Plugged holes in back of heads, then car wouldnt start, help!!!!!!! - Mustang Evolution

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Old 09-02-2012, 10:33 PM   #1
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Plugged holes in back of heads, then car wouldnt start, help!!!!!!!

so, i am new to this forum, and if i can get any help on this, i would greatly appreciate it. I have a 1995 Mustang GT with an automatic transmission. The only mods i have made to the car are BBK equal length shorty headers, BBK midpipe w/cats, flowmaster exhaust, iridium tipped spark plugs w/ 8.5 mm plug wires, summit racing distributer cap and ignition coil, bbk cold air intake, and bbk pre-calibrated maf sensor for 19lb injectors. i removed the air/smog pump and put a pulley in its place, when i bought the car there was no hoses or anything plugged in to it so i just pulled it off. i had underdrive pulleys, but took them off because the battery wasnt being charged as fast as it should have been. So i had pulled some codes from the car and i got code 312 after running both the koeo and koer tests, and it said something about thermactor air misdirected...i read something online about plugging two holes in the back of each cylinder head with the same kind of screw used to secure the headers to the heads. i read that if they werent plugged, it would cause that code to come up, and could cause exhaust leaks, etc. so i plugged the holes. i went to start the car up, and it would die immediately unless i held down the gas and brought the rpm's up to 2000, 3000, etc. it sounded terrible, so i pulled the screws back out, went to start the car up, and it still sounds terrible and dies almost immediately, without any check engine light. i dont know why, but something told me to unplug the connector to the maf sensor. once i do, the car starts up and sounds decent, but the check engine light comes on (obviously for the maf being unplugged). while i was plugging and unplugging the holes in the back of the heads, i found a hose that was disconnected, it was right behind the upper intake manifold. i have no idea where it goes, or where it comes from, but its connected to a plastic joint that another hose connects to, and runs into the fender in the back of the engine bay, passenger side, right below where the connector is for plugging in a code reader. sorry for the long post, but i wanted to make sure i gave all the information i could. HELP IS APPRECIATED!!!!!!!!!!!
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Old 09-02-2012, 10:48 PM   #2
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Quote:
Originally Posted by Bigblue85
so, i am new to this forum, and if i can get any help on this, i would greatly appreciate it. I have a 1995 Mustang GT with an automatic transmission. The only mods i have made to the car are BBK equal length shorty headers, BBK midpipe w/cats, flowmaster exhaust, iridium tipped spark plugs w/ 8.5 mm plug wires, summit racing distributer cap and ignition coil, bbk cold air intake, and bbk pre-calibrated maf sensor for 19lb injectors. i removed the air/smog pump and put a pulley in its place, when i bought the car there was no hoses or anything plugged in to it so i just pulled it off. i had underdrive pulleys, but took them off because the battery wasnt being charged as fast as it should have been. So i had pulled some codes from the car and i got code 312 after running both the koeo and koer tests, and it said something about thermactor air misdirected...i read something online about plugging two holes in the back of each cylinder head with the same kind of screw used to secure the headers to the heads. i read that if they werent plugged, it would cause that code to come up, and could cause exhaust leaks, etc. so i plugged the holes. i went to start the car up, and it would die immediately unless i held down the gas and brought the rpm's up to 2000, 3000, etc. it sounded terrible, so i pulled the screws back out, went to start the car up, and it still sounds terrible and dies almost immediately, without any check engine light. i dont know why, but something told me to unplug the connector to the maf sensor. once i do, the car starts up and sounds decent, but the check engine light comes on (obviously for the maf being unplugged). while i was plugging and unplugging the holes in the back of the heads, i found a hose that was disconnected, it was right behind the upper intake manifold. i have no idea where it goes, or where it comes from, but its connected to a plastic joint that another hose connects to, and runs into the fender in the back of the engine bay, passenger side, right below where the connector is for plugging in a code reader. sorry for the long post, but i wanted to make sure i gave all the information i could. HELP IS APPRECIATED!!!!!!!!!!!
just a tip. maybe paragraphing the different things would help us decipher the full post to best potential. but the more info the better.

