LW300 Cranks but won't start

(originally posted through Teranews.com but never propogated)

Several times in the last few days the '01 Lw300 has refused to start.
Cranks fine but won't catch. Fuel pressure is on the low side of normal
(40-43psi).

I put in a can of STP Injector cleaner last week and am wondering if this is
causing the problem? Anybody hear of this?

New fuel filter installed, Removed and inspected the EGR valve (Is not bound
and closes properly). Sprayed Carbureator cleaner into the throttle body to
remove accumulated grunge (MIL light came on for 50 miles and about 10
engine starts before going off on its own). When it is running, engine is
nice and smooth, no misses and no MIL.

I pulled every fuse that I could find and checked them, Pulled relays and
reseated. Still searching.

After the first failure to start, I read out the code and it showed P1780
"PNP switch / MIL requested by TCM" (Snap-On scanner). code would not erase
from the scanner. I later pulled the controls B+ fuse and the MIL light went
off. My mechanic friend said that whatever codes were set were more likely
effect of the engine not starting rather than a cause.

Rather than run the tank empty with the STP in it, I refilled the tank when
it was half full. Keeping my fingers crossed now but will likely take it in
to Saturn for check out. My son is getting married in Rhode Island (3.5 hour
trip) 7/28 and if the Saturn is not dependable, will have to rent something.

Oppie
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Took the car into Saturn the next day. I understand that intermittents are
hard to diagnose but all they found was a bad schrader valve on the fuel
rail (fuel pressure test port). When you take off the plastic cap, you leak
a drop or two of fuel. With the cap on, no leaks. They changed the schrader
valve core ($3.00) and charged me $110. and were confident they had fixed
the problem. Bull-shit! Unless there is something going on that I don't
understand, makes no sense... and the car stalled out at a trafic light
today. No MIL light came on so I'm guessing no code. Engine did restart
normally but I am not confident in the car or our dealer now.

 

I dont have my eSI software installed at the moment but I pulled this
off of a google search.

Saturn 2000 L series
TSB #00-T-28, replace main V6 relay in underhood fuse box. May set DTC
P1780.

 

And true to form, on the way home last night, the car died again - this time
while driving it. Let it sit for about 15 minutes with the hood open and
tried to start it every few minutes. After about 15 minutes, it started and
I let it idle. After about 4 minutes, it shut off again as smartly as if the
key was turned off. No stutter or anything. I think it's the crank angle
sensor still. Go ahead and try to convince the boneheads of that though. Of
note was that there was no oil leak anywhere but the crank sensor was rather
oily on its case. When cranking (while engine would not catch) no smell of
gas in the tailpipe. Fuel pressure OK.

Eventually the engine did start again and I drove it directly to Saturn
before they closed the gates. Left it off overnight and will see what
happens now. I think that I will rent a car for the wedding this weekend. I
no longer have sufficient faith that the car will be fixed properly again.

 

Thanks for that. The P1780 may just have been that I was able to start the
engine while being towed. Could make a screwy powertrain code. Anyway, since
there are several identical relays in the UHFP, I swapped them arround. No
difference.

We'll see if Saturn actually tries to read out the fault codes this time
instead... ;-)

 

I had a similar problem with my 2001 LW300 (114000 miles) and it turned out
to be the crankshaft position sensor. The car would die. Sometimes itt
would start after 10-15 mins. Sometimes it would not restart. The sensor
was replaced ($611) by the dealer in March and I have had no problems since
then.

 

Picked the car up from Saturn this (7/30) morning. They had it since last
Wednesday and couldn't reproduce the problem. Finally on Thursday, I asked
them just to change the crank sensor. Total cost was an hour of labor
@$99/hr plus the crank sensor $102.78. This not counting the somewhat bogus
$110 charged previously for changing a schrader valve on the fuel test port
they claimed was the cause.

Unlike most of the sensors that have the ability for the computer to
diagnose a stuck high, stuck low or an open circuit, no such ability for the
crank angle sensor. There is a code for low signal or erratic signal but if
the pickup coil opens, all bets are off.

Oppie

 

Drove the car for a couple of days to get my confidence back and then headed
off to Vermont for vacation. Put about 600 miles on it in the week and to my
great relief, not a single hiccup or trouble light. I am satisfied that the
root problem was the crank sensor.

Twice on the mountain roads, I saw a sudden appearance of an oil trail on
the roadway leading to the shoulder where a larger puddle was. A sobering
reminder of how wrong things can go out in the boonies... Everytime I saw
something like that (or worse like a burn spot on the shoulder where a car
caught fire and melted down) I checked the dashboard gauges and lights and
said a silent prayer of thanks that it wasn't me.

Oppie