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Also the Idle Air Control (IAC) has caused me a couple of problems and cleaning it with Carburetor cleaner helped for a while. I finally sprang for a new one. I would first check the IAC for erratic idle problems.
For stalling while driving, my 92 dodge, 5.2 L 150k hard miles, had the problem caused by an internal computer connection at the cable/computer connector. It would stall at idle or while turning a corner at 25MPH or doing 70 MPH straight on the highway. I replaced all the usual suspects- IAC TPS, CSS, Coil before I finally found a used computer on EBay. That fixed that problem.
I realized it was the computer because when I tried to restart the engine and turned on the ignition, the check engine light would not come on as it normally does and then go out. I would go to the engine bay and wiggle different wires and noticed that when I moved the computer connection, the check engine light would sometimes come on and only then the engine would start. I checked all the connectors and found it had to be in the computer connection under the epoxy(?) filler where I could not get to fix it.
Beyond these bits of info, good luck. (I couldn't read the whole thread, especially that guy that wrote the book.)
I realize it is an old thread, but I hope this info may help someone.
Dave
I have changed the plugs and wires. Checked the coils, changed the distributor and rotor button. Even swapped computers with an identical truck to see if that was the problem.
Once she shuts off she will not start. After letting her sit for a while she will eventually start.
There also seems to be no fire on the plugs after she does this.
I am not sure what could be the problem. I am at my end with this truck.
information. I have a Haynes service manual for my '98 Dodge Dakota 5.2L
(318) V8. The wiring diagram indicates various sensors on this type of engine
that provide information to Power Control Module (PCM) or engine management
computer. In my model there is something called an ASD (auto shutdown relay)
which is controlled by the PCM. For the PCM to operate this relay (which kills
the fuel pump/injectors via the Fuel pump relay) AND the power side of the
ignition coil, a sensor has to be either out of range or faulty.
It's hard to make any accurate diagnosis of your problem with virtually no
info to go on, but one place to start is the camshaft sensor. This is a Hall effect
(solid state) sensor that detects the camshaft "lobes" to determine the firing
pulse and spark for each cylinder. These have been known to go "wacko"
where they work sometimes and not at other times.
I had a 1999 Dodge Ram V8 that would run for 15 minutes,
then die and wouldn't restart for another half hour or so,
and then run again for 10-15 minutes and die again and this was
a repeatable problem. Turned out to be a defective camshaft sensor.
This is located in the distributor (under the rotor) and can be easily removed
and replaced with a screwdriver.
about 10 to 15 minutes of running and then wouldn't start again until left
for an hour or longer. No engine codes. Checked everything..fuel rail pressure
all the obvious things...he had it towed into the shop..they changed the crankshaft sensor first..didn't fix the symptom, so then they changed the cam
sensor (the one inside the distributor that replaces the old fashioned points) and
that fixed the problem.
These are solid state "Hall effect" sensors that detect a magnetic cam lobe
and generator a timing pulse to the PCM. Once in a while they go defective
in a strange way, but not completely. I carry a spare one around in my
'98 Dakota, just in case mine starts acting up like that.
So far, I've only had the stalling problem in very cold weather and only when
going from reverse to drive. Don't know what that one is about yet..
whether it's transmission temp related, engine temp related or some other
critical sensor that shuts it down.
I have heard that these "hall effect" solid state sensors they use in the distributor
for providing timing pulses to the PCM are known for "whacko" symptoms.
My 98 Dakota V8 stalls in reverse also in very cold weather, but not after
the engine warms up and it only stalls once at that..as soon as I put the
gear selector from R to D, it cuts out. Starts ok after that and I can drive
off..been like that for several years now..I was thinking it was a sensor, but
not sure which one, since the 46RE auto transmission used on my truck has
a temperature sensor, but it is a thermistor, which is a simple sensor compared
to these hall effect camshaft sensors.
I have a spare, so I think I will replace it and see if that solves the problem.
a number of sources..tires not being properly balanced or sidewalls on the
tires deforming at certain speeds causing a vibration at only a certain speed
and not at other speeds. I had a set of tires once that did that.
The other posibility would be u-joints on the driveshaft.
I have a 99 Dodge Dakota 5.2L. standard. Recently it has been stalling when I have slowed at stop lights or stop signs or when I have going slow around a corner. I have replaced the battery and cleaned the IAC. I was reading on either this forum or another one and read that it could be the Vehicle Speed Sensor. It also runs really really rich. Also both of the mechanics that I got to scan my truck got a no data reading. If anybody could give me any other ideas of what it could be that would be great.
