Can anyone tell me if it is possible to run that intake off of an '87 ECM that requires MAF. What I am curious about is when the MAF is disconnected, my car still run very good. I realize that the computer is not reading efficiantly, however is it just working on some kind of a "limp mode" and spurting a pre-set amount of fuel based on rpm and throttle position. I assume the MPFI is in an open loop when the MAF is disconnected.

What my thoughts are is if my injector harness will just plug right into the six injectors on the Falconer intake (I will fit it with 19lb injectors and can turn the fuel pressure down if needed). Will my fuel system pulse a linear spurt pattern through the rpm range without a MAF hooked up.

Basically, will it work without butchering my factory wiring and ECM to get this thing to run correctly. I need to retain the factory harness and sensor "availabilty" so I can re-fit original smog check functioning at a days notice.

 

There would be no way at all to meter fuel. I would HIGHLY advise against even considering something like this. You'd be far better off switching to a Speed Density system. If I had a camera I'd show you a picture of the adapter I'm building to avoid butchering the factory harness... it's not the prettiest thing in the world, but it'd take under an hour to fall back to MAF, most of that spent trying to figure out where to put the MAF sensor itself since my intake tract won't be plug and play in that respect.

 

Ya need a programmable computer like off one of them EFI carbs. They have 0 sensors but maybe an 02.

 

...

Gumby, you obviously don't have a clue what you're talking about.

Yes, Computer Controlled Carburetor ECUs are simple... they use an O2, CTS, TPS, and Tach.. but they are not designed to run an EFI system. They lack the complexity, processing power, and don't even have injector outputs anyway.

EFI systems all have one thing in common, and one primary requirement above all other components... a device to measure the amount of air entering the engine. With MAF systems, this is obviously the MAF sensor. With speed density systems, in its simplest form, it is tables based on MAP vs RPM (the MAP sensor being the key component). Both systems simply cannot operate correctly without their respective airflow measurement. Failsafe tables will get a car home, usually.. they are not designed to be driven on.

 

You should have a little bit more tact being a mod.

Your being an ***. Deal with it.

 

Tech, Here's my thought

If the computer does have what you are dubbing "Failsafe tables". I have run my car once for about 50 miles this way without the MAF hooked to try it. It ran very decent.

What I can do is run a digital guage hooked inline to the O2 sensor do I can have a stoich gauge in cockpit (Autometer CompZ; part # ATM-2675) and a good AFPR in the Falconer fuel rail. Wouldn't this just simply then act like a carbed engine and as long as I bump the fuel pressure up or down to run the basic desired RPM range wanted to run in the stoich zone. It won't run efficant I understand when it comes to clean burning, but what race car does with an intake setup for racing. I'd like to be able to pop this thing on with the factory intake remaining completely separate with its own original FPR and injectors. Simply clear the codes on the ECM and reinstall the factoy system?

Am I still off base with my thinking? My O2 sensor would still work with the Stoich gauge because it with have power to it, or I can just spend the money and run another redonant O2 bung and sender.

 

when the maf is disconected, the computer has a set value already programed into it t compensate for a disconected/fried maf (kinda makes you wonder that they knew about crappy mafs to begin with)

 

My assumption exactly. Thankyou. Is this by chance what is refered to as PE mode?

 

No, PE mode is Power Enrichment. It is just another table that the ECM uses under WOT (wide open throttle) to make the car go faster. Running your car without the MAF plugged in may seem fine but it also negates to use a couple tables including AE (accelerator enrichment) and PE. The generic tables built into the ECM are just to allow the car to run but you will notice considerable losses in power and fuel comsumption.

 

speed density seems like the only way to go to include all the fundamental sensors true, but speed density system compared to maf doesnt take to kindly to extensive engine modifications. so while switching to speed density may be a good idea because it includes all the sensors, you may run into problems with the sd not being to cope with your setup anyway.

 

I already stated that I ran the car without the MAF hooked for about 50miles and noticed no difference at all running and only a little wandering at idle (Very minor).

As for fuel consumption- like I give a crap- otherwise I wouldn't be building a race motor. Peerformance motors- in case you aren't aware, do burn more fuel. You need fuel for power.

No one has really answered my question though about will it work long term without frying anything. Is the portion of the computer that runs limp mode made of inferior electronics that are designed for only temporary function and not full time? As is anything like heat sinks, etc... that the main functioning system has but limp mode doesn't.

I personally don't care that the MPFI ecm is not reading efficiantly, All I am concerned with at this point is running that intake as if it were a pre-jetted carburator. As long as fuel pressure is set to run this at and near stoich in the powerband, I could care less if it idles a tad rich.

