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High idle, Code 84, 31 and low power

cbfomoco

Bronco Guru
Joined
Jan 21, 2004
Messages
1,029
Loc.
WV
Well I finally figured out and fixed my 41 code in this thread. http://classicbroncos.com/forums/showthread.php?t=280708

And I am still having some issues. I will recap what I have:


I have installed 91 mustang efi on my stock 302. Any way I am trying to fight out the last gremlins.
Here are my specs:
Motor is an old firing order 302 from a 79 t bird.
upper and lower intakes are explorer gt40 and explorer throttle body.
stock orange 19 lb injectors ( used not knowing condition)
stock a9l computer that efi guy fixed.
stock 91 reworked harness. ( tab and tad resistors) egr eliminator. is using a canister purge though with a charcoal canister and hooked to the intake ( vent on tank to canister to purge to intake)
Stock a1 cardone reman 91 mustang maf sensor or a 4 flange that efi guy said I can use( i forget application at this time) but it is a reman unit as well.
New: map sensor, temp sensor, stock fuel pressure regulator, bosch o2 sensors, in tank electric fuel pump, reman cardone dist with correct gear, new cap, rotor, plugs and wires 180 t stat ( I know it needs a 195 and have one just not put in yet.
I am not sure where timing is set as I can not see the pointer with the alternator on. I think I am in the ball park though and was set with spout connector removed.

I have these codes in:
koeo
84o
31 c


My check engine light is on. Idle has been set and is in range per dvm. Idle is about 1000-1100. Some times check engine light will go off but comes right back on when the throttle goes above 2500 rpm Tonight when driving it It did not want to go below 1000 rpm and wanted to be 2100 plus rpm and would not idle down.

idle seems to hunt up and down some. and could have a miss at idle but is not really pronounced and does not seem to be above idle.

I replaced the fuel regulator with an oem one( had and adjustable on it) with no change. I have a gauge in the rail and at idle I am about 32 psi but this does change some and have seen it go lower. I checked the vacc hose to the regulator and see no fuel. With the vac line unplugged and my finger over the line the fuel pressure will go up but motor does not seem to like it.

I took starting fluid and checked for vac leaks and no change.


Which of my two codes would cause the check engine light to come on and what can I do about it? Also what could be causing my high idle/ possible low power concern? Do I need to switch back to the mustang mass air? Could I have a bad throttle position sensor even though it is no code? I will try and check the throttle position sensor again to verify correct range.
I am open to testing and ideas. Thanks
 

SevenT

Contributor
Sr. Member
Joined
May 23, 2009
Messages
496
Loc.
Southern Colorado
KOEO codes

cbfomoco,

31 EVP circuit below minimum voltage of 0.24 volts. Hard Fault
84 EGR Vacuum Solenoid inoperative. Soft Code

If evap and EGR eliminated in harness, these should not show. Can you pull KOER codes?

v/r,

SevenT
 
OP
OP
C

cbfomoco

Bronco Guru
Joined
Jan 21, 2004
Messages
1,029
Loc.
WV
I will try pulling running codes soon. I wonder if the egr eliminator plug I purchased is bad? I did put resistors in for the tab and tad and the canister purge is hooked up and functioning.
 
OP
OP
C

cbfomoco

Bronco Guru
Joined
Jan 21, 2004
Messages
1,029
Loc.
WV
Well I drove it for a little bit this evening and it did better but still not where I think it should be. I put the 91 mustang mass air flow sensor back on. I don't know if that helped any or not but for the moment it is on there.

KEOR codes:

91( this is new had not gotten it before might be leak at drivers side header will look into)
32

Koeo codes :
84 o
31c
91 c

I did recheck my egr delete plug and it is making good connection could it be bad and cause the 31?
I am also thinking I my high/ poor idle might be my throttle position sensor. It is about the only non new sensor I have. I did loosen the screws with it running tonight and when I move it the rpm does change but I can not get below 1000 rpm. Any thoughts on this? Can I open up the slots in it?? Also I have not messed with the set screw on the throttle but don't know if someone before me has or not.

Also as a side note I ran it out of fuel tonight on the cyl balance test. I will refuel and try again.
 

tirewater

Contributor
Sr. Member
Joined
Jan 28, 2011
Messages
1,040
Loc.
San Francisco Bay Area
Wouldn't the O2 sensors incorrectly detect lean/rich conditions if running the old firing older if the ECU wasn't expecting it? Try running without the o2 sensors unplugged to force the engine to run open loop.
 

SevenT

Contributor
Sr. Member
Joined
May 23, 2009
Messages
496
Loc.
Southern Colorado
CEL Codes

cbfomoco,

You said in your first post that you had fixed a 41 code. That is:
Right HEGO sensor circuit indicates system lean - Hard Fault

Now you have a 91, that is the left bank. I would recheck the O2 hook ups and make sure there is no exhaust leak at the bungs. You can check and see if the throttle plate is hitting the stops at idle and if that is not allowing the engine to return to less than 1K at idle.
As for what tirewater said, I think the computer can compensate with the mismatch in firing order and it will not be noticeable. Try contacting EFIGuy on here to ask harness questions.

v/r,

SevenT
 
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