2000 Miata running lean. CEL keeps throwing P0300.
2000 Miata, 68,000 miles, running lean. CEL keeps throwing P0300. Have already replaced sparks, wires, coil pack, injectors w/ rings. Popping sound can be heard near air intake and rough idle. Most noticeable when pulling mildly on the throttle. Most symptoms when pulling away from a stop and when starting the car after it has been parked.
In fact was able to make it throw a CEL while car sitting idling on driveway and gently pulling throttle over a period of about 3 minutes. Whole problem began with a P0302 and a bad injector which was replaced.
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best answer here is that the sensors are not set for the poor quality fuel ( the octane ratine is probably to low for the ECM to properly maintain the air /fuel mixture ) you have the answer to your problem when you change back to quality fuel and it runs right. As a point of interest most small engines will not run right on e fuel mixes.
engine stalls.
can be 50 reasons
but are this.
needs a 60k mile tune up bad.
1: EFI system has 12vdc power loss. (see dash dim?)_
2: engine misfires. horribly and idle controls failed, (all will like that)
3: engine floods, same.
4: engine fueling drops so low and lean the engine stalls.
5: bad engine, cam time or sparking way off or 45 other engine prob.
there is a test for each one, need a list?
and last, 6: the ISC is stuck close, or EGR stuck open
did you pull the DTC scan codes, the CEL blink test?
from the ECU?
is the CEL glowing (lamp in dash) running?
omg, this is not a carb engine is it, many 87 were.
1987 is a cusp year, in USA for end off all carbs. (EPA rules)
In a crank no start condition it is always important to find the cause before throwing parts at a car. The only things required for an engine to run are; fuel, spark and air. At this point it sounds like you have no spark at all. I would begin chasing the circuit back from there.
On to the egi, pull an injector out keep it connected and try to start the car if fuel comes out you’re good. If not you may have a problem with that relay as they have been known to give issues.
But as you state you have no spark when cranking I would start there.
Here is a link to a well written walk through for diag on a crank no start condition
First off, flashing is a warning NOT to drive it-unlike a steady CEL, flashing indicates there is a problem that needs immediate attention. When you had the CEL before, did you get the actual code? It might still be related, or could be an entirely different issue, although it is now more serious. If you can, you should drive it very little and straight to a commercial auto parts store to have the computer scanned for code(s)-WRITE the actual codes down, very important, so you can get help for your issue. Pay particular attention to engine temp, how it runs, check oil...do not drive it if it is running hot, has little or no oil, or is running really bad, get it towed-not worth the risk in ruining the engine.
have you replaced coil pack? Check EGR passage through upper mainfold and make sure clean. also make sure EGR valve not stuck part way open. Also check crank and cam sensors along with MAF.
what are the new codes clearing / resetting doesnt fix the problem the p0171 code has about ten different causes just changing or cleaning the sensor may not have been your problem P0171 System Too Lean Bank 1 rescan and get all codes then look up each one most sites have causes and solutions for obd ll trouble codes
the blinking CEL light is an indication of a miss-fire, run the code retrival test to find out what cylinder is the one missing, at your miles it could be almost anything from a low compression issue to a bad distributor cap, a fuel injector could be the problem, run the test and get back to me, Kragen and other chain parts stores will test the system for codes for FREE!
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