Notices
Forced Induction Superchargers | Turbochargers | Intercoolers

Recent long crank times before start

 
Old 04-13-2019, 12:48 AM
  #1  
TECH Regular
Thread Starter
 
Join Date: Dec 2011
Posts: 484
Default Recent long crank times before start

My turbo street truck has recently started to crank for a looooooooong time before starting. A preliminary net search reveals things like fuel filter, check valve in the fuel pump.......

What's the best place to start here to figer' this thang out? So far no problem, but I drive this thing often and far, would rather get it figured out first.
ElQueFør is offline  
Old 04-13-2019, 09:04 AM
  #2  
TECH Apprentice
iTrader: (32)
 
Join Date: May 2004
Location: Vermont
Posts: 337
Default

Fuel pressure bleed down, does it start quicker if you cycle the fuel pump a few times?
Floader is offline  
Old 04-13-2019, 10:35 AM
  #3  
TECH Veteran
iTrader: (21)
 
truckdoug's Avatar
 
Join Date: Nov 2013
Location: Portlandia
Posts: 4,745
Default

bump the cranking fuel?
truckdoug is offline  
Old 04-13-2019, 09:16 PM
  #4  
TECH Regular
Thread Starter
 
Join Date: Dec 2011
Posts: 484
Default

I will experiment with multiple key cycles next time I'm driving it and see if that makes a difference..

Doug, what exactly in the cranking fuel? Cranking VE table or something else??

I have also wondered if richening up the primary VE table in the idle area cells would help. It idles pretty lean, sometimes pegs the WB lean while idling long enough.....
ElQueFør is offline  
Old 04-14-2019, 10:26 AM
  #5  
TECH Veteran
iTrader: (21)
 
truckdoug's Avatar
 
Join Date: Nov 2013
Location: Portlandia
Posts: 4,745
Default

so once you determine its not a mechanical issue

look under Engine> Fuel >Cranking Fuel> FA (fuel adder) Multiplier stage 1 vs time and bump fuel like 5% all around as an experiment. it takes a while since you want a cold start for every test.

and the going lean at idle could be a couple things.

First I would verify your base running airflow (Engine>Idle>Airflow>base running airflow) actually mathes your idle air needs. alternate tuning this, and your IAC effective area to get your IAC step count to around 50 or so. You'll probably have to do a couple TPS re-learns (i'm sure you know how that works)

once you have a stable hot idle then you can really dial cold starts.

another benefit to having the IAC effective area dialed is that throttle transitions become way smooth since the IAC can soften the airflow with the Throttle Follower
truckdoug is offline  
Old 04-14-2019, 04:51 PM
  #6  
9 Second Club
 
Join Date: Nov 2003
Location: Norn Iron
Posts: 12,246
Default

Originally Posted by ElQueFør View Post
My turbo street truck has recently started to crank for a looooooooong time before starting. A preliminary net search reveals things like fuel filter, check valve in the fuel pump.......

What's the best place to start here to figer' this thang out? So far no problem, but I drive this thing often and far, would rather get it figured out first.
recently for no reason, and without you having made any changes whatsoever ?

And what is your definition of loooooooooong ?

Like 2 turns, 5, 10, 20 ? a time period ? other ?

Presumably no fault codes are present ?
stevieturbo is offline  
Old 04-16-2019, 01:24 AM
  #7  
TECH Regular
Thread Starter
 
Join Date: Dec 2011
Posts: 484
Default

Yes Stevie, it seems to have come out of nowhere, best I can tell anyways......

Oh boy, hittin me with the data, numbers and whatnot lol. I get it though, it's the only way to really quantify something. Because otherwise it's totally subjective....

I'd roughly estimate that when it does this that it will crank for 5 seconds with nothing... Then I'll back off the starter and try again... Same deal.....

I should also mention.... When it's doing this, I will crank as mentioned in the line above and when I release the starter it will go totally (or nearly) quiet and THEN, the engine will fire off!!

