[Streight1]

In the past 6 months the truck went from running fine to dead in the water. It progressed gradually from running rough to stalling while driving to sporadic starting to not starting at all. I replaced the cap, rotor, spark plugs, checked for spark and put a meter on it to make sure it had good spark. I tried spraying starting fluid in the intake to no avail. Pulled the bed of the truck off to try changing the fuel pump and for the heck of it tried running the truck while the pump was in a can of gas. For whatever reason we tried starting the truck with the pump out of the gas and it started, when we placed the fuel pump back in the gas the engine wanted to die. I replaced the fuel pressure regulator but that didn't help. There is a small hole in what I believe is a breather line coming from the fuel pump assembly but not sure if that would have an effect. Tried unplugging one of the injectors at a time and no help.

Any advice would be greatly appreciated.

 

[TrailLeadr]

Well the truck would have run off the fuel in the lines. When you put the pump back in the tank the lines would have probably been dry.

Have you tried cycling the ignition on and off a few times to get the fuel lines primed? Can you hear the pump running when it's in the tank?

 

[hotwheels93]

Sounds like a fuel pump problem... but before you replace the fuel pump, check your fuel filter... Most of the time it's little stuff like that.

 

[Streight1]

The pump runs, I can hear it and it does spray fuel from the injectors. I replaced the fuel filter when the problems first started. I have a fuel pump and am going to try that to see if the old pump is not producing enough pressure. Does anyone know if and where there is a port to test the fuel pressure, like a schraeder valve, with a fuel pressure gauge?

 

[maxumpower]

How many miles are on it? I had a similar problem with a honda and after doing all the same things you did with yours i ended up changing the fuel lines and also had a bunch of crap in the gas tank. When i dropped the fuel pump in it would run like crap and run fine out of a gas can. Can you see inside the fuel tank where the pump pickup is?

 

[Streight1]

Can anyone tell me if and where there is a fitting to test the fuel pressure? I have looked by the throttle body and along the fuel rails on top of the manifold. If I could test the fuel pressure I might be able to narrow down the possible problem.

 

[Blacknight]

You can check the presure at the fuel filter, Disconnect the coil wire from the coil and by the filter diconnect the fuel line going into the filter, and have someone turn the key like they are starting it when the engine is turning your pump will be running and you should see alot of fuel comming out of the line. Remember DONT smoke around fuel and make sure if you have a drop light under the truck remove it to a safe distance to where you can still see the lines. I hope this helps you and might want to try to diconnect the fuel line past the filter and reconnect the line going into the filter and see that you dont have a faulty filter. It does happen.

 

[JoGirl]

Kinda sorta similar question....

As you know I just bought a 1993 1500 myself.

My truck had been hesitating when I stepped on the accelerator a few days prior, and died the other day when slowing down to turn a corner.

Three nights ago the truck started, then stalled after about half a block and wouldn't start again. I work nightside at our local newspaper and get off work in the wee small hours in our downtown area (not a good place for a woman at 2am), so I got it to the curbside and arranged a tow to highly recommended and reputedly honest mechanic. Today he called and said it might be electrical, might be fuel injectors - he wasn't sure yet. I was thinking it was possibly fuel pump related, but I am not at all knowledgeable in this sort of stuff (my experience stops at changing oil, filters and brakes). I was planning to attempt simple repairs myself, but smart enough to know to stay away from anything at all complex.

Since Streight1's symptoms sounded similar, I thought this might be a good place to post this.

Is the mechanic being straight with me or should I go get the truck and try to repair it myself?

 

[unplugged]

Test the pressure

Fuel pressure should be 9-13psi. A good accessible test point is at the fuel filter. Also check the return line for clogs. You should be able to blow air back through the line. A clogged return line can cause excessive pressure on the feed side. The TBI unit has a built in fuel pressure regulator:

From: AutoZone.com "The pressure regulator is a diaphragm-operated relief valve with injector pressure on one side and air cleaner pressure on the other. The function of the regulator is to maintain a constant pressure drop across the injector throughout the operating load and speed range of the engine."

