Problems after C&L Plenum and Accufab 75mm T/B install... NEED HELP!!!

03gtmustang

New Member
May 26, 2003
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Northern Va
I installed my plenum and t/b last night, but didnt take it out until this morning. When I turned it on I realized that the idle was jumping a little and not very smooth. I figured this was normal and would go away by tomorrow after I drive it a little. Well today its only gotten worse and I cant seem to fingure out why. Ive checked all my valves to make sure they were tight along with my botls. Do I need to do anything to my idler valve? If so which one is that and what do I need to do. I also disconected the battery to reset the computer but that didnt seem to help. I have the superchip microtuner which I changed the octane to 93 instead of the stock 87. Ive been running 93 for awhile with the chip and havent had any problems. I dont know if changing the octane affected the timing. Could the octane or timing have any effect on my idle. The idle is so bad that my engine shakes and causes the whole car to shake. Maybe my air/fuel ratio is off and im running lean? I havent gotten on it at all really since the install, I just brought it up to 4-5k and can feel a difference. Can anyone help me?
 
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Re-check all of your bolts and hoses to make sure they are all properly secured. Then, loosen your TPS a little and play around with it a little with the car on (just loosen the bolts enough to be able to move it around a little back and forth.) There isn't much movement, but move it until the idle settles down. (Hopefully it will.)

Question - did you install the C & L MAF at the same time as the plenum/TB? If so, put your stock MAF back on and see what happens if adjusting the TPS doesn't help.

Also, like the instructions from Accufab say, "Do not adjust the idle screw - it's preset from the factory."
 
BMan5150 said:
Re-check all of your bolts and hoses to make sure they are all properly secured. Then, loosen your TPS a little and play around with it a little with the car on (just loosen the bolts enough to be able to move it around a little back and forth.) There isn't much movement, but move it until the idle settles down. (Hopefully it will.)

Question - did you install the C & L MAF at the same time as the plenum/TB? If so, put your stock MAF back on and see what happens if adjusting the TPS doesn't help.

Also, like the instructions from Accufab say, "Do not adjust the idle screw - it's preset from the factory."

Which one is the TPS. I just disconnected everything and reconnected it, but nothing changed. I installed the MAF a little while before the tb and plenum. Maybe about a month or so ago.
 
The TPS is short for "Throttle Position Sensor". As it's name suggests, it's located on the throttle body and tells the engine management system what the position of the throttle plate. You should have installed two new bolts that came with the new throttle body when you swapped the TPS to your new throttle body. Try rotating it like I posted and report back.

Just for kicks, double-check your MAF connection again and make sure it's secure.

Did you mess with the idle screw at all? If not, good!

One other thing - did you use the new IAC gasket supplied in the Plenum kit? Or did you perhaps forget to install the gasket (even the old one)? This would cause a vacuum leak and idle problems.
 
BMan5150 said:
The TPS is short for "Throttle Position Sensor". As it's name suggests, it's located on the throttle body and tells the engine management system what the position of the throttle plate. You should have installed two new bolts that came with the new throttle body when you swapped the TPS to your new throttle body. Try rotating it like I posted and report back.

Just for kicks, double-check your MAF connection again and make sure it's secure.

Did you mess with the idle screw at all? If not, good!

One other thing - did you use the new IAC gasket supplied in the Plenum kit? Or did you perhaps forget to install the gasket (even the old one)? This would cause a vacuum leak and idle problems.

I checked my MAF and the connection is good. And nope I didnt mess with the idle screw. And I did use the new gasket for the plenum. All together there should be two gaskets right?
 
Okay, I just messed with the TPS and it made it worse. I think that is the problem though. I didnt mess with it that much because I dont want to piss off my parents, but I think I just need to mess around with it for a couple minutes and find the right position. When I tried to take that thing off the stock T/B it was pretty much impossible to get off. I ended up stripping the screws and had to cut off the heads with a dremel tool. Maybe Ford doesnt want people messing with it just for this reason.
 
03gtmustang said:
I checked my MAF and the connection is good. And nope I didnt mess with the idle screw. And I did use the new gasket for the plenum. All together there should be two gaskets right?


Actually, in your case, you might have seen three: Yeah, I believe there are three. A new gasket for inbetween the TB and Plenum, one for the IAC, and one for the EGR.