 

Like I already said, it will run but you will not notice a difference involving the tables. The problems will present themselves when attempting WOT. Without the MAF involving a ecm that needs the MAF, you will not get decent and reliable performance gains. The fuel comsumption increases because the computer can't operate correctly since the MAF is disconnected and the ecm goes into limp mode, not because you have a performance engine burning more fuel.

 

Sorry about the double-post.

 

Yes Dean, it is possible (sorry I'm posting late, My net was down). Your ECM has a special table that negates certain data to remain running under certain conditions. Yes, it is called Limp mode. It doesn't use real time data, just a linear fuel/timing map. The whole idea of a MAF/MAP system is all in the name of gas mileage. However, this "preset map" can be modified (or so I've been told). Anyone can force their computer to use this preset table by simply diconnecting the Coolant temperature sensor (at least on MAF cars). Limp mode was designed as a fall back protocol for damaged componets (MAF/MAP, EGR, CTS, O2S, and I think the IAT sensor, have to look it up.). It was also designed to aide in troubleshooting damaged ECM related, fuel injection system input devices. The pulse width of the injectors will go to a preset in this mode (will take data from TPS to measure fuel delivery). The MAF/MAP inputs will be ignored completely. SO, what this means is that if you want to do it that way, YES it will work, BUT you will need some special mapping done for this file in your ECM. (I'm worn out so I hope I didn't make too many mistakes...)

 

Now there's a famous misconception. Don't blame the electronics for people's lack of desire to correctly tune their setups. Speed Density responds just fine to modification so long as you take the time to smooth out a new chip

(You're right, on the stock chip it responds horribly to modification since the VE tables no longer match up with the engine's VE... but anyone willing to invest in an EFI race motor should be doing it right, not trying to hack around it)

Dean, even carburetors have a means of measuring airflow, albeit mechanical... venturis.

Man, if you don't want to listen, that's fine. MAFless MAF is a horribly bad idea. I suggest either taking the time to learn exactly how these EFI systems work or investing in a half dozen weber carbs before blowing up your motor... but if you just want to stumble on with your misconceptions, I'm not in a position to stop ya. Just don't say you weren't informed that what you were doing is a very very bad idea thousands of dollars in wasted destroyed parts later.

Try asking this on the DIY Prom board... the number of laughs and flames you'll get should speak volumes for how absurd this really is.

 

He won't be blowing his motor...that's absurd. He darn sure won't be making as much power as he COULD though, that and his gas mileage would be horrible (but I have a feeling he's like me and doesn't care about mileage). It will run on the rich side of things under limp mode, not the lean side (I've proven this with scanning equipment before on my own car). It's not dangerous, just isn't a good idea as far as making power goes (unless some things are changed). There isn't a way to convert that intake to MAP anyhow, there's nowhere to put the sensor it seems (at a glance). BUT, there's no reason he couldn't modify a housing to fit over the velocity stacks so it could pull air over a MAF either. He'll be using the setup on an endurance basis more than likely (high rpm for extended periods), if it runs a little choppy at idle, it isn't a prob (again, more than likly). As long as he stays near say 13.0-14.0 A/F at about 3000-6000 rpm, he'll be fine (and there are mechanical wyas of achieving this. Sometimes you have to make it work with what you got

 

Tech, I tend to favor more what Fbod and I are saying and I'll explain why.

The original computer that GM used to run this intake was a programable electronic fuel injection module that determined fuel misture according to only engine speed and throttle position. This intake WAS INDEED run on a very expensive motor(s) without EVER the use of any air metering device other than monitoring the exhaust gasses for stoich (14.7 Air/fuel ratio),. If it was low, they'd turn down the fuel pressure to the injectors manually, it it was high, they'd turn it up. Fbod is also correct that it would always want to be ran favoring the rich side like you would on any carb jetting.

Carb venturies don't meter air, they create vacuum to draw in gasoline flow from the jets to create the desired fuel ratio. This is why both venturies and jets are adjustable in carburators. I know carburators.

Of course now, carbs suck gas into the ports- injectors force (Or spray) gas into the ports. Only difference. Get the proper amount of gas pulse from the injector to match the air volume coming in based on the air/fuel gauge reading stoich on the exhaust and you wount be losing any performance. I think the mistake hear is assuming the car will be running on limp mode without changing any fuel pressure for proper stoich at the tail pipe- I will be utilizing metering gaiges and fuel pressure adjustment.

