving on the way to work this morning
The awd is totally random for the ammount of time it waits before it kicks in, maybe at the most 2 seconds, some times it is normal that all wheels spin right off the bat.
The squeaking sound is what I think i should focus on, when it squeaks the rear wheels dont spin or hardly spin atall. It will squeak when i get all the wheels spinning anywhere over 4000 rpms. I can't tell for sure where the squeaking sound is coming from. To me though it sounds like the back but could be anywhere.

Is there something in the rear diff that causes this?
I think the transmission shop only had the front apart that is another thing that makes me think it is the rear diff. I wouldn't mind an experienced mans opinion
Where is the best spot to look for the squeaking?

Ricochet · #10 01-27-2007, 09:50 AM

Sounds like you need a 5 speed swap.

NoName · #11 01-27-2007, 10:17 AM

I am actually going to sell my car very soon. I just want to try get the awd working properly before i sell it.

Ricochet · #12 01-27-2007, 10:44 AM

I would sell it as-is then.. you'll probably lose money trying to fix then sell.

SVXRide · #13 01-27-2007, 11:55 AM

Sounds like your solenoid C might be on its way out. If you've got a car lift, it isn't all the difficult to swap in a new one. You can check my locker for pics of when SVXFiles and I did the work on my SVX.
-Bill

oab_au · #14 01-27-2007, 05:53 PM

Quote:

Originally Posted by SVXRide

Sounds like your solenoid C might be on its way out. If you've got a car lift, it isn't all the difficult to swap in a new one. You can check my locker for pics of when SVXFiles and I did the work on my SVX.
-Bill

The random operating action of the rear drive, that you say, goes along with a sticky transfer valve.

It does sound like the Transfer clutch is slipping under load, and producing the sound that you say. The slipping under load, can be the clutch itself, but as the Transfer valve is playing up, it is most likely that it is not getting enough pressure, and slipping.

Harvey.

NoName · #15 01-28-2007, 03:24 PM

Quote:

Originally Posted by oab_au

The random operating action of the rear drive, that you say, goes along with a sticky transfer valve.

It does sound like the Transfer clutch is slipping under load, and producing the sound that you say. The slipping under load, can be the clutch itself, but as the Transfer valve is playing up, it is most likely that it is not getting enough pressure, and slipping.

Harvey.

Solenoid C controls or is part of the transfer valve right?