Lil help needed with no start

A few weeks ago I was doing my daily driving. I parked the truck at work for about 5 mins, came back and the sucker wouldn't start. It turned over like a champ - sounded like it was flooded. I let it sit for a few hours and tried with no luck. I had it towed home and later that night I tried and it still wouldn't start.
Now for the fun... I let it sit for almost 2 weeks cause my schedule wouldn't permit me the time to mess with it. I got in and the bitch started right up! I'm not really sure where to start. Could it be the fuel pump is on the way out? I hate intermitent problems! I don't recall the pump whining when it had the no start. I also don't hear it now like I used to.

A few weeks ago I was doing my daily driving. I parked the truck at work for about 5 mins, came back and the sucker wouldn't start. It turned over like a champ - sounded like it was flooded. I let it sit for a few hours and tried with no luck. I had it towed home and later that night I tried and it still wouldn't start.
Now for the fun... I let it sit for almost 2 weeks cause my schedule wouldn't permit me the time to mess with it. I got in and the bitch started right up! I'm not really sure where to start. Could it be the fuel pump is on the way out? I hate intermitent problems! I don't recall the pump whining when it had the no start. I also don't hear it now like I used to.

You need to catch them in the act. :grinyes:
You might run a good fuel pressure check and check for codes.
The next time it does it check for lose of spark or fuel pressure.
And see if the old fuel pump has the hum sound.
Good luck MT

PS
Good way to check/test fuel pump is to hook a pressure gauge up and tape it to windshield or mirrow and drive it. Make sure fuel pressure stays in specs.
Even a few lbs low will cause a no start cold.
Good Luck and let us know how it goes.
MT

Try this, because of the oil companys complience with the new EPA demands. (thats their excuse) They have run their tanks dry at the gas stations. that means all of the crud and water that makes its way into them that was supposed to be stopped by the filters could have found its way through and into your gas tank.

Check or replace your fuel filter, if it hasn't been done in a while you have to do it any way.

Check your intank filter sock, it could also be partially clogged, causing the different sound from the fuel pump. Replace that anyway if you go through all of the trouble of dropping your tank.

When you go to replace your fuel filter. Run a piece of rubber tube from the tank side of your filter tube and into a container, while you watch have someone turn your key to the acc. position but do not start it, watch for the flow of gas, it should flow at a prescribed rate. Look at your manual to see how fast it should fill your container. Have them turn off the key way before the container fills to account for the ebb.

Sorry about the lack of order, but do the flow test first. it takes maybe 30 min from start to finish, And will tell you if the problem is ahead or behind the fuel filter.

JUst to answer a couple of the things posted.

I have no problem with a cold start. The fuel filter's age is unknown and will be replaced( I have it on work bench waiting).

The only code I'm throwing lately is the P0441 which is evap. I wouldn't think this would cause a no - start. I cold be wrong of course..

I live in the stix and drive 40 miles each way to work. I almost never let the tank get under 1/4 tank.

The problem is I'm afraid of getting stranded again.
I'll check the pressure for kicks

Is it possible the pump is overheating and shutting down?

JUst to answer a couple of the things posted.

I have no problem with a cold start. The fuel filter's age is unknown and will be replaced( I have it on work bench waiting).

The only code I'm throwing lately is the P0441 which is evap. I wouldn't think this would cause a no - start. I cold be wrong of course..

I live in the stix and drive 40 miles each way to work. I almost never let the tank get under 1/4 tank.

The problem is I'm afraid of getting stranded again.
I'll check the pressure for kicks

Is it possible the pump is overheating and shutting down?

Yes it is possiable all the more reason to put a fuel pressure gauge on it and drive and check it.
GLet us know how it goes.
MT

Went out last night and the beast wouldn't start!!! First test down - got spark. No whine from the fuel pump. should I be checking any relays etc??

Went out last night and the beast wouldn't start!!! First test down - got spark. No whine from the fuel pump. should I be checking any relays etc??

First check for voltage to relay and then for voltage to fuel pump.
Some have a fuel pump prime connection . Good place to test.
If voltage to fuel pump and good ground and no run.
You have found the problem.
Sometimes a good whack on the bottom of fuel tank will wake up a dead pump but it will not live long.
MT

Been trying all day to get the damn filter off. I soaked it with pen oil and will try it again in the morning. Still no life from the pump. I found the relay under the hood but how do you test it???

Been trying all day to get the damn filter off. I soaked it with pen oil and will try it again in the morning. Still no life from the pump. I found the relay under the hood but how do you test it???

