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2004 Acura TL 3.2 all of a sudden would not idle, cut off, had a engine light for map sensor, replaced, did no good, then engine light for P300, P301 etc., cleared codes none came back. Have a Launch scanner X-431 Pro mini. Did scan and comes up I believe a rich condition. The R.P.M. was 991, else it would stall. Just got the scanner and new to this stuff so if more info would be helpful, let me know. I was thinking of cleaning the E.G.R. ports along with the injectors for a start along with checking resistance on E.G.R. and Oxygen sensors. Any advice would be great... Thanks..
What does the EGR position sensor voltage read at idle? That'll be your fastest and most accurate way to determine if the EGR is stuck open. If it's sitting close to 1.00V, it's closed. Remove it and plug off the intake port if you really have doubts.
Resistance test the EGR and O2's if you want, but I'm not sure it'll tell you what you want to know. We can already see that the upstream wideband sensors are working - the fuel trims are adapted and the widebands are sitting at stoich. If the problem still exists right after startup when the system is in open loop, then it's definitely not an O2 problem.
Are you able to do a relative compression test? Use the 'Injectors - All' function in the Pro Mini to disable all the injectors so you can get it to crank and no start. If you don't have a scope, you can still listen to the engine for any obvious inconsistencies.
I'll second Tyler as I used to see stuck open EGRs at my dealer when those cars were prevalent. Anything on the EGR valve lift sensor above 1.5 volts and I suspect unwanted EGR flow. 1.15 is ideal fully closed for this model. I've also seen carbon get stuck in there and it's a $FREE.99 fix to extract the offending bit of carbon and reassemble. This was especially common before they pulled exhaust gas directly instead of the modern EGR pipe that pulls from catalyst treated exhaust like they do nowadays. All of that being said, I've seen a leaking EGR valve with proper voltage, so blocking it off temporarily with a bit of cardboard(very briefly) is a quick check.
Honda engines like factory spark plugs. Autolites and the like can cause issues big time.
I've also seen some high mileage cars have weak spark due to tube seal failure letting oil in the spark plug tubes and impeding proper spark.
It's worth noting that valve adjustment is not likely here, those actually are typically quite loose when I would check them per the service interval.
You could also check for bad gas. Did this issue happen after a refueling? Has it sat for a particularly long time?
Last edit: 5 years 8 months ago by TechNick. Reason: Forgot something :)
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