Gauge Cluster stuff

txredgt · Sep 30, 2010

So I just bought an 01 Cobra cluster and I am looking at putting it into my 02 GT. I already pulled the back off my cluster and put it on the cobra white face gauges so that process is done. I did this because of two reasons: 1) My milage is less that was on the Cobra cluster (By 25K) and 2) so when I resell it I don't have to risk the chance of someone questioning the milage since that is a pretty big crime if I remember correctly. After I put it all back together with the Cobra face gauges and the back and guts of mine it works great, tach, gas, battery, oil, temp.. all of them except for the speedo. I thought this might be an issue obviously since the GT cluster is a 150 and the Cobra is 160. I do have an SCT Tuner and put a call into AM to ask them if there was a fix but the tuners were out until tomorrow so I will call back then. Is there an easy fix to this or should I wait till tmw? Is another option to get it calibrated by a shop? I know the handheld can do it for gear changes but will it be able to do this as well? I am just trying to brainstorm and get some ideas and thoughts from other ppl! Either way its going to look much better than those original gauges that were in there. If it comes down to it I guess I can just live with the milage if its the only way. Thanks fellas.

nyuk98gt · Oct 1, 2010

ahall2004:

Not much help here but at least your thread will get a bump to the top.

I ran a search (using "cobra cluster") and found some good threads. From what you describe, it sounds like you have done everything correctly. Are you sure that the connection(s) is properly seated?

From the threads I found, it *should* be plug and play even if you are using a cluster that is a model year earlier or later than your car. "Skud" had a problem with his instrument cluster swap because the circuit board turned on the rear defrost (and eventually blew a fuse).

I did not find anybody who needed to flash the PCM to somehow correct the 160 mph speedo (vs. the 150 mph GT speedo). This should not be required in your car either.

HTH,

Chris

wmburns · Oct 1, 2010

I am having problems understanding how this WOULD work. If I understand this correctly, the OP has taken a GT cluster and used a Cobra overlay. Same movement behind the speedo.

To me, it would have been a surprise if it did read correctly. Why? Because the movement behind the overlay is the same. The speedo movement is deflecting exactly the same for 70MPH as it did before. BUT the overlay goes to 160 in the same amount of sweep that the GT took to do 150. The speedo should be off by 6.6 percent.

Could the other theads have swapped the entire Cobra cluster movement and all? Is there something about the swap I am missing?

This can be double checked by using an ODB2 scanner to access the PCM's vehicle speed PID. Compare the PCM speed to the indicated speed on the Cobra cluster. Check to see the error percent. Is it 6.6%?

Now what to do. I am not sure. Perhaps swap the movement. Perhaps swap the entire cluster. Just remember to retain the PATS board or it will be necessary to re-program.

OBTW, are you aware that the mileage is stored in the PCM and the cluster?

nyuk98gt · Oct 1, 2010

wmburns:

That's an interesting detail (swapping overlay vs. swapping the whole cluster). I read, perhaps incorrectly, that the OP "swapped clusters" by putting his GT cluster electronic board on the Cobra cluster. That *should* make the Cobra cluster work based on the threads I have read (here and elsewhere). If he just swapped the overlay then, as you point out, the speedo and maybe other gauges will not work properly (accurately).

ahall2004:

Please explain in detail what you did. (Sorry, I am a little slow on the upshot.)

Chris

txredgt · Oct 1, 2010

wmburns said:
I am having problems understanding how this WOULD work. If I understand this correctly, the OP has taken a GT cluster and used a Cobra overlay. Same movement behind the speedo.

To me, it would have been a surprise if it did read correctly. Why? Because the movement behind the overlay is the same. The speedo movement is deflecting exactly the same for 70MPH as it did before. BUT the overlay goes to 160 in the same amount of sweep that the GT took to do 150. The speedo should be off by 6.6 percent.

Could the other theads have swapped the entire Cobra cluster movement and all? Is there something about the swap I am missing?

This can be double checked by using an ODB2 scanner to access the PCM's vehicle speed PID. Compare the PCM speed to the indicated speed on the Cobra cluster. Check to see the error percent. Is it 6.6%?

Now what to do. I am not sure. Perhaps swap the movement. Perhaps swap the entire cluster. Just remember to retain the PATS board or it will be necessary to re-program.

OBTW, are you aware that the mileage is stored in the PCM and the cluster?

I swapped the motherboard looking thing from my GT to the Cobra. If I had left the Cobra as is it would have read the milage on the cluster. Others have gotten around this by having a locksmith reprogramming their keys to the new setup but I didn't want to show the more milage than I had. After driving it I actually think its closer than I had thought and I will be using my GPS system to check it closer.. I used the SCT to turn off Pats so that could have helped me too. I will let yall know what the gps results are.

OBTW I was told if this does not fix things I could go to the dealership and have them recalibrate the speedo or possibly do it on a dyno as well. We shall see.. and burns I thought it would be off for this reason as well so we shall see. I did write down 2 sets of RPMS and speed when I still had the GT cluster in and they seemed to match close up, maybe a mph or 2 off but you wouldnt know it.

wmburns · Oct 1, 2010

Can you post some pictures? I would be interested in seeing what exactly is involved with swapping the PATS receiver board. PPL post up about that sort of thing all the time. I have read posts saying it is possible. But it sure would be nice to see for real.