Find the gray wire to fuel pump. Check for good 12 volts on it with volt/ohm meter and also check for good ground to fuel pump.
Look for the fuel pump prime connector. single wire with a plastic end on it .
May be red gray or green conbination. If you can not find it look forthe wiring plug in to fuel pump underneeth.
MT

What side will these wires be on? Do I have to drop the tank to see them?

What side will these wires be on? Do I have to drop the tank to see them?

The fuel pump plug wiring is in will be in front of fuel tank drivers side.
Gray is fuel pump power wire and black ground.
Prime connecter and relay is under hood.
Again gray for fuel 12 volt power to pump power. The relay is usually fused for power.
If you need a wiring pdf on it e mail me at [email protected]

But it may be tonight before i can send it back to you..
MT

The fuel pump plug wiring is in will be in front of fuel tank drivers side.
Gray is fuel pump power wire and black ground.
Prime connecter and relay is under hood.
Again gray for fuel 12 volt power to pump power. The relay is usually fused for power.
If you need a wiring pdf on it e mail me at [email protected]

But it may be tonight before i can send it back to you..
MT
:banghead: Ok I'm pretty lost on this. I see the wiring for the pump. There is no spot to probe it under the truck.
I have no idea what you mean by the "relay is fused" nor can I find the prime connector. I assume it's under the hood - I've searched but still can't find it.

What is the probablity of the problem being with the wiring or relay verses the pump?

I've given up on removing the fuel filter since I started really screwing up the line nut! I guess I'll breack out the torch!:p:screwy::nono:

:banghead: Ok I'm pretty lost on this. I see the wiring for the pump. There is no spot to probe it under the truck.
I have no idea what you mean by the "relay is fused" nor can I find the prime connector. I assume it's under the hood - I've searched but still can't find it.

What is the probablity of the problem being with the wiring or relay verses the pump?

I've given up on removing the fuel filter since I started really screwing up the line nut! I guess I'll breack out the torch!:p:screwy::nono:

The pdf is in the mail let me know if you get it.
It could go either way but if fuel pump has never been replace it may be it.
If it no go or run give it a thump on bottom of tank.
Let us know how it goes.
MT

Just a thought - Could I pull the fuse/ relay box up and probe the connectors on the bottom? It looks like there are only 3 screws holding it down. What kind of trouble could I get into??

Just a thought - Could I pull the fuse/ relay box up and probe the connectors on the bottom? It looks like there are only 3 screws holding it down. What kind of trouble could I get into??

Good place to test. Just be carefull and do not short anything out.
There is suposed to be a fuel fump prime connector in the fuse/relay box someplace but who knows.
The gray wire feeds th efuel pump power. Look at the pdf.
You can also catch the gray power feed at the oil pressure switch.
Good luck
MT

Good place to test. Just be carefull and do not short anything out.
There is suposed to be a fuel fump prime connector in the fuse/relay box someplace but who knows.
The gray wire feeds th efuel pump power. Look at the pdf.
You can also catch the gray power feed at the oil pressure switch.
Good luck
MT


You're funny! Like I know where the oil pressure switch is! LOL!!! I'm barely treading water on this testing crap! Throwing the pump in is what I can handle. All the diagnostics are tough for me to wrap my head around!

You're funny! Like I know where the oil pressure switch is! LOL!!! I'm barely treading water on this testing crap! Throwing the pump in is what I can handle. All the diagnostics are tough for me to wrap my head around!

Just remember proper testing. It can save a lot of throwing parts at it it does not need.
If a no start check for good hot blue spark to plugs.
You need good ign and spark to set the fuel pump and injectors in motion.
If good spark check for proper fuel pressure. If no fuel pressure or pump does not fire up check for voltage and ground to fuel pump.
Also a good all data DIY online sub may help led you threw some of the test.
http://www.alldata.com/products/diy/index.html
Good luck and let us know how it goes.
MT.

If you don't hear the pump priming when the key is turned on, Most likely is the fuel pump. Relays can give you a problem, but 95 percent of the time, it's the pump. You can thump the bottom of your fuel tank and sometimes it will cause the pump to come on and prime. Turn the key to the on position and wack the bottom of your tank. It the pump whines, then repalce your pump. Carbon build up from the brushes get between the brushes and armiture and prevents the pump from coming on. I've taken the pumps apart to see what causes the problem. Only to find the brushes nearly worn out. Like MT said, it's near dead and you'll have to replace it.
SC

OK, I've got the SAME problem. The only thing is that I didn't know it was intermittent until now.

