The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1988 - 1998 GMT400 Chevy & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 11-13-2019, 03:58 PM   #1
lucky_7
Registered User
 
lucky_7's Avatar
 
Join Date: Mar 2013
Location: Muskogee, Ok.
Posts: 123
Cold start / Long crank

1997 GMC 1500 5.7L vortech. 147,000 miles, I have done a tune up less than 2 years ago that included, plugs, distributor cap and rotor.

Problem has been an intermittent long crank on the first start of the day, or when leaving work after my shift. Normally has been 2-3 seconds. New problem is that the long crank is getting worse (6-12 seconds) and sometimes it takes two cranks to start . It also seems to correspond with the colder temps here in Oklahoma this week.

Truck runs fine once started. It has all the power when needed. No stuttering, or slow acceleration.

Last edited by lucky_7; 11-14-2019 at 10:13 AM.
lucky_7 is offline   Reply With Quote
Old 11-14-2019, 09:32 AM   #2
speedygonzales
Registered User
 
speedygonzales's Avatar
 
Join Date: Jan 2006
Location: Smithfield, VA
Posts: 1,435
Only ever encountered 2 causes for this in my 20+ years

More than likely it's due to a stuck open fuel check valve in the sending unit.

Next cold start (where you would normally encounter the problem) do this. Turn Key On Engine Off for 5 seconds DO NOT CRANK THE ENGINE.
Then turn the key off for a few seconds.
Then do KOEO again for 5 seconds.
Do this process for 6 times
After the 6th time, turn it over like you normally would to start and see if this time it fires up quickly without having to crank it.
If it does now fire up quickly (after having primed the fuel system) that clearly proves the check valve is stuck. The only way to correct the problem that I've ever seen in 20 + years of owning mine is to replace the fuel sending unit.

If that does not change the problem, I guarantee the cap and rotor are the problem.

But for now focus on the culprit being the fuel problem.

As a "never hurts to try" you might consider using a complete fuel system treatment for several fill ups. I have had the stuck check valve problem 2 times in 20+ years of ownership and still to this day don't know what causes it to stick but I'm pretty sure it's not debris since the sock on the pump is a fine mesh. Good luck to you.
__________________
99 Z71 (98 body style)
Pride and joy
speedygonzales is offline   Reply With Quote
Old 11-14-2019, 10:12 AM   #3
lucky_7
Registered User
 
lucky_7's Avatar
 
Join Date: Mar 2013
Location: Muskogee, Ok.
Posts: 123
Re: Cold start / Long crank

Thank you Sir, I will give it a try.
lucky_7 is offline   Reply With Quote
Old 11-19-2019, 05:19 PM   #4
speedygonzales
Registered User
 
speedygonzales's Avatar
 
Join Date: Jan 2006
Location: Smithfield, VA
Posts: 1,435
We're waiting

Been a week, how about an update?
__________________
99 Z71 (98 body style)
Pride and joy
speedygonzales is offline   Reply With Quote
Old 11-19-2019, 10:14 PM   #5
lucky_7
Registered User
 
lucky_7's Avatar
 
Join Date: Mar 2013
Location: Muskogee, Ok.
Posts: 123
Re: Cold start / Long crank

Sorry. Been busy, just rebuild the front end. Trucks starts normally if I cycle the fuel pump a few times. I can't change the sending unit until later, just spent 600 on the front end. I'll just keep 1/2 tank for now in case it goes all the way out.
lucky_7 is offline   Reply With Quote
Old 11-20-2019, 11:02 PM   #6
Kudzupatch
Registered User
 
Kudzupatch's Avatar
 
Join Date: Apr 2013
Location: GUNTERSVILLE
Posts: 572
Re: Cold start / Long crank

very interesting. I drove to the Great White North one winter in my Suburban. Woke up to teens and it did the same exact thing. Never had given me any problem before and never knew why. SO RARE we have that low of temp here and when it does I rarely go anywhere. But good to know.
Kudzupatch is offline   Reply With Quote
Old 11-21-2019, 01:08 PM   #7
lucky_7
Registered User
 
lucky_7's Avatar
 
Join Date: Mar 2013
Location: Muskogee, Ok.
Posts: 123
Re: Cold start / Long crank

Yeah. Not sure what the colder weather would have to do with it other than chilling the valve which may shrink it some resulting it a tighter fit. Or some residue or corrosion broke free and stuck itself in the check valve. Whatever the case, the problem has cleared up recently.
lucky_7 is offline   Reply With Quote
Old 11-25-2019, 10:25 AM   #8
special-K
Special Order
 
special-K's Avatar
 
Join Date: Nov 2004
Location: Mt.Airy,MD
Posts: 70,757
Re: Cold start / Long crank

It might be as simple as it takes more fuel to start in cold and you are still getting enough for warm weather. I mean, that is the function of the choke in carburetors, fuel enrichment

I thing to try, if you haven't already, is take the cap off and clean the inside with Lectramotive. It could have carbon but not real bad yet. I watched an old mechanic years ago take my just installed cap, toss it in the trash, pull out one he just replaced, and put it on my truck with a crank/no fire problem on a rainy night. Not all caps are created equal. Things have probably changed, but back then I learned black cap = crap and the colored ones were better bakelite. He put a tan one on my truck and from then on I only used Standard Blue Streak caps (blue). That was back before HEI. I've used black with no issues now, most all are now. Haven't had that problem. But I still only buy quality brand caps
__________________
"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC

'67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi..........'The 67' (project)
'72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok...'The 72' (rolling)
Tim

"Don't call me a redneck. I'm a rough cut country gentleman"

R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586

Last edited by special-K; 11-25-2019 at 10:32 AM.
special-K is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 05:02 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Copyright 1997-2013 67-72chevytrucks.com