 

[84fiero123]

I had an ignition module give me similar symptoms.

Mine was 50 bucks, easy to replace and it has been running like a champ since.

I believe there is a test procedure to check the module but right now I can not remember it. STML

Anyone remember the test procedure for the ignition module?

PS

You need to add your vehicle info to your signature, it makes answering questions so much easier if we know. Some of us, (Me especially, STML) have trouble remembering what all of our new, and even old member have for vehicles.

Hell I need to put the engines for the vehicles in mine.

 

[JoGirl]

You think it's the ignition? Even though it started out by cutting out when accelerating?

Wasn't sure if I should have posted in this thread or started a new one - hope that was okay...

 

[84fiero123]

You think it's the ignition? Even though it started out by cutting out when accelerating?

Wasn't sure if I should have posted in this thread or started a new one - hope that was okay...

I’m easy, just ask my wife. As far as starting a new thread, why?

I had a similar problem with the ignition MODULE in the distributor of my 94 Burb. Replaced the module and it’s been running fine ever since.

I’m hoping someone will remember how you test them, because for the life of me right now I can’t remember.

Anyone?

 

[JoGirl]

Hope you didn't look too hard to find the testing procedure - I haven't had a chance to get back until now.

My problem is solved and I found a great (and kinda cute) mechanic!

The guy called me today and said it was only the fuel pump - he quoted me $285 for parts (new) and installation. I had checked a couple parts stores and could not believe I heard the mechanic correctly, so I called him back and he assured me it was the correct price! Told him to go for it and I picked the truck up 6 hours later. Runs great!

Not only was that too cool, it gets even better...

I bought the truck less than a week ago from my future son-in-law's parents. The kids must have told them, because when I pulled out my $$$$ to pay the garage, the (actually REALLY cute) mechanic said it was already paid for! The folks I bought it from had been there earlier and paid for it, as they felt terrible about it happening at all.

Isn't that absolutely incredible?

Wanted to share that with you - I'm so glad that most all people in this world are so considerate and thoughtful.

So even though my first gmtruckclub.com saga had a quick and happy ending, I appreciate your response! Thanks bunches for your input.:happy:

 

[84fiero123]

We are here to help. Or at least try to help. Looks like you got it covered, keep that mechanics number, it’s hard to find an honest one.

That’s just it without testing things, fuel pressure, ignition module or what ever the problem you can replace a lot of good parts before you find the real problem.

We try to help as much as we can with our knowledge of vehicles, but without testing things you really can’t tell what is wrong.

Again glad to hear you got the problem solved.

 

[unplugged]

DIY Control Module testing

The "ignition/control module" can be tested as follows:
From: AutoZone.com

• Perform a no-start diagnosis of the ignition system.
• Use an ohmmeter to ensure that the ignition module connection to ground is good. One lead of the meter should be connected to the ground terminal at the module and the other to a good ground. Zero resistance indicates good continuity in the ground circuit. Any resistance reading during this test is unacceptable.
• The most effective method of testing for a defective ignition module is to use an ignition module tester, if one is available for that module.
• Keep in mind that ignition modules are very reliable. They are also one of the most expensive ignition system components. So, if a module tester is not available, check out all other system components before condemning the ignition module.
• The control module can be tested at any of our store locations.

 

[84fiero123]

thanks

The "ignition/control module" can be tested as follows:
From: AutoZone.com

• Perform a no-start diagnosis of the ignition system.
• Use an ohmmeter to ensure that the ignition module connection to ground is good. One lead of the meter should be connected to the ground terminal at the module and the other to a good ground. Zero resistance indicates good continuity in the ground circuit. Any resistance reading during this test is unacceptable.
• The most effective method of testing for a defective ignition module is to use an ignition module tester, if one is available for that module.
• Keep in mind that ignition modules are very reliable. They are also one of the most expensive ignition system components. So, if a module tester is not available, check out all other system components before condemning the ignition module.
• The control module can be tested at any of our store locations.

I knew there was a test for it, but for the life of me couldn't remember how to do it, thanks.