TCCoA Forums banner

1 - 16 of 16 Posts

·
Stroked and Blown
Joined
·
2,395 Posts
Discussion Starter #1
Hello

Okay, A few months ago, the entire top half of my car was redone. Ported/polished heads, intakes, 212/218 cam, 56 mmTB. It also has true dual exhaust now. My MAF is stock as well as the fuel injectors. What are the best size fuel injectors to go with? Car is probably running too lean. What is the best size MAF to go with? This is a 1996 Tbird 3.8 n/a. I don't ever plan on using nitrous.

Thanks
 

·
Stroked and Blown
Joined
·
2,395 Posts
Discussion Starter #3
Lonnie even said the cars probably running too lean. It rides rough, the gas mileage is around 14-15mpg. The stock fuel injectors are probably being maxed out. Trust me, the car isn't running normal. The guy who installed everything said I would probably need another MAF.
 

·
Registered
Joined
·
718 Posts
First off it wont be lean running part throttle or at idle,, so if its running rough it most likely the cam or a intake leak.

Only with a dyno run or a WOT blast and a rich/lean (widebad hopefully) can you tell if its lean.

personally i would go with a set of 19lb injectors over the stock 14's but that should be all you need.
 

·
Registered
Joined
·
202 Posts
you might need a chip tuned to your setup.
 

·
Stroked and Blown
Joined
·
2,395 Posts
Discussion Starter #7
I had the car checked out and the compression is great. 120 all and 150 running. There are no vaccum leaks either. The sparkplug test resulted in "car running too lean" The sparkplugs still look brand new, so no fuel is getting down there. I've driven it about 1,000 miles like this. (I'm lucky I didnt melt a piston. I guess those Mobil 1 Synthetic Oil changes have paid off) I'm going to go with the 19lb injectors and a 80mm MAF and hopefully, this should balance things out. I'll then take it to a dyno shop and have it tuned properly.
 

·
Registered
Joined
·
718 Posts
can I ask exactly how you determined the car was lean by the plugs????

I assume you took it to the dragstrip and ran a WOT blast and after you crossed the traps you quick shut the engine off.. because thats the only way to determine by the plugs if the injectors are too small and running lean.

if you simply drove around a while and then pulled the plugs then they should be clean and nice.. because its the job of the computer and 02 to keep the engine at 14:1 and be good on gas.

2nd,, a 80mm would not be your best bet as it would be too big for your combo.. a 70mm should be more then enough.

What you want to achieve is the MAF runs on a 5V signal,, at WOT say at like 6000RPM you want it to be as close to the 5V as possible.. if you say run a 80, or 90mm maf or bigger you will not be using the maf to its full potential this causing poor performance let alone gas mileage. Bigger is not always better. you want the best possible resolution from your meter.
 

·
Stroked and Blown
Joined
·
2,395 Posts
Discussion Starter #9 (Edited)
Actually, I took the car to the shop that installed all the stuff and they tested it. The sparkplugs still look new so no fuel is getting down there. My car is not stock, it does have mods. They are listed in first post and at the end of this post. I called Tom at Supersixmotorsports and he also said the car would run much better with 19lb injectors and a 80mm MAF. Tom is real good with the 3.8's so I wont doubt what he is saying. Tom and Lonnie BOTH said my car is probably running too lean and the shop that checked it out also said it's running too lean. I'm going to assume that the car is indeed, running too lean. If not, then I'll find this out on the dyno after I get the new stuff installed.

Current Mods:
212/218 Comp Cam
56mm TB
ported/polished heads & intakes
true dual exhaust
Underdrive pulleys
removed silencer
transgo shift kit
2600 stall Marauder converter
all of this got me mid/high 17 sec 1/4 mile times. Before all the mods, it went 16.9. Something is definantly wrong here.

It's pretty apparent that the stock 70mm MAF and 14lb injectors need to be replaced, now that there's alot more air getting in.
 

·
Registered
Joined
·
718 Posts
The Ford computer will adjust itself (to a point) to either add or remove fuel. If your 02 sensors are working correctly,, then it will see a lean and add fuel based on the fuel maps both Long Term and Short Term Maps.

What I am saying is that there is no way with a correctly working MAF and 02 sensors should you be running lean below 4500 RPM.. Now if you start winding it out then thats another story.

