1997 Blazer has trouble starting
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Beginning Member
Joined: Jul 2011
Posts: 16
1997 Blazer has trouble starting
Hello all, im new to this forum, my name is Trevor i'm from Wyoming.
Before I start with my explanation i'll tell you a bit about my Blazer. Most info may be irrelevant to my problem but more information never hurts. It's a 1997 2-door 4.3 vortec with a manual transmission. It's bone stock (except air filter and exhaust). My known problems are: Shocks are a little worn out, AC won't hold a charge, ABS doesn't work (havn't looked into it, likely just a sensor), Air Bag light is sometimes on, its random. ABS light is always on, Check Engine Light is rarely on, but only pops on when I take a corner too fast or powerslide through the dirt. Also turns off in those situations if it is on, likely loose/worn wires. Transmission syncros are going out. About 175,000 miles on it.
Now for the problem at hand. Most of the time it starts, but it still cranks for longer than it should. Usually starts on the 2nd or 3rd try. After I can get it started it runs great. Sometimes, it just won't start and ill have to push it to start (woot for manual trans). This problem has been progressively getting worse throughout the months and I want to fix it before it won't start at all.
Heres a few things i've checked. It's getting fuel just fine, though, I haven't checked the pressure yet. I'm sure the fuel line isn't clogged or obstructed and I changed the fuel filter not long ago. I ran Z-max through my fuel and my engine when I bought it. The fuel pump runs as intended, runs for about 3 seconds after trying to start, and turning the key on. Spark plugs are fine, they're new. I even checked to see if they were firing and they're fine. Just changed my cap and rotor a couple days ago, same story. The battery is fine I got a new one a few months ago, the best battery I could get that would fit in there. It cranks pretty damn fast when im trying to start it. I'll try to post a video later. I hooked it up a computer thing and the only trouble codes I got were: Mass Air Flow circuit - low output and O2 sensor heater core. (I think, I forgot exactly what the o2 sensor was, it was a while back)
Thank you for your time, and im looking forward to your feedback.
Before I start with my explanation i'll tell you a bit about my Blazer. Most info may be irrelevant to my problem but more information never hurts. It's a 1997 2-door 4.3 vortec with a manual transmission. It's bone stock (except air filter and exhaust). My known problems are: Shocks are a little worn out, AC won't hold a charge, ABS doesn't work (havn't looked into it, likely just a sensor), Air Bag light is sometimes on, its random. ABS light is always on, Check Engine Light is rarely on, but only pops on when I take a corner too fast or powerslide through the dirt. Also turns off in those situations if it is on, likely loose/worn wires. Transmission syncros are going out. About 175,000 miles on it.
Now for the problem at hand. Most of the time it starts, but it still cranks for longer than it should. Usually starts on the 2nd or 3rd try. After I can get it started it runs great. Sometimes, it just won't start and ill have to push it to start (woot for manual trans). This problem has been progressively getting worse throughout the months and I want to fix it before it won't start at all.
Heres a few things i've checked. It's getting fuel just fine, though, I haven't checked the pressure yet. I'm sure the fuel line isn't clogged or obstructed and I changed the fuel filter not long ago. I ran Z-max through my fuel and my engine when I bought it. The fuel pump runs as intended, runs for about 3 seconds after trying to start, and turning the key on. Spark plugs are fine, they're new. I even checked to see if they were firing and they're fine. Just changed my cap and rotor a couple days ago, same story. The battery is fine I got a new one a few months ago, the best battery I could get that would fit in there. It cranks pretty damn fast when im trying to start it. I'll try to post a video later. I hooked it up a computer thing and the only trouble codes I got were: Mass Air Flow circuit - low output and O2 sensor heater core. (I think, I forgot exactly what the o2 sensor was, it was a while back)
Thank you for your time, and im looking forward to your feedback.
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Beginning Member
Joined: Jul 2011
Posts: 16
UPDATE: I went to the parts store and bought the only test gauge they had and it fits! 
. Also, when I started it up to go to NAPA, it fired up quicker than it ever has.
I've never tested fuel pressure before and im a newbie to mechanics so bare with me. I tested it right after I got back from the parts store, when the pump is priming (key on, ignition off), with ignition on, and waited 10 minutes and repeated.
First tests:
Vehicle running: 53 psi
Pump priming: 52 psi
Ignition on (trying to start): 48 psi
10 minutes later:
Vehicle running: 42-58 psi (needle bouncing back and forth rapidly) pressed the pressure release button on the gauge and same deal.
Pump priming: 52 psi
Ignition on: 48 psi
After I was done and turned off the vehicle and took the key out the needle went down to 43 psi
Also, I left out some useful information on my first post. I can only start it if I do these steps: Turn the key on, let the pump prime. Turn the key off and then turn it all the way to ignition. If I just jump in and turn it straight to ignition, it won't start. If I turn the key on and let it prime for 3 seconds then turn it to straight to ignition afterward, it won't start. I have to follow the specific steps or it won't start. Turn key on, then off, then ignition, and it starts. Only way it works.
