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Jeepfreak94 12-01-2012 03:49 PM

Throttle Body and Injector Swap Problems
Alright guys. I just completed the throttle body (95 XJ 4.0) and 703 injector (96 Neon 2.0) swap on my 94 YJ 2.5. I cleaned the throttle body and injectors. Swapped the IAC &TPS from the 2.5 TB, installed new seals on the injectors. Reset the ECM (battery disconnect and touched the + &- for 1 min.). Started up fine, the idle is moving up and down ( I took the IAC out of the housing and cleaned them both with carb cleaner), but I think it is trying to find its 'set'. Went for a short drive, the response is great, feels like it has a little more power and is much sharper. Ran great under 3k rpm. When I tried to accelerate moderatly and got above 3k it felt like it was cutting out and fell flat on its face. The CEL turned on and stayed on. Got back home and checked the codes. Codes for IAC, AIT and MAT(what my Chilton manual said, I think MAP).
I think the IAC is still trying to find its set and the AIT is seeing anlot more airflow and is confused. Should I have swapped the MAP sensor off of the 4.0 XJ? Sorry to be long winded, but I would rather seek knowledge from someone who has done this before instead of just throw parts at it.

Speedy4x4 12-01-2012 04:11 PM

How is your fuel pumps condition?
Fuel lines?
Almost sounds like your fuel isn't keeping up with your now improved airflow.

I'm no expert. Just the feeling I'm getting.

Jeepfreak94 12-01-2012 07:59 PM

Fuel should be fine. Ran great before the swap. New filter install less than 100 miles ago. Well, closed the hood and left it alone for the day. Any other ideas?

Jeepfreak94 12-05-2012 02:40 PM

Ok guys. Need a little advice here. Going to run a fuel pressure test this weekend and ordered a new O2 sensor cause it has never been replaced in 90k miles. Then will reset the ECM again. Surely someone else has had this issue.

Jeepfreak94 12-16-2012 05:00 PM

Update. Replaced the O2 sensor. It was in very bad shape. Anyway, got my fuel pressure guage back and tested my pressure. 31 psi with the switch on but not running. Good. Started it up and the pressure shot up to over 60 psi. Bad. Checked the return line for any damage and found none. That explains why the jeep has ran a little warm and the heavy carbon on the O2 and tailpipe. When I had the fuel rail off to swap the injectors I sprayed it out with carb cleaner and may have washed debris into the regulator. Got a new one coming from Rock Auto. When I replace it I will try blowing out the return line. Hopefully that is the problem.
Anyone have any other ideas. Gotta hate it when an upgrade seems to cause more problems!

Jeepfreak94 12-25-2012 05:56 PM

Next update. New regulator, no change. Tried a different pressure test, same pressure. Bypassed the regulator and return line, 32 psi. Disconnected return line at the rail and the tank and hit it with shop air..clean as a whistle. Tried to blow air into tank from dice! Jackpot! Gonna drop the tank tommorow and pull the fuel pump module out to clear the obstruction and the tank. Picked up a new Bosch pump and inlet strainer at Advance Auto ($100 with a Lifetime Warranty). Lets see what I find in the tank! More info later.

stykthyn 12-25-2012 06:22 PM

hope it all works out. I did this swap a while ago and it was well worth it. I am probably going to install an adjustable FPR to take advantage of the 19lb injectors and go with a hotter ignition.

Irongrave 12-25-2012 07:03 PM

the 703s are the wrong injectors for the 2.5. I forgot the model number off the top of my head but its one of the fords. the 703s only work on 4.0s not 2.5s

scopymatt 12-26-2012 12:10 AM

yeah,agree.Fuel should be fine. Ran great before the swap. New filter install less than 100 miles ago.

stykthyn 12-26-2012 07:25 AM

you want the 4 hole 19lb injectors from a mustang/explorer

Jeepfreak94 12-26-2012 04:34 PM

Final update. Dropped the tank, even after 18 years it was clean as whistle. No sludge stopping up the return, but I found a nice little hole in the fuel well. The exact size of the return line! Seems when I 'clearanced' the new tank skid I must have forced the tank upwards and held it against the return line. Removed the tank from the skid and used a piece of clay to measure the clearance from the return to the bottom of the well. Less than 1/8". The return outlet sits over 3/4" lower than the pickup. The skid had slightly more than 1/16" of a bow to it. Bent the skid back out. I cut 1/2" off the end of the return line and filed a notch in the end of it in case it happened again the fuel could flow out the sides. Remounted the tank to the skid. Installed the new Bosch pump and strainer. Reinstalled the tank, checked for leaks and started it up. No leaks and a perfect 39 psi.
Runs great, even with the 703 injectors and 4.0 throttle body. Anyway, its been a long road but the old YJ runs better than ever!

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