Install New PP Throttle Body, Car Runs Like Crap!

Ok, I reinstalled the TB today cause I went back to stock for other reasons. I've got no prob with this TB until now and here's what I've found....

My vacuum went all to heck and I was seeing an AFR of 18.5 or so at idle, so air was getting in where it shouldn't. Never had this issue before so I started investigating. When I sprayed brake cleaner on the side of the TB at the springs for the throttle plate the car smoothed right out then almost stalled because I sprayed too much there. I tested it 5 times and its apparent there's a BIG leak there. There's a black plastic grommet there and the darn thing had a crack in it.....

So, I apologize as I was mistaken about this TB. It sat on a shelf in my shop for a month and now it leaks most of the time. Guess you get what you pay for.

Anyways, the TB has potential and actually flows very well. Just got to figure out how to seal up that shaft properly. Perhaps someone with some savy can work with power products on a better sealing option, as I tend to be a bit too blunt ;).

Frit

ps: We all make mistakes I guess :(.
 
PP Throttle Body

Mine leaks a small amount there, but not enough to even bother the idle air. The car is torn apart right now, installing a '94/'95 blower. I'll look at the leak when I get it together again, but overall I'm pleased with the PP TB.
Gerry
 
My 70mm BBK leaks at the shaft too. There are o rings on it, I replaced them, and it made it better, but I cant figure out a way to seal it completely.
 
PP Throttle Body

There probably isn't a way to seal it totally, since the shaft has to rotate freely, which means at least a small clearance. "O" rings may be the best solution to minimize it. Have to keep them lubed however to preclude wear or damage to the seal surface which would make the leak worse over time.
Gerry
 
My vacumm went from 20 down to 17 with a very badly running motor and my AFR went to 18 and 19 showing way lean. Before I went back to the stock TB it had no issues so sitting on the shelf must of dried that seal out.

Oh well, gotta take it off and see if I can seal it up.

Frit
 
Mine is brand new so the vacuum leak I have must be in the intake else although removing the PP body and going back to stock, the motor seems to run normal. I haven't been able to find the leak yet.
 
... Since the stock TB is the major inlet restriction, replacing it with the big TB increases flow dramatically and for some reason increases the effects of any vacuum leaks, even small ones....
Gerry

(Catching up so please forgive if already discussed)

If the plenum is stock size and not even matched, then how is he getting any more flow. Not sure how more flow could affect the vacuum leak symptoms but I'll put that one off until later :D

It's forced so it will only pull as much as the smallest opening\restriction.
Small gains unless you have opened it up elsewhere, especially the plenum.

I have SCP TB and made a new gasket for the IAC valve. I made the two holes to flow air about 75% the normal size. I read on a couple of boards this helps all Fords with the 'hanging idle'.
I had the same problem, the idle would hover around 2k then drop after a few seconds down the perfect mark of 750.

I could have done nothing with the new gasket but it has not done it since.
 
...The second is the large step between the big TB exit and the inlet plenum entrance. This is potentially a big turbulence generator (like to maintain laminar flow). I rounded off the plenum inlet step some, but I need to do a lot more before it will run as good as it should.
Gerry

And this would be what I was referring to earlier, port matching.

It will not increase the air flow volume but is smoothing the air flow out between the TB exit and plenum entrance, as mentioned above.

Won't cause this issue though.
I vote for adjusting and adaptive learning.
Mine seemed to really have to take several trips to get the idle settled in on a couple of attempts, other times it seemed rather quick to smooth out.
Nothing was changed before and after, just unhooked the battery for some stereo work.
 
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PP Throttle Body

I have ported the inlet plenum to match the PP 75mm TB gasket for the '95 blower and plenum I'm installing on my '89. Was pretty quick and easy with a Dremel tool and some sanding rolls. The big TB worked fine on the '89 plenum with only the corners rounded to smooth the flow. This sort of ported setup should now pull a lot more flow than that did. Can't reach any further inside the plenum to open the whole thing up more, so I guess this is about as good as I can get it.

I agree that it takes a lot of "Adoptive Learning" to get the idle right with the PP TB. It took me a several tries, with driving before the idle settled down to an acceptable, repeatable and steady level. I'll probably have to go through it again with new changes.
Gerry
 

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You may want to see if you can find a shaft seal at a bearing distributor. The bypass valves can leak at the shaft too. Ford put in needle bearings with seals on each side. Those are hard to get now, so you can use a regular roller bearing and add a seal beside it. If you can get the diameter of the shaft, the ID of the hole, and the depth you have to work with, you can probably find something. I forget if the PP TBs have a solid bushing or a needle bearing at the shaft - does anyone know? I am guessing bushing.
 
