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Author
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Topic: Cold Start Problem
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Scott G
Journeyman Posts: 72
From: Chattanooga, TN USA
Registered: Mar 2003
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posted 02-22-2004 09:37 PM
   
I have a 95GT that is all stock except for exhaust. When the gas tank is less than half full, and the car has been sitting for a while (overnight, or all day at work), it takes a little while to start. The problem becomes more noticable the lower the fuel level gets in the tank. If you turn the car on and let the fuel pump time out, turn it off, then turn it back on, it almost always will fire right up until the tank gets really low. Does this sound like a failing fuel pump, or something else? Thanks for the help.Scott
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Moneymaker
Administrator Posts: 26811
From: Lyons, IL, USA
Registered: May 99
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posted 03-04-2004 09:20 PM
What octane gas are you using?
The higher the octane the higher the flash point.
We had a TSB on HO 5.0's that specified this issue.
Most times a simple switch to 87 octane cures the problem.------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,& '04
First SS/MA in the TENS!
IHRA division 5 Superstock Champion
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
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Scott G
Journeyman Posts: 72
From: Chattanooga, TN USA
Registered: Mar 2003
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posted 03-04-2004 09:44 PM
I have been running 89, but next tank I will try to run some 87 through it and see if that fixes it. Unfortunately, I just filled the car up today and I don't drive it everyday, so it will be a few weeks before I know. Thanks for the tip, hopefully that is all that it is.Scott
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SUBMARINER MUSTANGER
Gearhead Posts: 1268
From: Grandview, Missouri
Registered: Jun 99
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posted 03-05-2004 12:18 AM
Sounds like you're on the right track as far as the fuel pump...the octane WON'T cause this drive-abilty problem as long your talking about a STOCK car. The first thing I'd do is find a fuel pressure guage, connect it to the fuel rail shrader valve, start the vehicle, note the fuel pressure, shut the car off and let it set. If your fuel pressure drops after setting for awhile, you've got a fuel pump problem. The fuel pump has a valve that keeps the fuel pressure from bleeding off which go bad after time. If that valve is bad, your fuel is bleeding back into the tank, and COULD cause the drive-abilty problem you're describing.------------------
Sub Stanger/1990 LX 5.0 convertible (AOD to T5 conversion....completed)& the BUN in the famous "SUB SAMMICH" in Atlanta! Past Mustangs: '84 GT 5-speed; '91 GT auto; '70 M-code Mach 1, grabber yellow; 2 '95 GT 5 speeds, totalled first one; '94 6-banger, wifes; '89 LX 5.0 vert, '90 LX 5.0 hatch, '69 M-code Mach 1, 4 speed. [This message has been edited by SUBMARINER MUSTANGER (edited 03-05-2004).] [This message has been edited by SUBMARINER MUSTANGER (edited 03-05-2004).]
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Moneymaker
Administrator Posts: 26811
From: Lyons, IL, USA
Registered: May 99
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posted 03-05-2004 12:27 AM
quote:
Originally posted by SUBMARINER MUSTANGER:
Sounds like you're on the right track as far as the fuel pump...the octane WON'T cause this drive-abilty problem as long your talking about a STOCK car. The first thing I'd do is find a fuel pressure guage, connect it to the fuel rail shrader valve, start the vehicle, note the fuel pressure, shut the car off and let it set. If your fuel pressure drops after setting for awhile, you've got a fuel pump problem. The fuel pump has a valve that keeps the fuel pressure from bleeding off which go bad after time. If that valve is bad, your fuel is bleeding back into the tank, and COULD cause the drive-abilty problem you're describing.
OK, you win. FoMoCo TSB's were wrong!
 ------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,& '04
First SS/MA in the TENS!
IHRA division 5 Superstock Champion
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
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SUBMARINER MUSTANGER
Gearhead Posts: 1268
From: Grandview, Missouri
Registered: Jun 99
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posted 03-06-2004 05:15 PM
I don't recall a TSB that addresses a cold start problem being related to fuel octane level. Tell you what Alex, when I get home tonight (I'm playing weekend warrior with the Navy right now) I'll log onto OASIS and see what I can come up with. I don't like winning that easily and besides, Scott hasn't gotten back to us yet. I'm sure the fuel switch would probably the easiest thing to try, so if it works out, we should know shortly. Oh, hope to meet up with you in Nashville!------------------
Sub Stanger/1990 LX 5.0 convertible (AOD to T5 conversion....completed)& the BUN in the famous "SUB SAMMICH" in Atlanta! Past Mustangs: '84 GT 5-speed; '91 GT auto; '70 M-code Mach 1, grabber yellow; 2 '95 GT 5 speeds, totalled first one; '94 6-banger, wifes; '89 LX 5.0 vert, '90 LX 5.0 hatch, '69 M-code Mach 1, 4 speed.
