87 2.9 no guts, no answers

[LeBronCo]

My 87 XLT has no power. Under load when I step on the gas the rpms climb, but it falls flat on its face. You can feel the motor struggling to make power. This just started on a trip on the way home on the freeway. Here's what I've done/checked.
New TPS, plugs wires, coil-good. Vacuum hoses-good, cat/muffler-good, fuel pressure good. Replaced both fuel filters, cleaned both pumps. Found some rust in the old rear filter. ???

 

[Uncle Gump]

Did you put a vacuum gauge on it to check for a restricted exhaust? Because it sure sounds like a plugged exhaust.

Is this intermittent... or it always acts this way?

Any check engine light?

 

[LeBronCo]

Mechanic says cat/muff are good. No check engine light and it is full time. Started on a trip home @ 35 miles on the freeway. Just lost power. Could barely make it up a slight incline. Next is to check the fuel filters again. If there's junk in them, then it's time to flush the tank. This thing is becoming more of a money pit than my x-wife!

 

[Uncle Gump]

There are some capacitors in the PCM that go bad and can cause some drivability issues. It is free to open up the ECM and check them. Not saying it is your issue but it is certainly a possiblity.

Read this thread on TRS and you can also search "capacitors" for more information. Doesn't matter that it's a 3.0L... all ECM's have them.

..92 ranger 3.o with fuel pump issues. | The Ranger Station

 

[LeBronCo]

Thanks Unc,
I appreciate your suggestions. Once I get this sorted out, this will be one to write about and share with the brotherhood.
Nelson

 

[LeBronCo]

I had a leak down test done and it reported 40%. Mechanic says it doesn't matter that compression is 185 all around if leak down is this high. I cannot believe that a one owner B2 in xlnt condition in/out with 130K miles has a worn motor. So far I've replaced the gas tank, both pumps & filters, new distributor/tps, cap, rotor, wires and plugs. Vacuum checks, new MAP sensor, new ECM. Checked back pressure/cat. Have I missed anything B4 I have to rebuild the motor?

 

[JerryC]

All cylinders or just a couple?
Did he say how it was leaking and how fast?

You could try this if it is the rings:
Engine Restore
It's the only miracle cure in a bottle that has at some good results from testers that aren't shills for the product.
I've been putting it in mine for a couple of years and I did notice a bump in power.

If it is valves you could try a fuel system cleaner to try to get gunk off the valve seats., and then if that fails get a valve job done on the heads.

I lost track of your threads, have you checked for vacuum leaks? From your symptom it would be a big one.

 

[Uncle Gump]

Something doesn't sound right to me...

With compression numbers like you posted... I would never even run a leak down. In all my years I've never seen an instance where compression was not the best indicator of overall engine health.

I'm going to agree with @JerryC ... I'm lost as to what is actually going on and you're trying to correct. Maybe you can start from the top after taking a deep breath... I know you're frustrated.

 

[LeBronCo]

All cylinders or just a couple?
Did he say how it was leaking and how fast?

You could try this if it is the rings:
Engine Restore
It's the only miracle cure in a bottle that has at some good results from testers that aren't shills for the product.
I've been putting it in mine for a couple of years and I did notice a bump in power.

If it is valves you could try a fuel system cleaner to try to get gunk off the valve seats., and then if that fails get a valve job done on the heads.

I lost track of your threads, have you checked for vacuum leaks? From your symptom it would be a big one.

So far I've replaced the gas tank, both pumps & filters, new distributor/tps, cap, rotor, wires and plugs. Vacuum leak checks, new MAP sensor, new ECM. Checked back pressure/cat. After a fresh tank of gas it seems to be running better so I ran two cans of Seafoam in a fresh tank fill. We'll see if that helps. I changed the tank because we found rust in it. With what's happening now I plan on changing out the injectors and connectors if the Seafoam doesn't significantly improve performance.

 

[Uncle Gump]

I would probably test clean and rebuild the injectors you have before just buying rebuilt ones. It's "like a box of chocolates"... you never know what you're gonna get. The cost is minimal and there is a ton of videos for the process. There is also a filter on the inlet side of the injector... with your rust issue... it is certainly a possibility.

Fuel Injector Rebuild Kit | Ford Bronco II Ranger 2.9L 1986-1992 – The Injector Shop

 

[LeBronCo]

I would probably test clean and rebuild the injectors you have before just buying rebuilt ones. It's "like a box of chocolates"... you never know what you're gonna get. The cost is minimal and there is a ton of videos for the process. There is also a filter on the inlet side of the injector... with your rust issue... it is certainly a possibility.

Fuel Injector Rebuild Kit | Ford Bronco II Ranger 2.9L 1986-1992 – The Injector Shop

Thanx for the input. I got a smokin' deal on a brand new set of Bosch injectors from a local Bronco guy. I looked at the connectors and they were kind of crusty as well, so I'm going to replace them as well. Keep yall posted!

 

[JerryC]

A little tip about leak down. You can tell where it's bad by pressurizing the cylinder and listening to the intake, exhaust and PCV or dipstick tube.
Where the air comes out tells you the problem.

If it's not one of those, look in the radiator for bubbles or do the surgical glove over the opening trick and see if it inflates.

 

[LeBronCo]

All cylinders or just a couple?
Did he say how it was leaking and how fast?

You could try this if it is the rings:
Engine Restore
It's the only miracle cure in a bottle that has at some good results from testers that aren't shills for the product.
I've been putting it in mine for a couple of years and I did notice a bump in power.

If it is valves you could try a fuel system cleaner to try to get gunk off the valve seats., and then if that fails get a valve job done on the heads.

I lost track of your threads, have you checked for vacuum leaks? From your symptom it would be a big one.

Hey JerryC,
I'll recap the story for you of what started my thread. I was on my way home on the 15south about to exit on Gopher Cyn. (I live in San Diego) when all of a sudden the truck seemed to power down, kinda like when a diesel goes into limp mode. I cruised to the stop sign and proceeded up a slight grade on Gopher Cyn. 1st gear only got me to 12mph, 2nd to 22mph and 3rd; forget it not happening; no power. Had to downshift to 2nd to barely get over a grade that I should have been able to take in 4th. Absolutely no power under load. When I got home I ran all the vacuum checks. Had a backpressure test done at a local muffler shop. (I've owned several 2.9s over my lifetime) Brought it to my mechanic, he checked spark and fuel. Fuel was suspect so we pulled the tank. Full of rust, so I replaced it with along with both the strainer, both pumps and filters. Regarding spark, distributor and wires were both arching so I preplaced the distributor (with TCP), rotor and cap, wires and plugs. New MAP sensor. Ran a little better but not like it should. Mechanic said he ran a leakdown test and it was at 40%. He said that was bad even though the motor had 185psi all around. He said it took several cycles for the cylinder to reach 185psi. I found it hard to believe that a motor that started up on first crank, idles smooth as glass and revs flawlessly needed to be replaced. No smoke, no leaks, WTH? I was so disgusted I let the truck sit for a week or two in the garage. After that I started driving it just a few miles now and then. I figured I can't do any more damage to an already worn motor, right? I put 2 cans of Seafoam in a full tank of fresh gas and all of a sudden it started to pull better under load. I could reach 65mph on the fwy. Not perfect, but way better, so I started thinking that maybe with clean gas, etc. the initial problem probably had been caused from the crud in the tank. The last item on that check list are the fuel injectors which I'm replacing next. I've watched hours of videos on YouTube about various mechanics trying to solve problems with the 2.9. It is a swervy dog for sure! I'll let you know how things turn out after I replace the injectors and connectors.