gsxrsean Posted March 30, 2005 Report Share Posted March 30, 2005 Okay we inherited a 1990 Olds Cutlass Supreme SL 3.1L V6 71K a month or so ago. It had been stored for a few years but thought I would get it running since it would get better gas mileage than my trucks. Said to run perfect before storage. New battery and a change of fuel and fuel filter plus a oil change. It fired right up and drove fine for a day or so. Now while driving the Instrument cluster-odometer/spedo will reset to zero. When this happens the engine will surge and a dash light illuminates for a brief second and the A/C will stop working. The same thing happens when it starts to work and continues operating normally (surge in power and flicker of dash lights). It is also getting extreme engine idle responses. One minute the engine will sputter/spit/stall when coming to a stop sign/light. Then the next minute it idles extremely high. I am also getting fluctuating fuel mileage. Not sure what the heck is going on… I cleaned the Idle air control valve and throttle body, ran some gas treatment through. Cannot find the PCV valve nor sure how to even change the plugs/wires in the transverse engine with noo room.. Any Ideas? Regards, Sean Quote Link to comment Share on other sites More sharing options...
1990lumina Posted March 30, 2005 Report Share Posted March 30, 2005 For your idle you could try an idle relearn. You should probably do this anyway since the ecm lost power when you changed the battery. I'd also check the alternator output as if you aren't getting at least 12 volts from the system you will run into electricial problems such as you intument cluster going nuts. You are getting bad mileage because of the erratic idle I'm guessing. - Jeff L. Quote Link to comment Share on other sites More sharing options...
DOHCRagtopguy Posted March 31, 2005 Report Share Posted March 31, 2005 Check your electrical grounds. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted March 31, 2005 Report Share Posted March 31, 2005 yes, sounds like an electrical problem as far as the cluster goes. Quote Link to comment Share on other sites More sharing options...
Brian P Posted March 31, 2005 Report Share Posted March 31, 2005 Off the top of my head it seems like a bad ECM. If you could grab one cheap off ebay or a Junkyard, swap it, do a proper idle relearn and see what happens. Quote Link to comment Share on other sites More sharing options...
loominaz34 Posted March 31, 2005 Report Share Posted March 31, 2005 The plugs are not hard to change They're in holes in the heads that are plugged up by spark plug wires. I need about a foot in extensoins to get to the plugs though. :x Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted March 31, 2005 Report Share Posted March 31, 2005 How are the volts? My guess would be bad alternator. Quote Link to comment Share on other sites More sharing options...
JoroCorona Posted March 31, 2005 Report Share Posted March 31, 2005 Reseting Cluster, Engine Surging, and flickering of dash lights sounds like a shady ground somewhere. The idle fluctuations sounds like a bad intake manifold gasket or IAC. However a bad ECM would cause all of the above symptoms too, but I'd try to rule other things out first. Quote Link to comment Share on other sites More sharing options...
3.1LUMITIC Posted April 1, 2005 Report Share Posted April 1, 2005 Well first off i would check the alt... Mine was doing the same thing as mine... It was the alt over charging the battery. One of the regulators went bad in it.. take it to autozone or some other parts store by you its free to get it checked... You cant beat that with a stick. Quote Link to comment Share on other sites More sharing options...
Spoon Posted April 12, 2005 Report Share Posted April 12, 2005 I would recheck the battery cables for corrosion and tightness, next would be making sure the ground from the battery to block is in good condition. Sounds to me like you have a bad ground or connection somewhere. The erratic idle problem is probably just the idle needing to be relearned. Quote Link to comment Share on other sites More sharing options...
gsxrsean Posted April 12, 2005 Author Report Share Posted April 12, 2005 Okay I replaced the PCM/ECM and most things are back to “normalâ€Â. I had found a cheap one at a salvage yard out of a 92 Cutlass 3.1L car ran awesome buttttt the relays for the AC/Cooling fans would not work with it. So I purchased a new one (rebuild) and put my old prom chip in and the car started acting up again. Dropped the 92 PROM in and everything is back to working correctly with exception of AC and the Speedo works but seems to be off. So the culprit seems to have been my old PROM chip? I am guessing the speedo problem is because the 92 CS had a 4sp Auto and my 90 has a 3sp Auto??? Anyone know where to purchase PROM chips cheap? Don’t need a High Performance one. Thanks, Sean Quote Link to comment Share on other sites More sharing options...
Jcrow Posted April 12, 2005 Report Share Posted April 12, 2005 The dealer, I think price isnt too bad either, they can do it with your vin # Quote Link to comment Share on other sites More sharing options...
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