Now I understand that you think you have ALOT more air getting into the engine thats fine. but heck take a stock mustang 5.0L and they used 55MM MAF's!!! the Cobra motor got a 70mm,,, do you honestly think your engine is sucking in more air vs. a GT40 v8 engine (just for comparison).

I understand that all the guys listed know what there doing,, and unfortunetly there all in the business to make money also buy selling you there products and services.. I'm not knocking them at all many of them have built some great 3.8/4.2L,, with enough money I couldve made a 87 2.3L tourus fast! but more so I'm trying to help you with a more logical or FREE solution then simply throwing money at it and being pissed off cause it runs the same.

You never listed the rear gears your running,, I hope its atleast a 3.73 or higher! with the ported heads and that larger cam you negated alot of bottom end torque for what you first had,, and the LAST!!! thing you wanna do is loose bottom end torque in a heavy ass TBIRD/Cougar. so now you have 2 probs,, 1 is you lost bottom end torque and the 2nd is by the time the engine is in its powerband your running out of injector.

Now unfortunetly in order to run 19lb injectors you will either need a chip or recalibrated MAF,, being that your playing with a 1996 and OBDII I would highly recommend a SCT2 then your able to control more.

My first suggestion would be to get a laptop (i you dont already own) and buy a WideBand data logger and then you'll be able to learn for yourself where and what RPM you "MIGHT" be running lean.

Have you thought about the fact the injectors might be dirty?
Low Fuel Pressure? Weak Pump? Bad Fuel Pressure Regulator, Etc etc.

Just trying to help yah out,, if you dont want it lemme know

EDIT: one last thing,, for the record I ran the 14lb injectors on my 4.2L (splitport) and ran a 15.89 at the track and didnt see lean untill 5950RPM
 

·
Stroked and Blown
Joined
·
2,395 Posts
Discussion Starter #11
I appreciate all the help. I actually do have an Xcal2 for it but I don't own a laptop, therefore it's difficult to datalog. I've been sent 3 programs and the one on it now is the best so far. A guy in my local club may go over my car with me using a laptop to figure out what all is going on. He's not in a "business" either. Once I install the new MAF and 19lb injectors, I'm going to take it to him so he can straighten things out at least until I get a chance to get it dynoed. Oh, the gears are still the stock gears. I assume I will probably have to change these also.

So: 3:73's, 19lb injectors, 80mm MAF and I'm HOPING this will make the car reliable, more fuel efficient and perform better. The guy who made my tune is located about 1,000 miles away from me. It's hard for him to set me up a good tune by me describing to him what all I've had done to it. He could probably get me a better tune, if he was dynoing it. Because of this, I will probably find some dyno shop in my area.
 

·
Registered
Joined
·
718 Posts
why not get some 19lb injectors and keep your stock MAF,, and have em send you a new file for a 19lb setting???

that 70mm maf is not holding you back at all.

As far as hoping for better fuel economy,, well I would just throw that idea out the window,, more power = more fuel,, no ifs about it.

your setup should have a minumum of 3.73's,,, with 4.10 being best. that alone will kill gas mileage but will get your engine into the powerband it wants with tha cam you listed.
 

·
Stroked and Blown
Joined
·
2,395 Posts
Discussion Starter #13
why not get some 19lb injectors and keep your stock MAF,, and have em send you a new file for a 19lb setting???

that 70mm maf is not holding you back at all.
.

I think I may do this and just change the fuel injectors for now and see how she runs. Come to think of it, IF my car was running too lean, wouldnt my check engine light have came on? I did see the sparkplugs though, and they still look brand new. I dunno.:confused:
 

·
Stroked and Blown
Joined
·
2,395 Posts
Discussion Starter #15 (Edited)
I plan on getting the car dyno tuned after the 19lb injectors are installed. Is this possible, or do I have to get the Xcal2 unlocked, in order to change the fuel injector parameter to 19lb before I have them installed? (I've just read up that the End User Adjustability does not cover MAF or fuel injectors)

Will my car still start up and run with the 19lb injectors in it, long enough to get her to a dyno shop even though the Xcal2 fuel injector parameter has NOT been changed from stock to 19lb?
 

·
Registered
Joined
·
718 Posts
It will run pig rich without it being tuned with the 19's and might run funny,, but should get you there depending on distance.

whoever sold you the Xcal2 should be able to send you a new file via e-mail and then you can D/L it to the xcal.
 
1 - 16 of 16 Posts
Top