Crank but no start :-(

T

theophile

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'02 V8, ~63,000 mi.

Thursday morning (3 days ago), the car wouldn't start when I tried to leave for work. It cranked strongly, the engine just wouldn't turn over. It had been a bit low on fuel so I put 2 gallons in it (bringing to a quarter tank) and tried again. No go. Checked the forum and found threads talking about blown fuel-pump fuse, so I checked the fuse and it was fine. Then I tried it again and it started right up, no problem. I filled up the gas tank, and it was fine the rest of the day and Friday. I didn't drive it yesterday (Saturday).

This evening (Sunday) I tried to start it and it was back to cranking (strongly) but not turning over. I tried pulling and replacing the 20A fuse under the hood to see if that would help, but it didn't.

I still have a pretty much full gas tank. The car is parked in a climate-controlled garage. It is flat and level. I've never put anything but 93 octane in it. I have not recently done any work on it.

I'm guessing fuel delivery because the starter seems fine. I'd appreciate any tips or ideas to save time troubleshooting. Thanks.
 
FYI cranking/ turning over is the same thing, cranking but not starting (running) is what sounds like what's happening.

probably not related, but I had a similar problem my dealer chased for a while, turned out to be a loose wire going to the fuel pump (somewhere).
 
agreed, cranking and turning over mean the same thing, a seized motor wont turn over"

also starting and firing up mean the same.

so I would say it like the engine turns over and cranks but wont fire up and start running...



the first thing i would suspect would be fuel pressure... I would check the fuel pressure while its cranking and not starting and see if its where it should be. maybe a weak pump? maybe a clogged fuel filter, maybe something completely else...
 
Changing out the fuel filter would be my first go-to. They are so often overlooked and not changed out near as often as they should. They collect so much crap it's not funny. The instant you change the LS fuel filter, the throttle response and better idle is immediately noted.

Try taking an old used LS fuel filter and hold it reversed upside down above a collector pan and watch the brown mud come running out of it. It shocked me when I first saw this. With a dirty fuel filter the fuel pump has to work that much harder which will cause it to give out before it's intended life cycle.

Coils, plugs, fuel and air filters ... followed with either some STP or Seafoam through the tank ... always a good bet! CRC to get the carbon out. LOL


https://www.youtube.com/watch?v=-rLaJnmguYY
 
BigRigLS said:
Changing out the fuel filter would be my first go-to. They are so often overlooked and not changed out near as often as they should. They collect so much crap it's not funny. The instant you change the LS fuel filter, the throttle response and better idle is immediately noted.

Try taking an old used LS fuel filter and hold it reversed upside down above a collector pan and watch the brown mud come running out of it. It shocked me when I first saw this. With a dirty fuel filter the fuel pump has to work that much harder which will cause it to give out before it's intended life cycle.

Coils, plugs, fuel and air filters ... followed with either some STP or Seafoam through the tank ... always a good bet! CRC to get the carbon out. LOL


https://www.youtube.com/watch?v=-rLaJnmguYY
Click to expand...

Thanks. I'm about to get my hands dirty. I actually have a new fuel filter on hand, which I picked up a couple of months ago as part of an oil change special at Autozone. Even if this doesn't fix the problem, it probably needs doing anyway.

I'm suspecting fuel pump as I have not been able to hear the sound of the pump turning on or priming when I turn the key to "ON" as several threads on here suggest I should be. I suppose I'll need to do some pinpoint tests at the pump, along with the pressure testing at the rail.
 
Replaced the fuel filter and it fired right up. There wasn't any sludge or filthy gas coming out of the old filter though, so I don't know if that was the problem or another fluke. Time will tell I suppose.
 
A simple trick might be to tap your fuel tank with a rubber mallet and see if the car starts.sometimes the pump gets stuck and just needs a hit ( not to hard or you will damage the tank) but not to soft either. Works better when someone is cranking the car while someone hits the fuel tank. If the car starts you pretty much knows it's your pump goin bad. Good luck.
 
theophile said:
Replaced the fuel filter and it fired right up. There wasn't any sludge or filthy gas coming out of the old filter though, so I don't know if that was the problem or another fluke. Time will tell I suppose.
Click to expand...


I just replaced my 04 LSE filter as well and it also wasn't near as bad as the one I pulled out of my 01 LS couple years back. I did note however that the 04's filter didn't look that old, may have been changed out prior to my ownership.
 
That's a good reminder,guys! I guess I'll change both cars' gas filters soon. The one I just got probably was changed at the proper interval, but I'll just change `em out. No use making that fuel pump work any harder than it has to. don-ohio :)^)
 
I checked back over service records from before I owned the car, and they indicate that the fuel filter was last changed about 27,000 miles ago, which is interesting because the service interval is 30,000 miles according to the shop manual. So if it was the fuel filter that was clogged, then it happened right about on schedule.

Another observation: After changing the fuel filter I am now definitely able to hear the fuel pump priming when turning the key on. It's like a soft groan or hum coming from the back seat. Lasts maybe a second or two. I was definitely not hearing that sound during the times when the car wouldn't start. Assuming the fuel filter was indeed clogged, would that prevent the pump from priming when the car is turned on? I would think that I still should have heard the pump come on even if it wasn't able to push enough fuel through the filter.

I have this feeling that I'm not quite out of the woods yet.
 