I would STRONGLY recommend testing first instead of replacing parts. I went the replacing route. My friend checked the fuel pump and found it was getting no power. Told him to replace it anyway since the Blazer has 110,000 miles on it. Couldn't get any SES error codes on the tester. It was flashing 8's or something like that. Different friend couldn't get any readings with a different tester, assumed the ECM was bad and replaced that! Worked fine for a few days and I thought the problem was over.

Wouldn't start last night, no fuel pump noise either as before. Tried this afternoon and it started right up. In hindsight, the problem probably is that the ECM wasn't getting power, not the ECM was bad. Maybe the problem is in the ignition switch or a bad ground somewhere? I also have some EVAP code, although I don't remember which one.

This happened in my driveway both times. Glad it didn't happen somewhere else or while driving! I've got a 2001 2WD 5-speed BTW......

Please let me know what you find out, I'll do the same.

Thanks for all you help! It was the fuel pump. I broke down and took it to a friend of a friend's shop to have it done. I really don't have the time lately so I bit the bullet! In the process I found a mechanic that I like and feel I can trust. Worth the $$ to me!

Glad you got yours going OK muzzy.

Still have intermittent problems with mine. Does anyone have any ideas? I don't think it is the fuel pump since it has been replaced. The ignition switch is known to be bad on the '97 but haven't seen anything on my '01. Also, all the ignition switch problems I read here had no instrument panel lights when turning the key. I've got instrument panel lights but no fuel pump prime noise. Turns over but won't start.

I guess what I'm looking for is a way to know if the ignition switch is bad without buying a new one. Don't feel like throwing any more expensive parts at the Blazer to see if it *might* fix it.

Thanks in advance!

Glad you got yours going OK muzzy.

Still have intermittent problems with mine. Does anyone have any ideas? I don't think it is the fuel pump since it has been replaced. The ignition switch is known to be bad on the '97 but haven't seen anything on my '01. Also, all the ignition switch problems I read here had no instrument panel lights when turning the key. I've got instrument panel lights but no fuel pump prime noise. Turns over but won't start.

I guess what I'm looking for is a way to know if the ignition switch is bad without buying a new one. Don't feel like throwing any more expensive parts at the Blazer to see if it *might* fix it.

Thanks in advance!

Proper testing is the key.
Even if fuel pump has been replaced always check that fuel pressure.
Hook a fuel pressure gauge up and tape it it to windshield or mirrow and drive it and watch it and when it does check that fuel pressure.
If the fuel pressure is good check for good hot spark to all plugs when it does it to.

Hard to start.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.

MT-2500-

Thanks for the reply. I don't think I explained the problem well enough though. Sorry about that, let me try again.

The problem is intermittant. When I turn the key, before starting, I listen for the fuel pump prime noise. If it is there, the Blazer starts every time. If it is not, it won't start.

The problem seems to be electrical. When I first had the problem, we checked the fuel pump relay under the hood and it seemed to be working. Clicked when we turned the key. But the fuel pump wasn't getting any power according to my friend who tested it. Replaced fuel pump while the tank was dropped because of it's life expectancy at my mileaege, and of course it still wasn't getting any power. After replacing the ECM, it started fine. Assumed the problem was the ECM and it was now fixed. Found out later that the problem was intermittant.

Blazer hasn't been able to start yet today. No fuel pump prime noise, so I'm guessing it's not even getting power again.

MT-2500-

Thanks for the reply. I don't think I explained the problem well enough though. Sorry about that, let me try again.

The problem is intermittant. When I turn the key, before starting, I listen for the fuel pump prime noise. If it is there, the Blazer starts every time. If it is not, it won't start.

The problem seems to be electrical. When I first had the problem, we checked the fuel pump relay under the hood and it seemed to be working. Clicked when we turned the key. But the fuel pump wasn't getting any power according to my friend who tested it. Replaced fuel pump while the tank was dropped because of it's life expectancy at my mileaege, and of course it still wasn't getting any power. After replacing the ECM, it started fine. Assumed the problem was the ECM and it was now fixed. Found out later that the problem was intermittant.

Blazer hasn't been able to start yet today. No fuel pump prime noise, so I'm guessing it's not even getting power again.


You need to go threw the relay and prime circuits on fuel pump and see where it is losing prime or power or if it is. Check for 12 volt spower and ground at fuel pump.
Start a new tread /post and give engine sise and all history of what has been done and what is is now doing or not doing.
Every little detail helps.
MT