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SUBMARINER MUSTANGER
Gearhead Posts: 1268
From: Grandview, Missouri
Registered: Jun 99
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posted 03-06-2004 10:19 PM
Well, found this, but not sure if Ford is specifically talking about "octane" or if they're more concerned with the other additives (MTBE, ethanol, etc). It appears it's more of a hot weather related thing with vapor lock, and I don't believe it's that hot in Chattanooga this time of year. Anyway Scott, Ford does recommend swapping the fuel and see if that helps out. TSB is below: Printable View (6 KB)
Article No.
98-26-2 FUEL - INFORMATION ON GASOLINE - TIPS TO RESOLVE VOLATILITY RELATED DRIVEABILITY CONCERNS
Publication Date: DECEMBER 18, 1998 FORD: 1985-97 THUNDERBIRD
1986-99 MUSTANG, TAURUS
1987-99 ESCORT
1988-94 TEMPO
1989-97 PROBE
1990-99 CROWN VICTORIA
1992-93 FESTIVA
1995-99 CONTOUR
LINCOLN-MERCURY: 1985-97 COUGAR
1986-92 MARK VII
1986-99 SABLE
1987-89 TRACER
1988-94 TOPAZ
1988-99 CONTINENTAL
1990-99 GRAND MARQUIS, TOWN CAR
1991-99 TRACER
1993-98 MARK VIII
1995-99 MYSTIQUE
1999 COUGAR
LIGHT TRUCK: 1986-97 AEROSTAR
1987-96 BRONCO
1989-97 F SUPER DUTY, F-350
1989-99 F-150, F-250 LD, RANGER
1991-99 EXPLORER
1992-99 ECONOLINE
1993-99 VILLAGER
1995-99 WINDSTAR
1997-99 EXPEDITION, MOUNTAINEER
1998-99 NAVIGATOR
1999 SUPER DUTY F SERIES
MEDIUM/HEAVY TRUCK: 1990-97 F-700
This TSB article is being republished in its entirety to expand vehicle model coverage and revise the text.
ISSUE:
Some vehicles using winter blend fuels may exhibit a stall on start up and a no restart, hard start condition or a no start condition in unseasonably hot weather (greater than 27?C/80?F). These concerns may be related to fuel volatility from winter blend fuels during winter-spring and autumn-winter transitions and may result in a fuel pump vapor lock condition. This condition may appear to be a fuel pump failure but may be caused by winter blend fuel. ACTION:
Refer to the following text for further information. NOTE: FUEL TANK ADDITIVES WILL NOT RESOLVE THESE CONCERNS BECAUSE VAPOR FORMS FROM CAVITATION WITHIN THE FUEL PUMP. FILLING THE TANK TO FULL MAY BE EFFECTIVE. ADVISE CUSTOMER TO USE THE RECOMMENDED OCTANE GRADE PER OWNER MANUAL AND NOT A HIGHER GRADE. Explain to the customer that this concern may be due to a low tank level of winter blend fuel combined with unseasonably warm weather. Advise customer that filling the fuel tank to full may be effective in resolving this concern. Also, advise customer to use the recommended octane grade per their Owner Manual and not a higher grade.
BACKGROUND
Gasolines are seasonally adjusted, meaning they have higher volatility (vaporize easier) in the winter and lower volatility in the summer. Government mandates to improve air quality have resulted in significant changes to gasolines, such as the mandatory use of oxygenates (ethanol, methyl tertiary butyl ether (MTBE), and others) in the winter or the reduction of Reid Vapor Pressure (RVP) in the summer. The addition of oxygenates (especially ethanol) increases volatility while the reduction of RVP reduces volatility.
