Engine Floods When Accelerates...........Help

351turbo · Feb 28, 2009

1990 Lx 5.0 , GT40 heads , Explorer intake , Crane Powermax cam , I put 42# injectors and a C&L maf , because i am going turbo , after injector install , black smoke when i accelerate . I tried differant maf , tps sensor , Distributor , checked all connectors , changed regulator ,O2 sensors .........................still have the problem , no check engine light.................what next ? please help ..............all the plugs black ..............timing is 10 degree initial ,

BYRDPE · Feb 28, 2009

You gonna have issues just like you described trying to run 42lb injectors without a tune.

351turbo · Mar 1, 2009

i know i would need a tune , but the car should run half way decent , i have had other cars with 42# injectors , the ran fine without a tune , this thing is pumping out huge amounts of black smoke when i jab the pedal ,.........................

Mustang5L5 · Mar 1, 2009

Just because others have run fine doesn't mean this one will.

Did the probs start after you swapped the injectors?

bubba-dough · Mar 1, 2009

42lb without boost? Don't go with that injector until your ready for them.

351turbo · Mar 1, 2009

I have a Turbo Technologies turbo allready just dealing with the rich issue.............

bubba-dough · Mar 1, 2009

It said you were going turbo...I took that as it wasn't installed yet. My bad.

351turbo · Mar 1, 2009

thats ok , i am puzzled with this beinng so rich , pours out like a diesel

HISSIN50 · Mar 1, 2009

Are you throwing A-F limit codes?

Is your fuel pressure in the ballpark?

351turbo · Mar 1, 2009

fuel psi 39 base

jrichker · Mar 1, 2009

Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

See Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical

If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see EQUUS DIGITAL FORD CODE READER (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

351turbo · Mar 2, 2009

hook up a code reader , single self test pin not signaling the computor , tried grounding it still no trigger................?

jrichker · Mar 3, 2009

Computer will not go into diagnostic mode on 86-90 model 5.0 Mustangs

Disconnect the battery positive terminal before making any resistance checks.
The small voltage drop in the battery cables will cause incorrect resistance readings.

Computer diagnostic connector:

How it is supposed to work:
The black/white wire (pin 46) is signal ground for the computer. It provides a dedicated
ground for the EGR, Baro, ACT, ECT, & TPS sensors as well as the ground to put the
computer into self test mode. If this ground is bad, none of the sensors mentioned will work
properly. That will severely affect the car's performance. You will have hard starting, low power
and drivability problems. Since it is a dedicated ground, it passes through the computer on its
way to the computer main power ground that terminates at the battery pigtail ground. It should
read less than 1.5 ohms when measured from anyplace on the engine harness with the battery
pigtail ground as the other reference point for the ohmmeter probe.

What sometimes happens is that the test connector black/white wire gets jumpered to power.
There is a dark brown connector with a black/orange wire near the diagnostic connector. It is
the 12 volt power to the under the hood light. If this happens, it either burns up the wiring or
burns the trace off the pc board inside the computer. That trace connects pins 46 to pins 40 &
60. Only an experienced electronics technician can open the computer up & repair the trace if
it burns up and creates an open circuit.

The STI (Self Test Input ) is jumpered to ground to put the computer into test mode. The STI
has a gray connector shell and a white/red wire Jumpering it to power can produce unknown
results, including damage to the computer. The ohm test simply verifies that there are no breaks
in the wiring between the test connector and the computer input.

How to test the wiring :
With the power off, measure the resistance between the computer test ground
(black/white wire) on the self test connector and battery ground. You should see less than
1.5 ohms.

If that check fails, remove the passenger side kick panel and disconnect the computer
connector. There is a 10 MM bolt that holds it in place. Measure the resistance between
the black/white wire and pin 46 on the computer wiring connector: it should be less than
1.5 ohms. More that 1.5 ohms is a wiring problem. If it reads 1.5 ohms or less, then the
computer is suspect. On the computer, measure the resistance between pin 46 and pins
40 & 60: it should be less than 1.5 ohms. More that that and the computer’s internal
ground has failed, and the computer needs to be replaced.

If the first ground check was good, there are other wires to check. Measure the
resistance between the STI computer self test connector (red/white wire) and pin 48 on
the computer main connector: it should be less than 1.5 ohms. More that 1.5 ohms is a
wiring problem

The following is a view from the computer side of the computer wiring connector.

Diagram courtesy of Tmoss & Stang&2birds

Check out the diagram and notice all the places the black/white wire goes. Almost every
sensor on the engine except the MAF is connected to it.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds
(website host) for help on 88-95 wiring Mustang FAQ - Engine Information

Engine Floods When Accelerates...........Help

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