Engine GT40 Tubular Intake Install Problems....

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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Two things come to mind, gasket leaks, I had an issue with the lower intake to head gasket leak along the bottom at the lifter valley, also the plate between the throttle body and the intake can leak on the inside but you have the coolant tubes hook up so that is prolly good.
Do you have the stock mass air meter? You still have the 19lb injectors so the stock meter will work just fine.
There is this:http://forums.stangnet.com/showthread.php?t=698148
that has resolved many idle issues, just follow directions,
You removed the charcoal canister? Why?
 
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daredevil95

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Feb 20, 2011
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Thanks for the response, I'm going to do another smoke test today, check for codes again and yes, I was also thinking of the lower intake gaskets, I'm goin to play with this for one more day then disassemble both intakes and start over....I installed lower intake by myself so, it may of slipped? Therre is no water in the oil so, thats a good thing! lol...something positive! I remove the canister becuase it was hanging and cracked badly when I bought the car so, that's why that's gone. From what I read, it shouldn't matter except for some gas smell but, that hasn't happened yet. I should install a one way valve on the line. Anyways, hope something good happens today!?? Thanks
 

Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
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I’m leaning vacuum leak here. With the GT40 intake being the only thing that has changed, there’s no reason for it to behave that way. Car should easily be able to idle with that intake.

I’d unplug the IAC and open up the throttle stop screw a tad. If the car still won’t idle or is surging, I’d really suspect one of the lower gaskets may have slipped.

Before pulling it apart I’d probably investigate with a smoke machine and cap off some vac lines but this is what I’d suspect.
 
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Rdub6

So while I wait to figure out my rear end issues
Dec 29, 2017
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Sounds like you probably have checked these boxes checked already, but the intakes are slightly different with the piping/hoses coming out of the bottom of the upper. You’re sure everything is the same as it was with the original.
Sure seems like a vacuum issue to me as well.
Either way…… keep us posted on the results.
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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I've used studs in the intake bolt holes to keep everything lined up and it makes lowering the intake into place so much more precise.
I also used the cobra intake gaskets, I believe Explorer gaskets are the same.
 
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daredevil95

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Feb 20, 2011
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Hi, thanks for all the replies! I did the smoke test again, still getting smoke out of the EGR, TPS & TB butterfly lower shaft. That is, with the opening of the throttle body taped off and 2nd test with the CAI on, no leaks. I'm thinking the smoke leaks are normal based off what I read online but, I'm no expert. Now, the car finally ran for a little while, very erratic LOL...I have a bunch of codes finally! 10, 11, 40, 21, 94, 44, 33 & 18....this was the numerical order displayed on the code reader. I just got home so, I'm going to look up these codes and see what they are, seems like something is unplugged but, I'm certain everything is connected. Tomorrow I'll try stock MAF and TB? and whatever else anyone recommends?? Thanks for the help!


View: https://youtu.be/WA2xVJpFD0M
 

Rdub6

So while I wait to figure out my rear end issues
Dec 29, 2017
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Have you tried to drive the car and let the computer “learn” the car again after all the changes? Or have you just been starting it in the garage?
 
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daredevil95

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Have you tried to drive the car and let the computer “learn” the car again after all the changes? Or have you just been starting it in the garage?

About 2 weeks ago; the car ran great that one time. I drove it about 5 miles and everything was great, I parked the car and about half hour later, I go to park car in garage and it started this BS surging stalling again....hasn't ran correct since then (2 weeks ago).
 

rednotch

Founding Member
Aug 14, 2000
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Cars running the koer self test with the scanner plugged in.... Its trying to hold a high idle threw the iac so definitely an issue. How is the vaccum run to the egr it looks teed off in the video, and if its getting constant vaccum holding the valve open its not going to want to idle, if its not off the solenoid cap it.
 

daredevil95

New Member
Feb 20, 2011
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Hi, good news to report today, I followed the advice here and removed the vacuum line from the EGR and the car almost idled good.....almost, I then rechecked the TPS and this time I was getting conflicting readings so, I'm thinking my old TPS was on the fritz, worked sometimes then wouldn't work. I swapped the TPS and we're good....that's where the video starts off at below. I want to say thankyou for all the help I got during these past couple days! Thanks again! Gene


View: https://youtu.be/fJTEooevSM8
 

Rdub6

So while I wait to figure out my rear end issues
Dec 29, 2017
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Glad to hear you got it running well! Just watched your video!
Other than it looks way cooler…… there any noticeable difference yet with the GT40?
 

