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Speed density idle question

  • Thread starter Thread starter 5.0aintslow
  • Start date Start date May 22, 2019
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5.0aintslow

Member
May 22, 2019
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Toronto Ontario
May 23, 2019
#21
  • May 23, 2019
  • #21
General karthief said:
i think you may be too young to catch the attempted humor.
but to answer your question is to remember how old those rubber lines are, some get hard and brittle and some rot and collapse so inspect and replace. Rubber grommets like the one for the pcv harden up and leak vacuum as well.
I find pulling the upper intake give you access to most everything you need to check.
Click to expand...
I promise you I’m not a 15 year old haha. I sensed sarcasm over humour so.. but yes, I’ll pull the upper off and check everything underneath. Thanks again !
 
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Boostedpimp

20+ Year Stangneter
May 8, 2003
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NJ
May 23, 2019
#22
  • May 23, 2019
  • #22
Vacuum is vital to a speed density car and your lines are what 19 or 20 years old.. I'd just replace what vacuum lines you have they are extremely cheap, cut to length and press on simple and could save you a world of head aches
 

5.0aintslow

Member
May 22, 2019
32
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Toronto Ontario
May 23, 2019
#23
  • May 23, 2019
  • #23
Boostedpimp said:
Vacuum is vital to a speed density car and your lines are what 19 or 20 years old.. I'd just replace what vacuum lines you have they are extremely cheap, cut to length and press on simple and could save you a world of head aches
Click to expand...
Thats where I think I’m gonna go with this yeah.
 

Rdub6

So while I wait to figure out my rear end issues
5 Year Member
Dec 29, 2017
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May 23, 2019
#24
  • May 23, 2019
  • #24
I was recently having issue with my ‘86. I thought I checked every vacuum line pretty good. Then I took my intake off to paint, and found a small hole in the line going to charcoal canister. Pulling that intake gave me access to everything. I would go that route as well!
 

5.0aintslow

Member
May 22, 2019
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May 23, 2019
#25
  • May 23, 2019
  • #25
Rdub6 said:
I was recently having issue with my ‘86. I thought I checked every vacuum line pretty good. Then I took my intake off to paint, and found a small hole in the line going to charcoal canister. Pulling that intake gave me access to everything. I would go that route as well!
Click to expand...
Did it?? That’s good to hear, glad you found your fix! Did you replace the intake manifold gasket while you were there? I may be full of stupid questions, but I’m new to this speed density stuff so bare with me ! Now I know for a fact my vacuum hose to the map sensor is toast, I’m out of town so I’m gonna wrap that line in electrical tape to see if that helps until I can get new hose.

Tonight I’m doing a full year down if I can.
 

General karthief

wonder how much it would cost to ship you a pair
5 Year Member
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May 23, 2019
#26
  • May 23, 2019
  • #26
5.0aintslow said:
I promise you I’m not a 15 year old haha. I sensed sarcasm over humour so.. but yes, I’ll pull the upper off and check everything underneath. Thanks again !
Click to expand...
it was humor, not sarcasm.
 

stykthyn

I want to measure mine. It doesn't look that tall.
15 Year Member
Jul 6, 2006
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#27
  • May 23, 2019
  • #27
Im 15 and a half
 

Rdub6

So while I wait to figure out my rear end issues
5 Year Member
Dec 29, 2017
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May 23, 2019
#28
  • May 23, 2019
  • #28
5.0aintslow said:
Did it?? That’s good to hear, glad you found your fix! Did you replace the intake manifold gasket while you were there? I may be full of stupid questions, but I’m new to this speed density stuff so bare with me ! Now I know for a fact my vacuum hose to the map sensor is toast, I’m out of town so I’m gonna wrap that line in electrical tape to see if that helps until I can get new hose.

Tonight I’m doing a full year down if I can.
Click to expand...

I had bought the upper to lower gasket before I took it apart, so I used the new one. Although when I took it apart, I probably could have reused the old.
I’d rather spend the few bucks extra for all new gaskets when I take something apart than to have to redo it when an old one leaks!

To answer your question, yes, changing the vacuum lines helped. I changed all of them at once, so I can’t say for sure if that one hole was the cause of ALL my problems or if some of the other old dried out lines were leaking too. Again, it was another small price to pay to change them all out and have peace of mind they won’t be leaking for quite some time!
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
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May 23, 2019
#29
  • May 23, 2019
  • #29
Smoke testing would be helpful here as well.

