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Discussion Starter #1 (Edited)
I'm having many problems but in my search I see that grounding may be my biggest problem.

The story, I got an 87 FSB from my uncle. Last plated in 2004 It had a new rear diff installed in 99 and was parked till 04. In 04 it may or may have ran, it was insured twice and registered once. When it did run last he thought it was the fuel pump cause it would run, but chug and stall sometimes.

My uncle is a back yard do it yourselfer like most of us here are but he is old school If it is mechanical he's ok.. If it has a PCM he is lost. The last time it died he towed it home and started throwing parts at it. (plugs, wires, cap and rotor, fuel filter, pump relay) that didn't work so he went on ebay and bought one of those giant old diagnostic machines. You know the ones the size of a rollaway toolbox with the green CRT screens.

Anyway he had no clue how to use it so the bronc sat till 2 weeks ago when i bought it. What I did in the order I did it. What i found upon inspection was a mouse nest under the upper intake. When I cleaned it out from under there i found 2 injector wires eatin so I got another injector harness. After replacing that I still had nutting. :cry But I figured as much.

The relay is workin (eec relay also) and at least the front pump is working cause I hear it. I pulled the line off at the filter(after both pumps) and pumped out over 10 gallons of old fuel by jumping the relay before I ever tried to start it. I have fuel to the shrader valve on on the fuel rail. I have no voltage on any of the injector plugs I tested with the motor cranking unless you consider .04 to.10 volts as voltage for this application.

At this time I found out how to pull the codes and got code 63 as my only code. (TPS circuit below minimum 0.6 volts)I tested the tps and it tested fine. I got a new one tried it to no avail and returned it to the store and put old one back on. I know it said low voltage not bad tps but I had to see if that was the problem for my own piece of mind.

In another thread I got the very helpful advice that one of the small black wires to the batt. was an eec ground. The negative wires were all in bad shape and one was greened right out so I replaced the cable end at the batt. and made sure the connections were good. I plan to up grade the ground cables soon but want to make it run before I start throwing money into upgrades. I realize while upgrading them I may fix the problem. I have not pulled the wires out of the split lume but traced them in the lume to the firewall for obvious damage and found none. I have Taken the kick panel off and can see the eec. I have not messed with it yet.

Today I followed the negative and found it going right to the block down underneath the head but it also looked like it came off the same bolt with the same guage wire to what I suspect would have been the frame. This wire looks like it was cut. Is this the correct factory frame grounding procedure? I cant find where that second wire may have once been grounded. I may remedy this tomorrow by simply running a separate frame ground if you all can tell me is it is indeed a cut ground? The braided body to block ground is still installed.

Are there any other issues that would cause this problem? I suspect the code and injector issue are related. Thanks for any help you guys can give me. I know very little about Fords. The only other Ford I ever owned was A 78 Farimont. It had the straight six and fouled #5 plug within 10 minutes of cleaning the plug but try as I might I couldn't kill it. I drove it to the jy when fuel mileage dropped to low. I guess this is long enough.
 

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dude, learn how to type long posts in paragraphs. it is really hard to read and I pretty much stopped about half way through it.


do you have spark? and you need to tell us what engine and such your working on
 

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Discussion Starter #3
Sorry Its a 5.0 C6 combo. It has spark and will fire with ether.
 

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ether is really hot and a weak spark will fire it off.

try dribbling gas in the throttle body and see if it will fire off and run on that.

if it does, then verify fuel pressure on the fuel rail. should be 40psi with the key cycled on and engine off.

and you mentioned you hear one pump, your model has 2 fuel pumps and 2 fuel filters. although one technically is not called a filter it will plug up over years of use and cause low fuel pressure. it is between the tank and high pressure pump.
 

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Discussion Starter #5
Yes it does have 2 pumps. I know the filter after the second pump is brand new i didn't know there were 2 filters. I figured if I was getting fuel to the second pump the intank pump had to be working. is this not the case?
 

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just because fuel came out does not mean it is building enough fuel pressure
 

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Discussion Starter #7
Ok. I've been itching to get back to the Bronco but I finally found some time. It will run on fuel. I pushed the valve on the rail without a rag on it this time. It only shot an inch and a half. When I pumped the fuel out it had nowhere near what I would expect for a pump that had to build 40+psi.

I've found the other filter. It doesn't look like it has ever been changed. I can hear both pumps working.

What would be my next step?
 

