ComancheKid45 Posted January 15, 2011 Share Posted January 15, 2011 Alrighty I got my 88 running again after a ECM swap but now it seems to have picked up an idle issue. It starts up great but runs like its missing. However if i unplug the vaccum line from the rear grommet on the valve cover to where it runs into the intake manifold it comes to life and seems to run great, once I plug that line back it the engine stalls out. I have swapped that line with another and even cleaned it out, there is no obstruction... Also is it possible that with so many attempts of starting and fuel being dumped into the engine that once i fired it up that all that could have killed my O2 sensor possibly hindering my running issue as well? Thanks for any info guys, youve been a great help :thumbsup: Link to comment Share on other sites More sharing options...
maddzz1 Posted January 15, 2011 Share Posted January 15, 2011 Does it start to run bad after it warms up? or as soon as you start it? When you first start the truck it runs in closed loop mode and uses a preset set of instructions and doesnt use the O2 sensor, once it warms up and switches to open loop mode then it runs off info from the sensors. So if it is running bad the whole time I wouldnt think it would be the O2 sensor. Link to comment Share on other sites More sharing options...
JeffN Posted January 16, 2011 Share Posted January 16, 2011 Tthis may sound weird, but smell your oil. If it smells like fuel you will need to change it asap, the fumes of raw fuel in the oil will play havoc with the sensors in the vehicle. (not to mention the scoring that could happen to bearings/cylinder walls) Did you change the spark plugs? they may be fuel fouled. Link to comment Share on other sites More sharing options...
ComancheKid45 Posted January 16, 2011 Author Share Posted January 16, 2011 It seems to run worse once it warmed up (o2 sensor) Ill be replacing that tomorrow and i think ill do a fresh set of plugs as well. Ill check the oil as well, its still very clean (less than 1k on it). Thanks guys! Link to comment Share on other sites More sharing options...
MJRemi Posted January 16, 2011 Share Posted January 16, 2011 This may or may not apply to your situation but double check your vacuum lines are all correctly in place. I spent money at a smog shop for repairs to get my 88 to pass smog. Five days later and $$$ I told the owner to cash me out since he couldn't figure out why it ran so rich. I took it to another guy recommended by a friend and within a few minutes he noticed the vac line from TB to MAP was dangling below the motor and the MAP was connected to a T above the evap canister. He corrected the problem and solved the smog issue. I felt like an idiot for assuming the first shop would have checked the lines for correctness and for not checking them myself upon purchasing the truck. Lesson learned! :oops: Link to comment Share on other sites More sharing options...
ComancheKid45 Posted January 16, 2011 Author Share Posted January 16, 2011 After an oil change, new o2 sensor and 6 new Champion plugs Shes back to her old self :thumbsup: Link to comment Share on other sites More sharing options...
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