Vaccum leak/tunning issues? - 2003-04 Mach 1 Registry Owners Club

Furinox · 09-16-2008, 11:26 PM

I just got my car back with the new motor in it and it appears that I have a small vaccum leak coming from the upper intake manifold gasket at the back. I can spray carb cleaner in that are and the car idles down. The reason I found it is because there is a hissing sound for about 2-3 seconds after I turn the car off. It apparently is a small leak since the car is running perfect.

My delima is I have an appointment to have the car tunned at 9:30 in the morning. How much is this small leak going to affect the tunning and is it safe to just replace it after I get the tune? I really don't want to reschedule and it seems im going to have to order the gasket since no one has it in stock.

rich1 · 09-16-2008, 11:42 PM

There is no way you will ever get a true A/F ratio with an air leak !

I doubt if he is a good Tuner will even try to do it if he hears or knows this.

Furinox · 09-16-2008, 11:55 PM

Quote:

Originally Posted by rich1

There is no way you will ever get a true A/F ratio with an air leak !

I doubt if he is a good Tuner will even try to do it if he hears or knows this.

think a small amount of black silicone/rtv would hold it until i can get ahold of another gasket?

rich1 · 09-17-2008, 12:15 AM

Your car ...youre choice ...But since you asked..

. No just wait and get it done right or end up getting it tuned twice !

3150Mach1 · 09-17-2008, 05:37 AM

Quote:

Originally Posted by Furinox

I just got my car back with the new motor in it and it appears that I have a small vaccum leak coming from the upper intake manifold gasket at the back. I can spray carb cleaner in that are and the car idles down. The reason I found it is because there is a hissing sound for about 2-3 seconds after I turn the car off. It apparently is a small leak since the car is running perfect.

My delima is I have an appointment to have the car tunned at 9:30 in the morning. How much is this small leak going to affect the tunning and is it safe to just replace it after I get the tune? I really don't want to reschedule and it seems im going to have to order the gasket since no one has it in stock.

There are a few vacuum hoses and the egr back there as well. It could be one of those. At the very back of the lid is a plastic thing with 2 vacuum hoses. This is the vacuum system for the egr. Make sure they are not leaking. They are tough to geton and easy to miss. If you deleted the egr then they need to be capped.

Then there is the one at the top rear of the lid and at the IAC.

Beefy Nugz · 09-17-2008, 09:55 AM

How do you know you need a new gasket with out taking it off and inspecting it, or have you already done this? I have noticed intake screws come loose before, maybe just take a torque wrench and check all the bolts.

ponygt65 · 09-17-2008, 01:54 PM

WHy not call the shop and tell them and ask if you can come in early to have a look at it? If it's something simple, should be quick and easy.

One thing is for sure, I would not tune it the way it sits. It will end up being a waste.

Furinox · 09-17-2008, 11:45 PM

well I took the gasket off and it was pretty mangled so I bought a new one today and it is sealing up even worse now. I cleaned both the upper and lower intake surfaces and found a small imprefection in the casting on the passenger back side. This is the same corner that would cause funny idle when spraying carb cleaner. The tuner at the shop said hes seen this one other time and they had to use silicone to get it to seal. So unfortunately I didnt get my tune today and I ended up using some silicone in the area that wouldnt seal. I'll find out in the morning if it did the trick or not.

rich1 · 09-18-2008, 12:08 AM

Good deal !

Furinox · 09-19-2008, 01:16 AM

Ok, so get this. It wasnt the intake at all -- It was a bad o-ring on an injector right below the corner of the intake.

ponygt65 · 09-19-2008, 12:52 PM

Quote:

Originally Posted by Furinox

Ok, so get this. It wasnt the intake at all -- It was a bad o-ring on an injector right below the corner of the intake.

Hmmm. Well, glad you got it squared away.

09-16-2008, 11:26 PM	#1
Furinox Registered User Join Date: Feb 2007 Location: DFW, TX Posts: 1,021	Vaccum leak/tunning issues? I just got my car back with the new motor in it and it appears that I have a small vaccum leak coming from the upper intake manifold gasket at the back. I can spray carb cleaner in that are and the car idles down. The reason I found it is because there is a hissing sound for about 2-3 seconds after I turn the car off. It apparently is a small leak since the car is running perfect. My delima is I have an appointment to have the car tunned at 9:30 in the morning. How much is this small leak going to affect the tunning and is it safe to just replace it after I get the tune? I really don't want to reschedule and it seems im going to have to order the gasket since no one has it in stock.

