Bronco 2 1987 2.9 starting issues, overheating | Ford Explorer Forums - Serious Explorations

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Bronco 2 1987 2.9 starting issues, overheating

Ikesbucs

New Member
Joined
May 26, 2022
Messages
6
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City, State
Ketchikan, Alaska
Year, Model & Trim Level
1987 Bronco II EddieBauer
Bronco II 1987 2.9 electronic fuel injection

Hey guys! So my bronco has ran half of the 3 years I’ve had it it’s now cranking but not starting. I have a list of everything I’ve fixed on it below. So Today I tried spraying a crap ton of starting fluid in air intake and the intake manifold and no start so then I moved onto spark plugs I replaced a spark plug and tested it by putting negative jumper cable from spark plug to negative on battery and had my wife start it. And there was no spark so I tried another spark plug and same thing replaced it with new one same thing. Tommorow I’m buying fuel pressure gauge to double check I have fuel pressure I just changed my tank fuel pump last week and I don’t hear it come on every time I start it ( I know it won’t come on if the system is already pressurized right?) anyway I’m thinking it might be fuel pump relay which I’m having very Hard time identifying the wiring schematic to tell which one it it is out of the four relays if I was confident my low pressure fuel pump was working then I would move on to distributor cover rotor spark plug wires etc but I can’t yet until I know my fuel pump is working I don’t even know what psi I should see when I attach fuel pressure gauge to a schrader valve on fuel rail I’m lost in the sauce and I suck at troubleshoooting. also Haynes manual says to relieve the fuel pressure you just disconnect inertia switch and then crank it for 15-20 seconds and the button will pop up but the button never pops up when I try that is it stuck and that’s why fuel isn’t pumping ?

Things I’ve fixed below

Fuel Filter
In-line fuel pump
Low pressure fuel pump
Starter
Radiator
Fuel injector o rings and cleaned injectors
Valve cover gaskets and cleaned covers

UPDATE She finally turned over! I just started thinking about how I didn’t ever even look at the eec/ecm (I don’t really know the difference)anyway the point is I changed the relay with the brown connection ( I also changed the fuel pump relay with green connection but that didn’t help it was already working now I know! )I changed the brown eec/ecm relay then I turned the key to on and heard the fuel pump prime and she started !! I didn’t even have to change the distributor cap rotor or spark plug wires I still will though it was literally the ecm/eec relay

Super excited BUT she is doing the same thing she has done for three years now that’s it’s running. She runs for 15/20 minutes then this ticking sound gradually gets louder and the engine kind of sounds like it’s bogging when I change gears and like kind of bogging when driving in 3rd going 25 mph so the ticking gets louder (I can’t tell if the clicking/ticking sound is from the lifters or the distributor) then as the ticking gets louder the oil light starts flickering and it seems to start bogging even more but she is running so awesome! Thanks for all your help 410
 



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First thing to do is check that the ecm is getting power. No power to the ecm, no power to the coil or the fuel pump relay. Once that is ruled out, check for voltage at the coil.
 






last week after changing my negative battery terminal I had a crank but no start condition. Turns out that the ECM ground at the battery did not get hooked back up. Check your ground at the NEGATIVE battery terminal for the ECM for a loose or bad connection.
 






1987 2.9 here we go!

Okay so the 87 has two fuel pumps, in tank “boost” pump simply a low pressure
Pump that is responsible for feeding the high pressure pump on the frame rail.
Both pumps and powered by the same wire abs both pumps should run when you first turn the key, they should run for a second to prime the fuel system, everytime you turn the key. No boost pump and you will get low fuel pressure and a long crank, won’t start or run well on hills. Eventually I got tired or replacing
Boost pumps…
First I cut an access panel in my bronco ii hatch so I can get to the fuel puNo very very easily no need to drop tank. Next I installed a single high pressure pump into my fuel tank sender (89-91 bronco ii style) then I replaced the rail mounted high pressure pump with a second fuel filter. Now I have a single fuel pump, I used a walbro 155lph pump.

The fuel pressure at the rail should be 34-42 psi

The fuel pump relay is the green one
There are three relays
Ecm power
Fuel pump
Ac wot throttle

No spark on a 2.9l is almost always a bad tfi ignition module located on your distributor. Most 2.9l owners will keep the finger wrench and a spare tfi in the glove box. The old tamiya rc car 4 way lug wrench is the perfect tool for replacing the tfi in the truck on the side of the road, hard to reach back there

First check all your fuses, next check for power at the eec/pcm

Then check for fuel pumps to prime and check fuel pressure

87 bii with a 2.9 is getting up there in age, there are several fusible links to check in the charging system wiring

A simple multi meter can check for ground and power at the relays with key on

You can check for computer/‘accessory power at a fuel injector red wire,’with the key on the red wire should have battery + voltage
 












1987 2.9 here we go!

Okay so the 87 has two fuel pumps, in tank “boost” pump simply a low pressure
Pump that is responsible for feeding the high pressure pump on the frame rail.
Both pumps and powered by the same wire abs both pumps should run when you first turn the key, they should run for a second to prime the fuel system, everytime you turn the key. No boost pump and you will get low fuel pressure and a long crank, won’t start or run well on hills. Eventually I got tired or replacing
Boost pumps…
First I cut an access panel in my bronco ii hatch so I can get to the fuel puNo very very easily no need to drop tank. Next I installed a single high pressure pump into my fuel tank sender (89-91 bronco ii style) then I replaced the rail mounted high pressure pump with a second fuel filter. Now I have a single fuel pump, I used a walbro 155lph pump.