 

I think everyone overlooked here is that I only want to know if the factory ECM had pre determined pusle tables for the injectors as long as the TPS was hooked and everything else was disconnected or broken (EGR,IAT,o2,MAF, ICT) You guys have basically answered me yes it does have the linear failsafe charts.--Sorry guys, but thats all the advice I was asking DOn't need a leachure about blowing motors from running lean or a lecture on wasting gas milage.

Thank you everyone for the help

 

No problem, let me know what methods you take to tune it if you try this. I'm looking for a way to ditch all this real time EFI crap anyhow (the only thing keeping me from going carb is the nitrous and the fact that I like how the stock plenum looks =P (oh yeah, and laziness, lol). I suppose by all of this it means that you ARE in fact going to be bidding on the Falconer display??? PLEASE say yes! :lala: :hail:

 

If that was all you wanted to know, why did you even ask? You said you already drove the car 50 miles.

 

I was trying to figure out if the car was still running off the tables on the prom (aftermarket prom), or if the computer was taking over with a different set of tables. I am trying to find out if I even need to bother with a different prom chip to run this intake.

If the ECM has its own failsafe tables, then that is what I am looking for to run this thing without any sensors (other than a TPS). and just retaining the prom thats in it for ignition curve

I also asked if its bad on the computer heat wise or anything like this- If your an expert, how about answering that for me instead of being sarcastic- Personaally at this point, I would not trust an answer from you. Also your comments on another board about being able to produce an intake of this caliber for under $1000 AND make a profit in incredibly naive. I have seen the thing you welded together and I would not pay $50 for it. Do you have any idea what a casting of this caliber would take + injectors + TB's+ velocity stacks + linkage- I rest MY case. (I suggest you watch who you challange verbally) This was simply thying to find out more info on the factory ECM unit itself, something I have never studied yet.

 

?
Are you serious? You can get by with unplugging the MAF but NOT unplugging more sensors on top of that. The ecm would have no reference regarding certain tables. Did you already try unplugging everything except the TPS and seeing how it runs?

I tried answering your questions and when I told you what you DIDN'T want to here, you simply ignored the information I gave.
And yes, I can make those intakes for the price I gave. I think your naive thinking that it can't be done for under that. Profit, I'm not trying to make $500 off of it. But if you would want to give me more money, that's up to you. I know what would need to be done but of course no one has stepped up to the plate.

You wouldn't give me $50 for what I am using now. Good, neither would I. That's a test casting. Why would I pour a bunch of money into the car and not get any gains out of it? We have had to modify that intake several times over to become happy with it. My whole car is that way. I won't make anything 'pretty' on the car until I get the gains I expect out of it. But I suppose spending $1250+ on an intake and hoping that you can frankenstein the ecm to make it run will be worth it.

This is exactly why I stopped posting here the first time. It's like some of you guys have a chip on your shoulder or something. I tried to help and I get this. I suppose it doesn't matter I have been flashing gm computers for a couple years and selling that product or have been working on these chips since February. The only reason I joined this board was for the DIY prom section.

 

Dean, just swap to a '730 (or '749, if you ever intend to run boost!) - they are both MAP based. Simply hook up the MAP to a vacuum port under one of the throttle body

 

Thanks Doward, And congradulations to you and your new better half.

The thing I don't get (so explain it to me please) Jericko is how did this Falconer intake in existing for manage to run properly on the motor it was on without the use of any air flow monitoring? I stated a fact that the original ECM used toorun this motor with this intake ONLY registered engine speed(RPM) and throttle position (TPS). They could dial up or down the injector pulse width based on what the exhaust readings were delivering- that was it. So please explain how it worked for them and not for me trying to run this setup some how, some why without MAF or MAP

I completely understand that I am not relying on the primary function of the ECM that requires MAF to work properly, I WANT TO USE the linear tables and run this primitive only dialed to the air/fuel ratio at around 4-7000 rpm. This will never be used for a daily driver, only disired use would be running on a road course at the 4-7K range for the day. You have to also remeber that this intake provides the flow for those rpms and I'll fit the injectors and fuel presssure to match those rpm levels also. I am not trying to use the normal function of the EFI tables.

I am building a motor that will produce power from 3-7k but will fall on its face with the reatricted stock plenum. However, For street use and smog reasons, I have to build it to marry the stock intake manifold still for those porposes. I would like to be ablee to drop this in so it will breathe the higher R's and spin to 7K (Bottom end will easily hold 8K). This is an impulse buy- opportunity knocks and these are very rare- I am tring a ditch effort to figure out if this is compatible for my thoughts- You have to realize the motor it will be intended for.