As mentioned, speed density cars are VERY sensitive to vac leaks as their fuel curve is based on manifold pressure. A leak will change this pressure and directly alter the fuel
 
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General karthief

wonder how much it would cost to ship you a pair
5 Year Member
Aug 25, 2016
27,856
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polk county florida
May 23, 2019
#30
  • May 23, 2019
  • #30
stykthyn said:
Im 15 and a half
Click to expand...
Now that's sarcastic!
 
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stykthyn

I want to measure mine. It doesn't look that tall.
15 Year Member
Jul 6, 2006
5,232
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May 23, 2019
#31
  • May 23, 2019
  • #31
General karthief said:
Now that's sarcastic!
Click to expand...
I show up when needed
 
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5.0aintslow

Member
May 22, 2019
32
4
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Toronto Ontario
May 23, 2019
#32
  • May 23, 2019
  • #32
For the hell of it, I pulled the map sensor hose while it was running and she died. Even though that hose has had its glory days, it still holds enough vacuum to keep it going, still gonna replace it. Now I’m gonna do the base idle set.

Also, anyone ever done any map to maf swaps? Just watched a couple vids, it doesn’t look that hard really, just getting the a9l and mafs
 

5.0aintslow

Member
May 22, 2019
32
4
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Toronto Ontario
May 23, 2019
#33
  • May 23, 2019
  • #33
Tps sensor also reads a solid 0.97, spec key on engine off is 0.95 and 1.00v soooo don’t think it could be tps
 

stykthyn

I want to measure mine. It doesn't look that tall.
15 Year Member
Jul 6, 2006
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May 23, 2019
#34
  • May 23, 2019
  • #34
Maf swap is extremely easy. Make sure its running perfect before hand so you you aren't chasing multiple issues afterwards
 

5.0aintslow

Member
May 22, 2019
32
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May 23, 2019
#35
  • May 23, 2019
  • #35
stykthyn said:
Maf swap is extremely easy. Make sure its running perfect before hand so you you aren't chasing multiple issues afterwards
Click to expand...
How much is it do you know? I’m from Toronto which sucks, guessing most of you guys r from the states huh? You got everything cheaper down there lol.

For an a9l, mafs wiring and looming I’m looking at 600$ cdn , maybe 450$ US?
 

5.0aintslow

Member
May 22, 2019
32
4
18
Toronto Ontario
May 23, 2019
#36
  • May 23, 2019
  • #36
Just did base idle set, when I unplugged the iac, it stalled. Turned it in half turn to see if that did a thing, sure enough it did a thing. Didn’t like it at first, had to feather the throttle a bit, but the computer picked up on it and kept the revs steady at 700 with the iac still off. Shut it off, pulled both terminals and now I’m playing the waiting game.

Gives me time to contemplate weather I’m going to mad swap it
 

stykthyn

I want to measure mine. It doesn't look that tall.
15 Year Member
Jul 6, 2006
5,232
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May 23, 2019
#37
  • May 23, 2019
  • #37
Shouldn't stall. Will want to but should hold and not die.
 

stykthyn

I want to measure mine. It doesn't look that tall.
15 Year Member
Jul 6, 2006
5,232
2,652
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gainesville
May 23, 2019
#38
  • May 23, 2019
  • #38
5.0aintslow said:
How much is it do you know? I’m from Toronto which sucks, guessing most of you guys r from the states huh? You got everything cheaper down there lol.

For an a9l, mafs wiring and looming I’m looking at 600$ cdn , maybe 450$ US?
Click to expand...
Why are you wanting a maf? Unless you're changing the cam/valve train you would be better off with SD
 

5.0aintslow

Member
May 22, 2019
32
4
18
Toronto Ontario
May 23, 2019
#39
  • May 23, 2019
  • #39
stykthyn said:
Shouldn't stall. Will want to but should hold and not die.
Click to expand...
Really? As soon as I unplugged it it died. Didn’t try to stay going.
stykthyn said:
Why are you wanting a maf? Unless you're changing the cam/valve train you would be better off with SD
Click to expand...
Mafs less headaches. Everybody who I’ve talked to about it says it’s just issues.
 

stykthyn

I want to measure mine. It doesn't look that tall.
15 Year Member
Jul 6, 2006
5,232
2,652
223
gainesville
May 23, 2019
#40
  • May 23, 2019
  • #40
5.0aintslow said:
Really? As soon as I unplugged it it died. Didn’t try to stay going.

Mafs less headaches. Everybody who I’ve talked to about it says it’s just issues.
Click to expand...
Having done the swap i would beg to differ. If it solves an existing SD issue you either had a bad ecu, wiring, or vacuum lines. All of which can be solved much more easily with some simple diagnostics and 20 dollars in supplies.
 
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