The fuel pressure at the rail should be 34-42 psi

The fuel pump relay is the green one
There are three relays
Ecm power
Fuel pump
Ac wot throttle

No spark on a 2.9l is almost always a bad tfi ignition module located on your distributor. Most 2.9l owners will keep the finger wrench and a spare tfi in the glove box. The old tamiya rc car 4 way lug wrench is the perfect tool for replacing the tfi in the truck on the side of the road, hard to reach back there

First check all your fuses, next check for power at the eec/pcm

Then check for fuel pumps to prime and check fuel pressure

87 bii with a 2.9 is getting up there in age, there are several fusible links to check in the charging system wiring

A simple multi meter can check for ground and power at the relays with key on

You can check for computer/‘accessory power at a fuel injector red wire,’with the key on the red wire should have battery + voltage
Thanks so much for info! I actuallly did the same thing with low pressure pump and just cut out a panel in the hatch super easy!

How is the single high pressure pump idea working ? Which is an awesome idea actually I will do that later after I get this thing started.

I took out the line going into my high pressure pump from low pressure and there was fuel and also hearing a click from low pressure when key turns to on not a whirring sound like Haynes says but what I have done is

Change
Tfi ignition module
Ignition coil
 






The 89-90 bii had a simple pump in the tank
The 91+ ranger and explorer both went to single in tank pump too, after 91 no more boost pump

It works great mine has been like this for may years

Do you still have no spark?
 






The 89-90 bii had a simple pump in the tank
The 91+ ranger and explorer both went to single in tank pump too, after 91 no more boost pump

It works great mine has been like this for may years

Do you still have no spark?
Sweet I’m gonna. It the same 155 pump in the tank you were talking about? I’m gonna have my son do it he wanted a little project lol

I put in new spark plugs and Still no spark I bought a distributor cap, rotor, and new wires but haven’t installed them yet doing that today I bought a multimeter for when after I’ve done everything I can switching out parts and it still doesn’t start then I will get to the wiring because I don’t even know where to start with that so hopefully the distributor stuff works!!

I hooked up fuel pressure gauge and turned key to on position and followed the haynes and actual gauge instructions hoping it to read 40 psi and it was zero fuel pressure!! My battery died right after that so maybe not enough juice in battery shop said it was bad cell so after today getting no battery I will have a pretty solid update about all that stuff.
 






The 89-90 bii had a simple pump in the tank
The 91+ ranger and explorer both went to single in tank pump too, after 91 no more boost pump

It works great mine has been like this for may years

Do you still have no spark?
UPDATE She finally turned over! I just started thinking about how I didn’t ever even look at the eec/ecm (I don’t really know the difference)anyway the point is I changed the relay with the brown connection ( I also changed the fuel pump relay with green connection but that didn’t help it was already working now I know! )I changed the brown eec/ecm relay then I turned the key to on and heard the fuel pump prime and she started !! I didn’t even have to change the distributor cap rotor or spark plug wires I still will though it was literally the ecm/eec relay

Super excited BUT she is doing the same thing she has done for three years now that’s it’s running. She runs for 15/20 minutes then this ticking sound gradually gets louder and the engine kind of sounds like it’s bogging when I change gears and like kind of bogging when driving in 3rd going 25 mph so the ticking gets louder (I can’t tell if the clicking/ticking sound is from the lifters or the distributor) then as the ticking gets louder the oil light starts flickering and it seems to start bogging even more but she is running so awesome! Thanks for all your help 410fortune
 






Finally get her started! It was the ecm relay. Super excited BUT she is doing the same thing she has done for three years now. She runs for 15/20 minutes then this ticking sound gradually gets louder and the engine kind of sounds like it’s bogging when I change gears or disengage the clutch to switch gears and like kind of bogging when driving in 3rd going 25 mph just example so the ticking gets louder (I can’t tell if the clicking/ticking sound is from the lifters or the distributor) then as the ticking gets louder the oil light starts flickering and it gets brighter and seems to start bogging even more but the end result is after 15 minutes of driving it’s

1.)LOUD TICKING FROM DISTRIBUTOR IS SEEMS LIKE (because it speeds up when you
rev it/ don’t know if lifters do that as well?)
2.) LOUD BOGGING KIND OF LIKE HOW A SEMI TRUCK SOUNDS. IT MAKES BOGGING NOISE LIKE WHEN YOU CHANGE GEARS OR LIKE WHENEVER YOU DISENGAGE THE CLUTCH AND THE. SWITCH TO NEW GEAR ITLL MAKE BOGGING NOISE UNTIL YOU GIVE HER THE JUICE
3.) OIL LIGHT GETS BRIGGTER AND BRIGHTER AND BRIGHTER OVER THE 15 min and smokes out of the back of the valve cover gaskets back as in closer to rear of vehicle here is everything I’ve changed and fixed on it

Fuel Filter
In-line fuel pump
Low pressure fuel pump
Starter
Radiator
Fuel injector o rings and cleaned injectors
Valve cover gaskets and cleaned covers
Ignition control module
Ignition coil
Spark plugs
Fuel pump relay
Ecm relay
 






The oil light comes on if there is less than 5-7 lbs of oil pressure.
 






You are losing oil pressure and the lifters are starting to get noisy on the pushrods as pressure drops.

Most times oil pressure loss is due to sludge in the engine.
I would drain your oil and replace it with diesel oil (15w-40)
Diesel oil contains detergents which will break up the sludge
Run it with 5 quarts of diesel oil and see if oil pressure issue slowly fixes itself.

There are other methods to fighting sludge, I prefer diesel oil when it is a severe oil starvation issue like you are having
 






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