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Discussion Starter #1
Thanks for reading my post.I've got a 1992 mustang lx conv. 2.3 vin m. The car runs good most of the time except in the summer on sunny days when the temp is
90+(this is my second summer with this problem).I'll be driving for 20 mins under regular conditions and my car will start to bogg,then sputters and dies.
you try to start it right back up it dies.If you try to give it gas(from a little to all the way to the floor) to save it from stalling it pings and pops and
dies.If I wait 20-30 mins it'll start right up and drive. if it's still sunny it will mess up again in about 20-30 mins.if I only let it "cool off" for like
5 mins it'll go about 20 feet and stall again. If I happen to coast in to a car wash and hose down my engine compartment its good to go for about 20-30.
Now what I have done...
I've scanned it with a Autoray E-Z scan 6000 and retrieved the mem codes.A few were still on from before.I replaced the maf last year and didnt clear the mem
I
126 map/baro
157 maf
172 o2
173 o2
186 injector
327 egr
556 fp relay
And heres what I've replaced...
maf-used not tested
ignition mod -used tested
intergrated relay control mod(multifunction)-used running when removed
o2 sensor

I replaced these part's and cleared the codes.I drove it all night long (86 air temp 210 engine temp) and rescanned it. no mem codes koeo\koer both
passed.next day (104 air temp 200 engine temp) about 20 mins driving it sputters and stalls same problem. I rescanned it no mem codes koeo\koer both pass.
Where do I go from here fellas?Is it the cat maybe?crankshaft position sensor getting hot?intake air temp sensor getting hot?bap sensor getting hot?fuel
pump?
It dosent have a "fresh" tune up,its been about a year and my gas grommit(fuel inlet meets tank) had rotted away so its got a inner tube wrapped around the
inlet.Its not air tight and I can only fill my tank little less than half way.
I thank you for any help you can offer. thanks Adam
 

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Discussion Starter #3
Sorry its taken me a while to respond. I checked my vacuum and it was good,I dident feel like I was getting the volume I should so decided to replace the pump.I know I needed to be able to fill my tank up so I got the grommit too
I've replaced...
gas grommit
Fuel pump
filter
regulator
coil packs

Now my car acts a little better but developed a more consistant sputtering and stalling problem, it started doing it at night insted of just the day. And now it acts up from first key turn before its drivin anywhere.
When it gets under 1500 rpm it sputters and dies.I can catch the motor from stalling by feathering the gas and getting the rpm above 2000. it sounds good above 2000 rpm, anything less and its sputtery,doggy, I have to feather the gas cause if i try to punch it it sputters and dies. What else can I try Thanks
 

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try your tps.
mine was doing same thing and that's what was wrong.
didn't throw a code for it either.
 

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ok for this your biggest concerns in the MAP/BARO sensor, the injector and the MAF.

it sounds to me like your fuel system is heat soaking and causing the stalling/hard starting, does it run rich (black smoke)

and just out of curiosity have you checked the knock sensor?
maybe its not working, causing the timing not to be retarded because of the difference in air temp fuel mixture, and its causing it to detonate, but the KS isn't picking up on it?

im just throwing out ideas here though haha.
 

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Discussion Starter #7
well thanks anyway dayvdayv26 but that wasent it. dbt4220 thanks for chiming in. I've unplugged the maf and it still runs the same.I've read up on the map sensor, I do have a vaccuum gauge and a split second before it stumbles and dies theres a drop in vacuum.Its not waiting to get hot any more, it starts right up drives for a couple blocks then boggs and dies.It won't start immediatly up but if I wait a few minutes it'll go for another couple blocks then the same thing.there is a odd old gassy smell while this is happining.I do have the exhaust loose at the manifold, not loose loose but enough to cause a leak to bypass the cats.egr problem maybe?I havent checked the knock sensor or crankshaft sensor.wouldent those throw a code? thanks guys
 

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the KS should throw a code but then again it may not.

ok from rereading your posts check the MAF, MAP sensor, or the EGR system.

check to see if the egr is backed up with carbon deposits, if it is unbolt it use a vacuum pump to manually apply vacuum and check the inside of it and clean it with a screw driver, knife, something of that nature, no solvents etc.
 

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heres a chart that may help also. :bigthumbsup

these are possible causes of spark knock.
 

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guess what i found there is actually a TSB for this issue.




