i just bought an 89 le from an auction and i'm trying to get it up and running. at first it was stalling out whenever i took my foot off the gas. i thought it was a fuel flow problem because the car had been sitting so long so i changed the fuel pump & filter. i ran the codes and it gave me the following: 14 - coolant temp sensor, 24 - vehicle speed sensor, 42 - electronic timing spark. i changed the CTS (code 14 the cheapest one) and now it idles at 1700 rpm and the speedometer stopped working (and code 14 came back).

i'm not really what you would call the machanic type and i don't wnat to start spending a fortune just buying parts. does anyone have any suggestions on what I should do next??? :?

Sounds to me like something is disconnected. Have you checked the harnesses at the ECM and the firewall (both sides)?

First I'd clean the IAC, it controls the idle speed. Code 14 is a high temp reading, usually a short. Code 24 can be triggered by extended high idle (above 1300 rpm) while not moving. Code 42 indicates a bad ESC but if real it often will not start at all.

Just a high idle will not make a 3800 overheat if all else is OK - have you checked the thermostat ?

i thought about the t-stat but the gauge on the dash reads normal. i'm going to start checking connections and i'll let you how it turns out wish me luck

The codes you dumped may be history (happened at some time in the past) and not current. Usually disconnecting the battery for a few seconds will clear the codes and you can see what is still setting.

well i've checked all of the wiring and everything seems ok... i dumped the codes from the memory, but this time when i started the car it ran ok for a few minutes but when it got to normal operating temp it hic-cupped and the ses light came on again and it locked up the scanner (snap-on scanner). it kept telling me that there'* was no connection.

i'm begininng to think that the ecm is bad. i would like to know if the ecm is interchangable between year models. i found a couple at the salvage yard and wanted to try them first before i spent money on a new one. any ideas????

If the ECM in your car is a 1228253 then it was used from 88-up (until "E" trans) in n/a 3800s. You do need to use the right PROM. If the scan tool is acting erratic then is a good chance the ECM is bad.

That said, running OK until it warms up says it is OK open loop but when it goes closed loop (starts using the O2 reading) it goes wonky.

that'* correct. it goes crazy on closed loop. does that mean the ecm is bad or could it be something else. how do i find out which ecm i need to buy?

Well, I changed out the ECM and it looks like that did the trick! I've got a little more maintenance to do on it and it should be road ready. Thanks for all the help!