hard starting/wont start when hot

1bad67sbf · Jul 1, 2011

i got my car running for the first time from a roller but i think i have a vac leak due to very crapy power brakes/ poor idle but when i cut it off after 15+ min it wont restart. i moved the distributor around while cranking with no luck. i have a timing light but it seems not to work so i will get another tomorrow. what should a safe timing be? 14*?

DocG · Jul 3, 2011

What year is it, have you checked the codes?

1bad67sbf · Jul 4, 2011

its my 92, i think it was over heating so im putting a water pump on it. i had a standard rotation pump not the reverse one. i got the timing cover yesterday and i will get the pump this week.
do i need a scan tool to read codes? im sure it has more issues to figure out because my CEL will be on one day and off the next.

Mustang5L5 · Jul 4, 2011

When it doesn't start when its hot, try holding the gas pedal to the floor and starting. This turns off the injectors to allow for starting a flooded engine. Ipjust be ready to let off the gas when/if it starts.

I had this issue before, and it ended up being a faulty EcT that showed a code 21 in the engine running codes.

1bad67sbf · Jul 4, 2011

that was the only way it would start was when it was on the floor but after a few more min running that would not work.
when it does start it revs to 3k on its own then falls slowly back to idle.

Mustang5L5 · Jul 4, 2011

Time to pull the codes.

But to answer your question 10-14 degrees should be a safe timing start point

HISSIN50 · Jul 4, 2011

And keep looking for vac leaks.

1bad67sbf · Jul 4, 2011

thanks for the help, i know 96 and later is easy OBD2 but what it the procedure for my 92? do i need a scan tool or do i count flashes?

HISSIN50 · Jul 4, 2011

Count flashes. There should be something in the Useful Tech sticky (or do an internet search).

1bad67sbf · Jul 4, 2011

thanks

Mustang5L5 · Jul 4, 2011

Its pretty easy actually.

http://*******.com/index.php/topic,2471.0.html

All ypu need is a jumper wore and the check engine light will blink the codes.

A code reader is $20 and a great investment. I use mine all the time just to stay on top of things and do routine checks

1bad67sbf · Jul 4, 2011

is this OBD1?

Mustang5L5 · Jul 4, 2011

Yes, eec-iv is fords name...but it's OBD1

jrichker · Jul 5, 2011

Dumping the computer diagnostic codes on 86-95 Mustangs

Revised 3-Jun-2011. Removed the link to BATAuto.com and troublecodes.net instructions on codes and how to dump them. Post the codes you get and I will post 5.0 Mustang specific code definitions and fixes.

Here's the way 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.

Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.

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.

WARNING!!! 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. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and driveablity problems

Some 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.

Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.

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.
Or for a nicer scanner see http://www.midwayautosupply.com/p-7208-equus-digital-ford-code-reader-3145.aspx– It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

jrichker · Jul 5, 2011

Double post, internet hiccupped...

1bad67sbf · Jul 8, 2011

i still need to pull the codes but i put the right water pump on and ran the car and the motor seemed cooler but the rear of the car was pumping heat and i could not hold my hands behind the tail pipes. after another 5 min of running at 1200 rpms i looked under the car and the cats back to the catback exhaust were full blown f**king orange!!! the exhaust flow seems good so im guessing its runnning stupid rich.
i will try to get the codes pulled tomorrow but what do you think could cause it to run this rich?
i did remove the smog and was told that i could have cat issues but i thought they were going to run too cold not over heat.

Beasty306GT · Jul 8, 2011

Red hot exhaust means ur timing is way to advanced back it off some

1bad67sbf · Jul 10, 2011

i looked and it runs best with 30* BTD, if i bring it back some it starts shaking and gets harder to keep running. WTF? im also thinking about off road x or h pipe, but i dont want it to just over heat the mufflers.

1bad67sbf · Jul 10, 2011

the two codes i got were
Mass Air Flow Sensor Circuit Voltage Lower Than Expected
and
Fuel Pump Circuit Open–Battery To Powertrain Control Module (PCM)

jrichker · Jul 11, 2011

1bad67sbf said:
the two codes i got were
Mass Air Flow Sensor Circuit Voltage Lower Than Expected
and
Fuel Pump Circuit Open–Battery To Powertrain Control Module (PCM)

I need the actual code number to post the correct test path for the fuel pump problem. I will asume that it is for the 92 Model you posted.

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).

Changes in RPM causes the airflow to increase or decease, changing the voltage output.. 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 Mustang FAQ - Wiring & Engine Info

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

hard starting/wont start when hot

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