Can't pull codes and engine runs rough

I have tried to pull the codes and had no luck. I have a code reader and also have tried the paper clip trick. The code reader doesn't even show it's connected. Have run a ground wire too. When I try the other way it will do the first part where it checks the sensor but the codes will not come. The engine light just stays on and doesn't blink. Any ideas??

The problem I'm having is the trucks idles rough when cold but gradually gets better but never completely clears up. If I barely press the pedal and slowly accelerate it runs ok but if I press it it starts to sputter. I have changed plugs wires cap and rotor button, checked fuel pressure and it's fine. Also checked compression on each cylinder and they are fine. Any ideas??

Thanks

1990 ford bronco 5.8 efi

hey migraine I'm guessing you have a carburetor.  when you take the air cleaner lid off thats the big round thing that sits center top part  of the engine. it has a wing nut most likely . in the middle  . what is happening is when you look inside when you take the lid off you will see  the choke also known as the butterfly . it is activated by a heat spring  so when the engine is cold it allows the choke to remain open then as the engine warms up the choke will start to close but not fully.if its closed fully it will stall . I think whats the issue is when you start the truck cold your chokes not opening enough causing the rough running.. before you start the truck  when its cold use something to keep the choke wide open .like a piece of wood  then as it warms up  take the wood out and see how far the choke moved it should only remain open about 3/16 of  an inch sort of like the size of the metal shaft on  a standard ***** driver........don't really mean to go into detail with the air cleaner but your profile doesn't show the year of your truck or how much you know...............hope things work out well

Sorry it's a 1990 bronco. Fuel injected

Have you try'd cleaning your Idle Air Control Valve?



It can be found on the left of the intake barrels. I had to do this on my 1989 XLT.

Yo migraine,

I see that you know about the ground issues such as; 



...

Have you gone through this yet, 

No Codes?  by Ryan M?
To assist see this EEC IV Connector Pin LEGEND

&



EEC IV CONNECTOR PIN DIAGRAM

...

Check ground G104;

Ground Locations in a 90 from 90 Bronco EVTM; "...G100 LH side of Radiator support; G101 RH side of Radiator support; G102 RH side of Radiator support; G103 LH rear side of engine near knock sensor; G104 LH rear side of engine compartment, near electronic engine control (EEC) module, on the left fender close to the firewall; G105 LH Side of engine; G106 RH fender apron, near voltage regulator; G107 RH fender apron, at starter relay; G108 RH fender apron, at voltage regulator; G109 RH fender apron; G201 LH rear side of I/P (looking at the diagram it is at the bottom of the driver's side dash assembly. Screwed to the bottom edge, just to the left of the steering column. It is the ground for the instrument cluster); G202 Behind RH cowl panel; G203 RH rear side of radiator support; G204 On steering column; G205 Behind Center of I/P (Dash); near speed control amplifier; G400 LH side of cargo area; near rear light assembly; G401 Below LH side of cargo area; near crossmember; G500 Inside driver's door; near left door speaker" 

Source: by BroncoJoe19 (Joe) at Ford Bronco Zone Forums

G104

Check all ground cables and connectors from battery negative terminal to:

engine block to intake manifold,

frame, etc for corrosion, looseness,

& wire strand corrosion that may reach under insulation.

Yep I checked all of the grounds all seemed to be fine. I've also changed plugs wires cap rotor button. Injectors module map sensor. It runs rough when cold but gradually gets better but not where it needs to be. It has me stumped

Yo,

OK.  The inability to pull codes leads me to suspect the EEC.

EEC IV Capacitor Repair by seedpress @ http://broncozone.com/topic/20788-fuel-delivery-problem/

Use a 10mm Socket to remove the big Cable bundle connected to the EEC.

Unplug EEC under the hood, drivers side, very low on the fire wall, .

See attached  by Conanski in a 90. Sorry, error message claims that image can't be use.

 

Should be one small metal ***** holding it. Just slide it out, but be careful with the gasket for the firewall. You can reuse it.
Then remover the kick panel and take it out from inside cab.

Yo,