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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

---------------------------------- 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.

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Oppie
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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.

Reply to
BläBlä

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.

Reply to
Oppie

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... ;-)

Reply to
Oppie

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.

Reply to
Tom

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

Reply to
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

Reply to
Oppie

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