Jump to content
  • Sign up for FREE! Become a GM-Trucks.com Member Today!

    In 20 seconds you can become part of the worlds largest and oldest community discussing General Motors, Chevrolet and GMC branded pickups, crossovers, and SUVs. From buying research to owner support, join 1.5 MILLION GM Truck Enthusiasts every month who use GM-Trucks.com as a daily part of their ownership experience. 

Hard to start after sitting for a few days -- crank sensor?

Recommended Posts

My 99 with 5.7L is really hard to start when it has been sitting for a few days (usually at least 3 days).


It cranks over, but seems to run into resistance each time around. If I crank and hold it for about 5-10 seconds, it will fire, but what seems like only on a couple of cylinders, then dies. Sometimes, it seems to backfire. If I keep trying, It *does* eventually start (just the other day, I think it took about 20 tries over a few minutes to get it to start. Once it starts, it runs rough for about 10 seconds, then runs fine. I've checked the fuel pressure and it's fine (about 60 PSI), even after sitting for a few days. If I drive it for at least 10 minutes, it will start fine the next day. If I let it idle for 10 minutes, it's not enough to make a difference the next day. One of the weirdest problems I've ever encountered, for sure!


When driving it daily, or maybe letting it sit for one day, it starts right up with the normal crank time.


After talking with another mechanic, we were thinking it could be fuel leaking from the FPR into a cylinder, or two. My gas mileage was down, too, so we replaced the FPR (and the spider injector assembly, as well). We found evidence of leaking fuel, but it didn't fix the hard start problem. The mechanic that replaced the FPR/spider injection was talking with a buddy and suggested it could possibly be the Crankshaft Position Sensor (mentioning that there was a TSB for that sensor; though I haven't been able to find it). The thinking is that if the crank sensor is not working right, it could be throwing the timing way off and trying to fire at the wrong time.


I've been having this problem for the past 3 years. Has anyone else had this kind of problem? Does it make sense that a crank sensor could be the cause? I've tried throwing parts at problems, before, and I can do that again, but I know it's always better to diagnose. However, this one seems pretty hard to diagnose and it sets no codes when it happens.

Link to post
Share on other sites

My '96 did something similar during a brief cold spell. Cranked, sputtered, knocked, and died. I had my other down as well. Later, when it warmed to the mid 50s, all about 40 degrees warmer, it turned over just fine.

Another thought might be the gas pump. That you might be able to hear actually run for a couple of seconds.

Link to post
Share on other sites

Thanks for the replies. I have about 30,000 miles on the cap, rotor and plug wires. 60K on the plugs. So, it's not like they are brand new, but it's surprising that it runs just fine once it gets past this hard start. What makes you think the plugs, wires, cap and rotor are the likely culprit?


I also have plenty of fuel pressure (at about 60 PSI), even after it's been sitting a few days. And it doesn't happen just in cold weather. I typically drive it daily in the winter, except when I'm out of town. I've noticed it most in the summer, when I'm typically driving my other car everyday, and it usually sits for weeks at a time. In fact, the first time I noticed the hard-start problem was on a summer camping trip after it sat at the campsite for 3 days. It's been getting progressively worse (meaning harder and harder to start) over time.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Content

    • By OldDirtySpartan
      Hi all,
      Long time lurker who finally created an account. Y'all have been a wealth of info and I really appreciate it.
      I have a 2001 Tahoe LT Autoride with the 5.3. My father-in-law bought it new and I bought it from him when he upgraded to a 2019 Tahoe Premier. I've been going through the Tahoe since buying it from him. It was always maintained at the dealer and serviced at every interval.
      The issue I am having now is a hard start when cold. It takes at least 2 cranks to get it started in the morning or after a long period of not driving.
      I have searched the forums and found some help but no threads with results. Here is what I have done so far to remedy the issue.
      -New plugs
      -New fuel filter
      -New fuel pump
      -Techron in tank (one bottle so far)
      I have a new fuel pressure regulator coming and will swap that next but the telltale signs of failure aren't there (gas leaking through vacuum line).
      The truck had one other issue that has since been fixed. It would overheat (on the gauge) on hot days mainly at low speeds and belch coolant when turned off. I ended up replacing the fan clutch, coolant temp sensor, expansion tank, thermostat, and expansion tank cap.
      Any advice would be hugely appreciated!
      Thanks all!
    • By Steven_R
      1997 5.7 Vortec intermittent slow start revisited.
      Short version:
      I have a 1997 Express with a 5.7 Vortec and the CSFI system. It has 130k miles.
      It is hard to start after sitting. If I pulse each of the fuel injectors with an injector tester then it starts right up. Problem description is mostly in next post. The test procedure that makes it start is in the third post.
    • By RussellD
      I have a 1999 s10 blazer with a 4.3 motor i'm putting in a 2002 4.3 motor and the crank sensor whole is different what can i do? Are there any other differences i know about as well?
    • By Angler21
      Please help!!   2008 GMC Sierra. 4.8.  Replaced fuel pump and FSM last year. Replaced evap solinoid last week.  Truck doednt want to start.  Turns over on first try. Then starts on second try.   Could it be a fuel sensor on fuel rail? 
    • By Angler21
      Please help!!   2008 GMC Sierra. 4.8.  Replaced fuel pump and FSM last year. Replaced evap solinoid last week.  Truck doednt want to start.  Turns over on first try. Then starts on second try.   Could it be a fuel sensor on fuel rail? 
  • Recently Browsing   0 members

    No registered users viewing this page.

  • Forum Statistics

    Total Topics
    Total Posts
  • Member Statistics

    Total Members
    Most Online
    Kyle Genesse
    Newest Member
    Kyle Genesse
  • Who's Online   46 Members, 0 Anonymous, 2,524 Guests (See full list)

  • Create New...

Important Information

By using this site, you agree to our Terms of Use.