 

O.K- I finally got confirmation on this from someone very experienced. (My neighbor Gordon just git back from his river house- He's in his sixties and has been building performance motors professionally for 35+years) Gordon confirmed that the ECM WOULD indeed run like I assumed, but told me it was very simple for him to outfit it for me with a MAP sensor and convert the ECM top MAP (Just as Doward stated) He said why not just make it work better at all speeds and that he can easily do that for me while retaining the acess to go back to stock quickly.

 

I could swear I said something like that in my first reply...

 

Yes sir, you are correct- please don't blame me for asking and learning. I was just debating what I believed to be possibly a more simple fashion of primitive injection. Was only looking for topend. I would much perfer it to run in the standard metering fashion for efficiancy in all rpm ranges if it can be done easily- but it wasn't manditory for me and I was looking for a shortcut.

I still don't know how an IAC could be mounted to work though.

 

It can't...which is a major flaw in the MAP conversion idea Mounting a TPS would be simple enough, but not that IAC....

 

making the IAC work with that setup wouldn't be too hard either. you could actually just plumb it in to the base of the manifold...if there's some type of plenum area. just have it setup as a valve (well, it is just a valve). have a place where it can open and suck air in. but, does that manifold have anytype of plenum area? now that i think about it...i don't think it does...

 

Is the Falconer intake comprised of 6 seperate throttle bodies, with no plenum per se?

If that is the case, and 'idle air control' setup would be much easier, if done something akin to a carb - a fast idle setup.

Introducing more air into just one TB setup is not going to idle you up - in fact, it'll run like crap - you've now got one cylinder way lean.

You do not need any sort of means of air metering, if you are only concerned with race use. If you do not intend to drive the vehicle on the street much, you'll just need to tailor the fuel/spark maps specifically to your motor's airflow characteristics, at WOT.

I'm not saying the motor would not run well - you could very well have a smooth running motor, with no air metering, if you had the fuel map dead on - the thing is, is that your fuel map would never be as close to 'perfect' as that of an air metered setup - you simply can not have 1 fuel/spark map that is perfect for all air temps, humidity levels, etc. You can run without a MAF or a MAP sensor just fine, provided you tune your fuel and spark maps to the letter.

You will lose gas mileage.

You will lose part throttle response vs an air metered system.

You will run the same, at WOT. Why? Because you will peg PE mode over a certain % of TPS.

 

I think you guys are now seeing what I was getting at. This setup is like the old Hilborn injectors- they were either on or off (Full race only) There was no real partial throttle setup. This is why the linear tables sound so appealing if it would work. This intake is basically from what I see tuned for WOT use always like in the midgets.

Off and tapped through the corners, on full in exit and down the straight

A flow sycro is used to set idle air control on both sides to balance. Each TB comprises of three connected butterflies that are directly tied in sequence and can not be altered- yet left bank 3 and right bank 3 can vary if not syncro'd. Its like setting up Weber 48IDA's on the ol VW engines.

 

Side shot of linkage and TB's

 

The computer they used for the falconer intake was not the same computer that came stock in our cars. They custom built the computer to do what they wanted it to do. It didn't have nearly as many parameters that our computers do. Our computers are different than the computer that they used. All of the tables rely on other tables and other inputs so you can't just unplug the sensors you don't want and hope it works for the best. If you could find the computer that went with that engine you would be in business.

 

I fully understand about the computer they used. This is why I am trying to find out if the limp mode tables in ours would work basically the same as the primitive tables they used- My meighbor Gordon is telling me basically yes it is the same exact priciple the original computer functioned- but it is primitive to use with today's technology.

 

Great, if that's the answer you were looking for, more power to you.

 

I'm looking for the best solution to run this thing, thats why I'm asking. This intake is primitive also, so it is unreasonable to try and fit it with modern IAC and other sensors without trying to hack it.

No one can answer me for certain if the stock ecm will at least run it or not- none of you know for certain- it is all just speculation on your parts because this has never been presented in this old technology fashion.

I have someone who deals with modern day computers on a daily basis (has major $$$ in sophicsticated diagnostic and programing equipment in his shop) that is telling me it will work with the fuel adjustment and monitoring perimeters I discussed adding to the setup. Again, this is not for everyday street driving. It is a setup for ONLY all out track use and won't see any street lights. Its simply a temporary bolt on toy if I can acquire it.

I think I tend to trust his advice when he tells me he can make it work in the car for me without butchering my factory wiring withut costing me an arm and a leg. I only asked this advice here because he has been out of town at his river house and I needed some immediate imput on the subject. Thank you all anyways for trying.

 

There's a real easy way to try it. Just unplug ALL of the sensors on your car that you won't use w/ the falcon intake and see how it works.

