Anyone running a Quad 4 Getrag or 3.94 FDR getting VSS Code 24? (Page 1/2)
Raydar JUN 15, 03:00 PM
As the topic says...
I recently purchased an 88 GT with a Quad 4 Getrag. Bellhousing swapped to V6 style. (I knew this, going in.)
I keep getting a Code 24 after driving for a while. Speedo works perfectly.
I'm wondering if the Code 24 is caused by the speed vs RPM error introduced by the difference between the FDR in the stock and replacement trannies. Kind of a longshot, I suppose, but it is programmable in the ECM. It's also interesting that it doesn't set the code right away.
Am I over-thinking this?

I've read all the threads here that contain "Code 24", but have not started troubleshooting yet, other than having unplugged and reconnected my speedo connector.

Anyone else running a Quad 4 Getrag or, I suppose, an F23?

Thanks.
Quad GT JUN 15, 09:13 PM
I have a W41 in my "86 SE and no issues
Raydar JUN 16, 08:42 AM
Cool. Thanks.
sanderson231 JUN 16, 11:54 AM
I know that some Quad 4 Getrags (maybe all) use a different style VSS than the Fiero Getrags. I know that when I did my Quad 4 swap, I split the case and installed the plastic gear so that I could use the Fiero VSS. I think that the Quad 4 VSS outputs pulses instead of a sine wave. I'm not sure what kind of engine/transmission your car has but perhaps the code 24 is being set because the ECU is expecting a sine wave and it is seeing a pulse.
sanderson231 JUN 16, 05:25 PM
Also most of the Quad 4 Getrags have the same FDR as the Fiero. Only the W41 Quad 4 Getrags got the 3.94 FDR so they are rare.
Raydar JUN 18, 07:57 PM

quote
Originally posted by sanderson231:

Also most of the Quad 4 Getrags have the same FDR as the Fiero. Only the W41 Quad 4 Getrags got the 3.94 FDR so they are rare.



Hmmm... Interesting. Conflicting stories, over the years. I'll have to measure speed vs RPM, and see. (It has a lot more "giddy up" than I remember out of a 2.8.)

The VSS looks, outwardly, like the Fiero VSS, but I haven't pulled it out. (The speedo and odo both work perfectly.)
I've got another Quad 4 Getrag that very obviously is the magnetic VSS, but the VSS looks completely different, even on the outside.

Thanks for the info. Much appreciated.
sanderson231 JUN 19, 11:19 PM
Even with the 3.61 FDR a Quad 4 HO is much more capable and fun than a 2.8.

I have a W41 that will be going into my 84 Quad 4 in the next few months. I also have three other Quad 4 HOs in the garage. I have been contemplating stroking a 2.3L Quad 4 to 2.6L with the 2.4L Twin Cam Crank. The block will be bored to either 93 or 94 mm from 92 mm. With additional compression ratio (11.5:1) I think it could produce 230 HP.
Raydar JUN 20, 10:50 AM

quote
Originally posted by sanderson231:

Even with the 3.61 FDR a Quad 4 HO is much more capable and fun than a 2.8.




No doubt! It's better suited to the flavor of the car. Like an LQ1. (I have heard that the LQ1 was part of the inspiration for the Quad 4, but who knows...)

I did some experimenting yesterday. The scan tool is seeing MPH displayed, along with the speedo (which has always worked properly). So if there's a failure, it's intermittent, and between the speedo and the ECM. The light was NOT on.
Quad GT JUN 20, 03:27 PM

quote
I have been contemplating stroking a 2.3L Quad 4 to 2.6L with the 2.4L Twin Cam Crank

.

Could you turbo or supercharge it?
sanderson231 JUN 20, 05:25 PM
I know there have been a few turbo Quad 4 done. The 2.6L stroker is fairly straight forward. I just don't know if I want to spend the time on a turbo project.