Hello,
I recently purchased a Ford cam shaft part # M-6250-A312 (duration: 290 intake/300 exhaust
Duration at .050 in. cam lift: 214 intake/224 exhaust
Gross valve lift: .472 in. intake/.496 in. exhaust
Lobe separation: 107 degrees intake/117 degress exhaust
Peak horsepower rpm: 5,000
Peak torque rpm: 3,500
RPM range: 3,000-6,500)
I was told (By Down's Ford in NJ) that this would be compatible with my setup. I have a 1991 Ford F-250 with a 302 EFI engine, with a C6 Trans and 2200 rpm stall torque converter. I also added a Ford Motorsport mass air conversion kit part # M-9000T50. I had this part installed last week and I'm having the following problems: poor idle performance, stalling at idle and a slight hesitation on the bottom end,Top end screams like a champ though.
My question is, will the computer in the mass air conversion kit accept these new cam specs? Or do I need to get a chip made for the computer? Is there any other advice that you can give to me? Any help that you can give is greatly appreciated. If you need any further information regarding my setup, please feel free to contact me.

Thank you,
Jerry D

 

looks like you are in the same boat as I. I have the exact same setup but I am running a roller block with about 350 HP.

I am having the same problem as you. Low RPM hesitation and semi poor idle. I have narrowed mine down to a vacuum problem (ie cam seperation too much for adequate vacuum). I would check your vacuum and go from there. Mine is at 10-12 lbs which is too low.

I went a step further and used a buddies computer that was programmed for the same mods (his is a speed density from a mustang with the same motor, according to ford no computer diffrerence!) I connected swapped everything back to speed density and it ran completely horrible. There are people here who completely disagree with the mass air swap but this is an example where the speed density custom burnt chip does not work at all!!!!

Speed density seems to be ok if you don't get too radical and watch your vacuum. With my setup at 350+ HP I could not get it too work.

My next step is probably to swap out my cam for one with lower peak Torque RPM and less lobe seperation. I have not found the right one yet!!!!

 

wow, I just noticed..... a F350 with a 5.0??? is this custom?? also how does the 13" lift with 40 inch tires work out?

 

You guys spent a lot more money then you had to, why didn't you just get a custom chip for the speed density? It runs the same if not better when setup properly. Did you get a chip for the MAF when you put those mods on? It's a rather large misconception that speed density is hard to put mods on.


Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster American Thunder Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds .

That's it for mods now, saving for a Stang. Check out my Gallery for a look-see.

 

>You guys spent a lot more money then you had to, why didn't
>you just get a custom chip for the speed density? It runs
>the same if not better when setup properly. Did you get a
>chip for the MAF when you put those mods on? It's a rather
>large misconception that speed density is hard to put mods
>on.

Man, you gotta listen, a GOOD custom chip will set you back about $400. MAF is about $675 but is TOTALLY adaptable to more changes. I don't wanna spend more cash for reprogramming each time I decide to modify my truck. I built a SD cammed car and would barely run even with tuning.

SD will take tons of mods minus a cam or rockers. No SD car will run better than a MAF car, a SD car guesses for A/F and idle, MAF uses a direct source of air for the computer. Why resort to junk EFI if you don't have to?

Do what you feel is okay (I do what I know works), I've learned from experience and SD is not good for cam changes.

 

Well just go to the race track and see how many guys use speed density in their mustangs. Maybe a handfull. I've done several FI 5.0's and I guarantee that a mass air system will run better than home brewn speed density system. Why do you ask? Well The system that you talk about MUSTANGGT is a system that must be done right at a dyno shop. And then once that is done you have to take it there everytime you change something. Of course you can call in the modifications to a chip maker to program too, but how exact is this. Every engine is different. HP and TQ ratings can change easily! Mass air is not that way. If I upgrade from a stock air filter to a modified one I dont have to have my truck laid up waiting for a new computer.

Mass air is more sutable for back yard mechanics (Like Most Of Us). I am interested on where you get your info about why speed density, and batch fire injection is better? Think about it. Why would ford, chevy, mitsubishi, nissan, subaru, dodge, and several others switch to factory mass air setups.

I tell you that I have loved every kit that I have put into mustangs and trucks and recommend this to anyone looking at high performance. If you are just putting exhaust, filter, and ignition then I would stick with speed density. Otherwise It's worth the bucks not to keep changing computers all of the time.

