Hi,
Ihave a 1995 Camaro and the last owner replaced the gearing with 3.73's and the speedo is WAY off. I run about 70mph and it thinks I am doing 40mph. What/where do I go/do to calabrate it? Also, does anyone have a diagram for the vacuum lines? The car was wrecked and rebuilt with 2002 SS parts. It has a mild (very mild) cam, Pro.5 shifter, SLP exhaust and centerforce clutch. I am having problems with a SES light being on, but being a OBD1 I can's read it. The light come on about 1 min after running it and goes off every timeI shut it down... little help on that one???

Thanks!!!
Dan

 

Either it was calibrated for higher gear ratio than 3.73 or something is wrong with gauge or vehicle speed sensor. When going up in ratio indicated speed should read greater than actual. You can have someone tunethePCM for the gears.

 

Yea, I thought it should read faster than I am going because it had 3.73's put in it. Also, I got the SES engine checked (I have a OBDII reader but mine just said error) and the dealer said it was OBDII and that the Map sensor (I think that is what it is called- it is the one in the airbox) had an extension added to the wire that connects to the sensor and the gauge was too heavy so they are going to soder in a smaller gauge wire tomorrow. If that desent solve it I need to replace the sensor. It thought the intake temp was 314F so the car is running really lean. My speedometer always reads 40MPH when I go 70MPH and I just know I am asking for a ticket :-)

Thanks for the info, if you have a pic of the vacuum lines (should be a sticker under the hood, mine is gone because I have a 2002 SS hood) I would REALLY appreciate that.

 

You need to get the car scanned with an OBDI scanner and a OBDII cable. That is because GM used an OBDI PCM and an OBDII diagnostic plug. The MAP sensor is not going to affect what the speedometer shows. The input to the speedometer is from thePCM whichuses input from the VSSin the transmission.

 

I had it scanned. The computer said I had a intake air temp of 314F WoW! I had the solder the wires to the sensor together and than it read 99F (bout right) on my way home from the shop the light came on again UGGGGGG. Last time the computer kept saying I had a skipped 2-3 shift... I don't know, I have never shipped a shift and the skip shift has been disabled on the car. We will see. Thanks! Yes,I knew the MAP would not change the speedo. He said I have to re-gear the speedo??? Could somone lighten me on what to do???

 

You don't have to replace any parts. As 02StanGT has already said, you need to get someone or something that allows you to reprogram your PCM to callibrate for the different gears. You can get a local shop that can tune pre-OBDII LT1's, you can go for www.pcmforless.com and have them reprogram it or you can get a Hypertech Power Programmer or something similar.