4v Swap/Tuning???

GoBabyVroommm · Apr 28, 2004

I have my 96 gt computer running my 99 4v. It drives but it bogs a lot. I'm also using a return style fuel system on that motor 19 pound injectors. The motor isn't coil on plug it is coil packs now. Those are the things that might play a roll in the bogging.

I might go out buy a tweecer or pms and tune it myself. I just like to know if its a tuning problem or motor problem? What do you guys think?

mogs01gt · Apr 28, 2004

Its a tuning problem. I would either go find a cobra ECU from a older DOHC or a 99-01 ECU. The heads in a DOHC compared to a SOHC from a 96 is a HUGE difference.

Always go with the easier solution first. Pulling the motor and taking it apart to make sure everything is ok will cost more than a ECU.

200 bones:
http://www.stangparts.com/products/partpic.cfm?TypeID=27&ID=2464&Page=2&ShowSpecials=FALSE

GoBabyVroommm · Apr 28, 2004

I was thinking that but how the hell am i going to turn off P.A.T.s???

mogs01gt · Apr 28, 2004

GoBabyVroommm said:
I was thinking that but how the hell am i going to turn off P.A.T.s???

Not sure. I think you may have screwed yourself on your swap and may have to start over. Would have been easier with 99+ Cobra equipment instead of using the stock SOHC stuff. Even if it does cost more.

Mod Man · Apr 28, 2004

Did you delete the IRMC's? That might be playing a little part in the bogging and all if you have not. The GT computer isnt tune to open those. But it dose sound like its in the tune...

YLW99VERT · Apr 28, 2004

99 4v wont have IMRC's, 19 lb injectors seem small for a 4V, didnt the stock motor come with 24's??
Who did your tuning on the car after the swap?

Numbles · Apr 28, 2004

Ill answer a few of these for you dave.

For those who dont know dave had a big problem with the dealership who did the motorswap. Issue solved and the car is running. Somehow the 24's wouldn't work on his motor so he had to go back to 19's. And there is no tuning at all on the car.

Ive gotten a chance to ride and drive the car. It is loosing a lot of t/q in the low rpm but I drive a 5.0 so who knows. It should still pull harder in the lower rpms even with 3.73's.

I dont know if this will help but dave has a a/f guage and it never leaves rich. Maybe we will turn down the fuel pressure today and see what happens.

mogs01gt · Apr 28, 2004

Numbles said:
Ill answer a few of these for you dave.

For those who dont know dave had a big problem with the dealership who did the motorswap. Issue solved and the car is running. Somehow the 24's wouldn't work on his motor so he had to go back to 19's. And there is no tuning at all on the car.

Ive gotten a chance to ride and drive the car. It is loosing a lot of t/q in the low rpm but I drive a 5.0 so who knows. It should still pull harder in the lower rpms even with 3.73's.

I dont know if this will help but dave has a a/f guage and it never leaves rich. Maybe we will turn down the fuel pressure today and see what happens.

sounds like the ECU.

Numbles · Apr 28, 2004

I had this question the other day but dave didn't know the answer.

Would it be better for him to go with the AFM PMS. or get a mail order chip for the car. I dont know the benefits of the different tuning divices. But is the PMS cheaper in the long run or is a chip the route to go.

YLW99VERT · Apr 28, 2004

I would have Don at modular madness burn a chip for his car. He needs to get it tuned.

Roger_4.6_96 · Apr 28, 2004

GoBabyVroommm said:
I was thinking that but how the hell am i going to turn off P.A.T.s???

Install a new pats key real easy. Look HERE

lwkauble · Apr 28, 2004

Numbles said:
Ill answer a few of these for you dave.

For those who dont know dave had a big problem with the dealership who did the motorswap. Issue solved and the car is running. Somehow the 24's wouldn't work on his motor so he had to go back to 19's. And there is no tuning at all on the car.

Ive gotten a chance to ride and drive the car. It is loosing a lot of t/q in the low rpm but I drive a 5.0 so who knows. It should still pull harder in the lower rpms even with 3.73's.

I dont know if this will help but dave has a a/f guage and it never leaves rich. Maybe we will turn down the fuel pressure today and see what happens.

