EEC power relay trouble and "spontaneous" starting

[stm]

Hi. I have 2 troubles and need help:

1. I cheked some wireing in my Bronco 87 EFI, and find EEC power relay is not worked. I open cover on it - it was seriuosly rusted and stucked in OPEN position. Current is not run between thick terminals, they was opened... But engine is starts normally, all systems was ok - it's very strange. This relay powering PCM (EEC), injectors, 3 or 4 sensors and solenoids (egr, etc.), fuel pump relay - and, i think, engine willn't start in this situation. Why it looks like is OK?

I remove this relay from socket, but it's not will take any effect. I plug new relay - nothing, engine starts and work as with old stucked relay or with no relay.

2. And second strange thing. Sometimes (very rare) when i disconnect ground terminal from battery and reconnect it back in few seconds - engine starts "youself". I hear clicks from starter relay, fuel relay and it start! and at the same time key is OFF, keylock is in OFF position!!! At first time i was "scared" and disconnect negative terminal from battery again, but engine not stopped. I turn key on and turn it off - it not helped. Only when i put brake pedal - it was stoped! **** bro? It's situation return 2-3 times for a year. It smell as mistic story (may be Christine?))).

Diagnostic comp is locate only 31 in KOEO and 44 in KOER errors...

(low voltage EVP sensor and secindary air pump fault)

 

[NaturalRampage]

For your problem on #2, Does your truck have a remote start installed on it? I have one on mine and when I had to disconnect the battery to do some electrical work and when I reconnected it, the trucks pumps came on and in a few seconds later the truck started. I brought the truck back and it was because of some faulty wiring or something. Not sure but they fixed it for me.

If you dont have one. Im thinking the Solenoid might be the problem in your case. Cant say for sure though.

 

[miesk5]

yo,

From what you describe, check Ignition Switch and ckt; wiring fault or attempt by a previous owner or shop to bypass the EEC Relay @ switch ot at relay socket, etc.

Here is the EEC Relay Wiring Diagram in 87-89 Bronco & F series (Mitchell)

Source: by equivent (Beetlejuice) at http://www.supermotors.net/registry/media/280825_1

EEC Relay is "turned on" by Ign Sw; 12vdc from switch i1, R/LG to Splice & through W/LB wire to EEC relay coil and through coil to ground (black); this closes eec relay contacts that then provide 12vdc to Fuel Pump Relay's Coil, Coil, etc. from EEC Relay's Red wire (through splice)...

Ignition Switch Troubleshooting in 87-91 (from Factory Manual and the Ford Electrical & Vacuum Troubleshooting Manual (EVTM); w/Wiring Diagram & Continuity Testing (Logic Tables); miesk5 Note, It is out of order, so read the 2nd from left page first

Source: by Broncobill78 (Dave) at Ford Bronco Zone Forums

http://broncozone.com/forums/index.php?showtopic=14120

 

[miesk5]

yo,

Part 2

DTC 31

This code could be caused by several different factors. If the pintle position sensor (Ford calls it the EVP sensor) is shorted or open, you could have a code set. If the EGR valve becomes carboned up and does not seat fully, the EVP sensor gives a high reading and a code is set. If the diaphragm of the EGR valve is bad, then it, too, is flagged..."

Source: by Harry G

for more EVP Info & test LINKs, see my site @ http://www.broncolinks.com/index.php?index=414

such as;

Testing & Operation; "...The EGR Valve Position (EVP) sensor monitors the position of the EGR valve pintle. The EVP sensor converts the mechanical movement of the pintle into an electrical voltage signal which is relayed to the PCM. The EVP sensor is a linear potentiometer in which resistance varies with the EGR valve pintle movement.Voltage is fed to the EVP by the signal return circuit. As the EGR is opened the EVP directs more voltage to the EEC and less down the voltage reference circuit. The EVP sensor provides the PCM with information on EGR flow and EGR system failures. The EVP should read between 0.24 and 0.67 volts at idle with a closed EGR valve..." read more

Source: by Ryan M (Fireguy50) at http://oldfuelinjection.com/?p=35

==========

DTC 44 (KOER); Right Thermactor Inoperative; "...I had a similar issue that turned out to be the vacuum line to the Thermactor Air Bypass Valve. No CEL, just a code; 1. First check that the two vacuum lines are connected to the Vacuum Reservoir (coffee can) and the resevoir is in good repair with no leaks on the bottom. Frequently the can leaks or the vacuum lines are accidentally knocked off. Check the vacuum hose to the bottom of the Bypass Valve. Check the vacuum hose to the Diverter Valve. Check the vacuum hoses to the TAB/TAD Solenoids. Then check your TAB/TAD Solenoids. These are common easy to miss problems. Once these are ruled out all that is left is: Thermactor Air Supply Hoses. One-way Check Valves. Main TAB/TAD Valves..."

Source: by Seattle FSB

see more LINKs at http://www.broncolinks.com/index.php?index=416