Lil help needed with no start

[MT-2500]

Originally Posted by muzzy1maniac

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

[muzzy1maniac]

Originally Posted by MT-2500

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!

[MT-2500]

Originally Posted by muzzy1maniac

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.

[Southern Comfort]

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

[unionhill]

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.

[muzzy1maniac]

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!

[unionhill]

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!

[MT-2500]

Originally Posted by unionhill

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.

[unionhill]

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]

Originally Posted by unionhill

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