Article No.
98-23-10
11/23/98

MASS AIR FLOW (MAF) - SENSOR
CONTAMINATION - SERVICE TIP
FORD:
1990-97 THUNDERBIRD
1990-99 MUSTANG, TAURUS SHO
1991-99 CROWN VICTORIA, ESCORT, TAURUS
1992-94 TEMPO
1993-97 PROBE
1995-99 CONTOUR
LINCOLN-MERCURY:
1990-97 COUGAR
1991-99 CONTINENTAL, GRAND MARQUIS, SABLE, TOWN CAR, TRACER
1992-94 TOPAZ
1993-98 MARK VIII
1995-99 MYSTIQUE
LIGHT TRUCK:
1990 BRONCO II
1990-97 AEROSTAR
1990-99 RANGER
1991-99 EXPLORER
1994-96 BRONCO
1994-97 F SUPER DUTY, F-250 HD
1994-99 ECONOLINE, F-150, F-250 LD, F-350
1995-99 WINDSTAR
1997-99 EXPEDITION, MOUNTAINEER
1998-99 NAVIGATOR
1999 F-250 HD, SUPER DUTY F SERIES
ISSUE
This TSB article is a diagnostic procedure to address vehicles that exhibit lean driveability symptoms and may or may not have any Diagnostic Trouble Codes (DTCs) stored in memory.
ACTION
Follow the diagnostic procedures described in the following Service Tip. The revised diagnostic procedure is a more accurate means of diagnosing the symptoms.
SERVICE TIP

MASS AIR FLOW (MAF) DISCUSSION

MAF sensors can get contaminated from a variety of sources: dirt, oil, silicon, spider webs, potting compound from the sensor itself, etc. When a MAF sensor gets contaminated, it skews the transfer function such that the sensor over-estimates air flow at idle (causes the fuel system to go rich) and under-estimates air flow at high air flows (causes fuel system to go lean). This means Long Term Fuel Trims will learn lean (negative) corrections at idle and learn rich (positive) corrections at higher air flows.

If vehicle is driven at Wide Open Throttle (WOT) or high loads, the fuel system normally goes open loop rich to provide maximum power. If the MAF sensor is contaminated, the fuel system will actually be lean because of under-estimated air flow. During open loop fuel operation, the vehicle applies Long Term Fuel Trim corrections that have been learned during closed loop operation. These corrections are often lean corrections learned at lower air flows. This combination of under-estimated air flow and lean fuel trim corrections can result in spark knock/detonation and lack of power concerns at WOT and high loads.

One of the indicators for diagnosing this condition is barometric pressure. Barometric pressure (BARO) is inferred by the Powertrain Control Module (PCM) software at part throttle and WOT (there is no actual BARO sensor on MAF-equipped vehicles, except for the 3.8L Supercharged engine). At high air flows, a contaminated MAF sensor will under-estimate air flow coming into the engine, hence the PCM infers that the vehicle is operating at a higher altitude. The BARO reading is stored in Keep Alive Memory (KAM) after it is updated. Other indicators are Long Term Fuel Trim and MAF voltage at idle.

NOTE THE FOLLOWING PROCEDURE MAY ALSO BE USED TO DIAGNOSE VEHICLES THAT DO NOT HAVE FUEL SYSTEM/HO2S SENSOR DTCS.
Symptoms

^ Lack of Power
^ Spark Knock/Detonation
^ Buck/Jerk
^ Hesitation/Surge on Acceleration
^ Malfunction Indicator Lamp (MIL) Illuminated -
DTCs P0171, P0172, P0174, P0175 may be stored in memory

OBDII DTCs

^ P0171, P0174 (Fuel system lean, Bank 1 or 2)
^ P0172, P0175, (Fuel system rich, Bank 1 or 2)
^ P1130, P1131, P1132, (HO2S11 lack of switching, Bank 1)
^ P1150, P1151, P1152, (HO2S21 lack of switching, Bank 2)
OBDI DTCs

^ 181, 189 (Fuel system lean, Bank 1 or 2)
^ 179, 188 (Fuel system rich, Bank 1 or 2)
^ 171, 172, 173 (HO2S11 lack of switching, Bank 1)
^ 175, 176, 177 (HO2S21 lack of switching, Bank 2)
^ 184, 185 (MAF higher/lower than expected)
^ 186, 187 (Injector pulse width higher/lower than expected)
NOTE :DO NOT DISCONNECT THE BATTERY. IT WILL ERASE KEEP ALIVE MEMORY AND RESET LONG TERM FUEL TRIM AND BARO TO THEIR STARTING/BASE VALUES. THE BARO PARAMETER IDENTIFICATION DISPLAY (PID) IS USED FOR THIS DIAGNOSTIC PROCEDURE. ALL OBDII APPLICATIONS HAVE THIS PID AVAILABLE. THERE ARE SOME OBDI VEHICLES THAT DO NOT HAVE THE BARO PID, FOR THESE VEHICLES OMIT THE BARO CHECK AND REFER ONLY TO STEPS 2, 3, AND 4 IN THE DIAGNOSTIC PROCEDURE.

