No-start issue

L_King

L_King

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I have a 2001 LS V8.

This problem has come about a total of three times. I will get in the car and go to start it and it will crank and crank but not actually start and run. The starter is working as it should and the battery seems fine but after enough cranking it will start to get weak obviously. It is almost like it is not getting fuel, but it did it to me today and I have a full tank so I'm sure that's not the issue. I want to say it happens when I go to start it and cut the ignition a little to soon so it doesn't actually start. Like today I used the remote start so it could warm up a few min. before I left, and usually its quick to crank and start so the remote start is a pretty quick engage of he ignition. It seems random as far as I can tell, and I am kinda at a loss at the moment. Any Ideas? BTW no check engine light or anything.
 
I would suspect that the bearings on your fuel pump are starting to seize.
 
But (at least with my GM cars) the pumps tend to start making a lot of noise when they are going bad and I cant hear mine at all, ever. Not to mention if it was going bad why wouldnt I have issues while its running or driving?

Thanks

Lee
 
L_King said:
But (at least with my GM cars) the pumps tend to start making a lot of noise when they are going bad and I cant hear mine at all, ever. Not to mention if it was going bad why wouldnt I have issues while its running or driving?

Thanks

Lee
Click to expand...

Warning: Theory only...

As the bearing start to seize, the pump motor requires more power to operate. When you go to start the car, you are on battery voltage only, which is going to be 12.6 V and lower. While the engine is running, the electrical system voltage is usually around 14.5 volts. This means more power is available for the pump. I have actually seen this issue with these symptoms before, but not on an LS. On this particular car, it finally got to where jump starts from a running car were required for the fuel pump to be able to start running.

I haven't had a fuel pump get noisy before failure, but I'm sure that does happen sometimes.

Of course, your problem could be something else. If you want to be sure, measure fuel pressure while the problem is happening.
 
check voltage at pump

pull up base of back seat, open lid to pump, disconnect connector and check voltages, should be around 11.5v with key at run position. reconnect connector and turn key to run, you should hear the pump working. if nothing heard then pump motor needs replaced.
 
check fuel pump fuse. also pull the full pump relay and replace it with a know good relay or smack the relay with hammer a few time and reinstall. these items are in the spare tire well

while your at it do the same the the COP and engine control module fuses and relays. these items are in the engine compartment
 
another test

remove fuse pump relay from trunk, swap it with the horn relay in the engine compartment, honk horn. if horn honks, then relay is good. if fuses where bad then you could never start the car at all.
 
Thanks everyone. As soon as I get a chance I am going to start testing, and figure this out
 
Well with work and other stuff I have not gotten around to looking at this more, but I have to now! The car was running fine this morning while I was running some errands but I was leaving wal-mart and it was running rough almost like a bad plug or two or a lack of fuel...Well the it died so I started it back up and it wouldn't stay running. So then the battery quickly died as I tried to start it (by the way I was in the middle of a busy intersection, FML) eventually a cop came up and jumped me and it cranked great and even started for a half second, but wont stay running. Now it wont start at all. I am assuming it is my fuel pump and it has finally crapped out. What do you guys think.? It sounds like a pump to me but some suggest the IAC and the fuel filter.

If it is the pump, which pump do I replace the one on the passenger side or the driver side. I know one is a primary and the other is to equal out the tank, I just don't know which is which.
 
L_King said:
Well with work and other stuff I have not gotten around to looking at this more, but I have to now! The car was running fine this morning while I was running some errands but I was leaving wal-mart and it was running rough almost like a bad plug or two or a lack of fuel...Well the it died so I started it back up and it wouldn't stay running. So then the battery quickly died as I tried to start it (by the way I was in the middle of a busy intersection, FML) eventually a cop came up and jumped me and it cranked great and even started for a half second, but wont stay running. Now it wont start at all. I am assuming it is my fuel pump and it has finally crapped out. What do you guys think.? It sounds like a pump to me but some suggest the IAC and the fuel filter.

If it is the pump, which pump do I replace the one on the passenger side or the driver side. I know one is a primary and the other is to equal out the tank, I just don't know which is which.
Click to expand...

Sounds more like the IAC or the MAF to me. (now that your symptoms are a little different.)

Can you make it stay running by holding the gas pedal part way down? If so, your IAC is sticking closed.

If the gas pedal trick doesn't work, try unplugging the electrical connector at the MAF. Will the engine stay running now? If so, the MAF probably has some dirt or a bug on the sense wire inside.
 
When I was jumping it before I pressed down the gas to see if it helped, but no change. Ill have to double check it, and also do the MAF test before diving in to the pump.
 
Ok Now I am pissed!. I tested the fuel pump relay by swapping it with the horn relay well the horn still worked so I assumed that means the relay was good. Checked all fuses and everything looked good. I tried to start it with the gas pedal half pressed and got nothing. I disconnected the MAF and tried to start it and nothing. I finally decided to swap out the primary fuel pump (passenger side pump) with a walbro I had gotten from a LS in the salvage yard ( i don't usually use parts like that from salvage cars ) but thought id try. Well It looks like my pump was original so I swapped them out and turned the key...crank crank crank and nothing. It tries to start and nothing. I am at a loss right now.

To Recap: a hand full of times it wouldn't start after sitting over night but eventually it would even if I had to jump it because I drained the battery. Then yesterday while running errands I left a store hoped in and it was running rough then died. No matter how much gas I gave it or if I put it in neutral it died then stopped re-starting all together. checked fuses and relays, MAF and IAC test (half pressed gas) still no start.

WTF! anyone got any suggestions?

Thanks again for your input thus far.
 
Check for power to the fuel pump (for the first few seconds when you turn the key to run).
At the fuel pump connector...
Pins 2 (green with orange band) and 4 (black with red band) are the power to the pump. You have to measure the voltage with the red probe on pin 2 and the black probe on pin 4. Both power and ground are switched to the pump, so either could be faulty.

[Pin 1 (white with red band) is the fuel level sender signal. Pin 3 (brown with red band) is the ground for the fuel level sender.]

If the electric pump is working, failure of the jet pump can cause a loss of fuel pressure too.
 
I'll check that next. I don't know about these cars but I can always hear my GM pumps prime but I don't hear either of these pumps. Is that normal because it doesn't seem it would be.
 
L_King said:
I'll check that next. I don't know about these cars but I can always hear my GM pumps prime but I don't hear either of these pumps. Is that normal because it doesn't seem it would be.
Click to expand...

The pump is pretty quiet, and it only runs for a second. I normally don't notice it at all.
 
Well I fixed it (last week, but just got around to updating this.) Anyway after the new pump it would not start, you all saw that. Well I checked the harness for power and, hooked the car up to a charged starter, etc etc. Well after racking my brain and considering a few other possibilites I decided to go back and check the relay, and all the fuses for the fuel system. Well I dont know if I over looked this fuse or looked at the wrong one the first time, but the fuel pump fuse in the trunk was blown. More than likely due to the high resistance the bad pump was creating. Any how she runs great, with the exception of another issue, but its not related so I will start another thread i guess...
 
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