I am also confused about what is left in the cluster after swapping the Mother board. Is it just the movements?

Exactly what did the mileage show on the cluster? The original or the donor's. I have read post in the past stating on the 1999+'s the mileage is completely stored in the PCM. If the cluster is swapped, the replacement cluster will still show the mileage stored in the PCM.

I have read other posts where it was stated that the milege is stored in BOTH places. But the cluster retains the mileage display of the donor.

I guess I am too old school to use a GPS to check the speedo. I would use a stop watch on the Interstate mile markers holding a constant speed like 60 and time how long it take to go a mile.

Interesting thread. Thanks.

txredgt · Oct 1, 2010

wmburns said:
Can you post some pictures? I would be interested in seeing what exactly is involved with swapping the PATS receiver board. PPL post up about that sort of thing all the time. I have read posts saying it is possible. But it sure would be nice to see for real.

I am also confused about what is left in the cluster after swapping the Mother board. Is it just the movements?

Exactly what did the mileage show on the cluster? The original or the donor's. I have read post in the past stating on the 1999+'s the mileage is completely stored in the PCM. If the cluster is swapped, the replacement cluster will still show the mileage stored in the PCM.

I have read other posts where it was stated that the milege is stored in BOTH places. But the cluster retains the mileage display of the donor.

I guess I am too old school to use a GPS to check the speedo. I would use a stop watch on the Interstate mile markers holding a constant speed like 60 and time how long it take to go a mile.

Interesting thread. Thanks.

I actually don't have pictures of what I personally did but I used this writeup and it has pictures with it. The hardest part of the whole thing is getting the cluster out of the car, after that it is 6 torx i think is what they are holding the back plastic piece of it and then you can access the motherboard type thing.

How-to: Install Bullit guages in a 99-04 GT - Lone Star Stangs | The Texas Mustang Club

As to using GPS I just thought it would be the easiest and most accurate gauge of if it was working correctly or not. I know its close in the higher speeds (70 and 80 mph) since I tested the RPMs before and after the swap but lower is where I am worried and I do not want to go through a school zone not knowing if my speedo is accurate or not..

nyuk98gt · Oct 2, 2010

ahall2004:

From other threads, there is a "small odometer circuit board" that has to be swapped over, too. Did you do this?

wmburns:

Does your Shop Manual show this level of detail? (My '98 S/M doesn't have much instrument cluster info in it and there are a couple of other small manuals that support the '98 S/M.)

Thanks,

Chris

txredgt · Oct 2, 2010

Nyuk I did not swap the piece you are talking about unless its attached to the large circuit board.. I have another cluster I can pull apart to see if I can find that part but my odometer is reading my correct milage so I don't think its a problem.

nyuk98gt · Oct 2, 2010

ahall2004:

OK, thanks for the info. I am just a reader of Internet threads when it comes to the +99 instrument clusters so take my advice with some caution, lol.

Since your odometer is reading correctly and the engine runs, it sounds like you've done everything just right.

Chris

wmburns · Oct 2, 2010

Ford shop manual has no where near that amount of detail. The level of detail is limited to the diagnostic procedures and a generic picture.

As far as Ford is concerned, the cluster is to be replaced as a unit.

txredgt · Oct 8, 2010

I got it dialed in close to where it should be but its still not 100% perfect, within a mph or 2 at every point up to 70 so far. I first tried to change the tuner to 3.90's instead of the 3.73's that I have which got it close but I soon thought about that it would throw off my milage as well so I tinkered with tire size and rotations per mile stuff and got it to where it is now.

nyuk98gt · Oct 9, 2010

ahall2004:

Good work! I know that my car is a world different from yours but, just like your car, I had to keep adjusting the rear gear ratio in my SpeedCal to get the speedo/odo dialed in to 'perfection'. I do not recall exactly the pseudo-gear ratio that I used but it was not 3.73:1. I think that this is pretty common with most cars (not just Mustangs). The manufacturer sees no harm in having a speedo that reads 3 to 4% low.

Again, good work getting your speedo and odo sorted out. This ought to help others who do the same thing (if they use the search feature!).

Chris

txredgt · Oct 9, 2010

nyuk98gt said:
ahall2004:

Good work! I know that my car is a world different from yours but, just like your car, I had to keep adjusting the rear gear ratio in my SpeedCal to get the speedo/odo dialed in to 'perfection'. I do not recall exactly the pseudo-gear ratio that I used but it was not 3.73:1. I think that this is pretty common with most cars (not just Mustangs). The manufacturer sees no harm in having a speedo that reads 3 to 4% low.

Again, good work getting your speedo and odo sorted out. This ought to help others who do the same thing (if they use the search feature!).

Chris

Thanks! Its always great to come to a solution yourself (or with help but do it yourself). Stealership wanted 90 bucks to recalibrate the speedo and that probably would have messed with tune as well so I will keep it like this. And I do hope other people will look here first but I must say I think I would switch to a Mach or Bullit cluster since they are 150's and would just be simple pull the back off theirs and put the new faces on. Oh well I still like mine and got a great deal I think for them.

Gauge Cluster stuff

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