1999 Chevrolet Silverado, WONT START

[MT-2500]

Originally Posted by rmweber

All,

Ok, I went ahead and replaced the fuel pressure regulator. It did not help. Waste of 50 bucks. Oh well.

I called the dealer and they said that 55psi is fine for the fuel pressure. They said that they think it is related to the security system and that there may have been a technical service bullitin on it a while back....

I think I may be barking up the wrong tree with this fuel pressure thing.

more later

O boy.
To put it blunty if a dealer told you 55 lbs of fuel pressure is enough he does not know his rear end from a hole in the ground.

The injectors have to have 64-65 lbs of fuel pressure on a cold start.
After a COLD START IT MAY RUN ALL DAY ON 55 LBS OF PRESSURE BUT IT WILL NOT COLD START.
You can not leave home without it.

Find another dealer fast.

Run the complet fuel pressure test as posted.
And post back results.

A simple test is to shoot just a little carb cleaner / no starting fluid in the intake and see if it will start.

If the security system is the problem it will start for 30 seconds and then shut down.
MT.

[rmweber]

All,

I have been working on the truck all day,

I tried putting fuel additive in the tank to dry the fuel incase of water contamination. No dice.

I tried putting starting fluid into the intake. It will run on that if I keep spraying it of course.

The fuel pressure is still 55psi and does not leak down after I turn the key off.

The dealer says 55 is OK, but the shop manual says it should be 60 - 66 psi.

Unless anyone else has an idea, I guess I will go ahead and replace the fuel pump I guess.

The only other thing I can do is try to measure the pressure right out of the pump, but I need a special adapter for that.....

HELP, I am close to throwing in the towel and having it towed to the dealer.

Thanks for all the help thus far.

[rmweber]

MT-2500,

I tried to follow your post as best I could, I may have read it wrong.

I measured the cold fuel pressure and it was 55.

I measured the pressure when it was cranking and it was 55.

I cannot measure it when it is running obviously.

I replaced the fuel regulator so I assumed that would negate the need to do the return line fuel pinch thing.

I am thinking that it is the pump, what do you think?

Did I miss something in your post?

Thanks!!!!

[rhandwor]

I would use a line block it is a block of metal with a 1/8 inch bar bent to a L shape. I would clamp down on the rubber return line watching the pressure until I got 65 psi if it starts you are certain it is a fuel problem. Then I would shut down and pinch closed the rubber return line. Check the pressure if low buy a new pump. I saw on ebay a new delco for 110.00 which is cheaper than the dealer. If you don't have a floor jack pull tail light wires "disconnect". Unscrew fuel line at fill door. Unbolt bed get two men to help pick up bed and move to back of truck. Use a brass drift and loosen hold down after fuel lines are disconnected. remove pump install new pump and sock. Get truck running if no leaks reinstall bed.
Use a flashlight and find two flexable lines on back of engine. The metal clad will be high pressure. The rubber line with plastic cover will be return hose.
Check out today get pump fedx overnight. and go

[MT-2500]

Originally Posted by rmweber

MT-2500,

I tried to follow your post as best I could, I may have read it wrong.

I measured the cold fuel pressure and it was 55.

I measured the pressure when it was cranking and it was 55.

I cannot measure it when it is running obviously.

I replaced the fuel regulator so I assumed that would negate the need to do the return line fuel pinch thing.

I am thinking that it is the pump, what do you think?

Did I miss something in your post?

Thanks!!!!

The true test on a fuel pump is with return line pinched off or pluged or you can disconect the fuel filter check direct fuel pressure at fuel filter inlet line.
If the fuel pump does not put out 75-85 full pressure then replace it.
MT

[rhandwor]

The point of what he is saying is you may have two bad regulators check the pump before you spend your money and don't accomplish any thing. It would have been much easier to check the pump than to replace a regulator that was probably good. It would have saved you fifty dollars which could been used for a pump if needed. Also if the new regulator is bad you could get replaced free if the pump passes the pressure test. They just don't replace parts unless you can prove it is bad.
Once you decide to test it will be done in a short time it is not difficult. Four ways were explained to you.

[options13]

Do you have an extra key? I believe that you may have a transponder in the key . I've had 3 of them go bad on me in 3 other cars. It's an easy thing to check for. Just get your other key & see if she starts.

