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<title>The New Yorker that wouldn't Mark Giammalvo</title>
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<center><b><font size="+1"> </font><font size="+2">October 1996
By Mark Giammalvo</font></b></center>
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<td align="center" valign="top" width="20%"><img src="newy.jpg"
height="150" width="283">
<br>
View of the troubled 5th Avenue. <br>
<br>
<p><img src="aug20_15.jpg" height="150" width="200">
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Fig. 3 Good Fuel Pressure. <br>
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<p><img src="aug20_09.jpg" height="150" width="200"
align="texttop">
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Hooking up the fuel pressure gauge at the pressure tap on the fuel injector
rail. <br>
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</p>
<p><img src="aug20_08.jpg" height="150" width="200"
align="texttop">
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Fig 2. Checking for spark at the coils. Spark was present.
<br>
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<br>
</p>
<p><img src="aug20_07.jpg" height="148" width="200">
<br>
Another investigation of spark, this time at the plug wires. Spark was
good here too. <br>
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<br>
</p>
<p><img src="aug20_01.jpg" height="150" width="200">
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Fig. 6 Checking for spark at an injector harness with a noid light. Hmm..the
the light does not seem to pulse at regular intervals. <br>
<br>
<br>
</p>
<p><img src="aug20_02.jpg" height="150" width="200">
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Hooking up the lab scope's leads to a fuel injector while the injector
remains plugged in. <br>
<br>
<br>
</p>
<p><img src="aug20_06.jpg" height="200" width="266">
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Fi8. The Fluke 97 Lab Scope is showing that the injector does not open
all the time while cranking the engine. <br>
<br>
<br>
<br>
</p>
<p><img src="aug20_10.jpg" height="200" width="266">
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Fig7. The Chrysler in the intensive care unit. <br>
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<p><img src="aug20_12.jpg" height="250" width="333">
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Fig 10a. Scan tool showing the car's on board computer not allowing fuel.
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</p>
<p><img src="aug20_11.jpg" height="250" width="333">
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Fig.10b The scan tool showing "fuel allowed." <br>
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<div align="left">90 Chrysler New Yorker 5Th Avenue <br>
3.3 Liter 4spd/ At <br>
48,033 miles <br>
Cranks ok won't run </div>
<p align="left">Recently a customer phoned us regarding a no start
condition on her Chrysler. Since the car broke down over the weekend we made
arrangements to have it towed in on Monday. Due to the fact that we were
two weeks booked and counting, it was decided that I would break away from
my normal duties and look at the car myself. </p>
<div align="left"> </div>
<p align="left"> On a busy Monday morning came the
sound of the wreckers back up alarm. How I dread that- doot, doot, doot,
doot. Anyway, I went out to great the tow truck driver. After the towing
service left, I began my quest. The symptoms were still fresh in my mind
since speaking to the customer, "car cranks won't run". As I turned the ignition
switch to start their was no cranking sound from the starter motor-only the
click, click of the starter solenoid. Needless to say, the battery was dead.
Probably cranked to death by someone behind the wheel with a glimmer of
hope that this car was going to start. Not this time. Normally, in this situation
we would put the battery on charge overnight and look at the car again the
next day, but in this case I decided to take the battery out of the car,
put it on charge and then install a new battery from the stockroom so we
could continue with our diagnostic. </p>
<div align="left"> </div>
<p align="left"> Now that the loaner battery was
in place we again attempted to start the car. Now we had the car cranks
but won't run symptoms. Strangely enough, as the starter was held cranking
the engine would momentarily seem to fire but then would just crank again.
I decided to connect several spark testers in series with the plug wires
to ascertain whether or not we had spark. (See fig.2) sure enough, strong
spark constantly. Leaving the spark testers in place I decided that the
next step would be to check fuel pressure. (see fig 3). Luckily the 3.3
has a fuel pressure tap that is easily accessible. (Fig 4) As I hit
the key - bang- 45 psi on the gauge. My next step, was to peek inside the
air cleaner box just to make sure some fuzzy creature hadn't lined up 300
acorns across the air filter element. Although a restricted air supply is
rare, we've been bit by that one before. Better to find out now rather than
after being into the car for five hours. Air cleaner box clear! </p>
<div align="left"> </div>
<p align="left"> After discussing the test results
so far with my brother Glenn, we decided that it was time to go high tech.
