Speed sensor cause this?

[LantanaTX]

Originally Posted by edram454

I have a 1990 and I recently replaced the VSS (vehicle speed sensor.). That sensor can cause lots of problems. when mine went out, my car idled differently. It would not idle down under 1000 rpm at a stop light, the secondaries would not come on, I was throwing suspension codes and check engine lights, car ran a little rough and definitely losing power. Fortunately for you, the 1991 speed sensors are cheap and plentiful. It was easy to replace so it is worth the effort. My car idles at a 1000 rpm and when it comes to a complete stop will go under 1000 rpm to 800 or 900 rpm.

I didnt realize who much power I lost until I replaced it and now this car is a rocket again. My car has mods and it is a stock cube car but runs very strong 405 rwhp. The speed sensor for a 1990 if you can get it, is around 300.00. Your 1991 should be around 50 bucks. Good luck.

ed ramos #3028

Thank you, Did your speedometer work normally? It was mentioned above that if the speedo works then this sensor is fine. My speedo works fine, but your other issues it caused seem to be the same as me.

[LantanaTX]

Here is what I found searching the site:

"well here is the whole story about the src light coming on. This whole thing was caused by a bad velocity speed sensor (vss). It is located on the drivers side of the transmission. the part has been obsolete for over 10 years for the 1990 zr1 so getting one was very difficult. I managed to buy two of them. If your vss goes out, it will throw the src suspension lights on after 3 starts... if you drive a little you will get an engine service light and you will see that your secondaries have been killed also. My car sounded good but it felt a little down on horsepower and the idle quality was a bit rougher.

If the vss is not working, the car thinks it is not moving and the ecm gets confused when you are stepping on the gas but the car thinks its not moving.. The ecm will not throw the appropriate timing or gas so the car has a rougher idle and the idle down is impossible. I thought it might be my newly rebuilt gauge cluster but when I replaced the vss sensor today the lights reset themselves and the secondaries started to work again. What a difference!! It feels like it did when I bought it. The sensor was not to difficult to remove but it was very well stuck. It took a while but it came out. It leaked very little oil. I think the transmission was over filled anyway when we checked the fluid on the transmission. Car feels great and putting up some good power numbers."

[edram454]

Originally Posted by LantanaTX

Thank you, Did your speedometer work normally? It was mentioned above that if the speedo works then this sensor is fine. My speedo works fine, but your other issues it caused seem to be the same as me.

to answer your question, my speedo did not work at all. Thats how I knew my vss was bad. If your speedo works then it is not the vss.

ed ramos #3028

[edram454]

Originally Posted by LantanaTX

Here is what I found searching the site:

"well here is the whole story about the src light coming on. This whole thing was caused by a bad velocity speed sensor (vss). It is located on the drivers side of the transmission. the part has been obsolete for over 10 years for the 1990 zr1 so getting one was very difficult. I managed to buy two of them. If your vss goes out, it will throw the src suspension lights on after 3 starts... if you drive a little you will get an engine service light and you will see that your secondaries have been killed also. My car sounded good but it felt a little down on horsepower and the idle quality was a bit rougher.

If the vss is not working, the car thinks it is not moving and the ecm gets confused when you are stepping on the gas but the car thinks its not moving.. The ecm will not throw the appropriate timing or gas so the car has a rougher idle and the idle down is impossible. I thought it might be my newly rebuilt gauge cluster but when I replaced the vss sensor today the lights reset themselves and the secondaries started to work again. What a difference!! It feels like it did when I bought it. The sensor was not to difficult to remove but it was very well stuck. It took a while but it came out. It leaked very little oil. I think the transmission was over filled anyway when we checked the fluid on the transmission. Car feels great and putting up some good power numbers."

This is my post after I repaired my problem caused by my vss sensor not working. Like I said earlier, my speedo did not work so the sensor was the culprit.