I have only been able to drive it once since posting this but today I fired it up cold and I cycled the key a few times before attempting to start and it fired INSTANTLY... Kinda points to a fuel pump check valve or maybe a fuel pressure regulator??? (Stock LQ4 Reg)

Nah, no fault codes, other than the failed MAF of course since I'm 3 bar SD.
ElQueFør is offline  
Old 04-16-2019, 06:00 AM
  #8  
TECH Junkie
iTrader: (5)
 
forcd ind's Avatar
 
Join Date: Sep 2007
Location: woodbine, md
Posts: 3,333
Default

If it was a ck valve, you should be able to turn the pump on, wait for it to pump up,
then try a start. Depending on what operating system, some you can adjust the fuel prime.
Since it was ok, I would look for something, maybe do a comp. tune, plugs, fuel filter, etc.
You could even have dirty injs., not allowing a good prime. Those things are hard to track down.
forcd ind is offline  
Old 04-16-2019, 12:16 PM
  #9  
9 Second Club
 
Join Date: Nov 2003
Location: Norn Iron
Posts: 12,246
Default

Originally Posted by ElQueFør View Post
Yes Stevie, it seems to have come out of nowhere, best I can tell anyways......

Oh boy, hittin me with the data, numbers and whatnot lol. I get it though, it's the only way to really quantify something. Because otherwise it's totally subjective....

I'd roughly estimate that when it does this that it will crank for 5 seconds with nothing... Then I'll back off the starter and try again... Same deal.....

I should also mention.... When it's doing this, I will crank as mentioned in the line above and when I release the starter it will go totally (or nearly) quiet and THEN, the engine will fire off!!

I have only been able to drive it once since posting this but today I fired it up cold and I cycled the key a few times before attempting to start and it fired INSTANTLY... Kinda points to a fuel pump check valve or maybe a fuel pressure regulator??? (Stock LQ4 Reg)

Nah, no fault codes, other than the failed MAF of course since I'm 3 bar SD.
For over 10 years I ran pumps with no check valves and a system that bled down. Never in that time has starting ever taken 5 seconds.

Maybe 2 seconds at worst, but rarely even that. So there is no way that is in any way a problem.

By all means check fuel pressure when cranking and starting.

Check for fuel being injected ( not too much, not too little )

Check for spark

And of course check there is air available.
stevieturbo is offline  
Old 04-17-2019, 02:23 AM
  #10  
TECH Regular
Thread Starter
 
Join Date: Dec 2011
Posts: 484
Default

Were you removing the check valves from the pumps or using pumps that didn't have them?
ElQueFør is offline  
Old 04-17-2019, 11:50 AM
  #11  
9 Second Club
 
Join Date: Nov 2003
Location: Norn Iron
Posts: 12,246
Default

I never use check valves with 044's

But I moved to an in-tank setup with 450's in the last year or so.
stevieturbo is offline  
Old 04-18-2019, 09:18 AM
  #12  
10 Second Club
iTrader: (4)
 
rt338b's Avatar
 
Join Date: Dec 2013
Posts: 102
Default

That can be a timing error such as crank sensor or the reluctor wheel has moved. Only a guess as this can be a lot of fuel problems also.
rt338b is offline  
Old 04-19-2019, 12:01 PM
  #13  
TECH Senior Member
iTrader: (7)
 
Project GatTagO's Avatar
 
Join Date: Mar 2003
Location: The Druid City
Posts: 7,486
Default

Is this a swap into an older vehicle?