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Back to the injectors harness not having any power.
Did you ever ger power to the red wires on the injectors?????
If not you need to go back to this and locate the relay and fuse for that circuit and fix the problem, or the injectors will never fire even if you do have good fuel pressure.
 

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For a quick and dirty ground, try using your jumper cables, connect it to the bat neg, and the engine block. Then see if your injectors will work.

IIRC on my '90 302 the neg cable goes from the battery, to a clamp on the frame, where the insulation of the wire is stripped away, and then to the engine block. If you have crappy grounds you will have low voltage. Important grounds on the bronco are on both sides of the upper radiator support. The one for the PCM is I THINK on the fire wall, near it.
 

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Discussion Starter #11
Thank you everyone. My time to work on the bronco is limited to an hour or Two a week so it takes me a while to get back here.

So..... I tested the fuel system yesterday. I got 42 PSI after 4 key ons from 0 PSI. I released fuel pressure and tested for flow and pressure like the Hanes said. Still got 42 PSI with over 5 oz. of fuel so that seems to be spot on.

I still have not redone the grounds but I bought welding lead wire and eyelets yesterday and will start trouble shooting electrical in the next week After upgrading all primary grounds and checking all secondary(my choice for the braided straps)grounds for good connections. again I have nothing at the injectors and the code says low voltage at the tps.

Does my truck have an injector relay? If so where? I cant seem to find anything about it. Autocrap says I have one. Advance says no. Also the EEC relay seems to click a LITTLE softer and quieter than the furl pump relay. I have never seen or heard if a relay slowly wearing out. Not saying it can't. I've just never seen it in 3 years as a semi mechanic. Has anyone else experienced this or know of it happening.


This is where I'm at. Anymore help you guys can give?
 

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is your yellow check engine light on when you turn the key ON?

Also the injectors do not have a relay. They are in 2 groups of 4 each, called "banks". Each bank fires together...so 4 injectors fire at once. The EEC grounds each bank when it wants them to fire.

Also, the injectors have +12V all the time the key is ON. So check to make sure they have power when the key is ON, and make sure the EEC works. That will narrow it down greatly.

And let me know about the yellow check engine light.
 

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Discussion Starter #13
There is no bulb in the hole for the check engine light, but there is one in the hole next to it for engine in red if this makes ant diff. I do not have voltage on the red wire of the injectors.

How does one tell when their EEC goes bad?
 

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Gotta get power to the injectors or it'll never run. chase all the wires back to the ecu and check for continuity being you already found one rat nest in it. Put a bulb in the check engine light it is bulb #194 they come in a pack of 2 for a few $ and work in a ton of stuff on the truck I keep atleast one pack in the glove box at all times.
 

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The Red wire carries power to the fuel injectors. It should be "hot" whenever the EEC relay is turned on, i.e. key in the On position. These EVTM shots from Ford Fuel Injection may help you track down the issue:





The PCM is what completes the circuit to turn on the injectors.
 

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Discussion Starter #16
Thanks guys. You all are helpful as heck Checking all the wiring back to the EEC was my next project after redoing the grounds. I should have done this toda but I got lazy... I'll Let ya know what I find.


kf4amu Why was the check engine light so important? Other than its well known function was there another reason?
 

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Check power output of the EEC relay, it is connected directly to the red fuel injector wires as you can see from the schematic.

I'm 99 percent sure the yellow check engine light only comes on when the EEC is on, so I was asking you if it was illuminated to backup my suspicions your EEC is not turning on. Since you do not have power to the +V side of the injectors either, I'd guess a bad EEC relay.
 

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Discussion Starter #18
Thanks kf4amu. My dads been telling me to replace that relay for 2 weeks. It'll sure be a nice, cheep and easy fix but I'll have to eat crow. :D
 

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Discussion Starter #20
I found the body ground to the EEC and used jumper cables to ground it to the battery. Still nothing. So I replaced the EEC relay. No change

I traced the wires from the relay and the wire had power at the EEC. I don't know why but I didn't check for continuity of the ground. I followed the red wire from the injector harness back and found it good.

I unplugged the injector harness and found 12v there so I plugged it back in and checked at one of the injectors and had no voltage. I found if i mess with the connector I can get voltage at the injectors so I may have found my problem. I have another connector around somewhere so I can change it easy enough.
I have to put the fuel canister back in before I can try to start it.
The Yellow Check Engine Light does not work at all but the Red Engine Light does. The Rear ABS light does too.

If it does not start now and I still get fuel pressure I have to believe its the ground path or a bad EEC
 
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