I know this has probably been brought up on these forums before but I can't find it anymore so I apologize for repeating the thread. Maybe somebody could give me the link to another thread that may be able to help me.
Thanks,
Maybe the EGR .
I also replaced the EGR and the engine ran a lot better at high end. I didn't notice the problem because the computer would adjust for it. I noticed that at 80 MPH towing my boat up hill and floored, it would backfire because it was too lean. A new EGR fixed that.
Good luck with it.
Dave
I had to replace both on my 5.2.
Good luck,
Dave
IIRC, the O2 sensor is basically "out of the loop" until the engine has warmed up. O2 sensors do not work unless they are hot.
This would be my guess with no codes present. Changing the coil is the last
resort..I would change out the camshaft sensor first as these can be tricky to diagnose (hall effect semi conductor) and in some cases they don't always produce a fail code.
For an engine to run..you need 3 things, compression, fuel charge in the cylinders and a spark at the correct time..it's gotta run.
Since the coil primary is controlled by the PCM, it needs i/p from the camshaft (and crankshaft sensor) to provide the correct timing for the spark. The PCM
will pulse the coil primary to produce a spark for the correct plug based
on the position of the rotor inside the distributor cap. It then goes off to
the spark plug for the cylinder that is at top dead center after it's compression
stroke.
The rest of the ignition system is basically standard, cap, rotor, sparkplug wires and park plugs, so these shouldn't be giving the intermittent symptom
you are describing.
behind the RIGHT cylinder head. It is a hall effect solid state sensor as well
and detects notches in the flywheel/driveplate. The PCM receives those
pulses and processes it to control each cylinder's injector. O/P from the
sensor will fluctuate between 0volts and 5 volts DC.
To replace it, you have to remove the right front tire and inner splash shield,
disconnect the wiring harness connector and the bolts that hold it in.
Not as easy as replacing the hall effect camshaft sensor inside the distributor, which sits on a plastic plate held on with 2 screws.
On the dakotas, the ASD relay (auto shutdown) will be operated by
the PCM if it detects any kind of serious fault...and sometimes there
is no Pxxx code given, because the sensor is flakey but not completely
dead yet.
P0300 is no camshaft sensor signal..but this will be a complete failure
and the check engine light will come on.
P1391 loss of either camshaft or crankshaft sensor signal.
Note: these are hall effect semiconductor types of sensors and they can
have intermittent failures as their o/p depends on sensing a changing magnetic field on the flywheel or inside the distributor.
(see wikipedia for more information on these).
Try this, take the wire out of the coil that goes to the distributor and find a sparkplug wire
to fit into it. Connect the sparkplug boot to a spare spark plug and ground the plug against
the engine somewhere. Have someone crank the engine while you observe for a spark
right away..within the 1st second. If you do..then the it's the injector system/PCM.
There are two sensors that control fuel mixture:
IAT (on the intake manifold) determines the temp of the incoming air and sends a signal
to the PCM to adjust fuel mixture accordingly.
MAP (manifold pressure or mass air flow) this one will send a signal to the PCM to
adjust the mixture as well.
But don't replace them..you should be able to test them for proper voltage...0 to 5volts.
pump, IF it is the same as the older style Magnum 5.2 V8, you should have
a pressure regulator down in the fuel pump module. It maintains the
pressure on the fuel rail. So unless it is faulty, the fuel rail should have
some pressure on it on all times, when the ignition key is ON,
typically 45 psi.
I have an Actron fuel pressure guage (0-100psi) that I use to check mine on occasion.
These are cheap to buy $15-$20 and come with an instruction folder for
testing the pressure on the fuel rail test port..the one that has a black
plastic cap screwed on it.
Unscrew the protective cap and screw on the hose with the schrader valve fitting onto the rail. If the engine has been sitting for a long time, the pressure will bleed off, but as soon as the ignition key is ON (don't start),
the fuel pressure should be instanteous..within a half second.
As soon as you get a reading on the guage, leave it for an hour or so and
check the pressure again WITHOUT TURNING ON THE KEY OR STARTING,
it shouldn't drop down that much, if any..that is what they call a leak down
test and it will give you a relative idea of the pressure regulator valve.
The fuel pump is controlled by the fuel pump relay in the PDC.
Note: be careful when attaching/detaching the fuel pressure hose to the fuel rail test port, as some fuel may spray out around the fitting until it is tight. If the fuel rail is still under some pressure, until the schrader valve
closes tightly on the fuel test port, fuel can spray out on a hot engine..so
don't do this with a hot engine. They suggest wrapping a rag around
the test port fitting to catch any fuel spraying out.
