engine wont fire 1997 chev

[ratmn218]

1997 chev 5.0 liter truck, was starting hard before, now wont start, i hear fuel pump running.i have access to a fuel pressure gauge,what tests can i do to determine if fuel pump or fuel pressure regulater. im assuming it is either pump or regulater.

[Jeremy airjer W]

You should see 60-66 pounds of fuel pressure.

To confirm it is a fuel issue shoot some carb spray into the throttle body while somebody cranks it over. If it starts your on the right track. If it stay running its probably the pump.

If it doesn't start than you could have a spark or injector pulse issue.

[ratmn218]

if gauge is reading correct shows around 54 psi while pump is running,but then drops to 15 psi after pump stops then slowly drops from there,pressure regulator?

[Jeremy airjer W]

Looks like there is not enough fuel pressure. The fuel pump will have a check valve in it to hold pressure once the pump stops. If that check valve goes bad than fuel pressure will drop really fast. Typically a bad pressure regulator will bleed fuel pressure really slow. I think you have a CPI vortec where the regulator is under the plenum. Is so it is really hard to see if they are dripping but you can usually smell a stronger than normal odder of gas if you open the throttle plate.

If you follow the fuel lines under the truck, just in front of the transfer case on the drivers side there should be a spot where the lines transfer from metal to rubber and then metal again. One line will go to the filter and the other is the return line. Make a couple of light test pinches with a pair of needle nose pliers sometimes those lines are a rubber coated steel mesh style and you don't want to crimp those. If it squishes easily clamp down on it with the pliers (needle nose vice grips work o.k. for this. Turn the key on. Fuel pressure will build and if its the regulator should now hold since the return line is blocked. If pressure still drops like a rock its the pump.

Regardless of what is bad the pump should still be putting out more than 54psi. The CPI style injectors are especially sensitive to fuel pressure. One PSI will be the difference between driving home and walking home.

[ratmn218]

truck started this morning,if it starts after work going to a shop then,going to buy a new pump at dealer, what do i expect to pay?

[Jeremy airjer W]

$300 to $500 for the pump depending on which one you have. I think 97 is the split year. late models had a fuel pump module that was plastic and the above would be the cost.

Early models had a metal sending unit with a serviceable pump. those will run you under a hundred bucks roughly. I would recommend replacing the metal sending unti as long as the tank is down. They have issues with the connector inside of the sending unit burning up. The complete assembly will be about the same as the plastic fuel pump module, $300 to $500 dollars

[Macgyver55]

$300 to $500 for the pump depending on which one you have. I think 97 is the split year. late models had a fuel pump module that was plastic and the above would be the cost.

Early models had a metal sending unit with a serviceable pump. those will run you under a hundred bucks roughly$

You are correct, my 97 was the old style with a replaceable pump, but date of manufacture was 11/97. It was 87 dollars out the door for a GM (Delphi) pump. They seem to last better than the module style too. I had 155,000 when mine started acting up.

The Delphi module style for the later ones are around $250 I think.

[ratmn218]

so your saying i got lucky and it will only cost me 100 or less?

[Macgyver55]

so your saying i got lucky and it will only cost me 100 or less?

Not necessarily, like Jer said it was a split year, I believe its by date of manufacture. The early ones used the old style the newer ones use the module. You can fine the date on the drivers door sticker.

[catch22]

Just the pump can be had for $100 more or less, but like the MECHANIC said, do the entire fuel pump bracket/assembly as long as you'll be taking the tank down anyway. Besides, I sincerely doubt you can get the fittings loose w/o at least compromising the fuel lines on the old bracket. I broke one of the lines on the bracket doing this on my 1996 5.7 vortec, and to get the fitting out, I had to wedge a wrench in the frame and use a socket wrench to get it loose...Brutal. I got the delphi assembly at NAPA for $325. All in all, not that hard to do, I've gone about 9 months, no problems. As mentioned, the vortecs are REALLY fussy about fuel pressure, and the check valve is a known problem in these fuel pumps. Now doing the FPR...that was not as fun, as mentioned under the plenum, about $80 for the FPR. Good luck

[Jeremy airjer W]

Besides, I sincerely doubt you can get the fittings loose w/o at least compromising the fuel lines on the old bracket.

Nothing a torch won't get loose!