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2001 8.1 starting hard..

Discussion in 'Chevy Trucks' started by Mick76, Sep 28, 2011.

  1. Mick76

    Mick76 2000 Club Member
    from Maine
    Messages: 2,157

    Heres the deal, 2001 94K just had the spark plugs replaced.... they were the original ones and my mechanic broke off 3 of them trying to get them out..... he managed to get the 3 broken ones out but now when the truck is cold or has been sitting for 15 minute or so , I'll go to try and start it..... all I get is the engine turning over. bring the key back and try again and it starts (sometimes hard sometimes pretty easy)....... Would a bad or soon to be bad crank sensor be the problem ? anything else I should look at?

  2. BowTieDmax

    BowTieDmax Senior Member
    Messages: 152

    crank sensor
  3. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Was or wasn't the hard starting issue there before your mechanic replaced the plugs? What plugs did he use? Brand and p/n?
  4. Mick76

    Mick76 2000 Club Member
    from Maine
    Messages: 2,157

    BB...good questions... not a problem before i had them replaced but its a truck i don't drive that often (8.1 gas mileage and all) and I thought about the plugs being the wrong ones but it seems every little thing happens to this truck!...its been a big pita.....
    I'll find out the brand and pn for you
  5. Mick76

    Mick76 2000 Club Member
    from Maine
    Messages: 2,157

    BB... He went with the Bosch OEM plugs from napa
  6. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    The 8.1's are fussy about plug choice and Bosch is one they're never happy with therefore will cause misfiring, hard starting, rough idle etc. AC Delco 41-983's gapped to .050 (not .060) are what you want to use in any 8.1 regardless whether any issues were there previously or not.
  7. Mick76

    Mick76 2000 Club Member
    from Maine
    Messages: 2,157

    Thanks BB... I did just reverify the plug choice and he did put in the ac's like you mentioned above but with the .060 gap... i'm bringing it to him to have him regap and see where that takes me...thanks again!
  8. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,525

    I have replaced tons of the crap single tip bosch platinum for misfires. Never the double tip or +4. Not saying there good either. Delco are best in a gm. Sounds like possible fuel pressure though never seen new plugs start hard misfire yes. What does it do uf u cycle the key 2 or 3 times before u start the truck ? Try that and see if it starts normal then.
    Last edited: Sep 29, 2011
  9. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    If he used the correct plugs just tightening up the gap .010 won't fix it, there's something else going on.

    You're still not clear on whether the issue was there before hand so I can't give you an accurate prognosis but if it didn't have the issue beforehand have him check the intake duct at the TB and MAF to be sure he didn't dislodge it while working under the hood or to be sure he re-installed correctly if he had it removed. A small air leak downstream of the MAF will cause a hard start.

    If is WAS there beforehand then there's only a couple things that can cause it on an 8.1. An air leak in the intake duct as previously mentioned, lack of fuel supply while cranking or a faulty CKP...although they almost always manifest themselves with a stall once underway, not a hard start but it can happen.
  10. Brian Young

    Brian Young PlowSite Veteran
    Messages: 3,394

    Mike, I had the exact same problem with our 00 GMC. It had a 7.4L. I change plugs with the ones recommended, changed everything you could think of and same thing. I was at our Fisher dealer and we were talking about it, he said their lot truck did the same thing and they removed the throttle body and cleaned it very well and problem solved. He said they've done that to many other trucks, same type, same issue, (they're a garage as well). I did a quick cleaning, basically sprayed some throttle body cleaner stuff in there and it helped but then we sold it. The crank sensor in ours checked out ok while that issue was still there.
  11. larboc

    larboc Member
    Messages: 98

    your IAC is dirty
  12. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Both good tries and are two items that should be cleaned annually on any truck (although there is no IAC on a 8.1 so don't search for it too long) but neither will cause a hard start on an 8.1, only a rough and/or unstable idle. Drive by wire works differently than cable operated throttle body and will easily overcome a dirty throttle plate during starting.
  13. Mick76

    Mick76 2000 Club Member
    from Maine
    Messages: 2,157

    Didn't have the hard start issue before changing the plugs...... Mechanic was thinking fuel since if I cycle the key before starting it , it seems to start right up no problem but he'll look around for the other things mentioned.....thanks again and I'll post the findings once he figures it out!
  14. 496 BB

    496 BB Senior Member
    Messages: 789

    Did he change the wires? I know those are VERY sensitive to breaking and Ive done that to more then a few since they can be a royal PITA to get loose even with grease on em from last time. Wait till you see the price on em too. I went MSD last time.

    Id check the fuel pressure before anything. Mine went out with no warning at all but Ive had some go out starting with hard starts. If it runs good after you start it I wouldnt think it was that or plugs. Sounds like air intake is loose or sensor not plugged in on it. My damn K&N pops off the the TB all the time creating this problem.
  15. djagusch

    djagusch 2000 Club Member
    from mn
    Messages: 2,107

    I would ask how he got the 3 broken ones out? Could he of bent the valves getting them out? Could he left some material in the combustion chamber making the seats not seal or rings wear quickly.
  16. Mick76

    Mick76 2000 Club Member
    from Maine
    Messages: 2,157

    Well, my mechanic scanned for codes and found a faulty knock sensor which he replaced... he checked fuel pressure and all was fine.... i dunno.....
  17. REAPER

    REAPER 2000 Club Member
    from 60050
    Messages: 2,230

    Did that fix it?