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No power to ECM?

Jdgephar

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Sep 25, 2012
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1,318
Have you checked for spark? That would help see if the computer is working. Then you can wire the fuel pump to something else and see if it will fire up.

Sent from my SM-G981U using Tapatalk
 
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Bumper

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Loc.
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I DONT have spark nor do I have fuel pump. The EFI harness is grounded to the engine as the directions indicate. The EFI harness is connected to all of its appropriate locations and my ECM is BRAND NEW. All my fuses are good. The ONLY thing I have not done is change out the relays associated with the EFI harness. Maybe I will change those out.....maybe I will make it into a nice deer stand! LOL! So aggravating at times.....but one day....it will all be worth it.
 

Timmy390

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Conway, AR
Time to start tracing power........Verify power with Key off to all the relays. Verify all the relay's are grounded. Then try with key on You should see power on more terminals with key on

Tim
 

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UPDATE: After a full review of the circuit that controls the fuel pump....I found the problem and am now pumping fuel. The inertia wire (hot wire coming from the inertia switch to the tank) was shorting out on the tank. After dropping the tank and rewiring, she is squirting fuel. Then because its a pressurized system, it revealed all the loose connections in the fuel line and I got to play in gasoline for about an hour. Fixed all my fuel line leaks and confirmed that I do have fire coming from my coil to my distributor.....but she still wont crank. So I have fuel, I have spark, but still no crank. Oh, also it looks like my rear main seal is also leaking....got oil coming from that area after only attempting to crank a few times. The project continues.......
 

Timmy390

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YESSSSSS....PROGRESS....

Reset the timing to top dead center and verify firing order and plug wires.

Not that you have fuel your almost there. You might be losing a deer stand but gaining a running Bronco 😀

Tim
 

DirtDonk

Contributor
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Nov 3, 2003
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When you say it won’t crank, you mean the starter won’t turn the engine over. Correct?
No Click, no cranking starter, no nothing?
 

gnpenning

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Loc.
I have more questions than answers.
You are already past this part but for future reference there are a number of YouTube videos that show how easy it is to replace leaking capacitors and some will give you links to where they purchased replacement. They will tell you how to identify the positive and negative side so you can get it in correctly. Be careful with buying cheap capacitors like anything else.
 
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UPDATE: The old girl actually cranked and ran a bit last night. I gotta get her in time....but at least I know now that IT IS POSSIBLE that the engine will combust. I think I may be a tooth or two off so I may just go ahead and go through the whole process of finding TDC on the compression stroke and restabbing the distributor. Super excited. I now know there is a CHANCE. HAHAHA!! I cant thank you all enough....great bunch of folks on here.
 
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UPDATE: So I took distributor out, found TDC, and restabbed. She cranks quick and will idle but seems to be running a little rich.....black smoke.....too much fuel ....but I am not sure how to adjust that with EFI.....could it be that it just sat up for long and it needs to get hot and burn some stuff out/up? Ah the mysteries of Broncohood.....
 

Timmy390

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HELL YES....We got combustion.........Hard part is over.....well sort of.

EFI running rich can be a number of things. MAP, BAP, ETC, IAC and O2's can cause this.

Can you pull any codes?

Tim
 
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HELL YES....We got combustion.........Hard part is over.....well sort of.

EFI running rich can be a number of things. MAP, BAP, ETC, IAC and O2's can cause this.

Can you pull any codes?

Tim
I pulled the codes and the only ones that I got were the ones that I am supposed to get according to the Ron Francis harness instructions. They call them "soft codes". Because my engine DID sit for several years......I am gonna get my brakes bled so I can drive it....go down the road pretty easy for a few miles, and then drain my oil and my anti-freeze.....I dont know if this is the right thing to do or not, but I dont think it will be anything but beneficial.
 

DirtDonk

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Shouldn’t be a vacuum line to a BAP.
This is a MAF engine, correct? If so it is a BAP with no vacuum.
Only the MAP sensor with an SD engine gets a vacuum signal.
 

Timmy390

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Shouldn’t be a vacuum line to a BAP.
This is a MAF engine, correct? If so it is a BAP with no vacuum.
Only the MAP sensor with an SD engine gets a vacuum signal.
UGH...my bad.....So it's just open to the air right?

Check it for bug nests......Here in AR we have things that build nests in open pipes.

Tim
 

DirtDonk

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Absolutely! I’d forgotten about that but people definitely have suffered from spiders and mud Dauber plugs before. Not to mention the sensors just failing like any other electronic device.
Probably not big enough for a mud dauber to take interest in, but that was the first thing that I thought of when you mentioned bugs.

Both the BAP and MAP are identical devices internally so can be used interchangeably. Even the electric plugs are identical.
The difference is the MAP (manifold absolute pressure) has a standard hose fitting and the BAP (barometric air pressure) has the little plastic guard over it to make sure you don’t connect a vacuum line to it.
 

Rustytruck

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Feb 24, 2002
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10,875
make sure you have a 195 degree thermostat. wont run properly until the engine see's some heat.
 
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Absolutely! I’d forgotten about that but people definitely have suffered from spiders and mud Dauber plugs before. Not to mention the sensors just failing like any other electronic device.
Probably not big enough for a mud dauber to take interest in, but that was the first thing that I thought of when you mentioned bugs.

Both the BAP and MAP are identical devices internally so can be used interchangeably. Even the electric plugs are identical.
The difference is the MAP (manifold absolute pressure) has a standard hose fitting and the BAP (barometric air pressure) has the little plastic guard over it to make sure you don’t connect a vacuum line to
Hmmmmm......I have a MAF sensor and I have a BAP sensor.....but I dont think my harness has provisions for a MAP sensor. I will look at the directions/diagram for the Ron Francis COBRA 75 again....but I dont recall it having a MAP. Does this MAP sensor have any alternate names perhaps?
 
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UGH...my bad.....So it's just open to the air right?

Check it for bug nests......Here in AR we have things that build nests in open pipes.

Tim
Oh yea, we got those same bugs here in Mississippi. I dont know if a dirt dobber could get into that BAP....it has a little plastic piece and the hole is TINY....but it is in an easy to get to location so I will check it this afternoon.
 
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HOWEVER....this all could be a vacuum issue of some sort. The underside of the plenum that I have has six outlets. How can I best explain the current alignment.....two of the six are connected together and then go to the PCV valve. The smallest of them is connected to a device on my fuel rail that some would call a fuel pressure regulator I think....another goes to my brake assist and the last two are capped. I also have a vacuum line that comes off of my throttle body and it is currently connected to the oil fill tube on top of the valve cover. Any additional info on this is welcomed.
 

DirtDonk

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The last line you mentioned, between the throttlebody and the oil fill tube, is the other half of your PCV system. It’s not actually pulling a vacuum but instead is allowing clean filtered air back into the engine that the PCV valve is pulling out. Very simple and ingenious system that really keeps the insides of our engines clean.

The other ones are correct too, but it’s the capped ones that you need to worry about. Most caps these days are cheap pieces of crap and deteriorate in a matter of months and cause all sorts of vacuum leaks. Up to a point the Efi and computer can compensate. But at some point it’s just too much.
 
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