Ok, So I recently bought an 88 Iroc with a 4th gen interior including dash and gauges. Everything worked, except the speedo. Had a check engine light on, and when I scanned I got codes referring to the MAF. Anyways, I changed the MAF and those codes have disappeared. However I now have code 24 (I didn't have before), which from what I gather comes down to the VSS and it not reading a speedo (which is correct). So, my question is, can I bypass or is there a simple fix. I still need to get the box to get the 4th gen speedo working from what I can tell. But those are pricey. I'm also contemplating going back to the thirdgen console I have from my 87 (torn as I like the original dash better). If so, would the code disappear when I hook up my thirdgen speedo?

This code is causing the car to high idle when I fire it up. It won't kick down till I tap the throttle. And most of the time the car will die when I brake, unless I give it some gas to keep the rpms up.

Car is a 88 305 TPI with 5 spd.

 

The simple fix/bypass is to take the bulb out for the check engine light...


I recently fixed a similar issue in my 91 since I went from a 5 speed to a 6 speed and the 6 speed trans reads differently than the 5 did. Since I had an electronic speed sensor and an electronic speedo I was able to just get the Dakota digital SGI-5 and that fixed my problem. Since you have a mechanical speed sensor and electronic speedo you are in luck that you can simply get a box that will allow that to work (Dakota digital also makes this IIRC).


You could also swap dashes like you mentioned or you could change transmissions to work with the electronic speedo. I would recommend considering the t56 swap since you already have the speedo for it (if it's in the budget).