1997 explorer engine drop in, runs like complete ass, help!!

v8only

Active Member
Jul 3, 2003
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Figured I'd get more opinions.

It's a 97 gt40p explorer engine into my 86 gt vert.

It's SPEED DENSITY, not mass air.

I'm running the explorer 19 pound injectors, explorer efi intake, 1.7 roller rockers (double and triple checked the adjustment, I'm good here and positive of that) with tfs valve springs.

It's got a stock mustang ho roller cam in it, and timing set to 12 degrees.

Problem is, it runs like complete ass. it idles like it's got a wicked cam in it (bad bad miss) then I rev it up, and it misses like hell.

Dist plugged in right, firing order got right. Plugs are new (got the right ones, the autolite 746 was it, whatever is oem for an explorer) wires are good.

It runs RICH RICH RICH RICH RICH. fouls every plug I put in there black as hell in minutes. Smoke coming out the exhaust is so damn rich it burns your eyes.

stock mustang fuel rail, non adjustable fuel pressure.

Here is the kicker, before dismantling everything, the old engine ran like a top and jUST passed cali smog, so that's why I don't suspect bad parts.

Here is what has been done:

Fuel pressure:

16/17 with motor off
33/34 running

computer codes: koeo : 81

Koer: 4,12,21,22,16,13

vacuum: 12 to 13, slight wavering. This could be due to the engine idling and loping like crap too. (stock ho roller cam)


I swapped out the ect, and it did nothing. I have not swapped out the map yet, but I personally don't think that's the problem, it was just working on my old engine.

I've double checked vacuum, and have no leaks.

Also, i'm bypassing my tad and tab solonoids, and currently don't have the smog tube or bypass stuff hooked up. I'll be running the smog tube, but didn't plan on running the bypass stuff.

any suggestions here? i'm going insane.
 
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Jeremy, I dont have any great ideas. The vac thing concerned me when you mentioned it the other night and still does.

Though you have checked, it still seems like there is a leak if you are using the stock SD HO cam. Have you ruled out a gasket leak?

I have a shadetree test for that if you think it could be possible.

Otherwise, I am thinking that the SD puter is seeing that vac reading and its tabling is getting messed up, thinking you are at part throttle (even if the TPS says otherwise). We know how sensitive the vac signal is on SD set ups (FWIW, to compare with your old and new set-up, my stock SD cam pulls 19.5" hg at idle).

That is what came to mind initially. Best of luck getting it purring smoothly.
 
Fix the codes first. You have smome nasty one that can trick your fuel
mixture and ignition badly.

Code 16 - Electronic ignition - IDM circuit fault - Ignition Systems. Bad
wiring, possible bad TFI. The computer isn’t seeing the proper IDM signal
coming from the TFI circuit. There is a 22,000 ohm resistor in the dark green/
yellow wire that goes to pin 4 on the computer. Disconnect the TFI
connector and remove the passenger side kick panel. Then loosen the 10 MM
bolt to disconnect the computer connector. Use an ohmmeter to measure the
resistance between pin 4 and the dark green/ yellow wire on the TFI
connector. You should see 21 - 23 K ohms (21,000-23,000 ohms). If not the
dark green/ yellow wire is broken or has a bad connection. If this checks out
OK, measure between the dark green/ yellow wire and ground. You should
see 1 M Ohm or and infinite reading. Less that 100 K ohms means a short to
ground somewhere in the dark green/ yellow wire.
eec04.gif


See the following website for some help from Tmoss (diagram designer) &
Stang&2Birds (website host) for help on 88-90 wiring

http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

Diagram courtesy of Tmoss and Stang&2birds.
88-91eecPinout.gif


Code 21 – ECT sensor out of range. Broken or damaged wiring, bad ECT
sensor. Note that that if the outside air temp is below 50 degrees F that
the test for the ECT can be in error.


The ACT & ECT have the same thermistor, so the table values are the same

ACT & ECT test data:

Use Pin 46 on the computer for ground for both ECT & ACT to get most
accurate readings.

Pin 7 on the computer - ECT signal in. at 176 degrees F it should be .80 volts

Pin 25 on the computer - ACT signal in. at 50 degrees F it should be 3.5
volts. It is a good number if the ACT is mounted in the inlet airbox. If it is
mounted in the lower intake manifold, the voltage readings will be lower
because of the heat transfer.

Voltages may be measured across the ECT/ACT by probing the connector
from the rear. Use care in doing it so that you don't damage the wiring or
connector.

Here's the table :

68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61

Note that all resistance tests must be done with power off. Measuring
resistance with a circuit powered on will give false readings and possibly
damage the meter.