*GRAPH ON BOTTOM GOES HERE*

1. Look at the BARO PID. Refer to the Barometric Pressure Reference Chart in this article. At sea level, BARO should read about 159 Hz (29.91 in. Hg). As a reference, Denver, Colorado at 1524 meters (5000 ft.) altitude should be about 144 Hz (24.88 in.Hg). Normal learned BARO variability is up to +/- 6 Hz (+/- 2 in. Hg.). If BARO indicates a higher altitude than you are not at (7 or more Hz lower than expected), you may have MAF contamination. If available, Service Bay Diagnostic System (SBDS) has a Manifold Absolute Pressure (MAP) sensor that can be used as a barometric pressure reference. Use "MAP/BARO" test under "Powertrain," "Testers and Meters." Ignore the hookup screen. Connect GP2 to the reference MAP on the following screen.
NOTE REMEMBER THAT MOST WEATHER SERVICES REPORT A LOCAL BAROMETRIC PRESSURE THAT HAS BEEN CORRECTED TO SEA LEVEL. THE BARO PID, ON THE OTHER HAND, REPORTS THE ACTUAL BAROMETRIC PRESSURE FOR THE ALTITUDE THE VEHICLE IS BEING OPERATED IN. LOCAL WEATHER CONDITIONS (HIGH AND LOW PRESSURE AREAS) WILL CHANGE THE LOCAL BAROMETRIC PRESSURE BY SEVERAL INCHES OF MERCURY (+/- 3 Hz, +/- 1 in. Hg.).
NOTE BARO IS UPDATED ONLY WHEN THE VEHICLE IS AT HIGH THROTTLE OPENINGS. THEREFORE, A VEHICLE WHICH IS DRIVEN DOWN FROM A HIGHER ALTITUDE MAY NOT HAVE HAD AN OPPORTUNITY TO UPDATE THE BARO VALUE IN KAM. IF YOU ARE NOT CONFIDENT THAT BARO HAS BEEN UPDATED, PERFORM THREE OR FOUR HEAVY, SUSTAINED ACCELERATIONS AT GREATER THAN HALF-THROTTLE TO ALLOW BARO TO UPDATE.
2. On a fully warmed up engine, look at Long Term Fuel Trim at idle, in Neutral, A/C off, (LONGFT1 and/or LONGFT2 PIDs). If it is more negative than -12%, the fuel system has learned lean corrections which may be due to the MAF sensor over-estimating air flow at idle. Note that both Banks 1 and 2 will exhibit negative corrections for 2-bank system. If only one bank of a 2-bank system has negative corrections, the MAF sensor is probably not contaminated.
3. On a fully warmed up engine, look at MAF voltage at idle, in Neutral, A/C off (MAF V PID). If it's 30% greater than the nominal MAF V voltage listed in the Powertrain Control/Emissions Diagnosis (PC/ED) Diagnostic Value Reference Charts for your vehicle, or greater than 1.1 volts as a rough guide, the MAF sensor is over-estimating air flow at idle.
4. If at least tow of the previous three steps are true, proceed to disconnect the MAF sensor connector. This puts the vehicle into Failure Mode and Effects Management (FMEM). In FMEM mode, air flow is inferred by using rpm and throttle position instead of reading the MAF sensor. (In addition, the BARO value is reset to a base/unlearned value.) If the lean driveability symptoms go away, the MAF sensor is probably contaminated and should be replaced. If the lean driveability symptoms do not go away, go to the PC/ED Service Manual for the appropriate diagnostics.
NOTE DUE TO INCREASINGLY STRINGENT EMISSION/OBDII REQUIREMENTS, IT IS POSSIBLE FOR SOME VEHICLES WITH MAF SENSOR CONTAMINATION TO SET FUEL SYSTEM DTCs AND ILLUMINATE THE MIL WITH NO DRIVEABILITY CONCERNS. DISCONNECTING THE MAF ON THESE VEHICLES WILL, THEREFORE, PRODUCE NO IMPROVEMENTS IN DRIVEABILITY. IN THESE CASES, IF THE BARO, LONGFT1, LONGFT2, AND MAF V PIDs INDICATE THAT THE MAF IS CONTAMINATED, PROCEED TO REPLACE THE MAF SENSOR.
After replacing the MAF sensor, disconnect the vehicle battery (5 minutes, minimum to reset KAM, or on newer vehicles, use the "KAM Reset" feature on the New Generation Star (NGS) Tester and verify that the lean driveability symptoms are gone.

OTHER APPLICABLE ARTICLES:: NONE
WARRANTY STATUS: INFORMATION ONLY
OASIS CODES: 206000, 610000, 610500, 610600, 610700, 611000, 611500, 612000, 612500, 614000, 614500, 614600, 698298
 

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Discussion Starter #11
yeah I seen that tsb on All data a while ago when I replaced the MAF the first time. been to busy at work this week do do any more.I'm gonna check in to the egr stuff and probably that knock sensor. I did get the maf used so that might be worth checking out. I should have a knocking doner car in the next few days to try everything. thanks guys
 

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LOL yeah just reread the tsb and every time i do it makes me want to replace that maf.maybe go with new?who knows,this maf could have the same problem as the old one.
 

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id def. say check that MAF sensor but i cant seem to find the voltage specs anywhere if i find them from a reliable source ill post them up.

:bigthumbsup

at idle the voltage should be around .60 volt, on the signal wire, hope this helps. :)

the image is saying to use a breakout box but its not necessary, just test it directly at the connector of the MAF sensor.
 

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