I have a 1986 Bronco 2 with a fuel injected 2.9L and a 5 speed manual transmission.
My problem is that if I crank he engine over for more than about three-four seconds the injectors stop firing and of course the truck won't start. I would say about 90% of the time it fires right up within the first one or two seconds of cranking. Except for when it is very cold out or if the the truck was just shut off and I try to start it back up within a few minutes.

I know the injectors stop firing because I checked them with a noid light while cranking the motor over.

Has anyone seen this before or have any ideas of what might be causing it?

Thanks in advavce for any info.
Chris.

 

Thats a new one for me, have you checked for codes?

 

I finally had a chance to check for codes tonight and this is what came up:
13- RPM at idle out of range/low.

21- Cooling temp sensor out of specified range or ECT out of range.

31- Cannister or EGR valve controll system or EVP circuit below minimum voltage.

Would any of these cause the injectors to not fire?

Any thoughts, ideas?

 

I don't think they would, I'm wondering if you have a wairing or ground problem. How's the grounds for the engine and the one that comes off at the negative battery terminal to the radiator support.

 

I was about to start this thread but ill just through in my 2 cents. My 1985 B2 is doing the same thing, Diference is i got the 2.8 carb. not fuel injected. It starts right up first thing in the morning but if you turn it off and try to start it back up you must mash the gas to start it up like after 4-5 secs. of cranking it will come to life and be ok untill you shut it off. Also im wondering on where to get the code readings from on my truck. i can get a code reader i just dont know where to find the hook up! i've looked everywhere! Any light on this subject would be GREATLY apreciated.
FYI: i just installed new plugs and wires.
Thanks!
~Aaron~

 

I'll check all the grounds tonight.


As for checking codes on a carbed engine. I don't believe there are any codes to check because the enging is not computer controlled.
My EEC connector is in the engine compartment on the passanger side fender close to the firewall.

 

The 2.8 still uses the EEC-IV computer to control the carburator, it just works different than the multi-port EFI the 2.9 uses. Assuming the self-test connector is in the same place as on both of my Fords, it will be under the hood on top of the passenger side wheel well. Might be tucked down underneath something there.

 

Well I checked the ground wires today and they seem good ans solid. The battery ground goes to the frame and the engine. There is also a ground strap at the back of the engine.
It is not an intermitant problem so I don't suspect any type of faulty wiring. The injectors just simply don't fire if it is cranked over for more than three to four seconds. What about somthing in the distributor causing it. One thing I did notice when checking the timing was that with the key on, the injectors would fire (noid light flashed)when I turned it back and forth. Does that sound normal.

 

I'll keep thinking, anyone else have an idea???

 

These are just areas that may be causing your problem. ECA (computer) may be causing your problem, being that is what controls your ground for your injectors.Could also be an ignition switch problem.There are 3 wires from the ignition switch that goes directly to the ECA. Two of them are voltage and one is ground from the ECA. Did you check out the EEC Power Relay? This relay as well as the Fuel Pump Relay both are inline of the injectors but they are used primarily for fuel pump operation. Did you check out all the fusible links? There are 2 of them needed for the injector control. Fuse link L,(loctaed at RH fender apron) and fuse link R(located at starter relay)They are both 20 GA fuse links.
I would do the preliminary checks first.
Check Battery for state of charge and for clean tight battery terminal connections.
Inspect wires and connectors for breaks,cuts,abrasions, or burned spots.
Make sure all wires are connected correctly.
Unplug all connectors and inspect for coroded or burned contacts. Sometimes a big problem occurs from a simple connector not fully seated.
Sorry, I am tapped out of ideas. I would look more into the ignition switch being that you can cause the voltage to the noid lights when turning the switch on and off. Just my .02 cents worth.

 

I think I would look for something setting that code 13. If the computer doesn't see the signal won't it shut down. Might want to see if it maintains spark at the same time.( just a thought)

 

Give it a try but thats normally a IAC problem. If you need the pinpoint tests just let me know.

 

Okay, I was searching around for you and this is what I found. Read the ending reguarding the RPM issue.
When the ignition switch is turned on, the EEC power relay is energized, closing its contacts. Power is provided to both the fuel pump relay and a timing device in the ECC module. The fuel pump runs through the contacts of the fuel pump relay. If the ignition switch is not turned to the START positon, the timing device in the EEC module will open the ground circuit after appox. one second.Opening the ground circuit de-energizes the fuel pump relay(de-energizing the fuel pump). This provides for pre-pressurization of the fuel system. When the ignition switch is turned to the start position, the EEC module operates the fuel pump relay to provide fuel for starting the engine while cranking.
After the engine starts, the ignition switch is returned to the ON position, and power to the fuel pump is again supplied through the fuel pump relay. The EEC module senses engine speed and shuts off the fuel pump by opening the ground circuit to the fuel pump relay when the engine stops, or is below 120 RPM.

 

For code 21--run the vehicle for 2 minutes a 2,000 rpm. Check that the upper radiator hose is hot and pressurized. Check for codes again. If the code does not come back, service the other codes first. If it does come back, it can be a problem with the reference voltage circuit or the actual Enine Coolant Temperature sensor.
Code 13-- Could be the Idle Speed Control (bypass Air) solenoid. Before replacing the solenoid you have to check out if the curb idle is within spec. If it is, then replace the Bypass solenoid. If not, check engine vacuum hoses, check that the throttle plate is fully closed, check throttle linkage for binding. If all of these check out good, then replace the solenoid and recheck for codes.
As for code 31, I don't know. I have a non-EGR truck. Sorry. Hope this helps out some. If you need anymore info, just let me know.