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Longer Crank Times

21K views 22 replies 9 participants last post by  the cadillac man 
#1 ·
So I've noticed in the past few weeks that it's taking a little more cranking to get my 'lade started in the mornings. Usually it was a .5 second crank and she'd fire right up.
Recently I've either had to:

A. Crank .5 seconds, release. Crank again, fires up.
OR
B. Continue cranking for about 1 second and she starts.

After the first start she fires right up no problem. This occurs only after sitting overnight or all day at work.

Did some digging this morning, I've read everything from starter, to starter relay to fuel pressure regulator as the cause. My plugs and wires were done less then 15,000 miles ago, fuel filter has been replaced, throttle body has been cleaned, fuel line has been serviced. Any ideas?

Thanks!
 
#2 ·
So just a quick update, after reading all that I could find, I went ahead and replaced the fuel pressure regulator. Edmunds listed it as a commonly failed part on the 02's, so I figured why not just do it anyway, since by the looks it had never been replaced. It was only $50 bucks and was a VERY easy fix, took 15 minutes tops. I'll update on how this turns out.
 
#4 · (Edited)
Would there be a way of testing this?

If I told you that I turn the key to "On" for a few seconds before starting, would that be useful? My thought here was that if I let the fuel pump run for a couple seconds before starting, it would alleviate this issue. Unfortunately, it hasn't.

Or does anyone have any other thoughts on this? I watched a video on how to do the fuel pump, wow what a PITA. :rant2:
 
#5 ·
Could be the difference is in the fuel. Fuel producer change the fuel from winter to summer and I've found that the summer gas typically causes longer crank times. It's something to do with the length of the ?carbon chains in the fuel (I believe). Frankly I don't understand it all (obviously) but I thought I'd put it out there as a possibility.
 
#6 ·
Rolex said:
Could be the difference is in the fuel. Fuel producer change the fuel from winter to summer and I've found that the summer gas typically causes longer crank times. It's something to do with the length of the ?carbon chains in the fuel (I believe). Frankly I don't understand it all (obviously) but I thought I'd put it out there as a possibility.
Not really I had mine do this before in the summer and I know it was related to my pump which will give out on me someday and I also had it do it in the winter so it ain't the fuel blend,
It is your fuel pump going from age and wear trust me on this you better replace it before you get out and have to get a tow truck to get home.
 
#8 ·
gmercedesbenz said:
So I should be able to confirm this by using a fuel pressure gauge right? From what I've read the fuel rail has a schrader valve on it. Does anyone know where this is and what the pressure should be for the 6.0 at idle and off?
You should be able to measure it in multiple ways I think my scan tool can read the psi of the fuel pump but not sure.
 
#9 ·
PM sent regarding pressure regulator. Have you seen any improvement sense the install? I've got the same thing, but I believe it is the fuel pump's check valve going bad. The fuel pump is only activated for 3 seconds when you turn they key on, and will not run again until it sees a crank sensor input (meaning the engine is running), or unless you turn the key of and on again (then you get 3 more seconds). Essentially, as the check valve goes bad, fuel drains out of the line and back to the tank, so you are trying to repressurize the line everytime you try to start it.

----------

One more thing, if you use a fuel pressure gauge, what you're looking for, in addition to fuel pressure, is fuel pressure drop. That would indicate what I mentioned above. Let us know what you find out.
 
#10 ·
PM sent regarding pressure regulator. Have you seen any improvement sense the install? I've got the same thing, but I believe it is the fuel pump's check valve going bad. The fuel pump is only activated for 3 seconds when you turn they key on, and will not run again until it sees a crank sensor input (meaning the engine is running), or unless you turn the key of and on again (then you get 3 more seconds). Essentially, as the check valve goes bad, fuel drains out of the line and back to the tank, so you are trying to repressurize the line everytime you try to start it.
----------

One more thing, if you use a fuel pressure gauge, what you're looking for, in addition to fuel pressure, is fuel pressure drop. That would indicate what I mentioned above. Let us know what you find out.
that is a couple of great points there hybridpower i don't know about the op but i haven't changed my fuel pump and i am praying it don't fail anytime soon but i will be going to the dealer to have mine replaced cause i ain't replacing it myself.
 
#11 ·
I had the same issue on my 02, longer crank times but it was intermittent. It would do it once out of every 10 times. Now I let it sit in the on position for maybe 2 seconds before cranking it all the way and never have a problem. I guess it gives the fuel pump enough time to cycle some gas into the motor.
 
