head scratched EEC-iv system

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Rohan

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Hello Everyone,

   OK! i have a 1989 bronco 5.0l xlt 33x12.5x15. Friday 1/15/16 going to work started acting up. losing power, and then riving up to 40k then check engine light came on.

made it to a mechanic shop, they looked at and thought electrical but they don't work on electrical. gave me a place to go that nothing but vehicle electric.not open weekends. 

  what i have done so far myself is change fuel and EEC relays no cure. i have 40 psi at fuel rails pressure good. now comes the head scratching part. I can not get the codes. yes i have a ford obd 1 code reader i have used on truck before and it worked. this time it didn't preform the test, i went and did the Manuel jumpers to test no code flashes at the check engine light or meter. what i did notice which ever test method i did the fuel pumps would stay running( never did that before with the ford tester). what the bronco doing now still losing power when giving gas, strong smell exhaust like to rich mixture, idles at 10k normal 8k, and increase fuel consumption.

  so scratching my wondering why fuel pumps keeping running while setting up test mode (don't shut so test check cant run). Has anyone else had this problem, and  anyone have a clue what to do? one more in the morning had to use starter fuild once to start, but rest of the i can drive it ( slow take off that is) and start it any time.

 New fuel pumps and inline filter

 New coil and ignition module and ignition module connector

 New temp sensors one to gauge and one to computer

 Computer good mechanic did have spare put it in same thing happening

  Now i am think only thing is to find a complete engine harness from comp on. any help would be greatly appreciated

 thank you

  Duane. 

 

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Rohan

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dear supreme commander,

 thank you for your advice. it did start to work till the relays kicked on the pumps went on wont stop. tried it few different ground spots when turn 2nd 3rd 4th tries pump wont shut off to run test. unplug relay but test wont work without them.i also took connectors out of plastic holder one at time to brass brush them clean.

 

Seabronc

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Reading this post, it appears that you have more than one problem.

Q. Does the fuel pump run continuously when the tester is not attached?

The only reason you get black smoke is that it is running far too rich which also will cause the bogging problem.  This is all controlled by the EEC, it controls the ground of the fuel pump, it controls the length of time the injectors fire and it controls the idle speed.  The EEC depends on good inputs to make decisions on how to control everything. 

Have you disconnected the main connector where the wires pass through the fire wall?  If there is corrosion on at that point the EEC may not be getting the proper voltage levels from the various sensors.  Then again you may have a bad sensor like the TPS (Throttle Position Sensor).  By the way, an idle speed of 8K and 10K is off the charts, I assume that you meant 800 RPM and 1,000 RPM not 8,000 RPM and 10,000 RPM.  800 RPM would be a little high for idle in gear but not bad for idle in park or neutral.  At 8K I would be afraid to approach the truck.

Bottom line is that I believe you are looking at symptoms not the problem.

Attached is a diagram of the EEC control of the fuel pump, the pump doesn't connect directly to ground, ground to the fuel pump is switched on and off by the EEC.

I suggest that you get a copy of the EVTM (Electrical and Vacuum Troubleshooting Manual) for an 1889 Bronco.  It is far superior to a Chilton or Haynes, but if one of them is all you can get, they are better than, "a stick in the eye".  You can often find them on eBay, just make sure it is for a F150/F250/Bronco.

:)>-

Good luck,

89EEC 001a.jpg

89EEC 002a.jpg

1989 diagrams 001.jpg

 
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Rohan

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once in awhile since problems raised couple day ago it dose(like last time i tried above post for the ground alternative) stops when engine starts. pumps shut off right with ignition on till i hit test on code reader and the relays start clicking they turn back on and would not go off till ignition shut off. the main connect referring to where harness ties into the computer? mechanic took it off to test with ford comp he had to see if it was the comp. i was there look clean both male and female sides. still act up with test comp.that connects is in engine compartment,just comp went through firewall. i did order a bundle of factory Manuals this weekend. lol the electric only vehicle shop (Well respected) dose not take older then 95 year autos and hates drive ability issues(take to much time to short out for busy shop). yes Hayes and such are not that good leaves to much info out. 

 in the morning i am going to check the EEC comp and test connector grounds taken off and make sure they are cleaned up recheck test and then start on testing sensors.

BTW since first post i had both EEC and fuel pump relays have been replace(no help there lol).

 thank you both for your help 

 Duane 

 
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Rohan

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update 

  no i have not had time to break multi meter yet. i did how found 2 ground single bolt on fender by comp, single on front of truck by overfill tank, 2 wire single bolt front by battery, one on wiper motor, last one close to starter relay.

  i removed each one i found clean then and bolts with wire brush and also took of neg battery term. took it apart clean batt cable and the wire with it that connected to ground on front by connector. i clean each frame area of connection with 500 grit paper for clear connection.

  Duane

 

Seabronc

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Did that include the battery frame and engine connection?  Also, you should find one from the rear iof the intake to the fire wall.

:)>-

 
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Rohan

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OK no didn't check batt cable to where it ends at. will look again for another one in rear of intake. i did somewhat get codes  they are as follow but think it not reading right. most likely test plug shot. with tester off wire movement made tester flash.

koeo test:                    engine run: yes missed press pedal.

10                                 10

11                                  21 ECT out of test range

15                                 44 therm actor air upstream during test

11                                 77 operator error 

                                     52 power steering pressure switch always open or close 

then repeat but 10.

now i had a f150 86 pickup with this tester it would go and rev the engine once per cylinder to test them. now when it got to that point on bronco it would stall out.

Thank you again for the advise

 
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Rohan

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p.s. also got codes 40 an 222 during koeo test no listing in book for them

 
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Rohan

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sea bronc 

 i did get the Manuel you recommended

  electrical and emission trouble shooting 

 engine and emission trouble shooting

  truck shop Manuel vol a 1 of 2 and 2 of 2 

 truck shop Manuel vol b

been going through and finding no ground broke at the ends connections.

problem worsen to now when engine at full running temp it acts out and shouts down,

odd part if just turn ignition to on not start and at normal running temp the check engine light flashes and tach needle goes haywire bouncing around.

question : is there a wire tracer for autos that lets you know where the break in wire is? ex: Christmas lights i have a tester, similar to a elections tickler, that stop beeping in the wire stirring at a break in the wire.  

 thanks 

  Duane

 

Seabronc

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You are not looking for just broken connections.  You need to remove the battery, engine, frame and, fire wall connections, clean them, inspect where the lugs connect to the wire and look for any signs of corrosion.  If there is any corrosion where the lugs connect to the wire, throw the cable away and replace it.  If they are OK, clean the lugs and where they make contact, and then reattach them. After reconnecting the lugs, covering the connections with a little silicone grease would not be a bad idea to keep water from causing more corrosion.

:)>-

I don't know of any wire tracers for auto wiring. For other applications, yes.  Not a bad idea thou.  The problem, is a wire tracer like you are talking about needs to know the size and resistance of the wire.  I have to believe that if there is such a tool for cars it would be something that only a professional shop could afford to own. 

 
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Rohan

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well spent all day going to every ground i came across form the electric and emission ground index i test continuity with ground spot and device that i could have continuity. took off computer connection and this time very bright sunshine i did see some corrosion  on pins would this mean comp bad? some of them a real pain to get to lol

 

Seabronc

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Get a good contact cleaner from a professional parts store, let them know what you are dealing with, (not one of the big box stores).  You need something that can be sprayed in, a tooth brush may be able to get at the contacts better.  An electronics supply store may also have something good for the problem.

:)>-

 
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