The reason I didn't have three to work with/install is that my Accufab TB came pre-assembled to the Accufab Plenum.

So, did you remember to install all three gaskets? Might want to check the IAC and EGR gaskets to make sure you installed the new one provided by the C & L - unless they didn't provide you with one. Honestly though, I think you could re-use the old ones and it would be just fine.
 
03gtmustang said:
Okay, I just messed with the TPS and it made it worse. I think that is the problem though. I didnt mess with it that much because I dont want to piss off my parents, but I think I just need to mess around with it for a couple minutes and find the right position. When I tried to take that thing off the stock T/B it was pretty much impossible to get off. I ended up stripping the screws and had to cut off the heads with a dremel tool. Maybe Ford doesnt want people messing with it just for this reason.

Glad it looks like you found the problem. You should just go pick-up a new TPS at autozone - they are only $30-ish I believe.

Good luck - hope you fix it!
 
BMan5150 said:
Actually, in your case, you might have seen three: Yeah, I believe there are three. A new gasket for inbetween the TB and Plenum, one for the IAC, and one for the EGR.

The reason I didn't have three to work with/install is that my Accufab TB came pre-assembled to the Accufab Plenum.

So, did you remember to install all three gaskets? Might want to check the IAC and EGR gaskets to make sure you installed the new one provided by the C & L - unless they didn't provide you with one. Honestly though, I think you could re-use the old ones and it would be just fine.

Actually, now that I think about it I remember putting 3 in there. Ill mess around with the TPS some more and if that doesnt work then I guess Ill pick up a new one. Thanks a lot for your help.
 
Well I turned my car on this morning to leave for school and it stalled out after being on for about 20-30 sec and it was still in Park (auto tranny). But believe it or not the idle has improved. It drives fine until I come to a stop for about 30-45 sec then the idle goes from the normal 500 down to 300 then jumps up to about 700. So it jumps pretty bad from 300-700 and feels like its going to stall. Then when I put it in N it idles fine. Should I just keep on messing with the TPS?
 
03gtmustang said:
Well I turned my car on this morning to leave for school and it stalled out after being on for about 20-30 sec and it was still in Park (auto tranny). But believe it or not the idle has improved. It drives fine until I come to a stop for about 30-45 sec then the idle goes from the normal 500 down to 300 then jumps up to about 700. So it jumps pretty bad from 300-700 and feels like its going to stall. Then when I put it in N it idles fine. Should I just keep on messing with the TPS?

Since you said you're getting an MIL, I'd run to the local Autozone or Advanced Auto Parts, Pep Boys Auto parts store and get the code read for free. See what that says, and I still say it's quite possible you damaged your TPS when you removed it from the stock TB. Get a new TPS, install it, and see if it solves your problems. If not, you should be able to return it provided it's in like-new condition when you return it.

Have you called up accufab? I spoke to the owner and he's a friendly guy that might also be able to help you troubleshoot.

It's also not that difficult to uninstall/reinstall the IAC and EGR connections. Why not do this? You can make extra certain that the gaskets are installed correctly.

But first off, I'd hit your local auto parts retailer, have them pull the code, and buy a new TPS. See where all this gets you first before calling Accufab.
 
make sure you iac valve is clean and connected properly. also there is a little rubber thingy that connects to the plenum with 2 red lines coming out of it. make sure that is on there good. that for sure can make your rpm's jump around.
 
Ive got good news, I finally fixed the idle. It idles perfectly now. But my engine light is still on, Im hoping now that the idle is fixed it will turn off. I messed around with the TPS a little more and it worked. Thanks a lot BMan5150. I might buy the Pro- M Optimizer to tune up my a/f ratio. Ive heard of some people getting it after they got their plenum/tb and they ended up putting down around 20 to the wheels.
 
03gtmustang said:
Ive got good news, I finally fixed the idle. It idles perfectly now. But my engine light is still on, Im hoping now that the idle is fixed it will turn off. I messed around with the TPS a little more and it worked. Thanks a lot BMan5150. I might buy the Pro- M Optimizer to tune up my a/f ratio. Ive heard of some people getting it after they got their plenum/tb and they ended up putting down around 20 to the wheels.

Awesome :nice: - glad I could be of some help. I believe you can clear that code by disconnecting the battery and pressing down on the brake pedal for a few minutes. Otherwise, it should go off eventually within the next 100-200 miles.