Ohms measures at the computer with the computer disconnected, or at the
sensor with the sensor disconnected.
50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms

Code 22 MAP (vacuum) or BARO signal out of range. The MAP or BARO sensor
is pretty much the same sensor for both Mass Air & Speed Density cars. The
main difference is where it is connected. Mass Air cars vent it to the
atmosphere, while Speed Density cars connect it to the intake manifold
vacuum. Its purpose is to help set a baseline for the air/fuel mixture and
changes in barometric pressure. The MAP or BAP sensor puts out a 5 volt
square wave that changes frequency with variations in atmospheric pressure.
The base is 154 HZ at 29.92" of mercury - dry sunny day at sea level, about
68-72 degrees. You need an oscilloscope or frequency meter to measure it.


Baro or MAP test using frequency meter - run the test key on engine off. The
noise from the ignition system will likely upset the frequency meter. I used a
10 x oscilloscope probe connected from the frequency meter to the MAP/BAP
to reduce the jitter in the meter's readout.

If it is defective, your air/fuel ratio will be off and the car’s performance &
emissions will suffer
 
did you put your stock mustang cam back in the engine ???? if not , do so .....put the mustang injectors back on for good measure as well ......after you have done that , double check the injector harness ...cylinders 1 and 2 on the passenger side can get reversed pretty easily ........double check your vacuum lines , there are several on the explorer intake that you need to block off if you used the explorer intake ....make sure you got the PCV back in good ........and make sure you hooked your MAP sensor back up to a vacuum .......sounds like its unplugged ........
 
sounds like what 2000 said. Make sure you put you mustang injectors back in, and make sure your injector harness is hooked up correct. also and this is very important MAKE SURE you have all your grounds hooked up. It sounds like to me your in limp home mode or choke loop! That can cause it to run very poor and very rich!
tell us more about what has been changed? if the cam is set straight up (dot to do you should be fine) just tripple check the timing again, firing order and that your up on the compression stroke when your settting dizy at number 1!
good luck........keep us posted I have the nearly the very same setup going into my 1991 Gt soon, so I'm very interested in what you find, as I don't want the same problems....
Jack
 
2002BLGT said:
did you put your stock mustang cam back in the engine ???? if not , do so .....put the mustang injectors back on for good measure as well ......after you have done that , double check the injector harness ...cylinders 1 and 2 on the passenger side can get reversed pretty easily ........double check your vacuum lines , there are several on the explorer intake that you need to block off if you used the explorer intake ....make sure you got the PCV back in good ........and make sure you hooked your MAP sensor back up to a vacuum .......sounds like its unplugged ........

it's got a stock HO roller cam. the other day, I swapped in OEM mustang 19 pound fuel injectors along with a known good fuel rail and pressure regulator. NO change. All vacuum "looks" good, yet i'm pulling 12-13 pounds at idle which is way too low. If NOT a vacuum leak, what would cause the vacuum to be that low? This is driving me absolute nuts.

POWER302 said:
I thought explorers had 24 lb injectors stock?

19 pounders

Ford_Injector_Guide.jpg
 

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2002BLGT said:
if your running the speed density , take the MAP sensor off and do a vacuum test on it to see if its leaking down .....you have a vacuum leak if your only at 12-13 you should be close to 18

see, this is what has me stumped, the map is brand new. Not only that, but the old one worked perfect before hand, the map is not the problem.

Last night I sprayed the entire engine down while running with carb cleaner, hoping to hear the idle smooth out from a vacuum leak. NOTHING> I've been over the engine 100 times by now, and am 99.9% sure I don't have a vacuum leak.

YET, i'm only pulling 12-13 pounds, and it's missing, stuttering, won't idle, and is dumping gallons of raw fuel out the pipes, wtf gives?

the only thing for me left is to try a leakdown test.
 
A short while ago, one of the guys was having vacuum problems and suspected a leak, but couldn't find it. He pulled the lower manifold off and found that the gasket had slid down out of place. There was a gap between the gasket and lower part of the intake ports on the cylinder head. His engine was sucking oil into the lower intake, and he kept finding it pooled inside.
 
well

if you used the lower intake off the explorer motor then you didnt put the ACT SENSOR back in... cause the explorer motor doesnt have the ACT (AIR CHARGE TEMP SENSOR IN THE LOWER... they put it in the air box ... and if you put yours in the air box... the computer will not read correctly.. you will need to drill and tap the hole in the lower intake to mount that sensor... could be a huge problem for you... also you used 1.7 rockers.. I personally see that being a problem..... I for one have had numerous problems with 1.7s and not shimming the rocker for the proper adjustment... I understand everything thinks just bolt the down and torque them to 30ft lbs and be done.. but once the engine fires and builds oil psi.. the lifters pump up and now you have valves hanging open just enough to give you false compression readings... which would also give you bad vaccume readings... just do the checks and check that ACT SENSOR

13726548 counter clockwise rotation and fireing order
0 thousandths valve lash with proper adjustment
cam shaft dot to dot
1 cylinder tdc with valves closed and rotor pointed straight back

check these and get back to us
 
jrichker said:
A short while ago, one of the guys was having vacuum problems and suspected a leak, but couldn't find it. He pulled the lower manifold off and found that the gasket had slid down out of place. There was a gap between the gasket and lower part of the intake ports on the cylinder head. His engine was sucking oil into the lower intake, and he kept finding it pooled inside.