#12 ·
Sorry I dropped the ball on this, my issue hasn't gone away but during the summer months, it wasn't as bad. Now that we are getting back into the cooler evenings, I'm noticing the issue getting worse on morning start ups. It's now accompanied by a minor rough idle and some minor hesitation in stop and go traffic.

I'm going to guess that the general concenous will be the fuel pump? Plugs and wires have already been changed recently, throttle body is clean etc. The only other thing I can think of to try would be to clean the mass airflow sensor, but I don't think that's it.

I'm tempted to replace the fuel pump relay just for fun, but when I turn the key I can hear the pump activating for about 3 seconds.

Thoughts? I'm not against changing the fuel pump, that is just a big job either to pay for or do yourself. In a perfect world I'd like to do it myself, but I'm not sure I'm feeling that brave.
 
#15 ·
slowstang305 said:
I had the same issue on my 02, longer crank times but it was intermittent. It would do it once out of every 10 times. Now I let it sit in the on position for maybe 2 seconds before cranking it all the way and never have a problem. I guess it gives the fuel pump enough time to cycle some gas into the motor.
One sure sign it's getting ready to fail trust me.
 
#16 ·
gmercedesbenz said:
Sorry I dropped the ball on this, my issue hasn't gone away but during the summer months, it wasn't as bad. Now that we are getting back into the cooler evenings, I'm noticing the issue getting worse on morning start ups. It's now accompanied by a minor rough idle and some minor hesitation in stop and go traffic.

I'm going to guess that the general concenous will be the fuel pump? Plugs and wires have already been changed recently, throttle body is clean etc. The only other thing I can think of to try would be to clean the mass airflow sensor, but I don't think that's it.

I'm tempted to replace the fuel pump relay just for fun, but when I turn the key I can hear the pump activating for about 3 seconds.

Thoughts? I'm not against changing the fuel pump, that is just a big job either to pay for or do yourself. In a perfect world I'd like to do it myself, but I'm not sure I'm feeling that brave.
Sounds like the fuel pump because if it was the mass air flow sensor it would trigger the engine light and throw a code.
(ps the fuel pump isn't cheap but I do suggest going to the dealer)
 
#20 · (Edited)
Burn your tank down to near EMPTY and take it to the dealer. GM has a lifetime warranty on the fuel pump after you buy the first replacement. If/When it fails, you only have to pay labor, the pump itself is around $400. You have to drop the tank to replace the pump. Replace the filter while you are at it. Then, never let your tank get below 1/4 or so. The gasoline actually keeps the pump cool, which adds life to the pump.
 
#21 ·
Trulytex said:
Burn your tank down to near EMPTY and take it to the dealer. GM has a lifetime warranty on the fuel pump after you buy the first replacement. If/When it fails, you only have to pay labor, the pump itself is around $400. You have to drop the tank to replace the pump. Replace the filter while you are at it. Then, never let your tank get below 1/4 or so. The gasoline actually keeps the pump cool, which adds life to the pump.
You don't have to use your fuel up before you go to the dealer I had a half a tank when my fuel pump crapped out they drained the tank before they dropped it and put the fuel back after they remounted the tank.
 
#22 ·
:duck:

Fuel Filter.

Took it to the dealership yesterday and had them test the fuel pressure. They said it was a little low, but I had brought a fuel filter that I intended to change anyway and asked them to throw it on. Replaced the filter, pressure was back up to normal. However, the service adviser knew I was having issues with my cold morning starts, so the shop agreed to hold my truck overnight and try again this morning. Tested pressure this morning, right where it should be. Truck started right up just like it used to, no issues.

:woohoo:

Thanks for the tips on extending pump life and such, I actually never let my tank go below a quarter anyway, definitely agreed there.
 
#23 ·
gmercedesbenz said:
:duck:

Fuel Filter.

Took it to the dealership yesterday and had them test the fuel pressure. They said it was a little low, but I had brought a fuel filter that I intended to change anyway and asked them to throw it on. Replaced the filter, pressure was back up to normal. However, the service adviser knew I was having issues with my cold morning starts, so the shop agreed to hold my truck overnight and try again this morning. Tested pressure this morning, right where it should be. Truck started right up just like it used to, no issues.

:woohoo:

Thanks for the tips on extending pump life and such, I actually never let my tank go below a quarter anyway, definitely agreed there.
If I can I never let mine go below half
 
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