Boostedpimp

15 Year Member
May 8, 2003
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I would toss a vacuum gauge on the car and see what you get and the fact that it ran fine before the intake manifold swap tells me it is most likely a slipped gasket. If the vacuum reading comes back low I would order some more gaskets and pull the upper and lower off and see how bad the intake to head gasket slipped on you during install.
 

Praetorious

Member
May 22, 2020
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Glad its running better,i have a 89 and a 91 and between both cars i have had just about every intake that has been designed for a 87 to 93 Mustang on both cars, not sure why i just loved changing intakes back in the day,lol, my buddies used to tease me,"what intake you got this week??

I had issues for years with the famous idle thing,and when i say years i mean years,sometimes they ran good , most of the time idle issues ect etc, on my 91, the last intake i put on was the famous tubular,gave me nothing but problems and although i had my heart set on it because (have to admit it) that intake just looks bad ass,i could care how well or not well it flows,lol , it was gonna go on my car one way or another, you know what solved all my problems with both Mustangs and i mean solved them completely? about 20 dollars in hose clamps

What had happened is the original intake came with little clamps all over the place for all the miriad of hoses that go on a intake, well since ive had my cars since i was a young uneducated (trial and error) gear wrencher back in the late 80s early 90s i threw those claps away or they got lost, who needs them? i mean the hoses go in semi tight,that should be good enough,right?? NO.

Buddy after putting hose clamps EVERYWHERE on both my Mustang in every hose i could find both of my cars have been running for the last several years impeccably, idling problem?? have no idea what that is, rock solid needle, believe me, i did the smoke test, i even got me a stethoscope,no vacuum leaks anywhere i could find, oh they are there, you just can see them or hear them,they can be tiny sometimes,anyhow that was my cure, figure i would share it, might not be the solution for everyone but it worked for me.
 
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rednotch

Founding Member
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I leave the egr alone on mine other then plugging the intake ports at the lower or using non egr heads. I.E let the computer do its thing but there is no flow from the valve.... even if there is flow its not going to hurt anything when its working correctly. They code 33 from the running self test when you left the reader plugged in showed the valve wasn't responding so it wasn't getting vaccum correctly, you could fix that a lot cheaper then a chip if you want, there's nothing radical on the car that would need a locked in tune anyway and a chip to just delete that is kind of pointless.
 
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7991LXnSHO

wanna catch the space herp
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I would toss a vacuum gauge on the car and see what you get and the fact that it ran fine before the intake manifold swap tells me it is most likely a slipped gasket. If the vacuum reading comes back low I would order some more gaskets and pull the upper and lower off and see how bad the intake to head gasket slipped on you during install.
BA3EB2F8-B974-4A28-B519-0774D4877DC3.jpeg

This might help determine the gauge readings
(Source jrichker)
 
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daredevil95

New Member
Feb 20, 2011
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The car started and ran good today. No vacuum hooked up tp EGR valve. I ordered a BAMA 4 bank eliminator chip today from American Muscle. Matched it up to what I have done to my car plus, EGR delete. So, this should solve that pesky EGR messing with my idle! lol. Not sure what to do with blocking off lower intake, explorer intake? or leave it as is. See how it goes. It would of been cheaper to buy the EGR solenoid but, we installed one of these BAMA chips on my buddy's 93 and it truly made a world of difference. Has great idle and the burn pattern on the spark plugs is excellent so, $280 bucks later....I'll give it a try?
 

daredevil95

New Member
Feb 20, 2011
20
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Hi, I got a question, I have not yet received the BAMA tune with EGR delete. So, today I took the car for a long ride, EGR is still connected but, vacuum line not hooked up. Car idles great but, while driving the car feels like it is low on power and has a stumble, kinda like a cylinder is not firing but, not as severe as a non firing cylinder. The EGR is still plugged into harness with no vacuum. EGR solenoid is broken. Will this cause the car not to drive smoothly or should I be looking at something else?