the heads need to be plugged with a 5/8 11 short bolt 1/2-3/4" long. but i dont think those hose being plugged or ot wold cause a no start issue.

a vacuum leak, which is probably the hose you describe could definitly be your issue. your gonna need to locate were it goes.

i think the heater controls run into the fire wall in that area and may have a vacuum tree somewhere there.

im not sure if this helped yet. i attached a pic of the vacuum tree
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Old 09-02-2012, 10:48 PM   #3
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Re: Plugged holes in back of heads, then car wouldnt start, help!!!!!!!

I don't know what kind of holes you plugged, but the smog tube holes in the back of the heads requires a 5/8" x 11 thread short bolt, not the small 3/8" bolts used on the headers. Removing the smog pump and EGR requires an EGR Eliminator to keep the CEL light off. You can find them on eBay or make your own. There is a diagram in the Superchargers & Turbos sticky thread I believe.

Sounds like you need to find a diagram of the vacuum hoses and make sure they are all connected properly and if unplugging your MAF makes it run better then you either need to clean the MAF sensor or replace it.


If you do not already have one, I suggest you get a Chiltons Manual specifically for your car with the vacuum and wiring diagrams in it.


P.S. Posting long threads is ok, but try to include punctuation and paragraphs so it is easier to read and understand if possible.
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Old 09-02-2012, 10:51 PM   #4
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also with the maf unplugged. its sending the ecu into an open loop. since it runs better when doing that, whatever the issue is. is getting bypassed because of that. for instance an electrical connector of vacuum to an essential part is not being used because of the open loop.

---------- Post added at 10:51 PM ---------- Previous post was at 10:51 PM ----------

Quote:
Originally Posted by Trojan Horse
I don't know what kind of holes you plugged, but the smog tube holes in the back of the heads requires a 5/8" x 11 thread short bolt, not the small 3/8" bolts used on the headers. Removing the smog pump and EGR requires an EGR Eliminator to keep the CEL light off. You can find them on eBay or make your own. There is a diagram in the Superchargers & Turbos sticky thread I believe.

Sounds like you need to find a diagram of the vacuum hoses and make sure they are all connected properly and if unplugging your MAF makes it run better then you either need to clean the MAF sensor or replace it.

If you do not already have one, I suggest you get a Chiltons Manual specifically for your car with the vacuum and wiring diagrams in it.

P.S. Posting long threads is ok, but try to include punctuation and paragraphs so it is easier to read and understand if possible.
wow. that was about an identical post! lol
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Old 09-02-2012, 10:55 PM   #5
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Re: Plugged holes in back of heads, then car wouldnt start, help!!!!!!!

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Originally Posted by dreamstang View Post
also with the maf unplugged. its sending the ecu into an open loop. since it runs better when doing that, whatever the issue is. is getting bypassed because of that. for instance an electrical connector of vacuum to an essential part is not being used because of the open loop.

---------- Post added at 10:51 PM ---------- Previous post was at 10:51 PM ----------



wow. that was about an identical post! lol
Good point and yes it was almost identical and at the same time even.
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Old 09-03-2012, 08:24 PM   #6
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So, there are two plugs underneath the upper intake manifold, facing the firewall. One of the plugs was without a hose, and it was the same type of plastic connector that i saw on the hose that i found not connected to anything. Hooked them up, put some heatshrink to secure it in place, and it started up. Thanks for the help, guys. Now i can drive to work in the morning.
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Old 09-03-2012, 09:16 PM   #7
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Re: Plugged holes in back of heads, then car wouldnt start, help!!!!!!!

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Originally Posted by Bigblue85 View Post
So, there are two plugs underneath the upper intake manifold, facing the firewall. One of the plugs was without a hose, and it was the same type of plastic connector that i saw on the hose that i found not connected to anything. Hooked them up, put some heatshrink to secure it in place, and it started up. Thanks for the help, guys. Now i can drive to work in the morning.
You're welcome and glad you found the problem.
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