SC'ed with FMU and no chip with 42's

[94gsl5.0]

Have a Vortech SC'ed 94 5.0.....I plan on running 42# injectors with matching pro-m MAF, 255 lph in tank with in-line vortech, 4:1 FMU and adjustable FPR. What issues am i going to run into installing these over the stock setup that comes with the vortech kit. The motor is pretty much stock. I have access to a wideband for tuning and a FMU calibration kit. I would like to know what i need to be looking out for, also...

Before everybody calls out "custom dyno tune" ..... I cannot get a custom dyno tune right now since I am low on money and it costs upwards of 1000 to 1500 for the intial tune and burn in my area. For that kind of money i would rather get stand alone.

As of right now, have been running the stock injectors with FMU

 

[DFG 5OH]

stock injectors? wow...

TTT for ya!

 

[94gsl5.0]

Yeah the stockers seem to be holding up (surprised the crap out me) Actually running a bit lean on the bottom depending on the day but way too rich up top. However, I came across a killer deal for injectors and MAF and jumped on it.

I talked to my Local shop and said they have had some idle issues with the 42's and a calibrated MAF but nothing thats not livable. However, also said that 94-95 computers are kinda hit or miss as well. Hopefully someone here will have some insight into problems i could experience and what to do too alleviate them, without a dyno chip burn.

If worse comes to worse... try em out, don't like it, pull em of and save up for stand alone

 

[Redsnk95]

Take out the FMU for using the 42s. The main problems might be hot start problems. If the meter is good, then the part throttle stuff should be pretty close and same goes for WOT. Just some fine tuning to find more safe hp. Have you already bought the meter?

Troy

 

[VibrantRedGT]

Well the 42's on the stock computer is impossible. I've tried several times and my result was 10 foot streams of fuel out the tailpipes if the car didn't stall out (fouled plugs). Hot starts is an issue with 42's as well. Good luck but I gurantee it won't work. PMS, Tweecer, FAST, custom burned chip is your only solution. Hit up www.stangtuning.com and browse the classifieds. I believe I saw someone selling a 94-95 PMS 04 version under $800.

 

[94gsl5.0]

Redsnk95: I have already ordered the meter from coolblueperformance, its a PMAS (The new pro-m) The shop i frequent tells me i will still need an FMU to stay safe if sticking with the stock computer. As for the idle quality, they say hit or miss.

Vibrantredgt: The car's you installed the 42's on, they all had calibrated MAF's as well? What you said kinda concerns me since i take it a tweecer or such would have been able to modify my MAF curve, negating the need for an aftermarket MAF which i just purchased. Did i just waste my money when i should have just bought a base tweecer to get my car running with these injectors?

 

[Redsnk95]

Good, glad you went with a PMAS meter, Nick's cal's are awesome. The FMU doesn't do anything at idle or part throttle. I'd still remove the FMU especially with a stock motor.

Troy

 

[94gsl5.0]

So you have seen a stock puter work with 42's and a caled MAF? They were saying the reason i need the fmu still is because at wide open and no computer tune i am still going to need to see a pressure rise to stay safe.

I guess i just need to install the parts and see what happens, lol. Like i said, i have wideband so the A/F will be a known variable i am just worried about the thing starting and actually idling.

 

[VibrantRedGT]

Vibrantredgt: The car's you installed the 42's on, they all had calibrated MAF's as well? What you said kinda concerns me since i take it a tweecer or such would have been able to modify my MAF curve, negating the need for an aftermarket MAF which i just purchased. Did i just waste my money when i should have just bought a base tweecer to get my car running with these injectors?

Mine was cal'd for 42's. Yea, if you bought the Tweecer any MAF would have worked with those injectors.

 

[Venom351R]

Hopefully someone here will have some insight into problems i could experience and what to do too alleviate them, without a dyno chip burn.

Thats pretty much your only option. I had #30 Injectors and an FMU on my Paxton Supercharged 95 and it always ran like crap, took the FMU out and it was to lean. Went up to #42's but needed a tune. You cant throw a S/C and #42 injectors at the stock computer and expect it to be able to compesate for it w/ out a chip or getting a tweecer for it. Check around at some more places my dyno tune and chip was only $400. Someone is trying to hose you for $1,000

 

[94gsl5.0]

I understand... i would love to get it dynoed and chipped. But here in Seattle, there are two chip burners.... Carb Connection and Blood Enterprises.... both charging well over a grand apiece. Seattle has some of the worst cost's of living anywhere. For instance, my gear install and trac loc rebuild was about G (after a lot of shopping around too, turns out i needed a new carrier adding to the cost).

The reason for the overly large injectors for my current set up was because of a great deal i got on them. The PMAS MAF was not bad eithier. I guess i will probably have to wait to install them until i get a tuning device, leaning twords a PMS. Cheaper than a chip burn in my area, lol.

 

[94gsl5.0]

I e-mailed PMAS about this little dellima, they were very prompt in their response and in a follow up phone call, were very patient with me.

"With the meter calibrated for 42lb injectors, the FMU will no longer be required. Leaving it on the car will cause very rich conditions."

"As far as running the meter with no chip, you can run up to 42lb injectors with no tuning, but if you had a chip burned, it would benefit your car's performance. Your 94 computer will run with no chip, but ideally, a chip or a piggyback would be much better. Alot of people convert their 94/95 computers to the A9L from the 88-93 Mustangs, which combined with some type of tuning, is a great combo."