Andrew
Project GatTagO is offline  
Old Yesterday, 01:11 AM
  #14  
TECH Regular
Thread Starter
 
Join Date: Dec 2011
Posts: 484
Default

It's a 90 GMT400 with an 03 ish LQ4... Been driving for a year or two since I built it... Drive it all over the Oklahoma City Metro.. I have noticed that 1st crank cold it fires off instantly. If I drive it somewhere even in town and park it..... THEN I have to crank on it for a while for it to start again.
ElQueFør is offline  
Old Yesterday, 08:54 PM
  #15  
TECH Fanatic
iTrader: (38)
 
350SS's Avatar
 
Join Date: Feb 2004
Location: Houston, TX
Posts: 1,031
Default

id check fuel pressure like others mentioned

if you don't have one you can rent a fuel pressure gauge from autozone and see what it's doing in each instance

key on (does pressure build and hold or bleed off)
then while cranking, running (whats fuel pressure vs manifold vacuum)

like you said, could be a regulator, pump check valve or maybe a leaky injector

you can pull the rail with the injectors still attached, prime the pump and see if any are leaking
350SS is offline  
Old Yesterday, 09:49 PM
  #16  
TECH Regular
 
Dimeomboost's Avatar
 
Join Date: Dec 2014
Location: Emory Texas currently
Posts: 473
Default

I had this exact issue on 2 vehicles. Started fine when cold but when warm it would damn near sound like I killed the battery. Both came out of no where and it was the same fix for both. I increased heat shield at the starter I added an addition hot cable to the starter and i added big *** ground to the motors and both cars are fixed and running still to this day. All the extra heat under the hood just finally took its toal on electronics so I fixed it
Maybe not your issue but a easy enough one to fix
Dimeomboost is online now  
Old Today, 12:26 AM
  #17  
TECH Regular
Thread Starter
 
Join Date: Dec 2011
Posts: 484
Default

Originally Posted by 350SS View Post
id check fuel pressure like others mentioned

if you don't have one you can rent a fuel pressure gauge from autozone and see what it's doing in each instance

key on (does pressure build and hold or bleed off)
then while cranking, running (whats fuel pressure vs manifold vacuum)

like you said, could be a regulator, pump check valve or maybe a leaky injector

you can pull the rail with the injectors still attached, prime the pump and see if any are leaking
Yep, I need to check the fuel pressure. All good suggestions. I'm thinking the injectors ought to be OK, I decapped them and flow tested the **** out of them on my shadetree flow bench before I put them in... Doesn't mean they're still good of course, but I'd think they would be.

Originally Posted by Dimeomboost View Post
I had this exact issue on 2 vehicles. Started fine when cold but when warm it would damn near sound like I killed the battery. Both came out of no where and it was the same fix for both. I increased heat shield at the starter I added an addition hot cable to the starter and i added big *** ground to the motors and both cars are fixed and running still to this day. All the extra heat under the hood just finally took its toal on electronics so I fixed it
Maybe not your issue but a easy enough one to fix
Good info. Thanks for the suggestion. I don't think it's the heat, because last summer I drove it around and saw the hottest coolant temps I have with this setup with the shitty fan that used to be in it. Anyways, ECT was like 215-220*F IIRC was the hottest I ever saw it, I'm sure the underhood temps were pretty high also.. Never did it then though???

You're spot on about grounds. I learned the hard way from previous vehicular debauchery that you can never have too many grounds. I put pretty thick ground cables going between: block, body, frame.. A few of them are even redundant with extra grounds duplicating those three main areas.




Now let me ask you guys this... I stabbed a cam in this thing a ways back and subeone on this very forum was kind enough to help me get the idle airflow stuff dialed in after I installed the bigger cam.. I have always done all of my own tuning, thanks largely in part to all of the talent floating around on this board, among others.. RonSSNova, truckdoug, ddnspider, ChopperDoc, subeone, Lsxford, BCNUL8R... I'm probably forgetting some because it's kinda late and I'm a few beers in at this point, so apologies to anyone if I have forgotten! Anyways, subeone got me fixed up where it was much better than before.. However, the RPM sometimes will dive down, and rarely... the engine will kill out.... I'm not bitchin! Super grateful subeone et al! But, I wonder is there more improvement to be had there that could be causing this?
ElQueFør is offline  
 


Thread Tools
Search this Thread

About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: