2002 Suzuki Esteem MAF or something else

Hi KH, thanks for responding. Esteem is 1.8, wagon, o2. My original post said 130000 miles - should have said its kms.

Its been in 2 garages so far, i'm reasonably (but not absolutely) sure fuel pressure, timing got checked. Good acceleration (even when cold) should point away from fuel? Nothing done prior to problem developing except weather getting colder which seemed to make things worse. Your suggestion about electrical part failing when hot makes sense but what part - the maf would presumably be isolated from any heat other than the warmish air in the engine compartment (room temp?) Dunno where to go from here. Should probably get a scanner but that's another project! I've located a used maf but includes the throttle body. Can't I just change the maf only (2 minute job)? But if no improvement, then what? No way to tell if the used maf is bad.

Your point about the timing though could be worth thinking about -- too bad theres no wires to put my old timing light on. I remember there were vacuum advances on the old carbs but dunno if there is anything similar here.

I'm sure they did a scanner check but what has not been done and nobody seems willing, is to run the scanner while driving. I guess it takes 2 mechanics to do this.

Hmmm. Frustrating problem!

Hi I finally got a new (used) maf but no improvement except no pending codes have come back. I got a scanner - here are results Hope the format is readable.

Light acceleration_______Heavy acceleration
RPM MAF TPS throtttle
Idle .36 to.39 lb/min .3%TPS
1500 0.7 3.9% __________ approx 6
1750 1.4 10%
2200 2.5 25.7%
2500 2.9 20.3%
2500 2.2 15%
3000 3.3 24% ___________ approx 4?
3000 3.1 21%

Sensor Idle ____________ Fast idle
RPM 750 ____________1500
o2S12 v=.06 to.16______ v=.14 to.8
O2S11 .13.82 % -1.5 to +1.5__.5 to.89
TPS .3% _______________ 3.9%
MAF .36 to.39 __________.691
Ign Advance 7 to 9 ________ 29
IAT 73 ____________ 104 deg F
LT FTRM1% # -6 to -10.1_____-1.5 to -2.3
ST FTRM1% # 0 TO.7_______ -8.6
cOOLANT 199 ______________ 199

Diagnosing problem - conflicting evidence
Tried to line up columns with underliners

POSSIBLE CAUSE ______ NO__________ YES________________ NEXT STEP

MAF ________________ REPLACED__COLD EFFECT ______ TAP TEST
____________________ HIGH READINGS
_____________________NO CODE

PLUGGED CATALYTIC____DISCONNECTED___SOUND ___TEST - O2 SENSR OUT
___________________ NO IMPROVEMENT

FUEL PUMP/ FILTER____OK FIRST MINUTE__? ____________ FUEL TEST - MAX
_______________________TESTED?

COMPUTER _____________DRIVES____ ERRATIC? O2 __TERMINAL VOLTAGE TEST

EGU, PCV __________________________________________ INSPECT / CLEAN

VACUUM LEAKS ________NOT VISIBLE
_________________________TESTED

THROTTLE BODY ____________________________________ REPLACE?

Other than trying to reinspect & do a voltage test
all I can think to do now is to assess exhaust backpressure. Local shops have no parts for this car & i'm hesitant to try a muffler shop. I've put the alternator idea aside till I get a voltmeter but the belt sometimes squeals for a minute in the warmer weather (too cold now). I'm assuming from the data, its not a timing problem. Is it normal for the O2 and FTRMs to bounce around a lot?

Sure is a frustrating problem, hope you have some ideas. Thanks.

Hi KHL
Well, problem finally resolved. After another rec to get fuel checked, I found a more experienced mechanic who, on listening to boggy sound on test drive, became convinced the cat was plugged. Muffler shop confirmed this, changed it and presto, noise gone, performance back!

As to why the cat failed, hopefully, changing the maf explains it. I'll get to that belt too asap. Thanks for your help, good to know you're around.

Cheers

I got the same problem on my 1999 but you said '' Dealer ran car with exhaust removed - no improvement '' and at the end you said '' became convinced the cat was plugged. Muffler shop confirmed this, changed it and presto, noise gone, performance back! '' If you remove the exaust, the performance sould came back. For me the manifold came red hot and the performance was weak ''no power'' ive disconnect the IAT and came back to noramle. Ive been on road test directly after disconnect it and was going fine ''good power. Then 15 min later it was going like if I had flat spot on the TPS.

I was about to do a scan to see whats wrong with this. The cat dosen't came red hot but the manifold do. Unplug the iat came back to normal then 15 min later push the gas pedal down '' good power'' but something looks like flat spot happen just like if I realease the gas pedal. Wasent sound like a missfire. (After disconect the iat the manifold wasent red )