X-90 engine bogging under acceleration

[fixkick]

sorry, i keep forgetting this is the X90 sedan. please pardon me.... they are very rare,
wow all that is alien to me that very unique wire routing its electrically the same but routed special in x90.
nice photos, thanks.
i send them to witch hunter, $22 each for full clean (ultra sound) (was $19 for years)

bogging, for you , is, weak mAF or clogged injectors.
hard bog, not short. short bog can be, TPS dead. (dead spots)
if car drives ok, enough? try TechRon fuel additive, (benzene in the bottle)

http://www.walmart.com/ip/Chevron-Techro...z/16647989
1/2 tank of fresh fuel, and this bottle.
the balance test might find one injector weak, or more.. but if all 4 are weak, not.
the injectors have 10 micron screens inside, and the shop here, back flushes them to get them clean.

http://www.witchhunter.com/
washington state loc.

they will give you a full report, before and after, flow rates.

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if the engine is good, compression, it can breath, no cat melt, the engine actually can pump air fully. (im sure yours does)
and spark is good , then we have bad fueling. Only why remains.
there are 2 inputs for power.
MAF
and TPS.
just 2. (the ECU does match all air measured with correct fuel rates) and the 02 sensor is not part of acceleration only idle and cruise.
if the maf is bad, it will bog allday wide open throttle. (same with low fuel pressure)
if we had a scope we might see the injector pulses go to full length, this tells us the ECU is commanding full injections.
that leaves fuel pressure, (yours ok) and injectors clogged.

The TPS caused bogs are short lived ,until the MAF wins. the MAF always wins . i
It reports true flow (slowly) and the ECU sees that and wot FULL POWER HAPPENS, even with a bad TPS.
this should cover all angles here.

[dynabill]

hi All I'm not sure if this thread is still active, but, after reading this thread, fixkick and I ran through a tracker of mine a few years ago. we went thru all the same tests that you are going thru now. the thing that finally fixed the bogging was removing the intake and cleaning all the carbon out of all ports and internal cavities of the intake. I dont know if the motors are that much different, but the symptoms all sound the same. Best of luck Cheers Bill

[fixkick]

thanks bill, it is the same engine, just has unique wiring harness route's.


top fails are EGR is sticking open.
them main valve,
but it starts fine and idle fine, just total lack of engine power. (the egr likes to cause stalls , as you stop car? and if it stays stuck open, it will never idle right. at 800 so it is not EGR.
i think idles fine means, 800rpm, and the engine is not shaking hard.(misfire)
The P400s can be clogged passages, (the many) but a dead EGR, the engine has full power.

i'd say a weak MAF . (clean it) (tap it gently to see if it wakes up)?
The MPI TB has very few passages. (a blessing compared to the 8v)
if the IAC clogs?. the idle is way too low cold started. not 1200 to 1500 or so. rpm.
if the ISC electric clogs?, the idle speed, will be very low all times. (if it sticks , rpm can be almost any thing)
if the EGR port cogs the EGR 400, fails, but this will not cause low power, it only kills the EGR dead (and closed main) In, fact it will have full power, unless it pings.(not stuck open and stalling)
If the Butterfly valve sticks open? the idle screams full time, just like the a brick (or Toyota drivers floor mats) has fallen on the throttle pedal, and holding it open. a true danger in A/T cars.

In each case, full engine power happens, due to good engine, good fuel pressure and good MAF.
The maf is the one part that gives you POWER, if it ever under reports AIR, there is no added fuel and it causes way lean running.(bogging)
i think it's bad maf or bad gas. now.
The maf is easy to test with any voltmeter (better is a scan tool due to this shows what the ECU actually sees)

im sure his CAT is not melted and compression is 170+
and vacuum is near 19"hg

his FPREG was dead (only drop from 40 to 38.) the PFreg is a 1:1 reg. the reg must have full range to work right.
http://www.fixkick.com/sensors/tests/FPr...e_examples
if the pressure is too high the ecu may not correct it at light cruise. or at full throttle it will be very rich and misfire.
the FPreg regulator is what keeps wideopen throttle fuel rates correct. not in closed loop mode.
if pressure is too high those rates get to be too much.
way richer than 12.5:1 AFR.


keep in mind power loss, can be "rich misfire or lean bogging" white tip spark plugs or black.
The scan tool would show which it is.
LTFT would go way negative. like -40% trying desperately to correct a bad FPreg.
LTFT is long term fuel trim (the slow side that humans can see easy)


BTW on new cars with non loop fuel feed , the regulator is fixed and in the tank at the top of the PUMP.
so the ECU (now faster) has a a fuel rail, pressure sensor.
the new ECU (PCM) adjusts fuel Rates based on actual fuel pressure at all times. (it's just a new variable in the fuel equation in real time)