I have a 1995 f-150 with headers and duel exhaust. At the time the exhaust was done, I had converted the truck back in time to the carb days with a holley 600cfm. The exhaust shop welded the old O2 sensor on the passenger side before the cat. I recently got smart and put this thing back to fuel injected with a 347 with gt-40p heads and mustang gt intake and throttle body setup. I now am having issues with the stock truck ecm surging and making the truck run very unpredictably. I through a 95 mustang gt computer in the truck and the idle is smoth as glass. What is going on here? I think it is just because the truck ecm is calibrated for the old 14 lb injectors and small air intake system and the gt ecm is calibrated for the 19 lb injectors that are in it. My main questions are: 1. does anyone know if the 1995 f-150 only has one upstream o2 sensor? 2. How many o2 sensors are on the 1994-5 mustang gt? 3. How can I get the truck ecm to run with this setup? I cannot find a programmer for this year truck being OBDI. The mustang computer idles great and runs ok but the cel comes on when driving due to the lack of all the oxygen sensors. I need some input cause I'm pulling out my hair.

Stroked95

 

According the the Ford fuel injection site, there are two Ox sensors.
You may have other issues later.
The stock injectors are 19s but you now have about 40 cu/inches more and may run lean at WOT if you do much of that type driving.
The difference in ECM may be batch fire on the injectors plus the Ox sensors are not feeding back correctly for one type of ECM.
Next is the air meter; is it the right one etc.
You have to sort these things all out and make sure the right hardware is in place, then fix the faults.
Until then you don't really know what is causing what.
See what the codes are. This will tell you a lot about what general problem is as a begining point.
If you knew exactly what you have , I could be of better help.

 

Is the intake mass air or speed density? If the ecm is off a'95, then the intake needs to be mas air. Look into MIL eliminator to clear up the 02 sensor issue.

 

You cannot use a MIL eliminator on the HEGO sensors of a 95. They are essential control elements. You need to fix the problem, not just make the lights go out. The MIL eliminator is designed to be used on the 3rd HEGO sensor on '96 up trucks which monitors the performance of the converter.

You need a HEGO sensor on each downpipe
Was your truck MAF like the Mustang or was it S/D?
What all did you take from the Mustang besides the PCM and manifold?
What tranny was in the Mustang; what tranny is in the truck?

 

i appreciate the feedback so far. I recently drove this truck all the way from illinois to Texas with very little problems. one main problem was definately at wide open throttle, like one of you had mentioned. the truck just plain runs out of fuel due to lack of injector size, insuficcant fuel pump, lack of proper tuning, ect... the original truck only came with one O2 sensor and there is no wiring for the other down tube to install another o2 sensor. this is why I have a light on with the mustang pcm. the truck is and has always been a maf vehicle. the truck originally came with a two barrell t-body and intake. the truck now has stock 94-95 mustang gt intake, 65mm t-body and 70mm maf sensor. the injectors are the 19 lbs injectors from the mustang also. I was unaware the truck had 19 lb inj also but that makes sense due to them being the same color. I will find out what codes are in the truck as soon as I can, but I will asume they are O2 sensor missing signal and possibly egr codes. It has an egr eliminator kit installed but I'm not too confident it really does the job(ebay kit). The real question I had was about the programmers to make the stock truck pcm run well with the mustang intake, t-body, maf. If I can get it to stop surging with the truck pcm then I can set the idle and timing, but as soon as I start the truck, it freaks out and surges liek crazy. The mustang pcm works great, but has the light for the other 02 sensor. it also fires sequentially instead of port firing like the truck does, but none of that matters because the wiring is all seperate so it can fire sequentially given the proper signals from the pcm. I know this is long so I'm done, anything you can add will be appreciated. thank you

 

Might have to look at going to 24 lb injectors and a Mass Air meter that is calibrated for it if it is running out of fuel at high RPMs.. Check out C&L Performance for mass air housings and calibrated tubes.

 

Either way you're going to want to get a custom tuned chip. You've changed too many things for either ECM to have the proper look up tables to run properly in open loop, and possibly even when it's heated up and in closed loop mode.

Just my opinion, but the truck intake will probably give you a lot better low end torque. I suspect the intake differences are also the main cause of the idle problems, since the runner lengths are quite different.

 

I will get 24lbs injectors and a larger t-body and maf. do any of you have experience with 347 strokers? What is the best setup for the street. This is not an all out race truck, but i do want it to get up and go. I am thinking about getting the 24lb injectors, 70mm t-body and a 75mm maf to create a ventury effect. Is this about right or too big too small...what do you all think? i also have been having trouble finding what the stock 95 f-150 fuel pump is capable of. I'm not finding any specs on the max and also running gph of that pump. I'm assuming that the stock pump is too weak to use this setup but I don't want to spend a ton of money if i don't have to. any input would help. thanks

 

The first thing I would look towards doing is an intake change. Even in the cars the only advantage to the shorter runner intakes is at higher revs, with the trade off being loss of low end torque. In a light car you can get away with that, in a truck you can't.

The Explorer lowers flow very well, and the upper is probably better than what you have now. It would retain the single type throttle body, so you might be able to use much of what you have now.

The stock fuel pumps might work if you have a mild cam in the engine, but without knowing the flow characteristics of the cam/head combo it's hard to say.