as you know i fabricated and installed a m90 on my 95(with ODBII) OHV 4.0l.

i'm running a 190 in tank pump.
SC 30lb injectors along with the SC MAF (wires cut spliced to work).
the IAC and TPS are SC sensors (again wires spliced to work).
180degree autozone thermostat.
aeromotive adjustable fuel pressure regulator.

i'm running just about 14-15inches of vacuum at what SHOULD be idle.. i say that because the motor will either idle loopy and die, or rev to like 2k+.

i have the stock ranger computer, no chip, no tuner...nothing.

i had no driveability issues when i swapped in the maf and bigger injectors prior to the m90 install, but since then it only wants to play games at idle..

i was talking to my local SCT tuner and he was saying something to the effect of a 25% change in volume or something with the MAF, and the computer is still calibrated for the stock 19lb injectors, yad yada, something to that extent... and that all drivability issues can be cured with a tune and that none of it is a problem, just hurry up and get the truck in.


what are your thoughts doug, or anyone else for that matter?

i'm not very computer, tunning savvy so if you could explain to me possibly what you think may be going on and what needs to happen i would greatly appreciate it.

to the very best of my knowledge i have no air leaks.. i will check again to make sure but it's hard to tell because it's hard to keep the truck running at idle without reving the motor every now and then to keep it running.

Was Brian running a chip or program with his setups or was he ever using just the stock computer??
Again, any help or input would be greatly appreciated.

thanks,
matt

Matt - have you checked the voltage of the TPS at idle - hopefully it's below 1 volt (.9v is recommended). Are you running the full SC M90 setup with the TB inlet and bypass plumbing? Also, when I started playing with the Paxton on mine, I kept the PCM for 19# injectors, but ran 24's with the SC MAF and it ran perfectly - luck of the draw. If it's just a mismatch issue, a tune should be all you'd need to get it right, but you stated that it ran OK before the M90. I'd look harder at that M90 setup first.

Brian had a new tune from Doug to get his to run properly.


Bird

I agree, a tune should take care of it as long as all the wiring is right and the tps is adjusted. If all those parts you bolted on had worked right without a tune I would have told you to go play the lottery because luck was surely smiling on you!

By the way, nice looking truck. That generation of ranger was never my favorite but your truck just might change my mind.

everything from the TB to the blower is factory SC.. after that is my own. i made sure the bypass was connected and it works perfectly.

the tps is .98volts at closed throttle and 5volts at WOT...been up and down and all over that from the beginning.
maybe a good tune is what i need.. i just wanted the opinion of others who know more then myself about tuning and computers..

hopfully doug sees this and throws in a little tid bit as well.

thanks guys,
matt

everything from the TB to the blower is factory SC.. after that is my own.

Unless you are also using the SC pcm as well (which obviously wouldn't work) then the fact that they are factory parts is moot because as far as the pcm is concerned they are still an unknown entity. You still need a tune so the pcm has the proper tables to work with the big injectors and SC maf.

Unless you are also using the SC pcm as well (which obviously wouldn't work) then the fact that they are factory parts is moot because as far as the pcm is concerned they are still an unknown entity. You still need a tune so the pcm has the proper tables to work with the big injectors and SC maf.


that statement was more for bird so he knew the setup and what parts i was using.

i figured from the getgo that i would need a tune so that the fuel curve would be where i wanted it to be, but i never knew that i needed the tune just so the darn thing would run decent..

matt

that statement was more for bird so he knew the setup and what parts i was using.

i figured from the getgo that i would need a tune so that the fuel curve would be where i wanted it to be, but i never knew that i needed the tune just so the darn thing would run decent..

matt

Based on the fact that you say it worked fine with the SC MAF and injectors prior to the M90 install and if the bypass circuit is all working properly, then the only thing different that the pcm would see at idle from the setup previous to the M90 is the TB and if it's returning the voltages you say it's returning, then it should be idling properly. Are you sure you got the wiring correct on the TB and that it's returning the proper voltage on the proper wire? I would recheck that and the bypass.


Bird

when i put the sc blower on my truck i did have to adjust the idle screw .... with the isc disconnected .... i did have the remote optimizer which also helped with the idle and to get the corecta/f ratio..with the bypass hooked up or not it would idle the same ... the tb has an recessed idle adjustment screw next to the isc .... adjust that to get the rpm correct ....(without the remote optimizer thats all you can do) reconnect the isc and it should be fine ... unless something else is the problem like incorrect a/f ratio

If I was you... Dump the small SC MAF and find something else. If the tuner knows what he is doing....just about any MAF can be used...even a Pro-M. I wouldn't use anything less than 75mm.

The tuner should be able to get it running near perfect. Your combo isn't that exotic.

If I was you... Dump the small SC MAF and find something else. If the tuner knows what he is doing....just about any MAF can be used...even a Pro-M. I wouldn't use anything less than 75mm.

