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I just put a new MAF on my '95 SC and put the SC MAF on my 5.0, with the 5.0's electronics. Is there a tube to be replaced somewhere? There is more throttle response but not necessarily more performance. Could the SC MAF be causing the 5.0 to run lean? It has stock injectors, probably 19s. Thanks.
 

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Yes the SC MAF will cause the 5.0 to go lean in some places and rich in others. You need a chip with the proper MAF transfer function programmed into it for that MAF to work properly with the 5.0. The only MAFs that have the sampling tubes are the C & L type. They basically fool the EEC by sending it the wrong signals. The EEC thinks it is getting less air than it really is and cuts back on the injectors. It's the old way of cheating the system before people learned how the EEC really works and how to tune it properly.
 

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Of course I'm going to recommend one of mine...lol :D Just ask some of the other 5.0 guys that have my chips.

BOC single program chips

If you go with someone else make sure they use SCT.
 

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It also cranks up timing and causes part throttle detonation if the timing is too far advanced. Very bad to clatter.
I tapped my pressure regulator for a hollow brass 10-32 screw to bump the pressure after a 70mm airflow meter swap. Fixed the check engine light saying lean with that trick.
 

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Swapping a MAF will not increase your timing. Also increasing the fuel pressure does nothing for the areas that were already rich, you just made them richer. That is until the EEC figures out that you increased the pressure and cuts back on the injector pulse.
 

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I know I went about it the wrong way. But other than a little tip-in detonation on 87 octane it seems to run well.

My car needs a tune bad. Just can't make up my mind on how far I'm gonna go with it. Might even get a 351w or an exploder p motor. I'm too much of a tightwad to spend $$$$ on a tune yet.

Maybe my terminology was wrong but u know tO-maw-tOes are tO-mA-toes no matter how it's pronounced.
Lets say one airflow meter reads 30gm/sec and one reads 40gm/sec on the same car just cruising. Wouldn't the 30gm/sec be considered less load and therefore fool the computer into using a different fuel/spark map with more timing lead and less fuel?

I just remembered my car has live data- I should hook up a scanner and see what each meter reads at different rpms/tps readings when I have time. You are likely correct in saying the curve isn't linear.

I have 3 different meters actually- the original which was smaller, slower and never 'clattered'.
'96 4.6 tbird meter [free] which was quicker and slightly clattered
'95 ported 4.6 tbird meter [$5.00]which is on there now and must be reading alot leaner to set off the lean code.

The raised fuel pressure was just a patch.

In hindsight bumping the initial timing to 14* might do more good than the bigger meter.
I'm definitely no expert on efi hot rodding. Every hot rod motor I've owned had a carb till this tbird. Heck, it's not even a hot rod motor...yet.
 

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Discussion Starter #8
Fancy that

Well, fancy that, Lonnie. I've already spent my allowance on some replace sans repair stuff for my SC. My next upgrade was to be a chip and I've already got your site in my bookmarks. I'll be in touch with you after the next tax return.
 

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No problem,

This car stuff isn't exactly easy on the pocketbook. I forgot to mention that in order to properly use the SC MAF you will need to use its electronics also. But if you are using them in the C & L meter then that makes it a little difficult. In order to use the 5.0 electronics in that MAF housing it would required a tuner to calibrate it either on a dyno or street tune then write a program for it. You would be better off finding a 4.6 Tbird MAF with the electronics. They are cheap and there are probably a number of people on this site that have them tossed away. Or if you don't mind some minor modifications you can go with a 94/95 Mustang GT or step up to the 02 GT MAF. All of these will still require programming to run properly. By the way I also do programming for the SCs too.

55,

The 5.0 use rpm vs spark for the timing. They do not use volumetric efficiency calculations to determine load type tables so your theory doesn't work. Now some of the late EEC IVs and all the EEC Vs do use these tables. But in your case if it did work that way all you've done is thrown off the calibrations to the point that the EEC can never receive the proper input there for you would never have a properly tuned engine.

Gutting, drilling and porting a MAF is worst thing you could ever do. I know some of the old diehards think it works and rank right up there with easy mods like putting in a resister on the TPS but it's all just a bunch of snake oil. The MAF is a precision metering device and just hacking it up completely throws off any calibrations it once had. If you had the right equipment to flow it and then could develop a good transfer function for it and be able to program all that into the EEC then you might have a chance. Otherwise you basically just ruined the MAF. Swapping electronics from one to the other is just as bad since each is calibrated to a specific meter. Only time this works is if you are using a C & L meter and they have done plenty of testing before they released their products. And like I said earlier, they still are not the best.

You are detonating more likely because you are running lean due to your uncalibrated MAFs.
 

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icantdrive55 said:
I know I went about it the wrong way. But other than a little tip-in detonation on 87 octane it seems to run well.

My car needs a tune bad. Just can't make up my mind on how far I'm gonna go with it. Might even get a 351w or an exploder p motor. I'm too much of a tightwad to spend $$$$ on a tune yet.


The raised fuel pressure was just a patch.

In hindsight bumping the initial timing to 14* might do more good than the bigger meter.
I'm definitely no expert on efi hot rodding. Every hot rod motor I've owned had a carb till this tbird. Heck, it's not even a hot rod motor...yet.
Well, I can only tell you that messing with a different MAF not calibrated to your engine/car is a sure recipe for grief and expensive repairs. your best friend is a knowledgable tuner, a dyno, and a little caution. also If you are doing any mods knowing the AFR youre running is absolutely necessary, when not stock. To alter a MAF Is absolutely bad mojo under any circumstances :(
 

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just take you old sensor off the 5.0 and put it on the supercoupe Sensor
 

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just take you old sensor off the 5.0 and put it on the supercoupe Sensor
After what has been explained, you base this on what?
 

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Gutting & cutting a maf does work, provided you re-flow it and put the new #'s in the eec :)

ok, yeah its a smart a-- answer :=) but hehe..
 

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WkStill said:
Gutting & cutting a maf does work, provided you re-flow it and put the new #'s in the eec :)

ok, yeah its a smart a-- answer :=) but hehe..
IMHO, you can do a lotta things with a MAF , and ya, it'll work , but how good, and for how long??? (the time interval till you melt down an engine, or sludge up a set of 02 sensors beyond redemption), or, if by sheer blind /dumb luck you come close to getting things right it will only be "close" to right , kinda-sorta, maybe... Going to a MAF that isnt calibrated to your car is the same story... Without a chip/flash , and a knowledgable tuner useing AFR's youre just wasting time/money and bandwidth talking about it here :D
 
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