MY MECHANIC REPLACED THE ORIGINAL STOCK 5.0 EFI ENGINE WITH A BRAND NEW SVO GT40 ENGINE. HE TOLD ME FORD NO LONGER HAVE THE ORIGINAL 5.O AVAILABLE IN BRAND NEW CONDITION...I WAS INSISTING ON BRAND NEW ENGINE BECAUS
E LAST YEAR HE INSTALLED AN OVERHAULED 5.O AND LOST A CYLINDER ..HAD TO CHANGE THE ENGINE...SO I INSISTED ON A BRAND NEW ENGINE AND HE RECOMENDED SVO GT40..AFTER COMPLETION OF THE INSTALATION THE ENGINE IDLE IS FLUCTUATING FROM 200RPM TO 1500. SOME TIMES 800TO 1600RPM...IT RUNS EXTREEMLY RICH AND ERRATIC... HE CHANGED THE INTAKE MANIFOLD..THE EGR VALVE THE O2 SENSOR..THE ECM....THE THROTLE SENSOR...THE TEMP SENSOR.. AND THE DISTRIBUTER WITH ALL THE SPARK PLUG WIRES AND NEW HI PERFORMANCE COIL AND OTHER PARTS THAT HE THOUGHT NEEDS REPLACEMENT...THE ENGINE STILL FLUCTUATES ON IDLE 200 TO 1600 RPMS. NOW HE SAID THAT FORD TOLD HIM HE NEEDS TO CHANGE THEMASS FLOW AND INSTALL AN M-9000-T51 AND ALSO INSTALL A STAND ALONE TRANSMISSION KIT BECAUSE OF THE AOD TRANS THAT IS NOW IN THE ORIGINAL 4X4 XLT BRONCO. CAN YOU HELP AND ADVICE WEATHER THIS WILL FIX THIS PROBLEM...IF NOT DO YOU HAVE ANY RECOMENDATION...I ALREADY SPENT OVER $7000.00and THEBRONCO RPM FLUCTUATES 1600 RPM AT IDLE AND SOME TIMES STALLS

 

First off, what year is the truck ? Yes it could be the Mass Air Flow Meter.

If the truck has MAP, I would say the vacuum line is at the wrong port or the MAP sensor is bad. Also, the idle air bypass could be dirty/clogged or defective.Has he scrubbed the throttle body & plates clean yet.Also check for restricted exhaust which may have burnt the piston on the first motor. Are the injectors wired correctly ? Does the GT40 use the 5.8 fire order ?
It can't be much!
Phillip

 

phillip, thank you for your quick responce ...sory i neglected the year ....its a 1987 bronco xlt efi with aod trans..the mechnic put me a new muffler and changed the pipes to a larger diameter ..i think 3 inch in lieu of the original 2.5??? inch. evrey thing is new ie the mapand all other sensors. the throtle body cleaned.. he wants he wants to change the mass air flow with the M-9000-T51 & install this kit for the AOD trans...this will cost me another 1000.00$ does it sound right????
THANKS AGAIN PHILLIP..........

george

 

>phillip, thank you for your quick
>responce ...sory i neglected the year
>....its a 1987 bronco xlt efi
>with aod trans..the mechnic put me
>a new muffler and changed the
>pipes to a larger diameter ..i
>think 3 inch in lieu of
>the original 2.5??? inch. evrey thing
>is new ie the mapand all
>other sensors. the throtle body cleaned..
>he wants he wants to change
>the mass air flow with the
>M-9000-T51 & install this kit for
>the AOD trans...this will cost
>me another 1000.00$ does it
>sound right???? THANKS AGAIN PHILLIP..........
>
>george

Sounds like you need a new computer. Your orginal computer was speed density and designed for the '87 engine and fuel flow. The new engine you installed probably has a higher fuel flow rate and your computer can't compensate for it.

Dustin

 

DUSTIN, THANKS FOR YOUR INPUT.. CAN YOU TELL ME WHAT NEW COMPUTER I NEED ?? WHAT TYPE OR MODEL ??THANKS AGAIN....GEORGE

 

>DUSTIN, THANKS FOR YOUR INPUT.. CAN YOU
>TELL ME WHAT NEW COMPUTER I
>NEED ?? WHAT TYPE OR MODEL
>??THANKS AGAIN....GEORGE

I wouldn't be able to help you with that as I do not know enough about computer compatibilities or what you need. Do you have any speed shops around you or one that specializes in Musangs? Maybe you can do a search on the internet for EEC's (electronic engine controls).