What is the A/f ratio @Idle and again @ 2500 rpms? also vacuum and fuel pressure needs to be given for idle and 2500 also. And if possible WOT. is the a/f ratio guage a bar graph type or numeric type? I really need to see the numbers. try to get the a/f as close to 14.7:1 if you have the capability of measuring it like that. Do you have a 4 gas machine that you can use? that can really tell you what's going on in your motor as well. give me some of the first group of numbers and maybe we can make a more educated guess at what to try next.

Larry

GoBabyVroommm · Apr 28, 2004

Finally i'm home!!!! Damn that PATS site is pretty cool i had to save it on my computer. Thanx for that one.

You know what i don't understand about my car?? I don't get how i can drop it from 3rd gear and doesn't move. When the thing hits 4000rpm its flying. Once i put it in 3rd gear slows down again, till it gets in the high rpm and starts moving again. I just don't understand what is happening????

Here is another thing. My low coolant pic comes on and off i add coolant but it comes back on after gettin on it. Did the 99+4v have a different radiator or something?

Some times the car takes forever to turn on too? When it turns on, its as if i have cams in there. After driving the car then shuting it off and on, its fine.

Can all this really be because of tuning??? Hell if it is damn i can't imagaine how fast it will be when its tuned.

GoBabyVroommm · Apr 28, 2004

My gauges read fuel pressure at 35-37psi near 40 psi at idle. When i floor the car the pressure moves just alittle

My oil pressure is kind of weird. The oil pressure goes up and down a lot at idle. At idle oil pressure is at 18-23 psi. If it is above 20 psi it is running good. When i floor the car the oil pressure goes up to 80-85 psi.

The a/f i have to see tomorrow if its hooked up right. To lazy to get under the car.

1ba96gt · Apr 28, 2004

I would take it to a performance shop and get them to sort it all out. You have a complicated issue that won't be able to be done right by mail order for 3 months sending it back and forth. It some what unique it sounds, and until a person were to see everything as a package they could only guess, what needs to be changed and what is being affected by it.

hioc1098 · Apr 29, 2004

I'm currently doing a swap to an 03 Mach I 4v. I'm using the return style fuel system and my 98 EEC. I'm reflashing the computer with a stock 4v tune and will begin my performance tuning from there. Your problem IS in the tuning. You don't need to swap computers. You only need to have a tumble port head tune flashed (or chipped) to your computer. Any competent tuner should be able to set you up. I have recommendations I can PM you if you like.

You'll also need to put the 24lb injectors in to work with the horsepower. The reason they probably didn't use the injectors is the different connectors. I don't know if this is the case with you, but it is with me. All I'm going to do is splice my 98 harness with the 03 injector plugs (soldering of course). Let me know if you have any questions and I'll help you as best I can.

Tim

lwkauble · May 3, 2004

GoBabyVroommm said:
My gauges read fuel pressure at 35-37psi near 40 psi at idle. When i floor the car the pressure moves just alittle

My oil pressure is kind of weird. The oil pressure goes up and down a lot at idle. At idle oil pressure is at 18-23 psi. If it is above 20 psi it is running good. When i floor the car the oil pressure goes up to 80-85 psi.

The a/f i have to see tomorrow if its hooked up right. To lazy to get under the car.

fuel pressure looks ok... the oil pressure belive it or not can go from 4psi to 90 psi on some cars... that's why the stock guages just show mid range oil pressure when its working, and 0 when it's less than 4 psi...

GoBabyVroommm · May 3, 2004

Hey Hioc if you do your tune yourself give me the numbers or let me download it. I hope you are going to use a tweecer because we can swap tunes. I'm going to get mine soon.

O crap it might not work i have a 99 4v with different crap on. I don't think it will work if i use your tune.

hioc1098 · May 4, 2004

GoBabyVroommm said:
Hey Hioc if you do your tune yourself give me the numbers or let me download it. I hope you are going to use a tweecer because we can swap tunes. I'm going to get mine soon.

O crap it might not work i have a 99 4v with different crap on. I don't think it will work if i use your tune.

I'm using the SCT software anyway. Sorry.

Tim

slvr00gt · May 4, 2004

Wow,
99 4v engine actually works, albeit badly, on 96 2v ECU. From my readings on the topic I figured it would not work at all. See cobrapoweredgt website for a lot of 4v swap info:
http://www.cobrapoweredgt.com/index2.html

4v Swap/Tuning???

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