I hope this helps you come up with some ideas with whats wrong with my rig. Thanks in advance.
. Also, when I started it up to go to NAPA, it fired up quicker than it ever has. I've never tested fuel pressure before and im a newbie to mechanics so bare with me. I tested it right after I got back from the parts store, when the pump is priming (key on, ignition off), with ignition on, and waited 10 minutes and repeated.
First tests:
Vehicle running: 53 psi
Pump priming: 52 psi
Ignition on (trying to start): 48 psi
10 minutes later:
Vehicle running: 42-58 psi (needle bouncing back and forth rapidly) pressed the pressure release button on the gauge and same deal.
Pump priming: 52 psi
Ignition on: 48 psi
After I was done and turned off the vehicle and took the key out the needle went down to 43 psi
Also, I left out some useful information on my first post. I can only start it if I do these steps: Turn the key on, let the pump prime. Turn the key off and then turn it all the way to ignition. If I just jump in and turn it straight to ignition, it won't start. If I turn the key on and let it prime for 3 seconds then turn it to straight to ignition afterward, it won't start. I have to follow the specific steps or it won't start. Turn key on, then off, then ignition, and it starts. Only way it works.
I hope this helps you come up with some ideas with whats wrong with my rig. Thanks in advance.
Beginning Member
Joined: Jun 2011
Posts: 23
From: Ky
The leak down is on the high side and the pressure seems quite low... The next step would be to get the pressure gauge adapted to the fuel supply line at the filter to isolate the pump from the rest of the fuel system. If you still find that the pressure is on the low side with the pump running and the pressure bleeds off, then the pump needs to be replaced. I'm guessing that the pump is the problem, but diagnosis is key to fixing it right the first time.
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Beginning Member
Joined: Jul 2011
Posts: 16
To cdw78: Thank you, I checked out that page before I made this thread.
We didn't think it was a fuel problem but after I got the pressures i'm starting to think otherwise. We thought that it was likely a VCM problem with the way I had to start it like I was fooling the security system or something. I don't know. It could be a fuel leak because the under the engine bay its really grimy even with that little plastic skid plate covering it. Could also be my oil leak causing all that though. I'll let you know when i get the results swartlkk. Hopefully I don't need an adapter to do so, my wallet is empty lol.
We didn't think it was a fuel problem but after I got the pressures i'm starting to think otherwise. We thought that it was likely a VCM problem with the way I had to start it like I was fooling the security system or something. I don't know. It could be a fuel leak because the under the engine bay its really grimy even with that little plastic skid plate covering it. Could also be my oil leak causing all that though. I'll let you know when i get the results swartlkk. Hopefully I don't need an adapter to do so, my wallet is empty lol.
Thread Starter
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Beginning Member
Joined: Jul 2011
Posts: 16
Thank you. I was accually looking at that thread yesterday when I was trying to find the right size gauge to get.
I'm having trouble finding a test port on the supply line. Have any specifics on where it might be?
I'm having trouble finding a test port on the supply line. Have any specifics on where it might be?
There isn't a test port under the truck. You have to remove the fuel filter and adapt the fuel gauge to the tube fitting. This may be a little more challenging. I had a lot of parts just laying around that I was able to use to put it together and I'm never looked into what, specifically is required. Basically, you need to go from the JIC fitting that the gauge requires to the tube fitting that threads into the filter. This can be done with just two fittings if you find the proper pieces. Fitting 1 will have the 7/16-20 JIC for the gauge to 1/4" NPT (either male or female) while fitting 2 will connect to either the line that goes into the fuel filter or the outlet of the fuel filter and have the corresponding 1/4" NPT connection to thread in and seal to fitting 1.
Your local NAPA should have the appropriate adapters. Just have them pull a fuel filter for your truck and bring your fuel pressure gauge with you. Match up the parts and away you go.
I believe that the outlet on the '97 fuel filter is the quick connect like the 98+ trucks so you could get a quick connect line service kit and then adapt that through a hose barb to 1/4" NPT to connect to fitting 1. Another way that some people have done this is to purchase the male & female quick disconnects, a ball valve, some hose barb fittings, a 'T' fitting, and the JIC fitting to make up an inline shutoff tool. But the quick connect service kits can be somewhat expensive and I know that you can get the two fittings I spoke about above for less than $5 out the door.
Your local NAPA should have the appropriate adapters. Just have them pull a fuel filter for your truck and bring your fuel pressure gauge with you. Match up the parts and away you go.
I believe that the outlet on the '97 fuel filter is the quick connect like the 98+ trucks so you could get a quick connect line service kit and then adapt that through a hose barb to 1/4" NPT to connect to fitting 1. Another way that some people have done this is to purchase the male & female quick disconnects, a ball valve, some hose barb fittings, a 'T' fitting, and the JIC fitting to make up an inline shutoff tool. But the quick connect service kits can be somewhat expensive and I know that you can get the two fittings I spoke about above for less than $5 out the door.