* ALSO*
My fuel pressure regulator also has a small clear plastic fuel dump hose to dump any fuel in the hose and release the pressure on the guage AFTER the ignition has been turned off, (before the pressure guage fitting is unscrewed from the test port.)
(They recommend putting the clear plastic fuel dump hose in a container to contain the gas, will be just around 10ml.
This should at least give you an idea if your problem is fuel pump module related, as replacing the fuel pump module inside the tank is a BIG job
and an EXPENSIVE one.
The tank has to be practically empty and you need to drop the tank onto a jackstand support to get at the pump.
Not a DIY job, in my opinion..so do the testing first..as it is a cheaper
way of troubleshooting.
Initially it 0 PSI (sitting overnight) and was 45psi with the ignition key turned on after 1/2 second or so. Turned off the ignition key and
left the guage on for over an hour.
Fuel rail pressure dropped down only to 35 psi, so the pressure regulator on mine works just fine.
cranking engine or engine cranking and not attempting to run?
Never heard of the term "ignition control monitor" on the Dakota.
Mine doesn't have one...just a camshaft sensor and a crank sensor that picks timing information for the PCM, which controls the fuel injection and the spark.
Sometimes they are referred to as ECU (Engine control unit)..is that what you mean?
Have you changed the camshaft sensor, as these are known to have
intermittent symptoms such as you are describing.
I have cleaned the IAC and the TPS, replaced Dist. cap and Rotor, plug wires and plugs. The cap and Rotor were very corroded. Runs fine for a few days, now today without pulling the trailer, after I drove 15 miles, stopped for 5 min., drove 4 more miles, the vehicle will not idle. stopped for 30 min, run OK. drove home 20 miles by the time I got close to home Won't idle. I guess the next action is to replace the IAC, then the TPS.
the PCM to change the idle rpm on the engine when there is additional
load, such as the A/C compressor coming on....but how did you
manage to clean the TPS sensor?
There is nothing to clean on these.
You can test the TPS with a digital voltmeter, by probing through the
insulation on the plug between ground and the o/p of the sensor .
There are 3 pins on this..Gnd/o/p/+5v.
Take the air cleaner off, turn key on (DO NOT START engine) and operate throttle by hand..if sensor is good, it will read around 0.5v closed throttle and around 4.5volt fully open.
That's all there is to it. Test it first, you may not need to replace it.
If the TPS sensor is out of range, you will get a P-0122 or a P-0123,
otherwise, it's within the range that the PCM accepts.
As far as the IAC (Idle Air Control) which is a motor, if it is truly faulty,
you will get a P0505 code (shorted or open condition in one or more
of the idle air control circuits).
Taking it off an cleaning it doesn't hurt, but I wouldn't replace it unless
I know for sure that's what is causing the problem.
aftermarket parts place all told me "no listing" on this. You are forced to
buy the entire fuel module at a cost of several hundred dollars! What
a scam! Besides that, you have to drop the tank, and in order to do
that, you have to have the truck on a hoist with a way of supporting the
fuel tank.
who was or still is. Yes, I do have a aftermarket fuel pressure guage and
Haynes manual on my Dakota, and check my fuel pressure on occasion..no problems there and I don't have a rough idle condition.
You are right that once the fuel pressure drops below 45psi, the truck will
stall at some point. There is NO inline fuel filter on the Dakota, (at least
my 1998), I have checked underneath.
As far as the stalling condition he mentioned, the ASD and the Fuel pump
relay are controlled by the PCM. The ASD shuts down the injectors and
the ignition coil or coils and the Fuel pump relay controls the fuel pump.
If the PCM senses loss of timing from either the Crank or Cam sensors,
it will shut down both.
them ahead of time and carry one with you in the truck at all times..otherwise, if the fuel pump fails on the road, it's towed into the nearest repair garage of your choice and the fuel pump is replaced at
the garage's price, which will be a lot higher than e-bay.
Based on my Dakota's past history of failure, I carry certain spare parts
with me in the truck at all times such as:
cam sensor,
wheel bearing hub
spare injector
and of course fuses, a OBDII code reader and a Haynes manual.
This year, I've added a spare TPS sensor after having transmission shifting
issues which turned out to be FINALLY a TSS sensor on the transmission.
I don't know if this is another one of those hall effect sensors, but for a
while it wasn't providing any clues (codes) and I had a lot of high rpm
hard (pressure) upshifts, until finally one day, the check engine light
came on and I read the code for the TSS (Transmission Speed Sensor).
I have a spare cam sensor ($30) in my glove compartment, which
is an aftermarket NieHoff AL437.
My spare TPS sensor is a STANDARD, (standardbrand.com)