 

Jerrico, the problem I have doing that is I don't have the prper adjustments on the car right now to monitor that and set the injector pressure to pulse more fuel pressure at WOT. Of course it will not run as well on the stock setup with no adjustment.

Now if I currently had an air/fuel ratio gauge and a true AFPR + diffent injector sizes to play with (Only have the stock 2.8's and 19lbers currently) I could mess with it quickly enough to richen or lean it to where it should be in the in the aprox 4200 rpm range that this motor handles mid powerband. If I unplug things now, I have no way to adjust it to optimum WOT levels.

 

No, what I meant is that you would at least know if the car runs. It seems like the first logically step before you start spending money on theories.

 

Doesn't idle worth a crap, but yes it runs with the IAC, MAF, AND ICT disconnected.

These MPFI have trouble enough ranging at idle when everything is 100%, At least with this crappy Calif pump gas.

 

When it's in limp, those sensors aren't used. It will run CLEAN at part and WOT, it will idle like crap (as if that matters). Dean, it will run it, ignore suggestions of adding an IAC (isnt possible, BELIEVE me, but you already know that). All you'll really need is a voltmeter or a wideband monitor and a fuel pressure regulator. Tune the fuel pressure by reading the O2 voltage (common sense, i know). People are trying to make this complicated for you, and it isn't.

 

Dean - The best possible setup for that, is going to be a standalone fuel management system, something like the Accell DFI, or FAST systems.

Best for the buck is going to be a '730 MAP based system, minus idle control (for that , you'll be working up something on your own, lol)

Cheapest route, that will run

Your current wiring/ecm, minus MAF. You will be doing some serious tuning, though, as our entire fuel tables are LV8 vs Injector PW. Which means - without the MAF, you'll be running solely based off RPM - and you know your fuel requirements are different for WOT @ 3k rpm, and 70% throttle @ 3k rpm. So you'd have to tune it specifically for WOT, and you'd be rich everywhere else.

If it were me, I'd be looking into getting a wiring harness + ECU out of a '730 based Fbody (90-92, V6 or V8)

 

With Grumpy's publication of his $60 source code based on the $58 (Speed Density Turbo) or Project Super AUJP ($6E Speed Density 350 TPI), you can run around disabling functions in the source code that you won't need, such as IAC routines. I'm sure the DIY Prom guys would be happy to lend a hand on such insanity.

 

Yeah.. it runs fine.. on a stock setup. The amount of work to make it run on a setup VASTLY modified from stock, though, makes it equally prohibitive as the Speed Density swap. If they're going to be the same degree of BS, might as well do it the *right* way and get a more efficient setup in the end.

 

Yikes, I'm not going to jump in on anything that was mentioned previously, but-

GM did release a special prom and service bulletin regarding a change from a MAF system to a MAP system. Besides the prom, it integrated a MAP sensor and re-used the same MAF signal wire, but the MAF relay got bypassed. GM did this because of many people complaining about the fragility of the MAF sensors.

My dad's old '87 Olds had this done to it. It was one of those 5-pin MAF's, with the MAT built into the MAF. (Two wires for MAT, 3 for MAF.) The MAP was bolted to the firewall. I forget where the vac source came from... but there was a few wire patches into the old MAF relay. Might be worth a search on http://www.alldata.com for the service bulletin.

 

bypass the relay.... .. yanno, that's not a bad idea, considering our 3 pin MAFs use the same weatherpack style connector MAPs use.... woohoo, down to only one extra wire I need to run to do my conversion (knock sensor)

 

I let the bidding run out being fairly confident no one was going to buy this entire useless display motor delivered to their doorstep for $1500. Trying to negotiate a deal with this guy for just the intake but he's not biting. Says he wants to relist the whole thing and try it again on EBAY. He's really trying to hope some idiot gobbles this thing up thinking it got the original race block, heads and crank in it when he damn well knows for certain it doesn't (At least he does now because I proved it to him that the casting #'s he has are crap) Everything is worthless except for the intake- thats only partly useless because of no fuel management module.

Every please keep a heads up for this again on EBAY

 

if this does work out, i would suggest investing in a wideband O2 with data logging ability as a standard O2 is almost useless at anything but Stoic. I can say it is one of the best investments i made to my car!

 

you might also want to post this on the efi board at chevytalk.org

 

I'm not trying to be mean or anything but I've noticed that more often than not, your advice hurts more than it helps. Rather than spreading misinformation, just don't reply to a subject that you're not familiar with.

This isn't a personal attack. It's just that I've noticed so much more misinformation on this board than any other board i've visited and that's how people get hurt. *shrug*