rebar Posted December 31, 2016 Report Share Posted December 31, 2016 Hello new here. My GF bought a 1994 deville 4.9 from her brother, who bought it from Mom, who bought it new. GF doesn't have the best history for doing maintenance and hasn't been using premium fuel. I was told a week ago the car started to run rough with barely enough power to get off the road and then died. She tried to restart it but ended up having it towed to a mechanic. The mechanic had no idea why it stranded her because it started and ran well for him. The other day I was doing errands with it and it began running rough after a warm startup and then died. I tried to restart it, but in would fire a second but not continue to run. I checked for anything apparent and didn't smell fuel from the exhaust. After about 15 minutes it started right up and drove well. Has anyone experienced these symptoms and then figured out what was wrong? I wish I could give you more details but I'm not the owner and I don't know much about this model. Its super clean and worth trouble shooting IMO though. Thanks! Link to comment Share on other sites More sharing options...
Bruce Nunnally Posted December 31, 2016 Report Share Posted December 31, 2016 Does it show any diagnostic trouble codes in history? When it is not running you want to check for causes -- either no fuel, no spark, or no air. Bruce 2023 Cadillac CT4-V Blackwing Follow me on: Twitter Instagram Youtube Link to comment Share on other sites More sharing options...
KHE Posted December 31, 2016 Report Share Posted December 31, 2016 Sounds like the sensor on the distributor shaft has a thermal open - that would explain why letting it cool down for 15 minutes allows it to restart. The codes will confirm this. With the key on, simultaneously press and hold the OFF and WARMER buttons on the climate control panel. The codes will be displayed on the information center. Write them down and post back here. Note which are current and which are history codes as well. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
rebar Posted December 31, 2016 Author Report Share Posted December 31, 2016 IO22 history AO12 Current No sir codes NO PCM PCM ? She was driving it today and it started to run rough again. But it didn't die, just scared her. Link to comment Share on other sites More sharing options...
KHE Posted January 1, 2017 Report Share Posted January 1, 2017 I022 = Panel dimming potentiometer switch circuit A012 - Low side temperature sensor circuit Neither of those codes point to the problem you're having. I would have expected a PCM code. You might try checking the fuel pressure when it acts up. Other than that, I'm at a loss. Intermittent problems are the most difficult to troubleshoot. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
Logan Posted January 1, 2017 Report Share Posted January 1, 2017 Ok....1994....2017s are being built now....so 23 year old car. Could be a bad ECM....you can try dropping it down and tap test it. Any stalling or glitches while running and tapping indicates a failing ECM. Pretty much any thing in the distributor...GM HEI units can have green pickup coils....rotted control module wires...cracked cap....burnt rotor...etc. It could be a bad engine ground. It is mounted to the engine block very near the starter. Can look ok...but does need to be taken apart and cleaned. Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 1, 2017 Report Share Posted January 1, 2017 The symptoms remind me of a 92 4.9 that we had here a few years ago. It ended up being the PCM, do a tap test as Logan states above. Also, check the fuses and relays for green/white corrosion, especially the pcm/ecm, fuel pump and coil/ignition and injectors. Put a fuel pressure gage on the Schrader valve on the fuel rail, a bad pump or relay may show up. Do you hear rattling under the car when the engine runs?, bang the cat converter with a rubber mallet and see if you hear noise like marbles. These cats can fall apart and clog the exhaust. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
OldCadTech Posted January 1, 2017 Report Share Posted January 1, 2017 Since you don't know the history of the vehicle pull the ECM as Logan suggested and tap test it, only with your hand though please I've had a LOT of ignition modules fail and show symptoms very much like you're experiencing. It especially becomes an issue if someone replaced the ignition module and did not put silicone grease under the module. The silicone grease acts as an insulator to help keep the module cooler. OR, the same thing can happen if they used a cheap after-market unit. The ECM was my first thought as well, they are easy to pull down and tap test, the ignition module is a bit more challenging... Do the easy stuff first BTW, don't worry about her not using premium fuel - the ECM will adjust. THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!! Link to comment Share on other sites More sharing options...
OldCadTech Posted January 1, 2017 Report Share Posted January 1, 2017 Ignition Module lower left in picture, just above the '33' of the time stamp Remove the glove box to access the PCM/ECM, tap test with the PCM removed from the holder and the engine running. As a personal preference I pull the passenger side hush panel to provide a little more room. THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!! Link to comment Share on other sites More sharing options...
barczy01 Posted January 1, 2017 Report Share Posted January 1, 2017 Possible fuel pump issue or check the main ground by the starter. Its a heavy gauge cable that tends to loosen up over time. Link to comment Share on other sites More sharing options...
cdgrinci Posted January 1, 2017 Report Share Posted January 1, 2017 Total guess (and just relaying similar symptoms but with my '00 Intrigue); crankshaft position sensor. I know it is just a shot in the dark (but that's what happened to me). Chuck '19 CT6, '04 Bravada........but still lusting for that '69 Z-28 Link to comment Share on other sites More sharing options...
rebar Posted January 5, 2017 Author Report Share Posted January 5, 2017 Thanks guys. If it was my car, I'd be on it. Id agree with her to abandon it.. But that would mean she needs a cosigner or down payment for another "problem car". Link to comment Share on other sites More sharing options...
OldCadTech Posted January 6, 2017 Report Share Posted January 6, 2017 Nobody said abandon it.......Did she give you a chance to work on it yet? THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!! Link to comment Share on other sites More sharing options...
KHE Posted January 6, 2017 Report Share Posted January 6, 2017 My bet is the issue is in the distributor somewhere - either rotted/corroded wires like Logan stated, a bad ignition module or a bad pickup coil. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
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