On the 4.6 its right past the air cleaner. (I'll post a picture) The M
in MAF stands for Mass. As in high speed. IME, when the MAF gets dirty
it causes pinging on acceleration. Have my doubts about this being the
problem. Live and learn.
Thanks, this helps. Funny thing, I paid 42 bucks to have it cleaned
2500 miles ago (part of a tune up). Looking at it now, it appears
there is old resin in one of the torx screwheads. I'll have to remove
the resin to get a torx bit into it. It's as if the screw had never
been removed! Hmmm.
Cleaning the MAF is an easy cheap insurance type thing. All
of them in domestic Ford products are made similarly. IIRC,
yours should be in the intake air pipe from the air cleaner
to the throttle body. I do not recall for sure whether the
5.8L engine had gone to the MAF system in '95 or whether it
was just the 5.0L They did not always treat them equally.
If it has a MAF try cleaning it. You will need a set of
torx security bits that are hollw if it has an MAF. You can
get a whole set for about $8.00US at places like Autozone or
Advance. If it still has the factory sealer on the head, it
was not likely cleaned. Once the screws are removed, it is
simply a matter of pulling it out. It uses an O'ring to
seal it which can be tight or stuck a bit.
If that does not correct the problem, I would next check the
TPS if it has not alrready been done. You can either just
replace it or use an analog meter to check the voltage
output by using a straight pin to penetrate the voltage
wire. It should rise very smoothly with NO GLITCHES or
flicker. At about 3/4 throttle, it will suddenly go well
above 4.0 volts to as high as 5.0 volts.
If you do not find any problem or a replacement makes no
improvement, you should check the joint between the upper
and lower intake manifold. Some in that vintage had a
problem sucking the gasket allowing an air leak that the ECM
may not always be able to tolerate. I like to use gumout or
similar carb cleaner to spray around the joint as it is
combustible enough to get a response from the engine and not
explosive like ether that can also damage an engins if it
hits a large leak and gets sucked in. You also have a
personal risk of bad burns with ether if it ignites. I
would avoid the ether for this. It is bad enough to use as
a starting fluid for someone who is not familiar with it's
unpredictable easy ignition characteristics.
Got the MAF sensor off. I couldn't believe someone or something
dripped resin, or melted plastic, or glue into one of the torx
screws! That crap was fused inside the head. Oh well, I got it off,
and the damn sensor looked clean as a whistle. I guess the mechanic
did actually clean it somehow. So, since I took it off, I cleaned in
again, let it dry, and put it back on. Cranked it up, and the same
I waited for the idle to finally come down from 1500rpm (taking longer
each time, it seems), and took it for a spin. Meanwhile the ABS light
goes off and stays off. I drove it hard. Hard accelerations, and
hard braking. I was pissed off, but I also wanted to see if something
would go really wrong.
Nope, nothing happened. In fact, the beast is really running good
(besides the mf-ing idle glitch.) It pulls very strong, winds up
nice. The brakes work fantastic. And it idles normally after the
intial kooky startup.
Next step is taking it in, dammit.
Thanks for all the help anyway, guys.
Today, I bit the bullet and took it in to a shop. Seeing how I just
dropped a grand on Tuesday for dental work, I wasn't looking forward
for another big bill, but waddayagonnado? I decided to go over to the
next town to a foreign car shop I've been to before. These guys are
intelligent and honest. I figure if I pay a few more bucks to get it
right, I might as well.
The owner, Bruce, is back in S. Africa on vacation. I talk to
Phillip, his stand in, and he works me into an afternoon slot. I'm
there 10 minutes, and he has the Bronco in a stall, hooking it up.
Meanwhile the entire place is swamped with Mercedes', Beamers, Jags,
you name it.
Phillip works on it, calls me into the gararge, I tells me the ECM is
clean, no error codes. In fact, the beast has idled normally the
entire time. He also pulled the ABS codes and printed them out for
me. Code 32, right front sensor problem.
So normal idling the whole time. We shut it down and start it up
several times. No glitches. All I can think of now is maybe it's all
the short driving I've been doing with the truck. All my driving for
a while has been short 1-3 mile jumps. Maybe this screwed up the
ECM? Possiblity, says Phillip. He says before he does more
(expensive) testing I should take it out for a long run. Hour or
That's where I am now. I'm going to take his advice, see if it calms
things down in the ECM.
You know what he charged me for 45 minutes of work? NOTHING. A big
fat nothing. Unreal. Beer run is coming up for Phillip.
