1989 Bronco 2 Help.

Nemisus · Jan 19, 2018

Greetings CB,

I know I am reaching here but I thought I'd ask the good knowledgeable people here for some help before going elsewhere. I know of a few specific Forums that might be better suited but I wanted to try here first.

My Brother in law handed over a 1989 Ford Bronco 2 to my Wife and I to give to my Son for Xmas. He's 8 and really wanted a Bronco like his Dad. Some of you know I have a 74 Ranger that I have been slowly working on.

Anyhow, the B2 has a special place in my heart since its the first Bronco I every had. It is unfortunately the only Bronco I can afford for my Son at this time.

1989 2.9L 2wd Auto

Anyhow, it came to us with after sitting since 2010. I was able to getting it running with a fresh battery. It starts and runs with a fresh Tune-Up (Plugs, Wires, Cap/Rotor) but after it gets warm with any kind of load on the accelerator the engine seems to starve for fuel and it begins to hesitate and stutter really bad. In most cases it'll just die. I can get it to start right back up. If I rev the engine slowly its okay but as I let off it will "backfire" through the intake. I can drive it down the block if I drive it conservative but if I give the throttle heave load nothing happens and the engines bogs way down and dies...

At first I thought Fuel Pump but per the Chilton Fuel Pressure Test Check using a Test Guage the Fuel Pump passed.

I also have no way of pulling codes on this system.

I know I am reaching but any thoughts would be greatly appreciated!

Thank you in advance.

Cheers

Nemi

Doyle · Jan 19, 2018

Sounds like fuel filter or vaccum leak.

B RON CO · Jan 19, 2018

Hi, Besides just checking the fuel pressure, see if it is steady or if it drops when you open the throttle.Also remove and plug the vacuum hose on the fuel pressure regulator and see what happens.
I gave also seen the pintle and egr passage all clogged up with carbon, but that usually doesn't cause such a big problem.
Good luck

Broncobowsher · Jan 19, 2018

Pulling codes is just like the EEC-IV that we use from mustangs. Connector is on the passenger side of the engine compartment closer to the dash.

surfer-b · Jan 19, 2018

If I rev the engine slowly its okay but as I let off it will "backfire" through the intake.

this is a lean mixture burning slowly, when the intake valve opens its still burning and backfires through the intake.
like others stated you need to check the fuel pressure when you stomp the throttle, if pressure is good then start looking for vacuum leaks, which sounds like it will be common to multiply cylinders. You may also chk the TPS, if not working proper it can cause a lean condition. There are several other things but I would start with the easy stuff and do process of elimination. A good way to chk for vacuum leaks if you don't have a smoke machine is to use water and a squirt bottle, spray the water on all vacuum lines, connections, intake manifold gaskets, intake plenum gasket and even on the injector bases where the O-rings seal, I have seen these go bad and cause vacuum leaks. When you find it you can here it sucking the water in and it will start to miss-fire. Good luck and let us know what you find because this can be common to any FI system and may help us in the future.

Nemisus · Jan 19, 2018

Broncobowsher said:
Pulling codes is just like the EEC-IV that we use from mustangs. Connector is on the passenger side of the engine compartment closer to the dash.

Well unfortunately there was some rodent damage. Only minor but that little plug... I believe my chilton refers to it as the VIP plug was chewed up good. I will need source a new one eventually but I repaired the best I could.

B RON CO said:
Hi, Besides just checking the fuel pressure, see if it is steady or if it drops when you open the throttle.Also remove and plug the vacuum hose on the fuel pressure regulator and see what happens.
I gave also seen the pintle and egr passage all clogged up with carbon, but that usually doesn't cause such a big problem.
Good luck

I learned this morning that when its cold she runs fine. Open throttle and all. Only when it gets warm does it run bad. Oddly the fuel pressure increases on the gauge when it begins to go bag.

Removing the plug from the Regulator increased the Pressure about 3 PSI as expected per the steps in the TEST.

Doyle said:
Sounds like fuel filter or vaccum leak.

I performed this step just moments ago and had no positive affect. I also thoroughly checked for vacuum leaks. Have not located any to this point.

Appreciate the feedback. I have a brand new fuel pump. Might as well put it in and see what happens...

surfer-b · Jan 19, 2018

Well unfortunately there was some rodent damage. Only minor but that little plug... I believe my chilton refers to it as the VIP plug was chewed up good. I will need source a new one eventually but I repaired the best I could.

you may have found your problem but to which wires is the million $ question, if they have chewed that part what else have they chewed on that you cant see

Nemisus · Jan 19, 2018

surfer-b said:
this is a lean mixture burning slowly, when the intake valve opens its still burning and backfires through the intake.
like others stated you need to check the fuel pressure when you stomp the throttle, if pressure is good then start looking for vacuum leaks, which sounds like it will be common to multiply cylinders. You may also chk the TPS, if not working proper it can cause a lean condition. There are several other things but I would start with the easy stuff and do process of elimination. A good way to chk for vacuum leaks if you don't have a smoke machine is to use water and a squirt bottle, spray the water on all vacuum lines, connections, intake manifold gaskets, intake plenum gasket and even on the injector bases where the O-rings seal, I have seen these go bad and cause vacuum leaks. When you find it you can here it sucking the water in and it will start to miss-fire. Good luck and let us know what you find because this can be common to any FI system and may help us in the future.