Connect the scan tool. (Fig 5) Logically this would seem to be the next
step, after all, we can verify a supply of fuel, spark and air. But are they
all being delivered? </p>
<div align="left"> </div>
<p align="left"> Our first concern was to make sure
TPS was not stuck too high. In some computer programs, if TPS is too high
the computer will think someone is cranking the engine with their foot to
the floor and stop fuel delivery to the injectors. We generally refer to
this on GM cars as "clear flood mode". Glenn is always reminding me how
nice it would be if we knew these different features of automotive computer
programs on each make and model but as you already know the manufactures
won't release proprietary information. Well, that's a subject for another
article. Let's continue. </p>
<div align="left"> </div>
<p align="left"> An analysis of the datastream revealed
TPS was ok. We also checked to make sure charge temperature (incoming air
temp) was close to coolant temp since the car was cold. They were both fine.
All other datastream inputs and outputs looked good. Now, I'd be lying if
I told you I didn't scratch my head a little. At this point we decided to
check injector pulse with a noid light. (Fig 6) we noticed something interesting.
As the car cranked their was no pulse then their would be a quick pulse
and the engine would make a cough like attempt to start but wouldn't.
</p>
<div align="left"> </div>
<p align="left"> The customer called to check on
our progress with the car. I told her that so far most everything we had
tested had shown ok. I also told her that her car had more equipment hooked
up to it than a person in ICU. (fig 7) At the end of our conversation I told
her that I would call her as soon as I had some reportable news. </p>
<div align="left"> </div>
<p align="left"> I have to digress here for a moment.
Recently I was at a doctors office with my wife. My wife had mentioned to
the doctor that I was often comparing medical testing on patients to diagnostic
testing on cars. The doctor promptly reminded my wife that people are more
complicated than cars. After we got home that evening I got around to thinking
about that statement. The more I thought about it the more I realized it
couldn't be further from the truth. Doctors work on only two models, male
and female. On these two models they know where every organ is located.
There is no change from year to year. When we work on cars we have to use
large databases just to find out where everything is because their is no
standardization. Whether it's a computer or a wiring harness or a solenoid,
we have to look up where it is before we can even attempt to diagnose or
test it. Then once we find it we need to know what specific action or output
we should look for because that can change from model to model and year to
year also. In addition, I have never seen a car help me my telling me where
the pain or problem is. Blood and gore aside, cars are more complicated than
people. Period! Back to the problem. </p>
<div align="left"> </div>
<p align="left"> After seeing this short intermittent
injector pulse we decided to check it with a lab scope. The lab scope showed
that the injector opened rarely. (Fig8) </p>
<div align="left"> </div>
<p align="left"> We decided to check for service
bulletins. After reading several, we stumbled on one titled "start/stall,
vehicles not equipped with Vehicle Theft Alarm (VTA)." (Fig9) Although
our symptoms were not really a start stall we thought the bulletin bared
reading just the same since our car did not have VTA. The bulletin mentioned
that on certain cars not equipped with VTA, the engine controller may in
error, look for a VTA signal and when one is not received, prevent the engine
from running. The bulletin also stated to look at theft alarm status on
a scan tool and that if "fuel not allowed" is displayed while cranking,
to replace the controller. (Fig 10a 10b) At first we could not find theft
alarm status on our scan tool so we called our tech line. After hearing
our test results they recommended replacing the controller anyway. After
checking the scan tool again we located theft alarm status and verified
" no fuel allowed" when cranking. We replaced the computer easily in the
left front fender adjacent to the battery. After cranking with the new computer
the 3.3 roared to life. Done! </p>
<div align="left"> </div>
<div align="left">Mark Giammalvo MAT, SAE, L1 <br>
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<center>Mark</center>
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