Well,at least now you can rule out the fuel filter. It probably contributed to your total problem. When I take a fuel filter off,I always drain it out,wipe off the inlet,and try to blow thru it. I have taken SOME off that were VERY hard to blow thru. don-ohio :)^)
 
Unless you are getting really bad gas, the filter should last way longer than the 30K change interval. No, even a completely blocked filter wouldn't stop the pump from running. The brushes on your pump motor may have a dead spot. If so, it will stop on the spot again eventually. When my BMW did this, I tapped on the top of the fuel pump cover with a mallet and that got the pump to work so that I could move the car out of the way until the new pump was delivered a couple of days later.
 
Yep, it's definitely the pump. Would not start again this morning so I pulled the back seat and checked the connector. I get constant +12V from one side of the harness and +12V from the other side with key on. But no life from the pump.

I think I already know the answer to this, but Autozone has the Spectra pump w/ assembly in stock for $160, and I really need to get the car back on the road. Does anyone know of any problems with the Spectra unit (or any aftermarket fuel pump for that matter)?
 
failed pump is kind of rare around here (maybe more to come)... But if OEM is not available, you gotta do what you gotta do... worst case it fails. Luckily its easy enough to get to..

again its rare enough i'd trust a second hand one by the way!
 
OEM appears to be available, but it is $650 to $700.
Search this forum, there haven't been many fuel pump failures, but I do recall posts from a few different members that tried one brand of fuel pump that did not work out at all (failure in months or less). I'd search to make sure it isn't this one.
 
Thanks. Yeah, I called the local dealership and they said they could have one by morning for $579.84. That's a bit rich for my blood. I didn't see any reports of problems with Spectra or Delphi on the forum. For whatever it's worth, Rockauto lists those brands under "Standard Replacement" as opposed to "Economy," so at least that's something.

Quick question though. Here is a stock photo of a replacement pump w/ assembly:
4.jpg

Here is an image of another product that Autozone also calls "fuel pump:"
5.jpg

Am I correct that the second photo is essentially the electric pump portion of the assembly shown in the first picture? As it appears that the problem is electrical (as opposed to, say, a clogged screen or something), I'm thinking I should be able to remove the assembly, replace just the electric pump component, and reinstall. That should work, no?

4.jpg


5.jpg
 
Yes, you are correct, but I think that the AutoZone pump is Airtex, and I think that is the one that was failing a lot.
Ebay (and other places too) has just the pump part for $30 to $50. One claims to be Motorcraft. I also saw Bosch and AC Delco. Those seem like safe brands...
 
Good points. Autozone has that pump part in stock for $120, with brand choices of Delphi or Spectra. The Airtex shows up on the Autozone website but is listed as unavailable.

I think I'm going to give the Delphi a shot. I know Delphi makes a lot of OEM parts so that gives me some measure of comfort.
 
Delphi should be good. I am interested as to how this works out long term, as I have no desire to pay $600+ when my time comes. It looks like changing it out is a bigger pain on the LS than the BMW was.
 
joegr said:
Delphi should be good. I am interested as to how this works out long term, as I have no desire to pay $600+ when my time comes. It looks like changing it out is a bigger pain on the LS than the BMW was.
Click to expand...

From what I can tell, it looks like the most difficult part will be loosening and removing the large retaining ring that holds the pump in. The shop manual shows a special wrench to get it off. Autozone has a universal one that can be borrowed, or it might be possible to rig something up.
 
http://deneau.info/ls/s6x~us~en~file=s6xa1007.htm~gen~ref.htm

NOTE: The routing of the internal fuel crossover tubes is critical to correct fuel system operation. Note the routing of the internal fuel crossover hoses at this time.
Partially raise the fuel transfer pump and disconnect the internal fuel crossover tube quick connect couplings.

Before removal, attach a non-conductive material to the crossover tubes. Then remove the fuel pump module and crossover tubes as an assembly, using the non-conductive material to pull the crossover lines through the gas tank.

NOTE: Install the fuel pump module and crossover tubes as an assembly.
Attaching the non-conductive material to the crossover tubes, pull the crossover tubes through the gas tank to install the fuel pump module.

^ This is the pain that the BMW does not have. (All the connections between the two pumps are outside of the tank, so I didn't have to mess with the transfer pump.) It does have more or less the same retaining ring. I managed it without the tool.
 
joegr said:
I just assumed it would be the same. Maybe it's not.
Click to expand...

It looks like the fuel pump design is different between Gen I and Gen II. Here's a scaled, cropped diagram of the Gen II pump:
gen2.gif

Here's the Gen I pump:
87563684.gif

You can see that on the Gen II the crossover lines connect to the module under the "hat," and therefore inside the tank, whereas on the Gen I, the inlet and outlet tubes connect through the "hat," and therefore outside the tank.

So it looks like the task is indeed more involved on the Gen II. On the other hand, I've read on several threads on here that the Gen I fuel pump is or has been a common failure item, so maybe the redesign that included routing the crossover tubes inside the tank resulted in a more reliable pump that rarely needs replacing.

For the sake of completeness, here's the Gen I manual on replacing the pump. Incidentally, it doesn't say anything about replacing just the electric pump component, so I'm hoping it'll be evident how to do it just by looking at it.

gen2.gif


87563684.gif
 
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