The tuner should be able to get it running near perfect. Your combo isn't that exotic.


well i have a 75mm maf but it had the factory 19lb meter on it... i knew the sc maf was really small so i took the sensor off the sc MAF and put it on my 75mm maf.

i was told that a 19lb factory maf may peg and not allow tuning for the 30ln injectors... make sense pete?

i was also double checking things today, and i dug up an old email from Brian where it looks like he said all of my vacuum lines, the egr and brake booster line should be connected to the INLET (NON-boost) side of the blower..
right now i have them ALL on the boost side...hmmm sound right to any of you?

matt

I ran mine with all the stock injectors and mas Tbody with the blower and never had a problem.
I also installed 24# with the mas and tbody without any tune and it ran just as good.

well i have a 75mm maf but it had the factory 19lb meter on it... i knew the sc maf was really small so i took the sensor off the sc MAF and put it on my 75mm maf.

That could be part of your problem right there. The maf wires and tuning are designed around the specific housing that you are using. When you chance the sensor from one meter to another it could be getting a completely different reading if the feed tubes aren't identical. As for it pegging the MAF, that has nothing to do with the size of injectors it's tuned for it is a factor of how much air it is setup to meter. If you still have your paper work from the Pro-M unit it should have a flow chart which will tell you how much air it's rated at metering. I'd suggest putting the correct MAF sensor back in the correct MAF housing and trying that to see if it fixes your problem.

That could be part of your problem right there. The maf wires and tuning are designed around the specific housing that you are using. When you chance the sensor from one meter to another it could be getting a completely different reading if the feed tubes aren't identical. As for it pegging the MAF, that has nothing to do with the size of injectors it's tuned for it is a factor of how much air it is setup to meter. If you still have your paper work from the Pro-M unit it should have a flow chart which will tell you how much air it's rated at metering. I'd suggest putting the correct MAF sensor back in the correct MAF housing and trying that to see if it fixes your problem.


i was thinking the exact same thing today. i've come up with a few things today that i'm going to have to do..

1) put the SC maf sensor BACK on the SC maf housing and put THAT whole assembly back in the truck (the stock ranger maf i would think could not handle the amount of air passing through).
2) when i take the manifold back off i need to plug all the vacuum ports i put in it for the brake booster/FPR, and such.. and tap more lines on the INLET side of the blower for all the vacuum lines. (this is also interesting understanding the logic of some because on the supercoupes the vacuum line for the FPR sees boost, it's on the blower side).

in any rate... i have a damn cyl #1 missfire that i absolutely can NOT get rid of and it's driving me up the wall. i changes autolite 764 plugs(gapped at .040), i put i BRAND new bosh 8mm wires and a brand new coil pack.. still having a missfire when you just barely touch the throttle (any gear). as soon as i get on it a bit more the missfire dissapears.. i'm checking the injector next.

thanks for the ongoing assistance guys... i think this may be the home stretch. i want more those vacuum lines, change MAFS, and fix this missfire... install the intercooler and then take it to be tuned and dynoed to cure drivability issues and make some power...

couldn't do it without your help guys, a sincere thanks.

matt

Two things:

First stop thinking in terms of injectors and mafs being related AT ALL from the factory. One has absolutely nothing to do with the other in the ford pcm. Only aftermarket mafs are fudged to “match” a certain injector size. So the practice of using a maf and injectors from the same vehicle is based on wrong info.

Second, I would allow the fpr to be boost referenced. When there is boost present in the manifold the amount of fuel the injectors can flow is proportionally reduced. By referencing the regulator to boost the fuel pressure is raised to compensate. That being said, if your injectors are big enough a good tuner should be able to make it work no matter which way you do it but if you change the boost you’ll need a retune. Whereas by referencing the fpr the fuel system will compensate somewhat for small boost variations.

Your spark plugs might be gapped a smidge too big causing that #1 misfire if it is only misfiring at high rpms, if at idle or low rpm's...I'm lost with you.
Jesse

Matt,this has nothing to do with your problem just a question.You runnin with stock or forged pistons.

LATER OMAR!!!.

the 19# injectors should be okay for you to get it up and running, if it willnot idle right it is not due to too small of an injectory you would see that at the upper RPM. I would but the factory MAS back in if that matches you injectors and gap your plugs at .035.

curt

i've been thinking about doing the same thing curt, thanks.

omar-factory pistons.

the misfiring is when you lightly touch the gas.. if you get on it a little more, or 1/4throttle-WOT it just dissapears..

i've been wondering if maybe the injector on #1 is no good..

i'll get a chance to work on the truck sometime this week.

thanks for the ongoing help guys, i apreciate it.

