I think this is pretty thorough but you should have a manual to refer to if you don't feel comfortable with what the throttle body parts are. Mine seems to run pretty well and I will drag it on Friday to see just how good it is. Good luck.
Parts needed:
1. GA16i throttle body, of course
2. Mallory 4307M fuel pressure regulator (or equivalent)
3. Holley fuel pressure gauge (or equivalent)
4. (2) brass ½” flare to 3/8” female pipe coupling (Watts brand #A-274 at Home Depot)
5. (2) brass 3/8”male to ¼” male pipe bushing (Watts brand #A-778 at HD)
6. (3) brass ¼”male to 5/16” hose barb (Watts brand #A-201B at HD)
7. (1) ¼” 90 degree angle brass fitting (HD or speed shop)
8. 3/8” male to 1/8” female aluminum pipe bushing (from speed shop or possibly brass at HD)
9. 3/8” male to ¼” female aluminum pipe bushing (from speed shop or possibly brass at HD)
10. Plumbers Teflon tape
11. About a foot of 5/16” fuel hose
12. Longer screws to mount idle speed control valve (ISC); not sure of exact size
13. Mixture heater
14. 2’ of vacuum hose
15. Gasket material
16. (5) hose clams for 5/16” hose
The regulator must be able to handle 14 psi of pressure, which is pretty low for fuel injection; the Mallory was about $100. The pressure gauge was about $15. I think the throttle body cost me about $45. Refer to a manual if you don’t recognize the throttle body parts referenced. Steps assume both throttle bodies are already removed. Refer to the manual for proper removal procedures.
Prepare the throttle body (TB= throttle body, E=E16i TB and G=GA16i TB):
1. Swap E’s ISC valve to G with two new longer screws (don’t need third screw)
2. Swap E’s air flow meter to G
3. Swap E’s throttle position sensor to G; I set mine in the same position as it was on E
4. Remove 3 large screws and one small screw from the top of E and G to remove plastic top cover
5. Note the orientation of the + and – terminals on the injector
6. Carefully twist out the fuel injector in each with a pair of pliers, being sure to keep the two o-rings with the injector, and don’t bend the brass prongs on top (use a rag with the pliers so you don’t scratch up the injector)
7. Swap E’s injector into G, making sure + and – are in the correct locations; injector is keyed to top cover so it won’t go on incorrectly
8. Put plastic top back on
9. Remove the two screws holding G’s pressure regulator/inlet barb to the TB; plug the vacuum port that goes to the regulator
10. Use the ¼”-18 pipe tap to thread the inlet hole where the regulator mounted; you might want to put a scrap of paper towel in the hole first to keep metal shavings from getting into the system
11. Using Teflon tape, install the ¼” x 5/16” hose barb
12. Plug G’s existing fuel return barb with a short piece of hose and a bolt and a couple clamps
13. This is a good time to clean the TB
Prepare the fuel pressure regulator (FPR); NOTE: These steps will be different if you use a different regulator and gauge:
1. Cut the flare portion off the two ½” x 3/8” pipe couplings right under the threads
2. Using Teflon tape, thread the 3/8” x ¼” pipe bushing into the pipe coupling, then thread the ¼” x 5/16” hose barb into the pipe bushing; you should have two of these assemblies
3. Using Teflon tape, thread the two assemblies into the FRP inlet port and the bypass port
4. Using Teflon tape, thread the 3/8” x ¼” pipe bushings into one of the outlet ports; thread the ¼” 90 degree elbow into the bushing then thread the gauge into the elbow
5. Using Teflon tape, thread the 3/8” x ¼” pipe bushing into one of the outlet ports and then thread a ¼” x 5/16” hose barb into the pipe bushing
6. Plug the last outlet port with the supplied pipe plug and Teflon tape
7. Plug the vacuum port
Note: you may want to experiment with different angle fittings to mount the FRP where you want it.
Other prep items:
1. I kept the mixture heater as a spacer but used a drill bit to drill out the 3 rivets and removed the actual heater piece
2. You may have to cut new gaskets if yours are torn
3. The two coolant fittings on the E manifold are smaller than the G TB fittings so I removed one of the two E hoses on the manifold and looped the remaining hose to the other fitting on the manifold. You will want to loosen the hose clamp so the hose can orient itself so it doesn’t kink.