Sounds like a shop to remember. It does take some use thru
several drive cycles for the ECM to completely "learn" your
vehicle. The ECM incorporates an adaptive system where it
learns the inputs from the sensors on your vehicle and the
responses of other sensor with respect to any adjustment it
makes. If it does not have this data "recorded" it resorts
to a table which is nothing more than a basic database
programmed by the manufacturer which are safe settings that
may or may not be optimum for your particular vehicle or
conditions. That is why the fault codes are usually cleared
instead of resetting the ECM after repairs. It is common
after some repair for the ECM to toss a fault code because
something is not the way it was. If the ECM is cleared, it
just assumes everything is OK as long as it is within the
base table specs.
You should keep in mind that the fast idle will kick in
every time the ecm senses a cold engine. If this is
happening too quickly, you may want to replace the ECT if
you have not already. They sometimes will act a bit flakey
before totally failing and preventing the engine from
starting. I replaced a dead one last night that had an
occasional failure to start when warm. Checked it stone
cold and found it completely open. I think they said the
new replacement was under $30 at the dealer. In any case, I
hope you have corrected your problem.
> What is the ECT, what does it do, what does it look like, and where is
Might want to stick this partial list in a folder for future references:
ABS Anti-Lock Braking System.
ACT Air Charge Temperature (intake air, after filter).
ATX Automatic Trans.
BAP Barometric (atmosphere) Air Pressure sensor.
BPP - brake pedal position sensor.... used to be called BOO -brake
BPS - brake pressure sensor.
CC Cruise Control.
CCS Cruise Controm Switch.
CEL Check Engine Light. aka: MIL Malfunction Indicator Light
CFI Central Fuel Inj, also called Throttle Body inj.
CPS Camshaft (or Crankshaft) Position Sensor - used for ignition,
CHT - cylinder head temperature sensor.
CKP - crankshaft position sensor.
CMDTC - continuous memory diagnostic trouble code - a problem that the
PCM has seen but may not be present now.
CMP - camshaft position sensor.
DPFE Differential Pressure Feedback, Exhaust - measures EGR flow.
DSM - drivers seat module.
EECIV The Engine/Trans Computer system
used from mid-80's - mid 90's.
ECM Engine control Module (before trans control > PCM).
EFI Electronic fuel injection.
SEFI Sequential Electronic Fuel Injection
EGO Exhaust Gas Oxygen sensor, also called O2 sensor.<br>
EGR Exhaust Gas Recirculation (valve).- reduce emissions by lowering
*ECT* Engine Coolant Temperature sensor.
GRVPS EGR Valve Position Sensor tells ECM/PCM how far the EGR valve is
open (EGRVPS is more commonly referred to as EVP) (Non-DPFE applications).
EOT - engine oil temperature.
EPC - electronic pressure control solenoid (inside trans).
FP Fuel Pump.
FPM - fuel pump module.
FPR Fuel Pressure Regulator.
FPS - fuel pressure sensor.
HEGO Heated Exhaust Gas Oxygen sensor, heated to reach op temp earlier,
also called O2 sensor.
IAC Idle Air Control (valve). Also referred to previously as ISC, IABP.
IAT Intake Air Temperature (sensor). interactive vehicle dynamics.
IMRC Intake Manifold Runner Control (late model, multi-valve variable
lighting control module.
MAF Mass Air Flow (sensor).
MAP Manifold Air Pressure sensor..used in engines without MAF
MLP manual lever position sensor.
MPLearn - misfire profile learn.
MTX Manual Trans.
OBDII Standardized powertrain control system from mid 90's (depend on
ODDTC - on demand code - a problem that is present at the time
of the test.
OSS - output shaft speed sensor.
PCM Powertrain Control Module (engine AND trans EEC).
PCV Positive Crankcase Ventilation (valve).
PIP Profile Ignition Pick-up - dist position pickup, ALSO the pulse
sent TO the ECM power steering pressure switch.
SAW - spark angle word signal.
SPOUT Spark Output, the ignition timing pulse sent back to the ignition
module based on PIP, engine RPM and sensor input.
TB Throttle Body.
TC Traction Control.transmission control switch... also known as OCS
-overdrive cancel switch.
TFI Thick Film Ignition - Ignition module used with EECIV, side of dist
on most models, remote on some later models.
TPS Throttle Position Sensor.
TSS - turbine shaft speed sensor.
VCT - variable cam timing solenoid.
VSM - vehicle security module.
VSS Vehicle Speed sensor (with or instead of speedo cable).
KOEO Key On Engine OFF, pulls memory codes
KOER Key On Engine RUNNING, real time error info
WOT Wide Open Throttle. Goose Test during KOER to test throttle position
sensor and engine response.
STI Self Test input, EEC - ground to start test
STO Self Test Output some time same electrical lead as the CEL, but
carries the test pulse or data.
