(11-15-2015, 03:00 AM)zukitrek Wrote: Good day sir. Glads to know you are back. (been working on my machines, (sunnyhere)
So as a recap of my idling issue, my TPS Idle switch volts and ohm numbers are ok by results I posted.
Now DLC jumpered I can start engine and getting 12's all the time endlessly as you saw on video. GREAT !
So thats:
A- my ISC could still be flaky even though I saw it live (2.20v) or ( well, the all love to gum up, this is a life long issue this,SERVICE issues)
B- my DMM is not the right one for regulating the duty to 7v. (my guess is this) but really , lacking a scope to prove other wise is all just a guess. ( one can not just guess. that is why GOD made scopes... to end the guessing.....OMG what is that noise. here??????
C- what else can I test? not much, lacking a scope or scan tool (both is prime) or a real duty meter......??????
What then could the problem when shifting to R or D and rpms dropping?
this is easy, so very easy:
1: ISC dead. (your test proved that for sure, it is dead (but worked a while after fiddling the bleed screw)
2: so lean and lacking power, the engine slows, in Drive and ISC cant get it to rise, (TOO LEAN)
3: engine misfires badly , rpm drops , ECU opens ISC , and drops more, due to what, gross misfiring. ( can can hear/feel engine power here)
said another way, engine lacks the power, or the ISC is failing, (pick one) A or B? (i'd bet A) but I'M NOT THERE>! with me TOOLS.
BTW this seems to be and on and off thing. Just this morning when I shifted to D RMPs did not drop sometimes it does.
well that could be just the (ISC working 1 time then not the next) if you could watch the isc signals, you'd know why, here is what would play out.
DRIVE drops RPM , ISC fails. (that is its job to stop that effect !) below shows you how it really works...
1: scope shows , in neutral., the pulses are way long high, its 12v,0v,12v repeats pulse . so that means the duty set too high, and when you select drive, the ECU sees rpm drop, and tries to increase the duty, but can't it already high. so cant no open a valve that is already fully open, so what happens, well the transmission huge load, causes RPM to drop.
2: or case 2, the neutral test , you turn on alternator loads, HL+blower and the Duty does not change, this means the ECU is messing up
or ecu is in limphome or TPS idle stuck at 5v failed.
see? see how a scope or read duty meter works.>> it tells you what is happening, or that you forgot to set the duty all this time, which is the case.
I find time this weekend after all errands to take a look at the ECU.
Buen dia!!!
what is a servo, do you know?
there are many examples, cruise control , fuel mixtures EFI, idle,
and a Sail boat auto pilot, (ever sail a boat with one, even with a TILLER , autopilot, (holds a course with the rudder)
or even a kite, the tail acts as directional control.
the the tail on a wind mill..?.. if falls off (the tail) and main rotor blades, spin out of control.
even your home HVAC thermostat is a servo. (holds the temp. no mater what)
the ECU is programmed to hold idle a 800 (hard coded, Not a/c on or idle up mode)
i does this with a simple software loop. (or other ways i dont wish to go into now)
but the loop just loops and checks rpm
if the RPM drops, it opens the ISC (sends longer pulses)
if the RPM rises, it closes the ISC ) (sends shorter pulses)
this loop is a servo (its endless, if TPS idle SW is closed.)
the FSM book has you set the duty cycle of the ISC for many reasons,
here is a list
1: engine is older. (cant suck as well? or has lower power, due to age.)
2: a new throttle body.
3: a used throttle body.
4: a TB that some person lacking tools tried to set and did so poorly or failed to see, there are vacuum leaks or engine is bogging /misfiring...
if the engine is strong, and not bogging and not misfiring
then the ISC is failing
and top of the list is setting the DUTY CYCLE TO SPEC.
when at SPEC< the ISC has no trouble opening, (not stuck) and adding plenty of air, and causing huge HP increases top match the loading effects of shifting in to DRIVE.
this is how it works.
not setting duty correctly invites all this.
one could un screw in the bleed and pray it works.
or buy a meter with a Duty mode.
when you unscrew the bleed, the duty will increase 1 for 1, as you unscrew(adds air) the duty will close valve longer (means stays at 0v longer)
if not the ecu is bad. (or some unnamed input is wrong, i sent you the 2 pages with all voltages on all pins.
you do release, that any ecu inputs can cause this (wrong inputs) its just a computer.
ive no idea at all how many inputs wrong could cause this, (be a long series of tests) to learn that.
but here are some
idle switch wrong.
limphome does this, per the book flat out tells you that.
Start line stuck high(my lil. theory)
spark timing way off. (retarded, timing will cause duty to be high (low engine power), and you go to drive and it(isc) cant open more.... failing)
PS (tech talk)
i think your meter is too slow, some cheap meters do that, too slow to average all signals.
2.5mS high and 2.ms low is 50% duty. 5ms is the period the freq is 200 times a second (Hz)
so if the cheap meter (converts) slower than 1,mS, it will fail. you need meter that converts 1000s times a second to get a running average. (about)
cheap meters might do this in 100 times a second, a hopeless meter... but in meters you do get what you pay for. in most cases.
the problem with cheap meters that have a duty mode (on dial), fail too say it's performance range.? sadly.
Fluke makes a meter that works but you wont like the price..
i have a bench pulse generator ( called a function generator)
that can make pulses just like the ECU.
i can connect to 10 DMM meters,
some work others don't. (20VDC range)
for sure old fail.
for sure cheap fail.(too slow)
but never on the FLUKE, the fluke meter works, but is $300 meter.
but luck happens......
to be a tech, you have to know the limits for your tools and meters. (or look like my dog ,chasing his tail)
MOST METERS CHEAP DO NOT EVEN SPEC THIS OUT. but heck its just $10, what do you expect?
the spec, is conversion rates, and band width allowed,.
