Just thought I would bring up the link where I found out about the Hall
Effect PickUp coil being a potential cause for this problem I'm having.
http://www.allpar.com/fix/stall.html
Anyone wishing to corroborate or deny the information - that would help
me.
What is the Speed Sensor or does the 94 Dak 5.2 not have one? Are they
talking about the sensor near the flywheel?
I may be mistaken by the fact that COLD TEMP has something to do with
the problem. I was thinking a temperature sensor device was the
problem, but looking here there are many other sources of problems for
a Cold start going to LIMP mode. For example; IAC, Speed Sensor?, Hall
Effect PickUp, MAP sensor . . .
I did some other MEASUREMENTS on my Dakota.
The Manifold Vacuum is ~ 19 in Hg
Fuel pressure at the rail port is ~38 psi
Coolant Temp Sensor 3.91K to 220 ohmS (cold to hot)
Air Charge Temp Sensor 14.67K ohmS cold @ 65oF
Where can I get specs on sensors?
My Haynes manual doesn't have this info.
I looked through allpar.com, no luck.
That range the coolant sensor is showing looks like the part is at
lease responding 18:1. I just need to know if it is in the right
range.
Regarding corroded splices:
Is there a way to install **bypass grounds** in parallel to existing
ground wires i the harness so that I don't have to dismount the harness
to do repairs to its poor wiring?
Excerpt:
***************************
* The *Hall Effect sensor* - this can fail and not set an error
code. However, if the computer gets no data from the Hall Effect
sensor, it will assume that the engine is not turning, and will
not provide any fuel. This is an inexpensive gadget that sits
underneath the rotor, in the distributor cap, *on cars without
distributorless ignition* (so this doesn't apply to cars made
after about 1996). A good first step and not hard to replace,
even
for beginners.
o In Steve Meade's case, in cold weather, the engine would
run
for about a minute, then die - each time it was started.
Using the gas worked to keep it running until it ran warm.
There were no codes set. In his case, he needed a new
pickup
rotor - part of the distributor ($113).
o The Auto Shutdown Relay (ASD) - actually, this rarely
breaks, but when it does, the engine stays off. One purpose
of the auto shutdown relay is to avoid "dieselling." It
kills all fuel delivery and spark. The ASD can be triggered
by a broken wire or short in another place -e.g. the fuel
pump.
o The MAP sensor - another relatively frequent cause of
stalling. This measures the air pressure in the manifold.
It
is usually mounted on a fender, costs around $25, and is
very easy to replace. You can test it - if your car won't
start, just unplug the electrical connection from the MAP
sensor.
o There is a relay between the computer (PCM) and coil, at
least on the 2.2/2.5 TBI, that costs about $12. If it
fails,
mechanics may try replacing the computer (thanks, Ronald
Knauf).
o ...and, of course, the *starter relay* - often this goes
and
it is misdiagnosed as the starter itself, the computer,
etc.
(thanks again, Ronald Knauf).
o *Fusible links*: John Auto Tech wrote, "try checking the
fuseable links located by the drivers side strut tower.
Give
each one a [gentle] tug to see if one stretches like a
rubber band."
o *Loose or dirty computer or battery connections* -
surprisingly common! Or (on vintage cars) check the hot
wire
going into the firewall plug... on the other side the wire
goes to the fuse box then to the dash- when it goes to the
dash it goes to the alt meter... it is a simple fix and one
that should be checked. (It is also a good place for a fire
- you've got loose hot wires and lots of loose insulation)
o The idle speed motor - this can, for example, cause
stalling
when the engine is cold, but not when hot. If you replace
the idle air control motor (IAC), also clean the throttle
body and reset the computer (you can just disconnect the
battery for a few minutes). This problem can also affect
newer cars such as the Neon which have no distributor.
o Plugged exhaust (e.g. catalytic converter). F.J. MacFarlane
wrote about this, noting that most or all US 2.2 carburted
engines had two converters in series.