[rmweber]

Originally Posted by rhandwor

My 2000 silverado has two disconnects at the fuel rail by the regulator. I use a k-d tool to disconnect these type fittings. My wifes malibu uses this type of fitting on one end of the filter. These would readidly available at a yard. You could cut off a section and put a bolt in the end and make a test tool. The filter end looks to be almost exactly 5/16 inch you could buy a 6 inch piece of fuel injection hose put a bolt in it and use two clamps to block the line for a test. I was going to check on a filter but I only had spares for my truck as I recently changed it. Check a piece of hose on a filter before purchasing it.
Your gage may be 5 psi low so judge according to at least MT-2500 test pressure. The tool looks like two bars with a piece of tubing for 5/16 and 3/8 fittings. They used to be around $6.00 although they make plastic ones also.
Mine is a 5.3L but yours surely has flexible with disconnects. One line is metallic cable and the other is gasline material with a plastic cover.If the truck starts during the test you are sure you have low pressure.

Which one of those lines by the regulator is the supply? The bottom one?

[rmweber]

Originally Posted by MT-2500

The true test on a fuel pump is with return line pinched off or pluged or you can disconect the fuel filter check direct fuel pressure at fuel filter inlet line.
If the fuel pump does not put out 75-85 full pressure then replace it.
MT

Ok, I am convinced to test with the return pinched. I bought a couple of small sections of hose to put on the return line. I just am confused on which one is the return. Is it the bottom one?

Also, once I get the hose on the return, I assume I should put the end in a jar or something to catch the fuel and then just pinch the hose until I get 65psi.

What does this do? Does this produce more pressure in the manifold than normal? If it starts then that means that my pump is bad?

I will try the test soon.

Thanks for the patience.

[rhandwor]

On my truck it is the bottom line. The top has metallic covering so it would the high pressure. The rubber line goes to the gas tank. I would slide back the plastic and pinch it down. If you are doing this no need to disconnect. I would pinch down until your gage reads over 60psi. Then I would try to start. If it starts shut it off and pinch down all the way. Since your pump is working it apparently has a dirty sock or is getting worn out.
The only reason for trying to start it for proving to yourself the pressure is the problem. This way you will know if its the pump or two bad regulators. A badly bent line from a stone will cause lack of flow and even though it has pressure the bleed will drop it the pressure below what you need.

[MT-2500]

Originally Posted by rmweber

Ok, I am convinced to test with the return pinched. I bought a couple of small sections of hose to put on the return line. I just am confused on which one is the return. Is it the bottom one?

Also, once I get the hose on the return, I assume I should put the end in a jar or something to catch the fuel and then just pinch the hose until I get 65psi.

What does this do? Does this produce more pressure in the manifold than normal? If it starts then that means that my pump is bad?

I will try the test soon.

Thanks for the patience.

If you are having problems with pinching off the reture line.
Just remove the inlet line from the fuel filter and hook your gauge direct on to it.
Post back the pressure you get there.

[rmweber]

All,

Ok, I tested the pressure with the return line pinched off. It made no difference. It still would not start and still would not go over about 55psi.

I also tried a different ignition key for grins.

I suppose the final test would be to test the pressure right out of the pump where it goes into the filter, I just need to figure out how to adapt the line to my guage.

I will try to work that out and report back.

Also, my old regulator had an adjustment screw on it, but the new one does not. Not sure why.

Anyway, let me know if this helps you to help me any.

Thanks.

[rhandwor]

If you had it completely pinched off the next step is a new pump. If you want to check at the filter go to a hardware store with a filter and get connections to screw your gage into.

[rmweber]

All,

I worked on the truck some more today,

1.) I took the bed off the truck to get at the pump. I put a T on the send line and put the guage on it and clamped the exit side. It measured 90psi.

I am not sure if this is a valid test though, since one side was clamped. I was not able to put it in line due to the fact that I could not adapt to the line. I tried to put it inline in place of the filter, but also could not adapt to the guage there.

Is it valid to test the way i did?

If it is, then that would suggest there is something wrong in the line somewhere..... I inspected the line, and it is well protected, very unlikely a stone would have hit it. I did not see anything obvious.

I did purchase a new pump, but I do not want to put it in if the one I have is not bad. It was EXPENSIVE.

ANY IDEAS?

Oh by the way, the dealer said that it should run on 55psi, and that that issue with the injectors not firing was related to another engine and does not apply to mine. However, the manual still says it should be 65.

I also attempted to reset the security system per the dealer by turning the key on but not starting the engine for 15 min, then off then on for 15 min, then off then on for 15 min.

No dice.

2.) I also tried to just put the guage inline right at the pump. I took a short hose from the send line, through the T and then right back into the pump return. That did not seem to work very well, it only measured about 10psi.

HELP! Now I have my cap and bed taking up another whole parking space! AHHHHHRGGHHHH....

[rmweber]

Oh, I pulled the pump and looked at the strainer, it looked ok to me....nothing obvious wrong in the tank..