-Sam


So in the end it looks like a piggyback of some sort is my next purchase. Unless someone has a A9L to sell me, lol. Thanks to Sam at PMAS for the advice.

 

[greenlantern]

Thats what Im doing. The A9L computer with the SCT chip had been working great for my combo.

 

[final5-0]

I e-mailed PMAS about this little dellima, they were very prompt in their response and in a follow up phone call, were very patient with me.

"With the meter calibrated for 42lb injectors, the FMU will no longer be required. Leaving it on the car will cause very rich conditions."

I agree.

"As far as running the meter with no chip, you can run up to 42lb injectors with no tuning, but if you had a chip burned, it would benefit your car's performance.

I would have to say you've got well over a 50% chance that 42's with a maf caled to match and a non modified pcm is NOT gonna work for beans for any driving condition except maybe ...... and I do stress the word maybe ...... wot conditions.

Your 94 computer will run with no chip, but ideally, a chip or a piggyback would be much better.

I agree ...... a tune will make things like they are supposed to be.

Alot of people convert their 94/95 computers to the A9L from the 88-93 Mustangs, which combined with some type of tuning, is a great combo."

-Sam

If a tune will make the original pcm work correctly...which it will..................

Why put in the older pcm AND an ignition upgrade and THEN use a tune to make things correct with the older pcm?

Just tune the pcm that is supposed to be in the car in the first place.

It appears that Silver Bullets, Wooden Stakes, or even a Necklace made from Cloves of Garlic is not enough to kill the Blood Sucking Vampire Internet Myth of the A9L pcm retro-fit.

So in the end it looks like a piggyback of some sort is my next purchase. Unless someone has a A9L to sell me, lol. Thanks to Sam at PMAS for the advice.

I'd just tune what you now got

Grady

 

[FlyBy763]

I run 42 pound injectors with a MAF calibrated for them on the stock computer and havent run into any problems yet. Yeah, it runs rich but it still runs. I had to bump the idle up some to get it to idle without stalling.

 

[final5-0]

I run 42 pound injectors with a MAF calibrated for them on the stock computer and havent run into any problems yet.

I'm just not as tolerate with my tune as you seem to be.

Yeah, it runs rich but it still runs. I had to bump the idle up some to get it to idle without stalling.

It is just my opinion

but

To me, these things look like problems



I really do see your point of view cause it all kinda boils down to this one Q

Are the two things you mention worth the $400 to 600$ for a chip or even more money for a self tuning setup?

I don't fault anybody for trying to make their combo work as it should without having to fork out the money for a tune.

If I could figure out a way to do it for less money, I could put some of that money in my pocket

Grady

 

[greenlantern]

It appears that Silver Bullets, Wooden Stakes, or even a Necklace made from Cloves of Garlic is not enough to kill the Blood Sucking Vampire Internet Myth of the A9L pcm retro-fit.
Grady

 

[FlyBy763]

I'm just not as tolerate with my tune as you seem to be.



It is just my opinion

but

To me, these things look like problems



I really do see your point of view cause it all kinda boils down to this one Q

Are the two things you mention worth the $400 to 600$ for a chip or even more money for a self tuning setup?

I don't fault anybody for trying to make their combo work as it should without having to fork out the money for a tune.

If I could figure out a way to do it for less money, I could put some of that money in my pocket

Grady

Dont get me wrong, I dont think its a good idea to run it this way for long periods of time. Im just saying that for temporary transportation it works for me. A tune is most certainly on the way and scheduled.

 

[Don 95Vert]

I'll rehash what I said in a couple of ealrier posts on this subject: If you think on a '94 and up you can just get by with slapping on a Pro-M or C & L MAF that has been calibrated to the injector size, you are mistaken - you'll still need a chip. The MAF is used to calculate airflow to the engine and it's also used to establish where load (volumetric efficiency) is. On '94 and up Mustangs, timing is determined by load. Say you get a MAF calibrated for 38# injectors (just a number). When Pro-M 'calibrates' the MAF, they adjust resistors to send less voltage to the EEC. In this example, it's cut in half - which, if it done right is theorectically perfect for adjusting the injector's pulsewidth. The problem is by cutting the voltage in half, the load calcualtion is also cut in half - so instead of the timing (on a T4M0 processor) being 25*, as it is stock, it is 38* at the lower load value. This may or may not be an issue with an NA car - it probably would be - but on a blower car it is VERY BAD. The other thing is the base fuel table is also based on load - and guess what - as load goes down, the fuel curve leans out. So you have more timing and less fuel - a bad combination.

That said, a very high percentage of the 'calibrated' MAFs I have seen are not calibrated for crap. Some of the later Pro-Ms have a 'split curve' which in theory sounds good - but in reality are almost impossible to tune. Most of the flow sheets they had provided that I have seen are not even close. Earlier Pro-Ms were not too bad though. Calibrated MAFs also do nothing to help hot start problems, that has to be done in the EEC.

I'm 100% with Grady on the A9L thing - makes no sense to me whatsoever. The later processors are tons more flexible to tune.

I'd never use an FMU with stock injectors on a blower car either, except MAYBE as a temporary band-aid. When the stock injectors are pushed so much, they go static and essentially stay open all the time and with the huge FP increase the spray pattern goes nuts not to mention the injectors can overheat and fail.

Just my $0.02

Don

 

[94gsl5.0]

Thanks for all the advice guys. As of now, i am going to hold of on the injector / MAF install and I am pricing out a Anderson PMS.... it never ends, but all of you know that. Time to spend more money