This sort of ported setup should now pull a lot more flow than that did.

Port matching looks good, nice work.

I still don't see how port matching will increase the flow volume though.
Maybe, arguably, the 'smoothness, turbulence or swirl' improves.

Without increasing the SC drive speed, and increasing the diameter of the other bottle necks same\smaller than stock TB bore of 65mm, then how is more volumetric flow getting through the system by replacing a TB or MAF?

If you just replaced the MAF, no more air gets by the stock TB so the volume wouldn't increase this way alone either.

Not arguing a point but just trying to understand how this would differ from a water pipe, or electrical circuit. I know little about forced induction.
 
PP Throttle Body

It was my understanding from other threads that the TB was the greatest restriction in the inlet, followed by the MAF. I increased the TB to 75mm and the MAF to 76mm, then ported a '94/'95 style inlet plenum to match the TB and installed a '94/'95 blower. This would appear to be about as good as can be done. All stock, the blower wanted more air than the inlet could deliver (causing some cavitation at high boost levels). These changes should correct that.
Gerry
 
The biggest restriction to start with is the MAF which is 55mm. I outflowed a stock MAF awhile ago and if I was still running it, it would be pegged. The 70mm stock MAF doesn't flow any better so its still a restriction. Second restriction then becomes the TB at 65mm. The inlet plenum is around 68mm internally at its worst point according to others.

I've now exceeded the capacity of the stock TB and when I put the 75mm back on I instantly gained another 50kg/h at 5500 rpm's so that shows that the inlet plenum can outflow the stock TB.

Also, if your relying on adaptive to fix your car, its time to get tune.

Frit
 
Port matching looks good, nice work.

I still don't see how port matching will increase the flow volume though.
Maybe, arguably, the 'smoothness, turbulence or swirl' improves.

...

Not arguing a point but just trying to understand how this would differ from a water pipe, or electrical circuit. I know little about forced induction.

Yes, the transitions in diameter do make a big difference. You will still get a pressure drop and some loss of flow, of course, but the losses will be minimized by using smooth transitions.
 
Install PP Throttle Body

I got it all together and drove it yesterday. (75mm TB, 76mm MAF, MAC CAI, KN filter, Gasket match ported inlet plenum, '94/'95 blower). Car runs very strong, scary quick for an old dude like me. Disconnected battery and let everything reset before starting the adaptive learning process again. Idle seems fine, a steady, repeatable 800-900RPM. Boost gage approaches 15lb. There is a miss under high boost levels, feels like ignition although plugs and 8mm wires are near new. No way to get a tune without going to the local Dealer, I don't have an EEC tuner. Overall quite happy with mods.
Gerry
 
Idle went berzerk

Wow this thread is a few years old but was very helpful.

Installed PP 75mm throttle body, C&L 76mm MAF, SCP 3" intake, 42 lb Bosch injectors, and 255 lph fuel pump. Chased the TPS adjustment for awhile due to hanging idle however it was exactly on the mark.

A few months ago started driving SC daily and using air when weather warmed up recently. Damned thing was stalling in traffic while at idle with air on. Idle would decrease when air was turned on rather than increase. Oh, also installed a new IAC on new TB and have been getting vacuum of 20 so not any vacuum leaks. Without much thought I adjusted the throttle stop screw to increase idle a little. It stopped stalling but idle was really high with air off. Idle went berserk and would even search from almost 2000 down to 1000 and then back up again. Really obnoxious.

Tonight I removed the intake tube to observe throttle, backed the stop screw all the way out, disconnected the battery and harness to IAC. Just like Rick said the throttle was sticking a little when butterfly was up against throttle body. Reinstalled intake tube, reconnected battery, and started it up with harness to IAC still disconnected like set up technique posted by S Mazza. It idled a little rough for awhile drooping down as low as 500 rpm sometimes but with a very small turn on the stop screw it settled at 700-800 rpm real nice. Wasn't sticking either. I shut it down and reconnected IAC. After starting the idle initially surged to about 2000 but only for a second. Came down much quicker than it had been doing. After running for awhile I turned on the air and for the first time in years the idle increased initially when compressor clutch engaged.

I jacked it up turning the idle stop screw cause it isn't an idle screw. It only needs turned in enough to keep butterfly from sticking. This technique of adaptive relearning to idle with IAC disconnected seems to work great.

Future plans to upgrade with MPx SC case and matching intake plenum because 75mm TB is much larger than OEM intake plenum.
 
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