cant hold idle after novi install & injector swap

How did you clear the codes? The neg battery cable should be disconnected for at least 15-20 minutes to make sure the comp is completely cleared out. After that hook it back up and see how/if it runs. If it's not the problem it won't have cost you much time and effort.

dump the codes again and look for a lean code from the o2 sensor. that might be your full throttle issue, never know

Danish88GT said:

dumped the codes again:
Code 33 - EVP - (R) EGR not responding properly during test - EVP
Code 56 - Vane Air Flow (VAF) or Mass Air Flow (MAF) sensor high - VAF MAF
Code 66 - Vane Air Flow (VAF) or Mass Air Flow (MAF) signal low - VAF MAF

Should i presume that my MAF is fubar?

help!

Click to expand...

If you disconnected the MAF while testing things and did not clear them, you could get MAF codes.

Code 66 MAF below minimum test voltage.
Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF heater (usually pins A & B). while the connector is plugged into the MAF. This may require the use of a couple of safety pins to probe the MAF connector from the back side of it.

There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables.

The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).

The MAF output varies with RPM which causes the airflow to increase or decease. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow. Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.

At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt

Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.

There should be a minimum of 10K ohms between either pin C or D on the MAF wiring connector and ground. Make your measurement with the MAF disconnected from the wiring harness.


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

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

Fuel pump, alternator, ignition & A/C wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Computer,. actuator & sensor wiring
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Fuse panel layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Vacuum routing
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

Code 33 - Insufficient EGR flow detected.
Look for vacuum leaks, cracked vacuum lines, failed EGR vacuum regulator. Check to see if you have 10” of vacuum at the EGR vacuum connection coming from the intake manifold. Look for electrical signal at the vacuum regulator solenoid valves located on the rear of the passenger side wheel well. Using a test light across the electrical connector, it should flicker as the electrical signal flickers. Remember that the computer does not source any power, but provides the ground necessary to complete the circuit. That means one side of the circuit will always be hot, and the other side will go to ground or below 1 volt as the computer switches on that circuit.
Check for resistance between the brown/lt green wire on the EGR sensor and pin 27 on the computer: you should have less than 1 ohm.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)

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


EGR test procedure courtesy of cjones

to check the EGR valve:
bring the engine to normal temp.
connect a vacuum pump to the EGR Valve
apply 5in vacuum to the valve.
if engine stumbled or died then EGR Valve and passage(there is a passageway through the heads and intake) are good.
if engine did NOT stumble or die then either the EGR Valve is bad and/or the passage is blocked.
if engine stumbled, connect vacuum gauge to the hose coming off of the EGR Valve
snap throttle to 2500 RPM (remember snap the throttle don't hold it there).
did the vacuum gauge show about 2 - 5 in vacuum?

if not, check for manifold vacuum at the EGR vacuum valve.
if you have manifold vacuum then connect vacuum gauge to the EGR valve side of the vacuum valve and snap throttle to 2500 RPM.
should read about 2 - 5 in vacuum

The operation of the EGR vacuum regulator can be checked by using a test light applied across the wiring connector. Jumper the computer into self test mode and turn the key on but do not start the engine. You will hear all the actuators (including the EVR vacuum regulator) cycle. Watch for the light to flicker: that means the computer has signaled the EGR vacuum regulator successfully.

Danish88GT said:

dumped the codes again:
Code 33 - EVP - (R) EGR not responding properly during test - EVP
Code 56 - Vane Air Flow (VAF) or Mass Air Flow (MAF) sensor high - VAF MAF
Code 66 - Vane Air Flow (VAF) or Mass Air Flow (MAF) signal low - VAF MAF

Should i presume that my MAF is fubar?

help!

Click to expand...

that's pretty weird. both HIGH and LOW for the MAF?

K, I need some more info about your set up, because it sounds like weare running the same setup, my motor is fairly stock with a Vortech S trim and 30lbers.


when you were running your 30# setup

What are you running for fuel pressure?
Is your car a mass conversion car or factory mass air?
Are you running the fmu and the bigger injectors? If so what ratio is the diaphram?

And I think your check engine light, is from your meter "pegging" because you are using a blower with a stock meter, you are pulling in alot more air than the sensor normally deals with, putting it out of it's parameters

Danish88GT said:

stock injectors atm.
stock maf
car is from cali stock with every piece of crap they can put on it smog ect.
i've installed a 255lbs fuel pump and the novi 2k right now. (discharge tube, fuel control unit,
i have larger injectors and maf but my idle got bad when i swapped. (& later other ****) and honestly i cant tell you the size of the maf or injectors.. the guy who sold it to me claimed it would make 400hp
what you are saying sounds quite possible.. i just dont know if i should try to install the larger injectors & maf again or not.. i've ordered a TwEECer so i can alter some things.. mabye that will help?

Click to expand...

Ok I was dealing with alot of the samething when I first started into this blower project, it will work, get it idling before you start with the tweecer. If you don't have the set-up done at first you could be chasing your tail

By the sounds of it your setup is almost identicle to mine, if you start it up with the 30's it will run kind of crappy till the computer gets out of it warm up phaze, and starts trimming back the fuel with the O2 sensors. Joe Da Silva up here in Canada was a great help to me, he told me to run at 37psi on the fuel reg with the vac line off, it will be about 32 or 33 with it on, he had me set my timing at 14 degrees with it set at 1 on the boost retard, and a one range colder plug. Get the car air/fueled after this because it's only way to be sure, but the setup works, if you are still having probs I would suggest it might be your mass air meter. pm me if you have anymore Q's