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what am I doing wrong, throttle body replacement

4K views 36 replies 8 participants last post by  145566 
#1 ·
I'm no mechanic but putting a throttle body on is not hard surely but what am I doing wrong.
Put a 75mm throttle body and plenum on my 96 2 valve, drove to the shop and up pop's engine light. I've disconnected the battery and did the whole reset thing but drove her again up pops the engine light. Checked and rechecked everything, so tonight I've reinstalled the 65mm factory throttle body leaving the new plenum and going fine. Only thing I miss is the throttle reponse from the 75mm. Help can someone tell me how I can get the 75mm to work or is stang just not keen on the bigger airflow?.
 
#5 ·
This.

These cars don't require any special tuning for throttle body/plenum upgrades, although doing so will maximize the benefits of said upgrade. Other than that you should not be getting any check engine light. I ran mine for years without a tune and had absolutely no issues, and many here could probably say the same thing.

S197's on the other hand (2005+ Mustangs) do require tuning for even so much as a CAI, but that's neither here nor there....

So, if you can post what code you were getting then we can go from there. Not very important, but may as well mention what tb/plenum combo you went with.
 
#8 ·
Bull S. A larger TB isn't letting in enough air to cause the sensors not to read properly. After the air passes the tb it gets crammed back down again once it reaches the heads. TB's don't make power, they "support" it. I bet he has a vacuum leak after installing the plenum.



Pickers- One step of above a hoarder.
 
#6 ·
Incorrect. 70mm is the highest you should go on stock motor no matter what plenum. 75mm is a setup when you want to get the max air for throttle response with a lot of horsepower. 75mm TB's do require a tune. Anything that messes with air/fuel ratio is going to throw off a sensor. Trust me, it's the TB. It needs a tune.
 
#13 ·
This is not true. These cars do not need a tune after a plenum/TB install. This is well know. I ran almost full bolt ons on my car for a long time on the stock tune and had no issues.

It is also well known that a 75mm will actually produce a tad more HP than a 70. Enough to notice? No...but to say a 75 is too big is not true either.

To clear everything up...a tune IS NOT REQUIRED with what the OP did. It's anyone's guess what code it was...

I love the Internet...
 
#7 ·
Cheers guys, im not sure of the code as i don't have the equipment for telling me fault codes.
I'm from Christchurch New Zealand and finding anything for 96 mustang is near impossible in fact it is impossible and no one really what's to help because they all believe I'm wasting my time.
I would love to get a tune or even a self timer but the only tuner wants $2500.
So I'm trying to do what I can myself.
Even importing parts from U.S. is expensive by the time you add shipping and taxes.

But man many thanks for the help
 
#9 ·
Here's what ya do MaddDog. Order a cheap obdii code reader via Amazon or the likes and report back w the code. http://www.amazon.com/gp/aw/d/B001LHVOVK/ref=mp_s_a_1_2?qid=1448352374&sr=8-2&pi=SY200_QL40&keywords=ford+obdii+code+reader&dpPl=1&dpID=51mQNq2INGL&ref=plSrch
Does it run worse or do you just have a light?
Hate to burst your bubble but the 75mm is too big anyway for your current setup, you were better off w the stock one as far as performance goes.
Pickers- One step of above a hoarder.
 
#12 ·
It was most likely a a TPS issue if the symptoms went away when putting the stock TB on. Def get a cheap OBD2 scanner to read codes.

Next move to the US where parts are cheaper...
 
#14 ·
Sorry I've been switching back and forth through the s197 and new edge's and I forgot that the older ones don't require a tune for the TB/CAI like the 3v's. Like the guy above said, I've never heard of a CEL coming on from a correctly installed TB. TPS's are fragile as **** and need to be handled correctly or it will throw a light. So make sure everything is a-ok. But 75mm... Too big man. But hey, that's all you if you want it. Sorry guys for the misconception!
 
#16 ·
What brand is the TB? Does it bolt down flush?
When you put the tps on the 75mm tb did the bolt holes line up pretty well or did you have to twist the tps a little one way or the other to screw it down? The tps is non adjustable, it's either in range of its not.



Looks like I picked the wrong week to quit sniffing glue.
 
#17 ·
what I've read, most 75mm TB's on these models, the TB doesn't line up with the original holes/the holes are too small. What 90lxwhite has stated, does it bolt down flush? TPS's are non adjustable like stated and if it's off even a cm, it will throw a code. And hopefully his week is going a bit better after he quit sniffing glue.
 
#18 ·
It's the bore of the plenum that's too small, 70mm is the max that will fit. Although I've heard if you're handy with a Dremel that you can make the stock plenum accept a 75mm tb.

But that's neither here nor there, iirc the OP upgraded both. And I'm not getting into the 70 vs 75 debate again (saw a post in here somewhere that suggested I should), there's enough competent information out there on the subiect already for anybody who feels like looking and due to the invention of Facebook I have resolved myself to not arguing with idiots.

90lxwhite - try exhaust fumes if you're jonesing, it will increase your chances of long term quitting success.
 
#19 ·
OP, reinstall the tb/plenum so the dtc pops up again and get the code checked, report back. Until then it's just gonna be us talking about nonsense and possibly irritating the forum mods.
 
#23 ·
Hey guys I installed a cheaper tb an plenum from sr performance. Didnt think it would be the bad as seen some dude on you tube install them easy as with good gains. As I stated throw the factory tb bad on not the same response as the 75mm but I don't no ahh. I'm listen to you guy's day 75mm to big just not sure what to do really.
All the bolt holes lined up perfect for everthing so nothing needed modifying.
Just new to the whole mod thing and trying to prove these knobs here in Christchurch wrong really.
 

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#29 ·
Yea sorry using my phone to view and write the messages, keeps predictive texting.

The SR Racing products bolted together perfect, also bolted to the manifold with no problems. No sealant was used either only the proper gaskets.

Just don't think the car likes the extra air, just going to find a mechanic who's willing to look at it.

Cheers for all help guys.

Lol if only she went as fast as the rear wing.
 
#30 ·
There's pretty much the same amount of air going into the heads as before, now it's just going in kinda like if it were going through a funnel. You're not really gonna make anymore power until you open the small end of "the funnel," which are the cylinder heads, or you force the air through the funnel.


Looks like I picked the wrong week to quit sniffing glue.
 
#32 ·
Well hey! Look at that! Good catch, that's definitely a vacuum leak right there.

You should be able to just pull the nylon hose out of the rubber fitting. I can't remember if they're glued in place or not. You could also use a small piece of rubber hose to repair it, as long as the tubing fits snugly inside.
 
#36 ·
Those little red lines from what I have figured out go to two different places, (1) the hvac controls and (2) the EGR dpfe sensor (controls EGR operation).

I would go with the above suggestion of using a short piece of rubber hose to fix the broken connection. May also need a small zip tie on either end if it doesn't fit over the nylon hoses snug enough.
 
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