Dustin

 

First, did your mechanic swap to mass air flow yet, or does he want to swap to mass air flow ? I ask because you mentioned the MAP was new, but the mechanic wanted to change the mass air,or do you mean change TO mass air ? Also,how about the air bypass valve,does it ohm out like it should ? Does the GT-40 use a 351W cam shaft, which would require a 351W fire order,as well as a 351W computer. ( possibly ?, becuase of bank fire vs. sequential fire). Try unplugging the MAP electrical to see if it smooth's out! What about fuel pressure before & after the pressure regulator ? I don't have anything on a GT-40,such as cam specs and comp. ratio,so I can't say if it would work with a MAP system.
Phillip

 

PHILLIP, THANKS AGAIN,REALY APRECIATE YOUR INPUT..YES HE HAD TO CHANGE TO THE NEW FIRING ORDER AND HE WILL CHANGE TO THE MASS FLOW SYSTEM.. IN FACT WE JUST ORDERED IT AND SHOULD HAVE IT NEXT WEEK ..MAY BE THIS WILL SOLVE THE PROBLEM.SO IT SEEMS HE WANTS TO CHANGE FROM MAP TO MASS..THE WAY I UNDERSTAND IT....DOES IT MAKE SENSE TO YOU?? I WILL LET YOU KNOW WHEN HE INSTALLES TO THE THE NEW MASS CONVERSION IN LIEU OF THE MAP... BEST REGARDS......GEORGE....PS I MAY HAVE MY MECHANIC COMUNICATE DIRECTLY WITH YOU....THANKS AGAIN

 

I will be out of pocket until the begining of next month,so I prolly won't be able to talk much to your mechanic except by e-mail. In lieu of this, here are some links I have found concerning mass air conversions.These are pretty much truck links, so be sure to look for Mustang links as well.
<a href="http://www2.austin.cc.tx.us/ESA/tc_auto.html">http://www2.austin.cc.tx.us/ESA/tc_auto.html</a>


<a href="http://efi332.eng.ohio-state.edu">http://efi332.eng.ohio-state.edu</a>/ (you have to navigate until you find the ford eec-iv stuff,pdf file starts on page 20)

Phillip

 

The reason you need the mass air is because of
the B-302(hiper roller cam) that comes in the
gt-40 motor. It is a 220 degree duration @.050"
lift with .480" max valve lift. This motor
idles around 800-900 rpms with this cam. You
might need a higher stall torque converter also.
And it also might not pass emissions with
this cam(it is not emissions legal). Sounds like
the mechanic did'nt really research all the
crate motors that ford offers. I know that
summit racing was selling new 302 motors complete
with fuel injectors/electronics for about $2,500.
The ford motorsport catalog also listed
some new 302s that were originally used in
crown vic's and pickups. Might be waisting money
converting it to mass air so it will idle properly
only to spend more to install a higher stall converter and then to fail the emissions test. A
$250.00 custom ground cam from Lunati or Crower
would be my solution. You want low end power not
high end for your bronco. Its not a mustang.
Just my 2 cents. Don't be discourged with
motor though it is an awsome motor, its just
you might need to change out the cam to something
a little less radical.
Rob

 

ROB, THANKS FOR YOUR INFO ..I THINK YOU ARE CORRECT IN YOUR INFO AND IT SOUNDS LIKE I HAVE LOST ALMOST $8000.00 .SOUNDS TO ME I NEED TO START ALL OVER AND GO BACK TO THE ORIGINAL SET UP...WHAT DO YOU THINK/??? SHOUL I GO BACK AND BUY A NEW 302 AND CHANGE BACK TO THE ORIGINAL SET UP OR CONTINUE WITH THIS MESS???i believe you are correct .......thanks again george

 

Since you already installed the motor, i would
keep it. Just change out the roller cam. Check
with www.crower.com, www.lunati.com, and with
www.cranecams.com. I don't remember the website
names but these are the 3 main manufacturers for
camshafts and a roller cam will run you anywhere
from 150-250(custom ground). Felpro gaskets should run around $50 for the job and should take
your mechanic about 4 hours to change. You can
also run the stock 5.0 H.O. cam. Its has a good
idle and pulls to 4,400. Check with www.corral.net and go to there classifieds. Your
guaranteed to find a new or fairly new stock cam
real cheap(maybe free since those guys alway add
hotter cams to their 5.0s and junk the stock
stuff!!). Good luck.

Rob
78 f150 w/302 h.o.-carbed
71 mach1 w/351c
89 must gt w/302 h.o
and soon to have 2000 expedition 5.4