Really Hard Start

Graya25 · September 14, 2010

My truck seems to not want to start right up lately. If I get in and crank for about 5 seconds....no dice. However, if I turn the key back and turn it forawrd again, the truck starts right up.

I'm thinking this is the fuel pump, but I really don't want it to be, I don't have the time to be dropping a 34 gallon fuel tank, reaching in and taking the old one out, and then reconnecting everything.

So could it be something else, like the relay or a clogged injector?

I already replaced the fuel filter about 9 months ago, so I doubt that's the issue.

Again, to put this in another perspective...think about starting an older truck like mine ('97) in 20 degree winter weather. The truck is showing the same symptoms it would during a cold start, but it's 65 degrees here.

I find it strange that if it is the fuel pump, this is the sonly symptom it's showing. I would expect the truck to have some hesitation going up hills and such, but once the truck starts up, it runs perfectly....

txab · September 14, 2010

But that is one of the symptoms of a failing fuel pump or pressure regulator. Check the regulator also take a fuel pressure reading with the key on and then another reading right after you turn the key off. It should hold pressure

rodram · September 14, 2010

... my bet is low fuel pressure due to a failing fuel pump

... the fuel pressure spec for these Vortec engines and injection systems is 61 to 66 psi

... some say their truck will run with fuel pressure of 58 psi... but getting below there you will have problems starting (exactly like you describe) and eventually performance/running problems, if it even starts.

As suggested above... get the fuel pressure checked

What you describe is exactly what my truck was doing as my fuel pump was in its final stages of life.... one time at the mechanic shop they said the fuel pressure was marginally OK... then a few weeks later they checked again and the pressure was way down in the low 50's ....

Save yourself a tow bill and get the fuel pump changed (after confirming the problem with a fuel pressure guage).... and when you change the fuel pump, also change the in-tank filter sock and the external fuel pump wiring harness.

Graya25 · September 14, 2010

Got underneath today after I started it up and there was a buzzing-type sound coming from inside the gas tank. It probably is the pump. I'd actually rather have it be the fuel pump than the pressure regulator, as I would have to take the top of the intake manifold out to replace that.

As far as fuel pumps go, should I go for ACDelco, Delphi or Bosch? The Bosch one has a lifetime warranty, but has a different electrical connector on it. Would the ACDelco and Delphi pumps directly connect to the harness?

I'm hesitant to buy the entire fuel sending unit as it costs upwards of $230, so i think I'll just replace the pump at this point.

I also don't have a fuel pressure tester, and seeing as those cost almost the price of a new pump, I'll just replace the 13 year old pump and the strainer.

Now I just need to figure out a way to syphon 1/2 a tank of gas out of a 34 gallon tank. This will probably be the more difficult part, besides dealing with the corrosion on the lines. Any ideas?

EDIT 9/15: It died this morning completely and will not start at all, aside from a few sputters. At least it died in my driveway than in a parking lot somewhere. I'm still waiting for the ACDelco pump to come from Amazon (overnighted it). As far as removing the bed, the rust looks too severe to do that, I'll probably be better served by just dropping the tank.

Another curious thing is that when cranking, the oil pressure gauge builds to about 50 and stops, is this an indication of the pressure of the fuel as well since in the 50s it won't start?

txab · September 15, 2010

Just lift and slide the bed back to get to the tank.

98trck · September 15, 2010

try this

I have to turn the key on wait three or four seconds

then turn the key to start

my truck does not hold the pressure when no running

i suggested it to somebody at work and it cured his start problem

PETE

rodram · September 15, 2010

when replacing the fuel pump.. definitely get an ACDelco from a dealer or a Delphi from a good parts house .. don't bother with any other brand ... no matter what the price...

... and some guys just lift and slide the truck bed out of the way so that they don't have to drop the tank .... it seems like about a 50-50 preference ... although if your bolts holding the bed to the frame are rusted, then this makes it a more PITA task....

Graya25 · September 16, 2010

Yikes, time and the elements haven't been too nice on my fuel lines

After I took these pictures, I heavily doused these areas with WD-40. I hope the lines aren't leaking and that I can actually get everything apart despite the corrosion. That and it looks like I will have to fight with some quick connects at the top of the sender....

radiator · September 17, 2010

Make sure that the top of your fuel tank isnt rusted through either. i just had to replace mine due to road salt and bad weather causing the top to rust through from the inside. Plus i had just filled my tank and all of the gas started to spill out as i drove.

Graya25 · September 18, 2010

Does any one know if in the first picture I posted above, if those are quick connect or threaded fittings. I thought they were quick connects, but there is nowhere to slide the tool in to undo the fitting, and neither side moves independently of the other. It looks like a threaded fitting, but I don't know for sure.

Please help if you know the fuel system!

minibike132 · September 18, 2010

Does any one know if in the first picture I posted above, if those are quick connect or threaded fittings. I thought they were quick connects, but there is nowhere to slide the tool in to undo the fitting, and neither side moves independently of the other. It looks like a threaded fitting, but I don't know for sure.

Please help if you know the fuel system!

It is a threaded fitting and there is almost no way you are going to get those apart without breaking the lines at the sender. If I were you I wouldn't even bother trying because all you are going to do is waste time. IMO the best thing to do with this one is get a new sender assy (gm only) will not come with a pump for this app but might come with the level sensor so you will have to still get a pump. Once you have all that cut the lines right at the nut on the sender side. This way you can get a socket on it rather then a wrench that is just going to round it off and make it impossible to get off. The goal here is to save the lines going from the tank to the front of the truck.

BTW the connector will probably be different. I can't remember the year break on the change but the original connectors to the sender were square 4 pins. There was a recall years ago to update the connector to a rectangular style (I don't recall the reason why). Just a heads up so you don't freak and think you got the wrong one when you open the box. There should be a new connector and detailed instructions there on how to switch the connector over.

Graya25 · September 19, 2010

The truck is running again, but yes I did have to run out today and get a new sender unit, which all things considered, isn't a bad thing (although it did cost me a good amount of money). I did have to break the old sender lines, and yes the connections were threaded. The truck runs better than it ever has in my possession, it starts up right away and has a better throttle response.

Now I just hope that the pump doesn't fail again, though this is why I got the ACDelco pump and strainer. I did have to get a Spectra or whatever Autozone had, sender unit. It looked exactly like the original sender and it has a 1 year warranty, I just hope it holds up as I don't know much about Spectra.