1996 3.5L Vision TSI (LH) - Occassional Hard Starting

Vehicle is a 1996 Eagle Vision TSI, 3.5L with 66K miles. New plugs, wires,
PCV, and air filter installed at ~60K miles. Battery is ~2 years old and
starter is original. Car runs very well, idles smoothly once started and
gets 29 MPG on highway using A/C.

I'd appreciate thoughts on a problem I have experienced occasionally with
difficult starting. The majority of the time the engine starts on the first
try without any problem. Occasionally, it won't start and requires retrying
the starter for up to 20 seconds before it catches. Once it gets started, it
runs rough for a few seconds before smoothing out. No diagnostic error
codes (just a "55") when you use the on-off-on-off-on key trick. No known
problems with the battery or the starter and the starter turns "normally"
when it is not starting and sounds strong.

I believe that the problem must be either something electrical or fuel
delivery related. I've thrown a bottle of Techron fuel injector cleaner
into the last full tank, but have not noticed any improvement yet. I also
plan to change the fuel filter this evening since it has been about 30K
miles since this was last done. Assuming these don't fix the problem, does
anyone have any thoughts on how I could narrow this down to determine the
root cause? Any other symptoms that I should be looking for if this is
the fuel pump beginning to give out? (I don't currently own a fuel pressure
gauge, so if this will be needed, I'd appreciate a specific make/model
recommendation.) Could the fuel pressure regulator be causing occasional
loss of pressure and causing the hard starting? If not fuel related, what
electrical area would you recommend I check given that most of the time this
problem is not apparent and the car runs fine otherwise?

I know there is a wealth of experience out here on this engine, so would
appreciate opinions and thoughts so thanks in advance for your response.

Bob

 

Enlist a helper to stand at the back of the car and watch the exhaust pipe
as you try to start it. (perhaps, since the pipe is on the driver's side,
you can hang out the driver's door and watch the pipe while you crank the
engine).

If you see black smoke in any amount when the engine finally catches and
as it's running rough, suspect one or more leaky fuel injectors.

Your fuel delivery system is fine at least up to the fuel rail, unless you
have high-speed/high-load running problems you haven't mentioned. Even a
filthy fuel filter and/or weak fuel pump will usually supply enough fuel
to start and idle the engine. When fuel demand goes up, *that's* when the
a substandard pump or partly clogged filter show themselves.

Not only do you have extended crank times, but also rough running once it
does start. A bad fuel pump outlet check valve (for instance) that would
cause the pressure to drain down would cause extended crank times but not
the rough running.

On the other hand, if the system's pressure is draining down through a few
leaky fuel injectors, all that raw gas would be in the cylinders -- you'd
have your extended crank time to repressurize the system, your extended
crank time to clear the overly-rich mixture out of the cylinders, and your
rough running thereafter. Another test you can do: Next time it gets
cranky, push the accelerator about halfway down while continuing to crank;
see if that shortens the crank time.

If a crank or cam sensor is getting wonky, or the MAP sensor is headed
South, this can also cause these kinds of problems, often without setting
a code. An easy check for the MAP sensor is simply to unplug it. The
computer will then not see it and will substitute fixed values. If the
black-smoke test is negative, you might try this to see if the car starts
more easily.

-Stern

 

Dan,

Thanks for the thoughts and suggestions here. Your note leads me in a
different direction than I was originally leaning (fuel delivery) and is
exactly why I posted my request for other ideas.

The fact that this only happens occasionally (maybe 1 in 50-60 starts and
generally when I am not driving it), requires the vehicle to have been
sitting for some time unused, and is not repeatable with any frequency makes
it difficult to diagnose. Nonetheless, I will do my best to try to have
someone else watch the exhaust or turn the key for me so I can see what is
happening at the exhaust myself.

I'll also keep in mind that it could be a sensor and that I can try to
unplug the MAP sensor but once again, the unpredictability makes this
difficult to do much here. Based on what you've said, I am now leaning
towards leaking fuel injector(s). Let's hope I can confirm this by visual
examination of the exhaust. That said, is there any way to easily diagnose
which one(s) are leaking or is a total replacement of all 6 the best
approach given the vehicle mileage and the cost of diagnosis by a good
mechanic?

Bob

 

You can pull the whole fuel rail assembly and leave it connected to the
fuel supply, put a twist of paper towel around the bottom of each injector
and a plastic bag over that, leave it sit for awhile and then remove and
see which paper twists smell of fuel...donno how "easy" that is...

 

Dan,

Sounds like a plan. I'll try to remember to post the outcome when I get
around to looking at this. As I indicated, it happens infrequently and is
basically an annoyance, but I would like to fix this before winter cause I
expect it might become a real problem then.

Bob

 

Bob,
On my 94' LHS there was one time that it wouldn't start at all. It was
the crank position sensor. That sensor supplies all timing to the rest of
the system and won't set a code when it is acting up.

Steve m..

 

My granddaughters '97 Intrepid ES has the 3.5 but it has 2 throttle bodies
on it..so I don't have a clue how you would check the injectors ..Did those
early 3.5's come with port injection?