Gasoline distribution practices often do not allow branded marketers to have much control over their gasoline's volatility other than RVP. Oxygenate (e.g., ethanol, MTBE) use is more dependent on local gasoline markets, rather than specific marketers practice. Therefore, it is difficult to recommend specific brands to avoid volatility related complaints. ------------------
Sub Stanger/1990 LX 5.0 convertible (AOD to T5 conversion....completed)& the BUN in the famous "SUB SAMMICH" in Atlanta! Past Mustangs: '84 GT 5-speed; '91 GT auto; '70 M-code Mach 1, grabber yellow; 2 '95 GT 5 speeds, totalled first one; '94 6-banger, wifes; '89 LX 5.0 vert, '90 LX 5.0 hatch, '69 M-code Mach 1, 4 speed. [This message has been edited by SUBMARINER MUSTANGER (edited 03-06-2004).]
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Moneymaker
Administrator Posts: 26811
From: Lyons, IL, USA
Registered: May 99
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posted 03-06-2004 10:30 PM
Yeah, I guess I never know what I'm talking about do I? In the immortal words of James Colburn's character in the greatest western movie ever made, The Magnificent Seven...... "you lost!"  ------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,& '04
First SS/MA in the TENS!
IHRA division 5 Superstock Champion
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
IP: Logged |
Scott G
Journeyman Posts: 72
From: Chattanooga, TN USA
Registered: Mar 2003
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posted 03-06-2004 11:01 PM
Thanks for all the help guys, since I don't drive the car all the time, it will be a bit before I get to try this again. I will be sure to put something up here when I do test it though. Thanks again.Scott
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Scott G
Journeyman Posts: 72
From: Chattanooga, TN USA
Registered: Mar 2003
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posted 04-21-2004 08:00 PM
Well, the problem got better with 87 octane, but is still there. It may be my imagination, but it also seems harder to start with a full tank and 87 than it did with 89. If I turn the key to run, wait for the fuel pump to time out, then try to start, it helps, but will still take a little while to start. Any other ideas? Thanks.Scott
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SUBMARINER MUSTANGER
Gearhead Posts: 1268
From: Grandview, Missouri
Registered: Jun 99
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posted 04-21-2004 08:13 PM
Did you ever get a fuel pressure leak down test done? I still don't think this problem has anything to do with what octane you're using. This sounds like a base fuel pump problem. I've seen this quite a few times where the check valve in the fuel pump goes bad and lets the fuel pressure drain back into the tank causing a long crank. That's why when you turn the key on, then turn it off, then back on again, that allows the fuel pressure to build back up. Have your fuel pump checked.------------------
Sub Stanger/Oxford White 2003 Mach 1...and a guy who LOVES his wife and kids! Past Mustangs: '84 GT 5-speed; '91 GT auto; '70 M-code Mach 1, grabber yellow; 2 '95 GT 5 speeds, totalled first one; '94 6-banger, wifes; '89 LX 5.0 vert, '90 LX 5.0 hatch, '69 M-code Mach 1, 4 speed.
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Scott G
Journeyman Posts: 72
From: Chattanooga, TN USA
Registered: Mar 2003
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posted 04-21-2004 08:19 PM
I was planning on putting a fuel pressure gauge on the car at some point this spring. In the meantime, I can just check at the schrader valve to see if there is any pressure after the car sits for a bit with a low tank. Thanks for the help.Scott
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hotstang
Gearhead Posts: 347
From: Murfreesboro, Tn USA
Registered: Jun 99
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posted 04-21-2004 09:23 PM
Get a good F/P regulator. it sounds like yours is letting the gas flow back and is bleeding off all of the preasure.
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Scott G
Journeyman Posts: 72
From: Chattanooga, TN USA
Registered: Mar 2003
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posted 07-08-2004 10:39 PM
Update: I changed the fuel filter, had no noticable effects on the problem. The cold start has gotten a little worse in that it now will do it with pretty much any amount of fuel in the tank.
It has also developed one other intersting thing. When you come up to a stop sign and push the clutch in, the engine will die down to about 500 rpm for a second or two then bounce back up to idle. It will only do this for the first few minutes after a cold start, and very briefly if at all after a hot start. Could these two problems be related? The car is running, and has been running for a while now 87 octane. Changing to that from 89 didn't seem to make much of a difference in this problem, unfortunately. Thanks for the help.Scott
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