o Clogged fuel filter or fuel line - this can be under the
hood or in the tank. Similar symptoms can be caused by a
weak fuel pump. There are, incidentally, two types of fuel
pressure test: one which tests an instant of pressure, and
a
more sustained test. The latter can often solve stumble and
stall problems that occur at highway speeds or under
acceleration.
o The speed (distance) sensor - see Ed Hennessy's notes
below.
o Spark plug wires - Rosegate noted that a problem with
missing cylinders was resolved by changing the wires. A
dealer failed to solve the problem, charging $130
apparently
to change a single wire. You can do this yourself in ten
minutes; you can get very high quality wires for $40 (four
cylinders).
o The oxygen sensor - somewhat expensive to replace (they
cost
about $40-60 just for the part), but since the oxygen
sensor
is the thing that tells the engine whether it's feeding too
much or too little fuel, it's pretty important. The oxygen
sensor can be damaged by bad gas or excess pollution from
another bad sensor or part. Bad oxygen sensors can cause
high idling, rough idling, stalling, lack of power, and
poor
fuel economy, not to mention excessive pollution. "An O2
sensor actually generates voltage and when active, varies
between .5 and 1.0 V. which is rich/lean. It's working ok
if
you see a wave between these numbers. If you see one steady
reading the sensor is likely bad. Don't forget the sensor
must be hot to stard working." - Wayne Moschella
o Fuel line cracks - it happens, and they can be hard to
find.
Turbo engines should be periodically and carefully
inspected
for leaking fuel lines, due to their higher fuel pressures.
Small, hard to see fuel line cracks can cause stalling and
non-starting. Check not just the main fuel line but also
delivery lines that feed individual injectors (thanks, R.
Jake Carr).
o Low fuel pressure - applies only to 1988-90 models (see
below).
o Jim Zellmer wrote: a rubber elbow coming out of the rear
intake manifold [may have a] crack that is not readily
visible from the front of the car. The crack would open an
cause a vacuum leak big enough to shut down the engine.
***************************
Complete article on STALLING here:
http://www.allpar.com/fix/stall.html
Ron
- - - - - - - - - - -
Hi Bernd,
Nope, I do not have access to scanner. I do have a
DVM/DMM.
Cold resistance of coolant sensor is 3.91K ohms
Warm/Hot resistance is 220 ohms
Ron
=======================
- Bernd wrote:
The splices are a solder joint - no connector unless
specified in the wiring diagrams. I'll pull down the
wiring diagrams for you and email them. You
can pierce the harness if you really need to, but it's
better to back probe
the connectors to prevent any possible corrosion from
the wire pierce (or you can seal it up with RTV). On
the injectors - they are ground switched -
The ASD relay powers them up and the ground switching
is controlled via the PCM.
If the vehicle is running rough on initial start but
no problems at normal temp...it doesn't sound like a
wiring issue (not ruling it out though). Do
you have access to a scanner? If you have a DVOM
(Digital Volt/Ohm Meter), check the resistance of the
coolant temp sensor when cold and when it's at
normal temp. Let me know what you find.
- Bernd
-----Original Message-----
From: rws [mailto:rwsam2002@yahoo.com]
Sent: Thursday, September 13, 2007 4:20 AM
To: DakotaTruck DML
Subject: DML: Re: Cold Starts causes Check Engine
Light + LIMP mode
Hi WiLieR & Bernd,
Re: auto or manual -- it's auto trans.
I will check the ECT sensor and FI wiring and see if
it solves the problem. NAPA said they had the ECT
sensor and was ~$14. Guess I need to drain the
coolant by at least half to prevent it from coming out
of the sensor port.
What do splices look like, crimp style or a Faston
type?
If I read 12v at each FI connector, that means it is
working correctly, right? Likewise, if I measure
resistance to ground on the other FI terminal it
should be zero, right? I may have to pierce the
insulation to measure 12v while engine is running, is
that OK?
On the wiring diagram the FI's grounds are two places,
one with 8
connections and the other with 7 connections - any
idea where the ground points are located?
I'm also going to clean the TB air horn that has more
carbon on it that I expected. It may be affecting the
IAC motor. I will remove it from the intake manifold
to do the cleaning.
Ron
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