Hey guys,

Engine not running, cold. With flashing engine lite I got
1 166 361 166 361 126 128 126 128.

is that 166 361, 166 361 - 126 128, 126 128 ? Some of these codes are not listed in my Haines book.

94 f150 5.0

Engine run RICH, idles high. Need to press gas pedal to the floor to start truck.

I unpluged the Map sensor didn't change much, should the engine stall out, when I did that?


thanks, mike

 

Zip Code Select | O'Reilly Auto Parts Might be worth investing in one of these or similar. I think you have read the codes wrong.
Pull the vacuum pipe off the Fuel Pressure Regulator and look for any signs of gas. If you find any replace the FPR.

 

166 No such code.

361 No such code.

126 Continuous Memory DTC 126 indicates the Manifold Absolute Pressure (MAP)/Barometric Pressure (BARO) sensor was out of self-test range. The code was set during normal driving conditions. Correct range of measurement is typically from 1.4 to 1.6 volts.
Possible causes:
Damaged MAP/BARO sensor.
Damaged EEC vehicle harness.
Damaged MAP/BARO sensor vehicle harness connectors and/or terminals.
Unusually high/low barometric pressure.

128 Continuous Memory DTC 128 indicates the MAP sensor vacuum has not changed more than 2 in-Hg (7 kPa) during normal vehicle operation.
Possible causes:
MAP sensor vacuum supply hose improper routing, blockage and/or linkage.
MAP sensor leak.

 

I errased the codes, removed paper clip while getting codes. I went for a 5 min. drive. Engine off (still hot) I got 116,126,128,327. While it's running (hot) I got code 116.

Where do I start with basic tools. I unpluged Map sensor it run fast and slow over and over. Check vacum hose on fuel pressure regulator, no fuel.

truck problems: it runs RICH, I need to depress gas pedal to start truck.

93 f150 5.0

thanks guys!

mike

 

Sounds like a bad 5 Volt Power Supply.
Chevk your VREF for 5 VDC +- 0.05 Volts

116 DTC 116 (ECT) indicates that the ETC sensor is out of Self-Test range. Correct range of measure is 0.3 to 3.7 volts.

Possible causes:
Low coolant level (ECT).
Ambient temperature below 10°C (50°F) (IAT).
Faulty harness connector.
Faulty sensor.

126 DTC 126 indicates that the Manifold Absolute Pressure (MAP)/Barometric Pressure (BARO) sensor is out of Self-Test range. Correct MAP/BARO tester range of measurement is typically from 1.4 to 1.6 volts.

Possible causes:
MAP/BARO circuit open between sensor vehicle harness connector and PCM.
MAP/BARO circuit shorted to VREF, SIG RTN, or GND.
Damaged MAP/BARO sensor.
Vacuum trapped at MAP/BARO sensor.
High atmospheric pressure.
Damaged PCM.
VREF circuit open at MAP/BARO sensor.
SIG RTN circuit open at MAP/BARO sensor.

128 see post above.

327 DTC 327 indicates that the EGR Valve Position (EVP) sensor signal is less than the Self-Test minimum value of 0.2 volt.

NOTE:
Because the EVP sensor is preloaded when attached to the EGR valve, a failure in the EGR valve causing the EVP sensor to lose preload may also set DTC 327.

Possible causes:
Damaged EVP sensor.
Damaged EGR valve.
Open harness.
Grounded harness.
Damaged Powertrain Control Module (PCM).

 

Subford

Sounds like a bad 5 Volt Power Supply.
Check your VREF for 5 VDC +- 0.05 Volts.

I have a cheap tester, I set the tester to 10 DCV (lowest setting). unpluged Map senser, key on. VREF to ground (the Block). I got 125 DC.
Is that close to 5 volts? Maybe I check somewhere else that would have 5 volts, to compare the tester result?




thanks

 

You should be using VREF (pin #26 BR/W wire) & SIG GND (pin #46 GY/R wire) for the ground and not the engine block.
Both wires will be at the MAP sensor.

If you are on the 10 VDC scale a reading of 125 would be 1.25 VDC or 0.125 VDC depending on were the period is. If that would be the true reading then you would need a new computer as the 5 Volt supply is bad in it.

 

You should be using VREF (pin #26 BR/W wire) & SIG GND (pin #46 GY/R wire) for the ground and not the engine block.
Both wires will be at the MAP sensor.

Do you mean test the Map BP signal wire or Signal return wire, when you say SIG GND? These are the names my Haynes manual has. Also I have different colored wires to the Map sensor. Green/blk, Gray/red, Black/w



93 f150 5.0

 

All of the VREF (5 volt Voltage Reference) wires are Brown wires with a White stripe and the SIG GND (Signal Ground [Return]) wires are Gray with a Red stripe wires on a 1993 or 1994 F-series truck. These wires will be at the Map, EVP and TPS sensors.

 

I get 1.25 dc volts on the EVP to. Still sounds like a bad computer? So that would make the truck run rich and I sometimes would need to depress the gas pedal to start the truck.

thanks

 

I found this on the net what do you think? The persons problem was he was getting 2.5 volts on all his SIG returns.

The GY/RD wire is SIGNAL RETURN. It is a dedicated ground circuit that is used by the sensors and is physically separate from POWER GROUND.

The two ground circuits should be connected internally in the PCM. Sounds like yours isn't making proper connection.

You can check this by doing the following:

Disconnect the battery and check the resistance between battery negative cable and SIGNAL RETURN. Value should be very low, preferably as close to zero ohms as possible.


Check to make certain any ground straps adjacent to the PCM are properly connected. Could be as simple as a loose/high resistance ground cable back there on the firewall.


I checked the resistance between battery negative cable and SIGNAL RETURN. I got 0 ohms.

 

Sounds like the truck is running in limp mode. There way another poster a few weeks back the had the same running and starting problems and it was a bad computer but he never check the the 5 volt supply.

Check and make sure none of the main computer plugs pins are pushed in. A few have unplugged and regreased the computer plug and put it back on and it fixed the problem also.

But it will never run right with only 1.25 Volts on the VREF wire.

That sound OK.

Here is how that is wired:


/

 

Why don't I get a code for all 7 sensors, if the sig. return wire has only 1.25 volts?

Thanks again


Ps All I get now for codes is 116 (ECT) I just noticed the coolant is low.

" 116 DTC 116 (ECT) indicates that the ETC sensor is out of Self-Test range. Correct range of measure is 0.3 to 3.7 volts.

Possible causes:
Low coolant level (ECT).
Ambient temperature below 10°C (50°F) (IAT).
Faulty harness connector.
Faulty sensor."

 

The Ground Return (NOT Sig Return) wire should have zero volts on it.
You only have the three sensors that get the 5 VREF, not seven.

 

OK, so why don't I get a code for the map, egr and tps? if they all have the 1.25 volts problem.