Accufab tb causing peeo drivability

[00stang37]

Accufab tb causing poor drivability

I installed an accufab 75mm tb and c&l plenum today and the drivability is horrible. The idle hangs around 1200rpm and it has multiple surge issues. While driving the rpms spike to 2000-2500rpm and hang there for a few seconds everytime the clutch is pressed in. The car will also drive itself in 3rd gear at around 30mph with my foot off the throttle until I hit the brakes. At idle if the ac is turned on it'll still idle around 1200rmp but as soon as the ac is turned off, the rpms jump to around 2000 for a few seconds. All the connections are tight and all vacuum lines are connected.

Anyone have any I ideas on what the issue could be? It drove fine yesterday with the stock tb and plenum.

I have reset the ecu by removing the battery for 30+ minutes and letting the car relearn the idle 3 times and still no change.

This video shows the high idle and rpm hang. I blipped the throttle to what would take me to about 1000-1250 rpms from a normal 750rpm idle. It looks like im holding my foot on the throttle but it was only a quick blip.

 

[StiEtr]

Vacuum leak?

 

[KLeech]

TPS could be going bad. Check the voltage it should be .99. Sometimes it may need loosened up and wiggled a little to get it in a better spot.

Return spring could be wore out not wanting to shut the throttle body the whole way as well, make sure it's fully closing under no throttle.

You did get all the vacuum lines hooked back up and correctly right?

 

[blacksheep-1]

+1 on the vacuum leak, the TB (by itself) should not cause a problem. IF you swapped over the TPS make sure it's indexed properly., clean out the idle control motor while you're there..should be good to go.

 

[01SilverGt]

Like they said make sure tps sensor is set to .99 to 1volt and your tb screw should practically be set all the way shut so its barely touching the tb.

 

[00stang37]

Ill try cleaning the iac and checking the voltage on the tps. As far as the idle st screw, it's a new tb shipped from American muscle and just out of the box I could see a thin gap where the blade wasnt fully closed against the body

 

[00stang37]

Ended up cleaning the iac, checking the voltage and tried various positions. I was able to get the car idling at 1000rpms but it still surged bad with any little touch of the throttle. I called accufab but no answer. Called American muscle and their tech support told me to try talking to a tuner. I was told it is more of a tuning issue and the 75mm tb is too big for my current set up and even a new tune will help slightly but the drivability issues will still be there. I reverted the tune on my car to stock and still no change at all.

Anyone else have any ideas on what the issue could be? All lines are connected and all bolts are tightened down good

 

[Stanger00]

You sure you didn't remove the gasket on the manifold by accident?

Sounds like a vacuum leak like the others said.

 

[KLeech]

You sure you didn't remove the gasket on the manifold by accident?

Sounds like a vacuum leak like the others said.

Yeah I was thinking the same thing. This is the exact reason I don't talk to any of those tools at American muscle. You don't need a freaking tune to get a throttle body to function correctly when you're cars computer has the ability to learn, you put a throttle body on not a supercharger for Pete's sake. If you're having that bad of drive ability issues there has to be a problem such as a missing gasket or something along those lines.

 

[blown98riored]

I had same issues on a Accufab TB. Tried everything thats been mentioned in this thread, with no fix to the problem. Long story short, It was the throttle blade not being centerd up. The way it is cetered up to the body... Loosen the star bolts holding the blade on to the pivot pin. NOT OFF!!! just loosin them enuff to where u can notice the blade shifts. It might move 1/2 cm(+/-). Once they are loose, move the throttle like u are going WOT, let off the throttle and tighten the bolts back. NOT SURE OF THE TORQUE SPECS FOR THE STAR BOLTS BUT IT ISNT MUCH!!

This fixed the idle from hanging up @1200rpm's. All in all it was the blade in the throttlebody was letting too much air by the blade.

GOODLUCK!!:shrug:

 

[blown98riored]

I have built 4 clones from V6 cars.. 3 to 4v setps and 1 to PI 2v setup. And I have ran across this problem a couple of times. Even on one of my own cars. If u are still having problems afte trying to center up the TB Blade send me a pm and maybe we can get a datalog or something and I will look at it and try to get you fixed up...And if it is possible, get a pic of the the TB looking in towards the blade.

 

[00stang37]

I unplugged the iac while it was idling and it didn't change anything. I sprayed maf cleaner around the spots I would expect a leak and came up empty handed on that also. Since its already apart again I went to ford and ordered all new gaskets.

Here's some pictures on the tb:

 

[blacksheep-1]

Just for grins, was the A/C cycling on and off during all of this? Because low freon (or a bad switch) can cause idle issues as well...probably not the cause, but while you're there.

 

[Kline12]

I have had a similar issue as well. My rpms hang when trying to shift gears or after a good rev. They are veryyy slow to come down. I have replaced the IAC valve completely as well as tried the little trick with making a gasket with a smaller hole in it to restrict air through the IAC with no prevail. I am going to watch this thread and try some of your suggestions to see if they help at all. I really have no idea what is causing it.

EDIT: I also have a stock throttle body. So I'm not sure if it would be related to anything like that with my car like it is the OP's.

 

[00stang37]

Just for grins, was the A/C cycling on and off during all of this? Because low freon (or a bad switch) can cause idle issues as well...probably not the cause, but while you're there.

Ac runs fine and ice cold. No cycling on and off.

 

[musclemustangcb]

My bbk 75 did that.....it was hanging up inside. The blade moved side to side.....I sent it back and got a accufab.....LOL issue solved.

 

[00stang37]

My bbk 75 did that.....it was hanging up inside. The blade moved side to side.....I sent it back and got a accufab.....LOL issue solved.

So I should send back the accufab and try the bbk? Haha....hopefully it was just a bad gasket and not the accufab but ill find out once I put it back together tomorrow. The tb blade looks fine to me but I could be wrong. It actuates and returns to closed smoothly

 

[00stang37]

All new gaskets from ford and triple checked for vacuum leaks with no luck. Ended up adjusting the stop screw and had to change the screw quite a bit but now it idles around 750-800rpms. The rpms drop slightly when comming to a stop and the rpm's drop slowly but simar to the stock set up.

How's this for an idle?