 

>wow, I just noticed..... a F350 with a 5.0??? is this
>custom?? also how does the 13" lift with 40 inch tires work
>out?
All custom man!
It was a F-250 at first,then i went to a solid axle (Dana 60) up front and a 60 in the rear....1 ton baby. So it really is a F250.
13" lift came from 6" suspension lift,3" body,3" reverse shackle kit,and 1" from adding the Dana 60's.

Back to the problem....i was thinking maybe a TPS sensor....i mean the vacume shouldn't be that bad,i don't think my cam too radical.
Any thoughts.

 

Brett D...at least someone out there likes that ease of operation as I do!

You may have a lack of fuel at idle? Or too much. I had way, way too much (at idle) when I used an E-cam a while back. I got an adjustable FP regulator and an adjustable MAF from Pro Flow.

Your computer should easily be adaptable to those changes as it isn't a monster cam.

If you still have problems, get a cam that specs out like:

212/218 or 214/220 w/.480" lift and 112-114LSA. I've learned that a narrow LSA (the e-cam is 109 and that B-cam is 110) causes idle problems too. So, 114 is preferable.

Good luck

 

Well,i replaced the throttle position sensor to day......still runs like *****.
It's gotta be something stupid and little ...right?

 

MAF is easier to tune, and overall is better. I take back my statement that SD will run better. However, SD can run as good. I learned a lot from "lightning2fast" and others when i wanted to put a supercharger on my truck. You don't need to reprogram the chip for every air mod. you do the major mods, and then convert with them. The only things you really have to worry about are cams and intakes. There are a few SD friendly cams that make the engine run suprisingly well with SD. Racers use MAF because they have the money, and it is easier overall. It's more difficult to have SD, but cheaper. I've read some posts here that discuss peoples opinions on the MAF vs SD discussion, and i belive it did come to the conclusion that you can modify an engine with SD, it's alil more difficult, but cheaper. I myself wouldn't convert, I believe you need a similar "400" dollar chip for the MAF as well, and this is the first time I've heard of MAF conversions for less then 700, but i havn't researched much into how much they cost. Keep in mind that sometimes a bigger MAF needs to be installed, or the chip. The MAF runs on volage I believe, and when to much air comes in, the output voltage becomes maxed, and there is more air going in than the computer understands. So you either need a bigger one, or a chip for the computer. I am not very experienced with MAF, so I can say that. But I can say that you don't need MAF to have a powerful modded motor, if you do it right. SD isn't as bad as people think. I am not extremely experienced here, so I'm not going to try to step on someones toes, i'm just giving my 2 cents i guess.


Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster American Thunder Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds .

That's it for mods now, saving for a Stang. Check out my Gallery for a look-see.

 

I got my mass air system for 650.00 from summit. It's a ford motorsport system that they advertise all of the time. It's worth it to me to spend the extra $200.00 and get the mass air system instead of the custom burnt chip. Also mass air will 90% of the time give you better fuel mileage and less emissions. Why do you ask? Well sequential fires each injector per cylinder rather than four at a time. Resulting in better fuel economy, performance, and less emissions. I just wanted the freedom to install whatever I want to my engine without having to get it dyno tuned to run perfect!!!


dvldog458: I'm sorry I got on a little tangent there..... Back to your problem.. Check your vacuum next and see what the reading is. This is the next place I would start!!!!! It may be a leak or too low vacuum!

 

I'm startin to get alittle pissed at this truck!Now it's running really *****ty.It won't even hold an idle......something else is wrong now.
It's gotta be something electrical,it has poor low RPM's and stumbles off idle,almost like its missing.Maybe a bad mass air meter?I'm lost on this one.

 

It can still be vacuum!! I wouldn't single that out! Check the vacuum and fuel pressure before you start throwing money at it! We'll figure this out!!!

 

You may have too much fuel at idle too. If you have an adj FP regulator, try turning the FP down to like 30psi and see if it will idle. That is how my E-cam car would idle. So I scored a tunable meter for it. If not, then...maybe you have vac to your EGR stuff at idle, that too is bad.

 

Oh that tunable meter will allow you to set Base and WOT injector pulse width. Thus allowing less/more fuel at Idle and less/more WOT.