ECT = Engine Coolant Temperature sensor. It is separate and
independant of the sender for the dash guage. It senses
coolant temp for the ECM. This is how the ECM knows to go
into cold start mode with the high idle. It is also used as
part of the calculations to detemine correct ignition timing
and fuel delivery. If the ECM "sees" a cold coolant
condition, it will go into open loop operation as if the
engine had been sitting overnite. If it is open as was the
one I replaced last night or completely closed, the ECM
either deliver too much or not enough fuel for the engine to
run as was that one. The ECM has no way to determine that
this sensor is out of range or near failing. It takes it at
it's face value so to speak and goes to the table for that
temperature range until it goes back to closed loop
operation. It may not store a fault code as long as it is
in a readable range even if grossly inaccurate. IIRC, if it
stores a code, it should be either 21 or 51on that year. It
has been a while since I was intinate with a 5.8L but,
IIRC, it should be installed in the water tube from the
intake to the throttle body. It will be much easier to find
with the air intake tubes removed. The owner picked up a
replacement for $24 if I heard correctly. Almost any good
parts store should have them as they are pretty muck common
to many of Ford's domestic cars and trucks. BTW, this
sensor can be tested and compared to a chart for correct
resistance values at various temperatures. The FSM (factory
service manual) and many others have this chart for testing.
Thanks man, I do appreciate your input. Today I bought a multi-
meter. What's the trick for measuring volts and ohms on these
sensors? Do you run the motor, or just have the key ON? And,
obviously these connections are closed with snap-type connectors. Do
you penetrate the wires with straight pins, then take readings off the
The ECT is a temperature sensitive resistor or what some
call a thermistor. It is supplied with a nominal 5.0 VDC
from the regulated side of the ECM. The resistance of the
sensor caused by temperature change is sensed by the ECM as
a variable voltage input. If this this is off, the ECM will
be basing it's calculations on the wrong engine temperature.
Modern EFI works so well, most people thinks their engines
are no longer temperature sensitive. This the sensor that
gives the ECM the ability to make it seem that way. If the
sensor is reading on the cool side, the engine will run a
bit rich all the time and may signal a false cold start
condition. Reading the resistance is just a measurement
across the terminals. The way it is made and usually
positioned makes this job a little difficult. You may want
to just penetrate the wires outside the plug to check the
values. Don't try to run the engine w/o it being plugged in
unless you want other problems
BTW, if you are looking to learn a lot about Ford EFI before
OBD2, tyhere is a book called Ford Fuel Injection by a
fellow named Probst for about $20 that has pretty much all
the info you would ever need to understand, test,
troubleshoot and repair the Ford EEC-IV systems. The public
library here has a copy of it. You may want to check it out
for a couple of days if yours has it.
This weekend I took it for 2 long drives. No effect on the problem.
If this ECM needs to learn something, it has a serious disability.
Tomorrow I'll play around with the multi-tester. I'm also going to
try to pull a code(s) using a self test method I found at
http://www.fordfuelinjection.com/?p . I'm pretty clear on the KOEO,
but will it work KOER? I guess I'll find out.
To get volt and ohm readings, do you leave the sensor connected,
pierce the wires with something (like a pin), then put the tester
leads on the pins? Is this the normal way to do it? And would you do
this KOEO or KOER? or both?
I have to believe this is something simple. The truck runs fantastic
except for this high idle. I keep looking at my rifles. No, not yet.
Leave the sensors connected. Use a straight pin to
penetrate the insulation for reading. The engine will run
poorly if at all with this sensor disconnected. Check it at
seceral points beginning when the engine is cold to be sure
it is responding to temp change in engine.
I also wonder if the shop just extracted the codes and ran
it thru the basic diagnostics. Not all shops have the same
capability to thoroughly test the system to the degree that
the Ford STAR tester can. It will thoroughly test each
sensor and record the values. A tech experienced with it
can damn near pinpoint a problem without ever touching a
wrench. Dealer diagnostic are expensive but, may be the
least expensive after the dust settles.
I had this same problem with my F150. I decided to bite the bullet and
pull the intake, so I went to the cars wash to clean the engine. After
I cleaned it it ran perfect. I hosed down the base of the air plenium
and foud the chincy (spelcek is my freind) gasket on top the manifold
was getting letting in air. It started as a long fast idle and would
stop after it heated up. It eventually got so the fast idle was a
On Jul 25, 2:28 am, firstname.lastname@example.org wrote:
Was yours a 1995 5.8liter? Do you mean you removed the air plenum and
put on a new gasket? I'm not sure what you mean about taking it to
the car wash. Are you saying it ran perfectly AFTER you washed it at
the car wash? I'm confused.
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