Occasionally she used to experience this problem, but DS recommended turning
the key off and on for some one else on a different vehicle to troubleshoot
a problem and this "cured" her trouble completely, we have not pursued the
problem further as this has worked so well,, it is just a habit now,, key on
wait for the pump to stop,, key off, key on wait again, then crank.. Lights
up instantly.. She doesn't use the vehicle much anymore and will wait for
the
real problem to manifest itself and fix it then.

DS also stated you can only do this twice in so many seconds,, he said there
is some kind of timer in the circuit that only lets you do it so often in so
much time...unfortunately I didn't save the post so I don't know how much
time. I learned my lesson and save the stuff that has good info in it now.

Overall once we got the intake manifold gasket and water pump taken care of,
this engine has been just about as bullet proof as you can get... 125000 and
counting smooth and very powerful for it's size.

Don't mention tie rods though,, ..... anyone know if there is a "permanent"
fix for these out there..?? On the 4th set, well 3rd not counting the
original.. {:-(

Thanks

Ted

 

Ted,

Thanks. Sounds like your granddaughter's vehicle may have a bad check valve
in the fuel pump. This is initially what I thought my problem may be as
well before Dan pointed out the rough idle after it finally started most
likely being due to raw gasoline leaking from my injectors into the
cylinders/combustion chambers.

I've done the water pump and timing belt thing twice on this vehicle
already. The second time was not really the water pump, but was due to
corrosion around the O-ring in the water pump housing that bolts to the
engine block.

I've had no problems with the intake gasket.

I've replaced one set of tie rods and the infamous sway bar links as well so
can relate to your comments here as well. I wish they had placed grease
fittings on the front end since this would probably have lasted a lot
longer.

Otherwise, I can't complain as it still drives like it did when it was new.
I'm preparing to hand it down to my oldest son so want to get everything
squared away before then so he does not have any problems.

Bob

 

Steve M,

Thanks for the reply. I presume your crank sensor failing caused a "hard"
failure. That is, the vehicle would not start at all once this sensor
failed. This is not the case with my vehicle since it starts normally the
majority of the time and only occasionally exhibits this "rough start"
condition. Even after it does happen, it might be a week or a month before
it reoccurs. I just have not really noticed any pattern to it other than
the engine has not been running for a period of many hours. I've had it
happen when the weather was sub-zero and most recently when the temperature
is in the mid-80's.

Bob

 

All the '93-'97 3.5s had the same induction system.

Well, no, this isn't a "cure". All you're doing there is pressure-priming
the system (which in your case is probably leaking down via a bad fuel
pump outlet check valve) so that the engine will start quickly. Nothing
really wrong with it, won't hurt anything, but it hasn't cured the
problem. I sometimes use the same "double prime" technique on my '89 D100
in cold weather. Sort of the modern equivalent of giving the accelerator
two pumps instead of one before initially cranking the engine. Also don't
think the on-off-on-off-on deal will get you diagnostic codes on your '97
as it will on earlier cars, but I could be wrong about that.

Again, you won't hurt anything, but the fuel pump will only run twice on
initial key-on within a certain time period, so additional key flicks
won't do anything.

-Stern

 

Also don't

Assuming the same OBD-II diagnostics were in place on '97s as they were
in my '96, the keycode method does work.

--Geoff

 

For future reference, the really good news is that you don't have to
save *anything* posted here, and yet you will always be able to find it.

This and several thousand other news groups are archived on Google for
posterity. Go to google and hit the "Groups" link just above the key
word box. Then drill down to find the particular group that you want to
search (in this case rec.autos.makes.chrysler). Then type in some
keywords that you remember from a previous post or thread, or that you
suspect might be in a thread that you're not even sure exists on the
subject of interest. Then check the box that says "Search only in
rec.autos.makers.chrysler" (or whatever ng you identifed), and hit
"Search". Notice that you don't have to search a particular group -
once you hit "Groups" and some keywords, and check the box to "Search
only in...", it will search any or all groups that you have narrowed it
down to (i.e., if you only drill down to the "rec." part, it will search
all ng's that start with "rec."; if you don't drill down at all within
groups, it will check *all* groups for those key words).

Notice that after a search is performed, you can tell it to sort what it
found by date (upper right). And when you click on a particular found
post, you can tell it to show the whole thread (again - upper right of
window).

You can also hit the "Advanced Groups Search" to narrow the search down
to dates (anytime, within the last 24 hours, week, month, 3 weeks, 6
months, or between...and...), specific author, and/or more complex key
word combinations.

Anyway - take a look at the archives search on Google, play around with
it, and you'll figure it out. Comes in *very* handy when you know an
answer to a certain problem was given but you can't remember what that
answer was. Takes the pain out of having to decide what to save to your
hard drive and what not to - because the answer is: Don't save anything
- *always* go to Google.

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with "x")

 

Thanks,,, this is the "one" I will save then !!!

 

I had a bad crank sensor on my wife's 93 3.5 that was intermittent
before failing hard. It would "stumble" at highway speed, and would
stall at idle.

Weirdness at starting sounds more like a fuel injector (or lower O-ring
more likely) leak, or just a drain-down of fuel system pressure. You
might try cycling the ignition 3-4 times (spaced apart by about 2
seconds) to cause the fuel pump to run longer than its normal one burst
of operation prior to cranking, just to see if its a loss of pressure.
(Or better yet, use a fuel pressure guage.... ;-)