My 1995 AWD has started running very bad lately. It recently failed emissions with high NOx reading. Codes are checked with Innova 3140 tester and are now Cylinder 6,DTC412, DTC538,DTC172. About to sell it on Ebay with 268,000 miles or donate for tax write off.
412 - "Cannot control high rpm level during testing." The Idle Air Control valve needs cleaned or replaced.
172 - "Lean Mixture, HEO2 sensor." Means your oxygen sensor is likely overdue for replacement. (The one closest to the engine.) They begin to slowly fail around 60,000 miles and are as good as gone by 100,000.
538 -"No Throttle Response During KOEO testing" Is a nothing to worry about code. It means that at a certain point during the testing procedure, you were to have pushed the throttle wide open. If you didn't or failed to floor the throttle within the given time limit, this code pops up.
Sounds like cleaning the IAC valve and a new O2 sensor would get you running again. And, yes, either of these will cause the engine run very poorly.
You can do a search for more information on these procedures, pretty simple repairs.
DTC 172 can also be a dirty MAF element or a failing ECT
the post about cylinder 6 is too short to tell us much of anything?
is this something from your scanner?
DTC306? can be spark plug, ign. wire, injector-injector wire or injector 6 circuit in PCM.
High NOx is usually a sign of a failed EGR system, valve or one of the tubes
can also be the NOx section of the CAT
High NOx is usually a sign of a failed EGR system, valve or one of the tubes
can also be the NOx section of the CAT
COOL dude!! I like a guy that knows more than I do!! What a brain he has !!
I just never got THAT good as a tech, worked @ independent shops with little service info, so finally quit and switched to finish carpentry and handyman work.
O2 sensor is one year old, new plugs and wires, new MAF sensor and cleaned and replaced the IAC sensor. Also 1995 4.0L don't show a EGR valve. I check the fuel pressure and it seems a little low. Max 29 psi @ idle and Max 31 psi KOEO
O2 sensor is one year old, new plugs and wires, new MAF sensor and cleaned and replaced the IAC sensor. Also 1995 4.0L don't show a EGR valve. I check the fuel pressure and it seems a little low. Max 29 psi @ idle and Max 31 psi KOEO
Fuel pressure IS a bit low, does the condition get worse at higher loads/ RPM.s or does the problem get better as the engine warms up ?
Stuck EGR could cause lumpy running if stuck open, since basically you then have a significant air leak in the fuel intake.
Try temporarily pulling off the o2 sensor plug & see if it runs better.
You will get another code but it is because you pulled the plug.
Aeroman.
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Green-96, XLT 2wd, 3L Vulcan, from Ontario, Canada
All original powertrain except alternator & starter motor. 292,000 kms & going strong !
COOL dude!! I like a guy that knows more than I do!! What a brain he has !!
I just never got THAT good as a tech, worked @ independent shops with little service info, so finally quit and switched to finish carpentry and handyman work.
High NOX is also caused by the engine leaning out, by excessive timing advance, and by faulty O2 sensors. Vacuum leaks, and intake leaks can cause the engine to lean out. An intake leak can also cause your O2 lean code.
BTW, didn't you have a lot of spark plug problems? Seems to me that a lean running engine would go through plugs in a hurry due to the fact that it melts the electrodes and tips.
You should repair the intake leak and rebuild the trans, inexpensive if you do it yourself.
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My Rides
1994 Ford Aerostar 4.0L AWD extended
175,000 miles
Fullblown 50 series catback system
590 watt sound system
AFE ProDryS filter
1990 Mazda B2600i
505,000 miles
Custom exhaust with BearCats high flow converter and a straight through muffler
Custom high velocity intake with AFE ProDryS filter
I really do like these vans, but don't have the place to do the work. I live in an apartment. The sparkplug problem was the thermostat stuck open. The lean running just started with the warmer weather.
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It recently failed emissions with high NOx reading. Codes are checked with Innova 3140 tester and are now Cylinder 6,DTC412, DTC538,DTC172. About to sell it on Ebay with 268,000 miles or donate for tax write off.
