Jscott Posted Friday at 02:41 PM Report Posted Friday at 02:41 PM Hi again. 90 old C/S 3.1. Really bad idle. I replaced the o2 sensor and iacv. After installing the o2 it ran pretty good and then it didn’t. Back to rough idle. Any thoughts on what the issue could be? I’ve heard of bad pcv/ map sensor/ coil pack. The erg is not gummed up. However I just had my battery tested and came back bad. The car starts fine but they said it was bad. I’m not sure if that has something to do with it. Any ideas. Thanks. Quote
55trucker Posted yesterday at 11:25 AM Report Posted yesterday at 11:25 AM My suggestion to you is to not throw parts at the issue, get a proper scanner on the engine, do a live readout & note in particular what the a/f display is showing you. A failed o2 sensor will only prevent the fuel system from going into closed loop. If the sensor HAD failed then something upstream caused it to. A check engine light will also light up. A bad map will completely throw off the ECM;s ability to configure a proper air/fuel ratio, that will be seen on a scanner as well. Another small item to look at is the wiring harness condition to the engine temp sensor, if it's faulty then that sensor cannot send the proper signal to the ECM to configure A/F ratio due to inaccurate information on the engine actual temp. That will be seen on a scanner as well. The 3 vital sensors needed for the ECM to calculate proper A/F ratio when the engine starts are the MAP, IAT, ENG TEMP. Quote
55trucker Posted 11 hours ago Report Posted 11 hours ago You're welcome....try to resist the usual approach of throwing money at a problem. Quote
Jscott Posted 10 hours ago Author Report Posted 10 hours ago I get it, I don’t want to shoot the parts cannon at it. lol. And suggestions on a live read scanner. Do they sell something like that for OBS1’s Quote
55trucker Posted 1 hour ago Report Posted 1 hour ago You're more than likely going to find yourself on ebay looking for one, everything in the market today is geared to OBD2. Some older models would read OBD1 & OBD2 up to a given year depending on the plug in cartridge. The interface for OBD1 was not a single standard plug, it varied on the vehicle manufacturer & so did the harness to the scanner. The item I own is an OTC 4000 enhanced. https://www.ebay.com/sch/i.html?_nkw=otc+monitor+4000+enhanced&_sacat=0&_from=R40&_trksid=p2334524.m570.l1311&_odkw=otc+monitor+4000&_sop=12 Quote
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.