Thanks, much, I think I'm going to pull the lower intake, see below

coming4you said:
if you used the lower intake off the explorer motor then you didnt put the ACT SENSOR back in... cause the explorer motor doesnt have the ACT (AIR CHARGE TEMP SENSOR IN THE LOWER... they put it in the air box ... and if you put yours in the air box... the computer will not read correctly.. you will need to drill and tap the hole in the lower intake to mount that sensor... could be a huge problem for you... also you used 1.7 rockers.. I personally see that being a problem..... I for one have had numerous problems with 1.7s and not shimming the rocker for the proper adjustment... I understand everything thinks just bolt the down and torque them to 30ft lbs and be done.. but once the engine fires and builds oil psi.. the lifters pump up and now you have valves hanging open just enough to give you false compression readings... which would also give you bad vaccume readings... just do the checks and check that ACT SENSOR

13726548 counter clockwise rotation and fireing order
0 thousandths valve lash with proper adjustment
cam shaft dot to dot
1 cylinder tdc with valves closed and rotor pointed straight back

check these and get back to us


great post guys, thanks for all of the advice.

The act has been under considerations. WHILE my explorer lower has the boss for the act, I, like a dumbass, in haste, completely forgot to drill for it. My act sensor is actually literally lying on top of the intake, bare naked. However, from what i've read, I was under the impression this wouldn't make a big deal, do you really think????


The roller rockers, I've been through several times. They've been shimmed and adjusted properly, this I'm 100% sure of.

I have verified #1 at tdc, and at the compression stroke by sticking my finger in the spark hole.

do you really think the act could do this???

I'm seriously thinking of pulling the lower again, as I need to drill for the egr coolant line too, which I forgot :(
 
i know you said your sure on your rocker arms,but i had the same problem with my 86. wicked cam,smoking,fouling plugs. i was going by the book and torqued them down,double and triple checked. i went back and tightened them down to where the pushrods had no play in them and boom my old car was back. also check vacuum lines under intake, had that bit me in the @ss once. let us know what was when you find it.
 
Here's an easy fix for the ACT...

The ACT (Air Charge Temp) sensor will probably need to be moved. The GT 40 lower manifold isn't drilled & tapped for it to go into the intake like the stock manifold was. There is a boss cast into the GT 40, but a machine shop will have to drill & tap the new manifold. The best spot for the ACT is the air box if you don't do the drill and tap thing. You get to cut and splice the 2 ACT wires in order to make them long enough to reach the air box. Solder the wire extensions on the existing wires & use heat shrink tubing to cover the splices. Offset the place where you cut the wires so that you don't have a big bulge when you put heat shrink over the 2 wires to cover & protect them. The air box gets a hole (5/8" or so) for the ACT drilled about 1 1/4" down & 1/1/4" in on the front top side near the upper radiator hose. A brass fitting nut from Home Depot or Ace Hardware secures the ACT into the air box.

If you are very clever, you will find that the ACT connector comes apart so that you can remove the pins. A very small screwdriver releases the lock in the front of the center insert, while another small screwdriver inserted in the back pushes it out. Once the center insert is out of the connector shell, the pins come out easily. New pins are available from AutoZone in a $5 electrical pin kit for Fords. Crimping the pins on the extender wires saves you from having to splice them twice: once to put the connector on and once to extend the wires.

6 ft black 18 gauge wire
6 ft green 18 gauge wire
6 ft 1/4" heat shrink tubing
1 ft 3/16" heat shrink tubing

Measure the 2 extender wires & cut them to length, crimp one set of pins on them. Then mate up the extender pins with the wiring harness & slide the 3/16" heat shrink tubing over them & shrink the tubing. Then slide the 1/4" heat shrink tubing over the pair of wires and shrink the tubing. When you are done you'll have about 1" of wire left without heat shrink tubing on it to strip & crimp the new pins on. Stick the new pins in the old connector shell, assemble it and you are done. It looks as good as factory. Some wire loom can be used to enhance the "Factory Look".