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  • SN95 4.6L Mustang Tech

Car Hesitates on a warm start

  • Thread starter Thread starter 03_TrueBlue_GT
  • Start date Start date Dec 8, 2010

03_TrueBlue_GT

Active Member
May 5, 2010
810
41
29
Houston, Tx
Dec 8, 2010
#1
  • Dec 8, 2010
  • #1
Hey guys lately I have been having an issue with my Mustang when I go to start it after it sits for a little while like ten minutes or less it hesitates and takes a little longer to actually start than normal, like it doesnt catch on the first sec of turning the ignition. (I hope that makes sense)

But I noticed it does this only when the car has been sitting in a spot for a short amount of time (ie like sitting at the dragstrip in the waiting lanes) and it does this every once in a while not all the time. Its just embarrassing that it does this especially at the track... It starts just fine on a cold start and I have checked the throttle for carbon buildup and I cleaned it as best as I could, it has Bosch Platinum spark plugs with only 15k on them and I always use Chevron fuel 87 octane. Btw it does this usually on warm days like in the 90's*

Any help is much appreciated!
 

sneaky98gt

10 Year Member
Apr 23, 2008
2,387
144
114
NC State University
Dec 8, 2010
#2
  • Dec 8, 2010
  • #2
I know EXACTLY what you mean, because mine does it too.

I've never found a solution, but I think I might have one now. It started doing it after I put the blower on, so I always assumed it was the tune and just made myself not care about it. But now, I'm having idling problems and I'm pretty sure it's the IAC. I used the IAC that came with the blower, so that was one thing that actually changed with the blower install. I'm swapping my old IAC (which didn't give these problems) back on next week, and I'll let you know if my car still does it after I do that.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
204
Houston Texas
Dec 8, 2010
#3
  • Dec 8, 2010
  • #3
If the key is cycled off/on/pause several times without cranking does this improve starting?

Tell us about any mods. PPRV delete?

If the throttle is held half way open during cranking, does this improve starting?

Do you have an ODB2 scanner? What does the PCM report for fuel pressure and intake air temperature?
 

03_TrueBlue_GT

Active Member
May 5, 2010
810
41
29
Houston, Tx
Dec 8, 2010
#4
  • Dec 8, 2010
  • #4
sneaky98gt said:
I know EXACTLY what you mean, because mine does it too.

I've never found a solution, but I think I might have one now. It started doing it after I put the blower on, so I always assumed it was the tune and just made myself not care about it. But now, I'm having idling problems and I'm pretty sure it's the IAC. I used the IAC that came with the blower, so that was one thing that actually changed with the blower install. I'm swapping my old IAC (which didn't give these problems) back on next week, and I'll let you know if my car still does it after I do that.
Click to expand...

Dang that sucks bro, by IAC do you mean Idle Air Controller? Sorry Im a newb at this stuff...


If the key is cycled off/on/pause several times without cranking does this improve starting?

Tell us about any mods. PPRV delete?

If the throttle is held half way open during cranking, does this improve starting?

Do you have an ODB2 scanner? What does the PCM report for fuel pressure and intake air temperature?
Click to expand...


I havent ever tried cycling the key to the on/off to be honest so I will give that a try. What I usually do is turn the key to the on position and let everything charge up like the dash and the fuel pump so I just dont get in and start it.. The only thing I have done is a BBK CAI and the car used to do the same thing before I got it.
And I have no idea what the PPRV delete is..

And yes I just went out and tried an OBD2 scanner and the AIT(im guessing Air Intake Temperature) said it was 78* Right now its 45* outside where Im at.
The Fuel Pressure was varying from 39.5 to 40 psi at idle.
 

03_TrueBlue_GT

Active Member
May 5, 2010
810
41
29
Houston, Tx
Dec 11, 2010
#5
  • Dec 11, 2010
  • #5
Not to seem like a jerk, but nobody else has any ideas?
Thanks again for the help its much appreciated!
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
204
Houston Texas
Dec 11, 2010
#6
  • Dec 11, 2010
  • #6
I am assuming that none of the tests suggested improved the condition.

Consider an injector cleaning/flow test service such as injectorrx.com.
 

hotcobra03

Active Member
Nov 29, 1999
969
4
39
poteet,tx
Dec 11, 2010
#7
  • Dec 11, 2010
  • #7
hard starts

you need to read the WMBURNS EXPRESS NEWS more ...hes 99.9% on the money
 

02NutStang

New Member
Dec 11, 2010
17
0
1
Venice, FL
Dec 12, 2010
#8
  • Dec 12, 2010
  • #8
What about a clogged fuel filter? By the way you will need a special tool to remove it, its not expensive and should be stocked at your local auto parts store, but I would try that and like wmburns said Injector cleaning.
 

03_TrueBlue_GT

Active Member
May 5, 2010
810
41
29
Houston, Tx
Dec 12, 2010
#9
  • Dec 12, 2010
  • #9
Thanks for the help guys , it turns out it was the stock fuel filter that needed to be replaced, I went ahead and changed it out and the car doesnt do it anymore!
 
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