09-16-2008, 11:42 PM	#2
rich1 AUTOMACHTIC Join Date: Oct 2007 Location: RTP/ N.C. Posts: 4,813	Re: Vaccum leak/tunning issues? There is no way you will ever get a true A/F ratio with an air leak ! I doubt if he is a good Tuner will even try to do it if he hears or knows this. __________________ UPGRADES...Tokico Illuminas Borla SS Catback , Steeda Underdrives , Strut Brace , HPM Lower K Brace , L /C Arms , U /C Arms , HPM PanHard Bar, K&N FRPK 2, GOODYEAR GT1 , MRT- H-Pipe , JLT VaporTraps , SLP-12'" Tips! , FRPP Shorty 1 5/8 Headers , Brembo D/S & PBR D/S Rotors ,FRPP Alum.DS ,Roys 3/8 Spacer , SVT Focus 255 pump SCTsw Chip PRO-DYNOjet NA 300.01hp /315tq (Auto) ,Innovate W/B ,Compucar Wet Kit (90jet) + Heater and E Gauge * 360 hp/385tq 12.5 -1/4 @112

09-17-2008, 12:15 AM	#4
rich1 AUTOMACHTIC Join Date: Oct 2007 Location: RTP/ N.C. Posts: 4,813	Re: Vaccum leak/tunning issues? Your car ...youre choice ...But since you asked.. . No just wait and get it done right or end up getting it tuned twice ! __________________ UPGRADES...Tokico Illuminas Borla SS Catback , Steeda Underdrives , Strut Brace , HPM Lower K Brace , L /C Arms , U /C Arms , HPM PanHard Bar, K&N FRPK 2, GOODYEAR GT1 , MRT- H-Pipe , JLT VaporTraps , SLP-12'" Tips! , FRPP Shorty 1 5/8 Headers , Brembo D/S & PBR D/S Rotors ,FRPP Alum.DS ,Roys 3/8 Spacer , SVT Focus 255 pump SCTsw Chip PRO-DYNOjet NA 300.01hp /315tq (Auto) ,Innovate W/B ,Compucar Wet Kit (90jet) + Heater and E Gauge * 360 hp/385tq 12.5 -1/4 @112

09-17-2008, 09:55 AM	#6
Beefy Nugz Registered User Join Date: Jan 2007 Location: St. Louis, MO Posts: 531	Re: Vaccum leak/tunning issues? How do you know you need a new gasket with out taking it off and inspecting it, or have you already done this? I have noticed intake screws come loose before, maybe just take a torque wrench and check all the bolts. __________________ SOME KENNY BROWN CHASSIS AND SUSP. COMPONENTS 4:10'S MAC LONG TUBES WITH O/R-X AND MAGNA FLOWS. ORANGE BLAST P/P INTAKE W/ SPACER PSR K-MEMBER WITH A-ARMS AND COILOVERS P1SC 9LBS. 422HP - 390TQ 11'S AND COUNTING

09-17-2008, 01:54 PM	#7
ponygt65 Registered User Join Date: Jun 2004 Location: Madera, CA Posts: 7,687	Re: Vaccum leak/tunning issues? WHy not call the shop and tell them and ask if you can come in early to have a look at it? If it's something simple, should be quick and easy. One thing is for sure, I would not tune it the way it sits. It will end up being a waste. __________________ Current Stable: NO stangs.....DON'T F'ING remind me. Previous stangs: 2003 Mineral Grey Cobra Vert 1965 Factory GT K Code Coupe - mostly original and numbers matching. 14.9 (best) GONE BUT NOT FORGOTTEN!! 2003 MACh 1 AB - MINE!..SLP LM1s, PHP Spacer, and a CAI, that wont' stop whistling. 2004 MACh 1 DSG - PHP spacer, BOrla Stingers, K and N CAI, Tune, X-pipe, 1" 1-piece raised shaker...yadda yadda.

09-17-2008, 11:45 PM	#8
Furinox Registered User Join Date: Feb 2007 Location: DFW, TX Posts: 1,021	Re: Vaccum leak/tunning issues? well I took the gasket off and it was pretty mangled so I bought a new one today and it is sealing up even worse now. I cleaned both the upper and lower intake surfaces and found a small imprefection in the casting on the passenger back side. This is the same corner that would cause funny idle when spraying carb cleaner. The tuner at the shop said hes seen this one other time and they had to use silicone to get it to seal. So unfortunately I didnt get my tune today and I ended up using some silicone in the area that wouldnt seal. I'll find out in the morning if it did the trick or not.

09-18-2008, 12:08 AM	#9
rich1 AUTOMACHTIC Join Date: Oct 2007 Location: RTP/ N.C. Posts: 4,813	Re: Vaccum leak/tunning issues? Good deal ! __________________ UPGRADES...Tokico Illuminas Borla SS Catback , Steeda Underdrives , Strut Brace , HPM Lower K Brace , L /C Arms , U /C Arms , HPM PanHard Bar, K&N FRPK 2, GOODYEAR GT1 , MRT- H-Pipe , JLT VaporTraps , SLP-12'" Tips! , FRPP Shorty 1 5/8 Headers , Brembo D/S & PBR D/S Rotors ,FRPP Alum.DS ,Roys 3/8 Spacer , SVT Focus 255 pump SCTsw Chip PRO-DYNOjet NA 300.01hp /315tq (Auto) ,Innovate W/B ,Compucar Wet Kit (90jet) + Heater and E Gauge * 360 hp/385tq 12.5 -1/4 @112

09-19-2008, 01:16 AM	#10
Furinox Registered User Join Date: Feb 2007 Location: DFW, TX Posts: 1,021	Re: Vaccum leak/tunning issues? Ok, so get this. It wasnt the intake at all -- It was a bad o-ring on an injector right below the corner of the intake.

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