Hey Surfer,

I learned this morning that this issue only seems to occur when the engine is warm. Something that I hadn't picked up prior to posting my problem.

Not sure this changes your theory but I thought I should add it. The warmer the engine gets the harder it is to idle. Giving it any kind of throttle gets harder.

I located a brand new IAC and TPS just last night cleaning my garage but learned they were for a 4.0 and wont work for a 2.9. Sucks because those are pretty spendy parts. Would have been nice to just throw on for good measure.

surfer-b · Jan 19, 2018

I have a brand new fuel pump. Might as well put it in and see what happens...

I'm thinking there are 2 pumps on this system, an intank pump and a frame rail

Nemisus · Jan 19, 2018

surfer-b said:
I'm thinking there are 2 pumps on this system, an intank pump and a frame rail

Hey Surfer,

I have a Generation 2 and got lucky enough that they made the transition to 1 high pressure pump in the tank.

I have had 4 of these Bronco 2's and am very familiar with the Hi/low pressure pumps on the Gen1 versions. Was a pain in the butt when one went out.

That being said I decided to go back out and retest the pressure when things were not going well.

While running good the pressure is within range at 35-40 psi. After a few minutes and under load the engine starts to run sluggish and under powered. Hesitating and the PSI on the gauge slowly drops to 0 PSI.

So when the engine warms up and begins to run bad, I loose Fuel Pressure. At this point I think for good for self satisfaction I need to drop the tank and put in the new pump.

I'll report back when its done.

SteveL · Jan 19, 2018

I had an 89 2wd bronco 2. I think I had 318k on it when I sold it. It ran great but was barely passing smog.

Nemisus · Jan 19, 2018

Well shoot,

Here's an update that I'd rather not make! Instead of saying a new fuel pump made all the difference I am here to report that upon dropping the Tank I learned the following:

1: Tank is full of pin-holes hiding under the OEM coating. Leaks pretty bad when you start to mess with it.

2: Filler tube is cracked and does not make a positive seal at the tank. When I went to remove it I didn't have to unbolt it... I slide right off.

3: Both Fuel lines Snapped with out any effort before I could reach up and properly remove them. This indicates the were weak and possible already cracked.

The above 3 mentioned discoveries are enough IMO, to limit the Tank on a properly functioning Fuel Pump to pressurize the system adequately enough to perform.

Of course I am just throwing out my thoughts and could be way off. Either way the problems have to be fixed before I can continue my journey. Maybe I'll get lucky and this will be the solution either way.

SteveL,

While the EB has always been the Dream for me. I do have a special place for the Bronco 2. Often considered as the unwanted Bronco in the line of Bronco made by Ford. While this is my first 2wd version, the 4wd version once properly upgraded can be quite the trail demon. I had an 87 a full width solid axle conversion that was unstoppable.

Anyhow,

I must now go shopping for some parts. I am lucky to have a Pick-N-Pull close by.

half cab · Jan 19, 2018

I bought one new in 1984. Put a set of buckshots on it and that thang would go well here in the mud. Low on power but long on heart.

surfer-b · Jan 19, 2018

I would say u found ur problem. Good luck with the fix

Glass Pony · Jan 20, 2018

SteveL said:
I had an 89 2wd bronco 2. I think I had 318k on it when I sold it. It ran great but was barely passing smog.

I hear ya, I had an 1986 Bronco II and it would barely pass smog when it was brand new. When it got a little older I would retard the timing, run it through DMV, bring it home and put the timing back.

Nemisus · Jan 20, 2018

half cab said:
I bought one new in 1984. Put a set of buckshots on it and that thang would go well here in the mud. Low on power but long on heart.

Hey half cab,

When I was 16 the first vehicle I bought was a 1984 Bronco II. Made a deal locally with a guy to make payments. Looking back I do believe I paid too much. The hardware store I was working at the time paid me just enough to fit the bill. 84/85 came with the Carb'd 2.8 and was something to be desired. That 84 opened the door for me though. After that I ended up having many really cool B2's.

surfer-b said:
I would say u found ur problem. Good luck with the fix

Yeah I am thinking so. I have already located the filler tube and tank. A brand new tank is only 99$ from LMC. Oddly the filler tube is more. Going to take a look at it to see if its something I can repair.

Glass Pony said:
I hear ya, I had an 1986 Bronco II and it would barely pass smog when it was brand new. When it got a little older I would retard the timing, run it through DMV, bring it home and put the timing back.

One thing I did with all my Ranger Based Vehicles (RBV's) is keep a brand new CAT boxed in the garage. A friend and I went in halves on a new one some years back since he had an 86 (An 86 I gifted him since I had too many), and every time we needed a SMOG we just mounted the new CAT. Worked really well. Passed with flying colors every time.

1989 Bronco 2 Help.

Nemisus

Jr. Member

Doyle

Bronco Guru

B RON CO

Bronco Guru

Broncobowsher

Total hack

surfer-b

Bronco Guru

Nemisus

Jr. Member

surfer-b

Bronco Guru

Nemisus

Jr. Member

surfer-b

Bronco Guru

Nemisus

Jr. Member

SteveL

Huge chevy guy

Nemisus

Jr. Member

half cab

Guru Bronco

surfer-b

Bronco Guru

Glass Pony

Bronco Guru

Nemisus

Jr. Member

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