Steve P Posted October 20, 2003 Report Share Posted October 20, 2003 My dad just bought a 91 Grand Prix STE last week. The car is having the same troubles as this person. My dad was mostly working on the car so I don't know all of the problems. I looked at it yesterday and this is what I noticed. 1. Speedometer stays at 0. 2. Trouble starting sometimes, hold the gas to keep it on. 3. Odometer doesn't move (don't know if this is a related problem) 4. SES light on 5. Check Gauges light also on. 6. Fan starts up and shuts off I checked the trouble codes, and I get a "check connection" problem for a while then Code 51 pops up. I removed the memcal but had to put it back in because I had to move the car. All of a sudden the speedometer and odometer works, but the SES and Check Guages lights are still on. The engine also runs smoother when idling. So I am going to replace either the memcal or entire ECM. I found an ECM on ebay but don't know if it is right for my car. I'm pretty sure it is though. http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33596&item=2438211607 Also, does anyone know where I can find a memcal for the car. It costs $95 at the dealership. Thanks for helping the new guy:) Great website BTW! Quote Link to comment Share on other sites More sharing options...
99RegalGS Posted October 20, 2003 Report Share Posted October 20, 2003 The odometer uses the spedometer signal to figure out the mileage and since the spedometer doesn't work niether will your odometer. The ECM is for a corvette not your GP. Thats all that I can help you with. Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted October 20, 2003 Report Share Posted October 20, 2003 When code 51 comes up, its usually a bad ECM. 51 is a weird code. That ECM you found I think will work, its the same number on it, the 1227727 or whatever the number is. Just get a MEMCAL for you STE and it should work. Wait til some one else replies to clarify that, Im not 100% on that. Quote Link to comment Share on other sites More sharing options...
Steve P Posted October 20, 2003 Author Report Share Posted October 20, 2003 Thanks for the replies. Yeah the ECM is a 1227727 just like the one I already have. I'm pretty sure I can swap it but I just wanna be sure. Quote Link to comment Share on other sites More sharing options...
99RegalGS Posted October 20, 2003 Report Share Posted October 20, 2003 Sorry about the bad info on the ECM. Quote Link to comment Share on other sites More sharing options...
Steve P Posted October 21, 2003 Author Report Share Posted October 21, 2003 Sorry about the bad info on the ECM. No problem. Quote Link to comment Share on other sites More sharing options...
Steve P Posted October 25, 2003 Author Report Share Posted October 25, 2003 Got the new ecm and used the same chip. Fixed the SES light and the fan problems. Now to find out why the Check Guages light is on. Could battery problems cause the CG light to come on. When I rev the engine, the battery guage fluctuates. I'm guessing I need a new alternator. Other than that, the car runs perfectly. Quote Link to comment Share on other sites More sharing options...
RareGMFan Posted October 25, 2003 Report Share Posted October 25, 2003 Grand Prix' of this era are notorious for that CG and Low Fuel light coming on. You may need this procedure to fix this: http://www.w-body.com/service/checkgauges.html If that doesn't help, I'm not sure where to go from there. Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted October 26, 2003 Report Share Posted October 26, 2003 Got the new ecm and used the same chip. Fixed the SES light and the fan problems. Now to find out why the Check Guages light is on. Could battery problems cause the CG light to come on. When I rev the engine, the battery guage fluctuates. I'm guessing I need a new alternator. Other than that, the car runs perfectly. Glad to hear its working (except for the CG stuff) Quote Link to comment Share on other sites More sharing options...
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