Mount the TB:
1. Using good original or new gaskets, mount the TB to the manifold using the original hex-head bolts (if you don’t use the mixture heater you will need shorter hex-head bolts)
2. The throttle cable should hook up normally, just don’t pull it too tight and increase the throttle speed
3. Plug in all electrical connectors
4. On the E TB there is a vacuum hose that runs to a port on the drivers side; this will be on the passenger side of the G TB, hence the need for a longer hose
5. Run a 6” to 8” piece of hose from the FPR outlet to the TB inlet
6. Hook up the fuel return barb to the existing fuel return hose back to the gas tank
7. Hook up the fuel inlet barb to the existing inlet hose that used to go directly to the TB inlet
8. Mount the FPR
Start the car and let warm up; adjust the TPS and idle speed if necessary. Adjust the fuel pressure to 14 psi. Because of a slight difference in the G TB, the air cleaner doesn’t fit exactly right but it is close enough.
The hardest part of this is gathering all of the necessary parts. I think I captured everything here.
The other possible method I have not tried is to actually bore out the E TB and just swap the throttle shaft and throttle blade from the G into the E. The only drawback I see is that there is a plugged passage pretty close to where the edge of the new opening will be but I think this was just used to drill an internal passage, and it could be filled with something to smooth out the bore. This would eliminate the whole FPR hassle and expense and would greatly simplify the process.
Thank you for the write-up, you've done it much more thouroughly than I would have been able to (It's been almost a year since I've done the swap, many small details I forget), and all those P/N's you listed will surely help ease the pain of it, which in retrospect, isn't that bad at all.
Wonderful job.
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We finally had a dry Friday night at the track for testing. The new throttle body plus the cooler air reduced my 1/4 mile time by 1/2 second, from 20.8 seconds to 20.3 seconds. Still not fast but it's an improvement.
After tackling the proper fuel pressure, the TPS is what was giving me all the grief for idle speed. It was rather close to 800 rpm after that. Didn't take me much adjustment.
One thing I can think of, possibly, is that I didn't have any coolant line going into the TB, and I adjusted that 'wax pellet' cold idle adjuster... thing-a-ma-jig... (ahem.) to where it wasn't anywhere close to affecting the throttle.
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I've been messing around with the GA16 (G) and E16 (E) TBs again because I couldn't get the G to work well on my car the first time. I took my E TB to the machine shop to have them bore it out and install the G butterfly but the machine shop said he couldn't do it. So, I went home and ripped both apart. Part of the problem with the G TB is the "wax pellet" idle junk on the linkage side and the fact that it uses a different fuel pressure, requiring a stand-alone fuel pressure regulator (FPR) to drop it to 14 psi. What I have done now is to take the top half off of both TBs (not just the plastic top piece, but the whole top half) and put the E top on the G TB. The tapered bore on the inside matches up like it was meant to be this way. This gets rid of the "wax pellet" crap and puts the E FPR and E hose barbs on the G TB, doing away with the stand-alone FPR. Except for a little grinding where the E FPR hits the mount for the ISC valve, it bolts on with no problem. Putting the E top on the G TB also solves the air cleaner mounting problem I had (interference with the wax-pellet idle crap). It also eliminates the need for most of the fittings and misc. pieces to adapt the FPR.
I also started working on how to mount the Dodge TB CAI adapter to the E TB. It will take some more grinding to fit the adapter over the ridge on top of the E TB. This is a work in progress and may take a while. More later.
Last edited by gspot : Mar 30th, 2004 at 11:08 PM.
so Gspot, any huge difference? just wondering if it ran bette rwith your setup, and also if you got that CAI to match up ok. and anyone who does this try to publish your gas mileage...its somethign i'm interested in
__________________ Student at UTI Avondale 2nd place SkillsUSA/VICA WA State Automotive Maintenence '04 had an 87 pulsar...still planning CA20DET
1970 Chevy BelAir 350V8 300hp...soon to get M21
I'm the one that wrote up the instructions for doing the swap. Crazy Mart's response sounds about right. I wish I could say the new TB helped a lot but I'm not sure my car has run correctly since I did the rebuild and put the new TB on, although I don't blame the TB. I'm actually considering a swap to the GA16DE in the near future or just getting rid of the car.
Once you have both the GA16i and E16i TB, the parts swapping is pretty easy if you follow my detailed instructions.
GA16i throttle body swap write-up!
Linear Mode
