1998 Protege LX 1.5 Litre M.A.F. Sensor

[Mark1998]

Ive been all over the net and google, Bing, Lycos but i still cant figure this thing out. Rough Idle check engine light ON...Code says Bad M.A.F Sensor.. Replaced M.A.F Sensor...Lights out runs great...2 weeks later Check Engine Light ON...Code says TPS bad...Replaced TPS...light out runs great...2 weeks later..Rough Idle..stalling at stop lights and stop signs...idle is 850-400-1200-200 dies...starts right up idles rough again...check forums and google...they say Clean EGR and IAC...NO CHECK ENGINE LIGHT...cleaned IAC...EGR...120,000 miles...timing belt great shape..new tune up..new exhaust and intake manifolds both were cracked when i bought it last year..Google hits say Fuel Pressure Regulator..$ 80.00 later new FPR still idles rough as hell..great on the highway still dying at stop signs and stop lights...get it home...remove battery cables over night...next morning Running Great first time in 3 months...get off the highway to go home speed limit 35 mph....car dies..wont start..like its not getting fuel...Google results..Oil Pressure Sensor shut down fuel pump..added 2 quarts of oil..Running again...nice easy idle 850 rpm..4 days later...car dies going down the highway at 70 MPH....just dies...wont start...tries...idles up to 3k and then just dies....unplug M.A.F Sensor...starts idles runs great...shut the hood get home plug in M.A.F Sensor....car dies Immediately...call auto parts warehouse.com new M.A.F Sensor arrives (2 year warranty replacement)...awsome new M.A.F. sensor...unplug battery install new MAF sensor...install battery...car idles up to 3k rpm and dies...unplug new MAF Sensor...car runs great...plug in old maf sensor..car dies...WTF!!! 3 sensors intake manifold, exhaust manifold..new fuel pump new fuel filter...fuel pressure regulator and now it wont start if i install the MAF sensor?!?!? H E L P, ME Please!!!

 

[Dan-O]

Looks like both of us are in mostly the same boat. I've been scouring the web for possible solutions, but leads are scant, if nonexistent.

Am I correct in saying that your issue is mostly a once-warmed-up issue and that starting it when warm is troublesome? Or has it now migrated to cold starts?

My issue only happens when the car is cold--as in I haven't driven it for the day yet. Once I get it to start and idle by itself it's golden. Sometimes when going to start it after it's been warmed up I get absolutely nothing (dash lights all on), then a delay and it starts. But it primarily does a start-and-immediately-die thing. I can catch it and rev it up (though I feel the engine's resistance to it and see light smoke from the back, which I think is incompletely burned fuel), but then when I let it go it does or sometimes holds on at 300 RPM. On the third or seventh attempt it starts up completely normal, like nothing was ever wrong.

The tune up included air filter? Are there any cracks in the air hose from the MAF to the throttle body? Are you still getting codes? Apart from my EGR-related code (it's cleaned out now, including the pipes from the EGR solenoid unit to the intake manifold and from the exhaust), I get no CEL/codes, nothing. If that's your case it's quite frustrating. Does your car consume oil (I'm at 1 qt/~2500 miles, 190k on the car currently)? Automatic trans or manual?

If air, fuel, and spark are needed to make a car run, then I'll add "control" or "governance" to that list. Air--if you have good air filter, good hoses, cleaned IAC, EGR, new manifolds and your exhaust isn't leaking, then your "air" seems fine to me. Fuel--new pump, filter, FPR, and if you're getting no fuel smell and your throttle response is good (I guess you could check fuel pressure, but if the rest is new and responds fine, I personally don't see the point...but I could be wrong), then the fuel system seems fine. Spark--how new/old is your battery? Volts should be 12.XX by itself and 14.XX when running (the sign of a good alternator). You have new plugs, wires, cap, rotor, right? The distributor and ignition coil unit are all in one (convenient but expensive), I suppose that could be a suspect (in both our cases).

My governance suspicion comes to mind here. The sensors, many of which you've replaced. I've replaced fuel pump relay, ignition relay, and 100A fuse (main relay) and no change for me. MAFs not working for you seems like there is something fishy going on that is "above the law" and by that I mean the ignition tumbler unit on the steering column (I haven't tested it on mine yet) or the ECU. I've had mentions by the shop saying that their equipment had a hard time trying to connect or talk to my computer (for diagnostics). Hrmm.

I don't know if the O2 sensors could be giving your car fits when it's warm (that's when they are "online" and talking to the computer to help regulate fuel, air, and spark), but I've read when they're going bad they make your car go funny...but then we're OBDII here and there are codes that will be thrown for a bad sensor or sensors?

Wish I could help/help more. These cars are good solid cars (it's been great for 8 years, minus the recent issues within the last half a year), I'm sorry your experience is proving otherwise. And if your car is not throwing codes, it's just flat frustrating, especially as we've put a good chunk of money and/or time into the cars. If I think of anything or find a solution I'll post it here. The problem can't hide forever, or at least that's what I keep telling myself to keep me hunting and optimistic... Hope you find a solution quickly.