matt

you seem to be having a lot of problems related to either to rich or to lean at idle .... what is your maf voltage at idle .... it should be between .7 and .9, by blower and turbo ran best at .88 . if you look at the sc tb inlet all the vacuum lines connect to it, so there is no reason why they need to be hooked up any other way, i had all the vacuum lines connected to the boost side of the tb on both the sc blower and turbo motors .... if the bypass is open of closed doesn't matter because the air is still metered .... i did run it with the bypass opened all the time for testing of the intercooler (with no idle problems at all) to see what the temps were in and out .... i gapped my plugs at .035 ..... i went from a n/a 4.0 to a sc blower to a sc intercolled to a turbo to a turbo intercooled all without a chip, stock computer ... with the last set-up i was putting out 291hp and 345tq .... all tuning was with a pro-m remote maf calibrator ...... and yes i chip would have gotten me more power but since i was the setting so many times i didn't want to spend money everytime to get it programmed, plus dyno time, if i could find someone to even program it for me ... also i did have idle problems with the breather on the valve cover( it is not metered air) so i did connected it to the inlet tube before the blower .....

do you have an a/f gauge ... what is the voltage of you o2 sensors

just an update...

put stock injectors and maf back in the truck and found out that the problem was the splicing of the maf wires.. i just need to fix the TPS problem and find a good spot to plumb the egr to.. i'm really thinking about just deleting it altogether. i was reading that i could remove that and the two sensors and all the vacuum lines extra on the driver's side of the motor..that would be nice, and i know the tune would get rid of any problems.

truck makes 19" of vacuum at 1000rpms now. as soon as i get rid of the idle lingering high problem it should be all set..

the maf wire mixup was why i had so many problems at idle.. i no longer have any cutting out, no sputtering, no missfiring. it runs smooth at any rpm (thank god, bout time).

i'm replacing all the pintle caps and going to set up some kind of rig to pump injector cleaner through all the 30lb injectors and then i'll put them in and go from there.

thanks for all the help guys.

matt

just an update...

put stock injectors and maf back in the truck and found out that the problem was the splicing of the maf wires.. i just need to fix the TPS problem and find a good spot to plumb the egr to.. i'm really thinking about just deleting it altogether. i was reading that i could remove that and the two sensors and all the vacuum lines extra on the driver's side of the motor..that would be nice, and i know the tune would get rid of any problems.

truck makes 19" of vacuum at 1000rpms now. as soon as i get rid of the idle lingering high problem it should be all set..

the maf wire mixup was why i had so many problems at idle.. i no longer have any cutting out, no sputtering, no missfiring. it runs smooth at any rpm (thank god, bout time).

i'm replacing all the pintle caps and going to set up some kind of rig to pump injector cleaner through all the 30lb injectors and then i'll put them in and go from there.

thanks for all the help guys.

matt


Sorry, I've just seen this.

You need to get a 96up GT 80mm MAF and then get it tuned by an SCT dealer. The computer is set up to run alot leaner then the s/c truck needs and if you confuse it with different maf's and stuff then you're not doing anything but causing yourself more headache's. One dyno tune, if you have a good tuner, and all of your issues will be gone. The EGR can also be removed in the tuning files as well.

Get it tuned, you'll be alot better off.

Later Doug

Sorry, I've just seen this.

You need to get a 96up GT 80mm MAF and then get it tuned by an SCT dealer. The computer is set up to run alot leaner then the s/c truck needs and if you confuse it with different maf's and stuff then you're not doing anything but causing yourself more headache's. One dyno tune, if you have a good tuner, and all of your issues will be gone. The EGR can also be removed in the tuning files as well.

Get it tuned, you'll be alot better off.

Later Doug

not as sorry as i am!
so i can't use either an 89 or 91 supercoupe MAF? i have both just sitting around.. the 91 is a 75mm.

if i can't i guess i'll just have to pick one up.

thanks for getting in here and giving your input Doug..better late than never!!
thanks to all that helped,
matt

No, don't go backwards with your setup! Using anything old like that will definatly be a step in the wrong direction. A 80mm GT maf can be had for most of the time less then $50 off ebay or some other mustang site. It is also very easily adjusted to your tuning using the SCT software and a dyno, I just done one this weekend on a 04'.

Check out my other post for more info on that.

Thanks, Doug.

I think the reason doug suggested the 96+ GT maf (correct me if I'm wrong here Doug) is because most tuners will have the transfer function for that MAF because it is more common for them to be tuning mustangs. But if you can find a tuner that has the transfer function for the SC maf it should work just fine. You may give up a bit of hp because it's 5mm smaller but not a heck of a lot.

Unless the range on the SC maf is to low and Doug thinks you might peg it.

Definately running bigger injectors is going to cause issues as well as a MAF thats not tuned to work with current ecm.I am running 72lb injectors and would have never ran good without tuning and adding the hex codes etc etc.With the injectors you may get with a lower base fuel pressure to help with idle.Even when i ran the 36lbers on the 30lb file it ran rich at idle.There are some good sites out there that have the needed transfer files for the bigger MAF.I am using an 80mm from a Mark VIII.