Godsson314 Posted May 8 Report Share Posted May 8 Hello! I have a 1995 olds cutlass convertible. The car rides smooth but after a harder acceleration (switching lanes on the highway) it can feel like it sputters. When coming to a stop at a light the revs are high and low (1.5 to below 1) sounding and feeling like it will cut off. I have the 3.4L. I switched out the IAC valve but that was a short fix, smells of gas in the garage if ran and getting horrible gas mileage. Looking for a great mechanic in San antonio if you know one! Anyone have ideas? Quote Link to comment Share on other sites More sharing options...
GTP091 Posted May 9 Report Share Posted May 9 Running rich could be all kinds of things. The car is dumping fuel in to balance out something wrong. A good shop can still pull data from the ecm. That’s really the only way if you’re not going to wrench it yourself. Could be a bad O2 sensor., vac line leak, FPR is shot, even a bad temp sensor can make the ecm run the car rich. Godsson314 and jiggity76 2 Quote Link to comment Share on other sites More sharing options...
Schurkey Posted May 12 Report Share Posted May 12 What is the fuel pressure? How old are the usual "tune-up" items--plug wires, spark plugs, O2 sensor, verify PCV, EGR, and EVAP systems. Check cranking compression pressure. How old is the timing belt? Connect a scan tool, verify EVERY sensor and computer output. Check fuel trims. O2 sensors get lazy with age. If the O2 sensor has more than 50,000 miles or 5 years on it, it's probably due for replacement. If there's a misfiring cylinder, it can drive the O2 sensor to report a false-lean condition. That will drive the computer into rich-command. Expect that the rich running has murdered the catalyst. Godsson314 1 Quote Link to comment Share on other sites More sharing options...
Godsson314 Posted May 12 Author Report Share Posted May 12 16 hours ago, Schurkey said: What is the fuel pressure? How old are the usual "tune-up" items--plug wires, spark plugs, O2 sensor, verify PCV, EGR, and EVAP systems. Check cranking compression pressure. How old is the timing belt? Connect a scan tool, verify EVERY sensor and computer output. Check fuel trims. O2 sensors get lazy with age. If the O2 sensor has more than 50,000 miles or 5 years on it, it's probably due for replacement. If there's a misfiring cylinder, it can drive the O2 sensor to report a false-lean condition. That will drive the computer into rich-command. Expect that the rich running has murdered the catalyst. Question...how do you connect a scan tool to a 1995? Quote Link to comment Share on other sites More sharing options...
Amanita Posted May 13 Report Share Posted May 13 1 hour ago, Godsson314 said: Question...how do you connect a scan tool to a 1995? I don't have experience with the older on board computers but a standard OBD2 scanner will not fit a pre-96 car. It's a different system. Godsson314 1 Quote Link to comment Share on other sites More sharing options...
Schurkey Posted May 13 Report Share Posted May 13 (edited) 21 hours ago, Godsson314 said: Question...how do you connect a scan tool to a 1995? EXACTLY the same way you'd connect to any other vehicle with a diagnostic connector. '95 is no different in that regard. Find a compatible scan tool, use the correct adapter, connect it to the diagnostic connector. You may need to supply "12 volt" power to the scan tool via a cigarette-lighter power adapter or similar. Follow the instructions for the scan tool to type in the VIN number or whatever it takes to make the tool "talk" to the on-board computer. Guys get all weird about pre-OBD2 vehicles and scan tools. No need. Just use a DECENT scan tool, and it'll work out just fine. If you use a craptastic "code reader", or some consumer-grade bottom-feeder junk tool, you can expect it to be useless or worse, problematic. Edited May 13 by Schurkey Godsson314 1 Quote Link to comment Share on other sites More sharing options...
Schurkey Posted May 13 Report Share Posted May 13 19 hours ago, Amanita said: I don't have experience with the older on board computers but a standard OBD2 scanner will not fit a pre-96 car. It's a different system. An "OBD2 scanner" doesn't work on a '95, because '95 is not OBD2. Therefore, you'd need a scan tool compatible with what is now known as "OBD1". They tend to be more expensive, and need a different adapter/connector for every brand of vehicle since there's dozens of proprietary connector bodies on the vehicles. Every manufacturer used a different style of connnector. GM alone had several depending on application. A decent scan tool will work with GM products from 1980 1/2, onward to the limit of their software--often post-2000, perhaps all the way to 2024. Mine goes up to 2007, but since I don't own a vehicle newer than 2003, I'm all set. Godsson314 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.