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2.9 Bogs off throttle, codes 41 and 25

rang-a-stang

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106
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Location
Camarillo, CA
Vehicle Year
1986
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
Total Lift
3"
Tire Size
31x10.50R15
I'm almost ready to torch this truck.
Quick background:
Bought the truck about a month ago, engine ran great, just needed valve cover gaskets, new fluids, thermostat, and hoses (already had all new cap, rotor, plugs, and wires).
We also spent a night with some degreaser and washed 30 years (and probably 15 pounds of gunk) away
Symptoms
-Right after we pressure washed the bottom and did the passenger side valve cover gasket, it does not want to idle cold and generally does not run very well. It is a chore to start. I really have to feather the throttle to keep it running when cold. Once it is warm, it idles fine but if you goose the throttle, it bogs (cold or hot). It's like a delayed throttle. KOEO yields no codes. KOER yields a 25 (if I tap on the block while KOER is running, 25 goes away) and a 41. Vacuum looks good.
Video with Vacuum gauge, showing the bog
What I've done:
I ordered a new O2 sensor because it was cheap but I do not think this is the problem. If it was the O2 sensor, wouldn't it run fine when cold/open loop?

I also rebuilt ALLLlllll my EFI related grounds. They all come together at a bus bar next to my battery, now. The grounds are great. At least I think this is all my EFI grounds.

If I unplug my fuel pressure regulator it runs WORSE. When it is idling, if I put vacuum on the EGR port, the engine stumbles and runs like crap (as it should). When I unplug my IAC valve, engine immediately stalls. I do not hear any exhaust leaks upstream of the O2 sensor. I have a spare new MAP sensor and swapping it does not change the symptoms at all.

Thoughts?
 


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rang-a-stang

Active Member
U.S. Military - Veteran
Joined
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Messages
106
Reaction score
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Points
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Location
Camarillo, CA
Vehicle Year
1986
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
Total Lift
3"
Tire Size
31x10.50R15
I unhooked the O2 sensor. No change.

When I unhook and plug the vacuum line for the MAP sensor, I get my throttle response back but it still runs like crap. I did not run KOER with the vacuum line unhooked. Should I? Should I assume this is my problem and get another one? The other MAP sensor I have is new but we all know "new" doesn't mean good. I also checked the plastic vacuum line to make sure it holds vacuum and it does. I put a vacuum line at the MAP sensor nipple and there is good vacuum there so the line is good.
 

rang-a-stang

Active Member
U.S. Military - Veteran
Joined
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Messages
106
Reaction score
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Points
28
Location
Camarillo, CA
Vehicle Year
1986
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
Total Lift
3"
Tire Size
31x10.50R15
MAP sensor has 4.95V on reference pin. Ground measures .7 ohms to the battery post. Exchanged the MAP sensor for another one at McParts. Put it on, no change. Driving it, it feels like there is a gnarly vacuum leak so we sprayed some carb cleaner and found the upper to lower intake manifold bolts were not torqued very well so we re-torqued them to 10 foot pounds. That cleared the 41 on KOER but no change is driving symptoms. We're popping flares; made an appointment with a local mechanic. :cry: This is the first time I have sent a car to a mechanic for a diagnostic in close to 10 years. I feel defeated.
 

JerrySab

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Messages
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Reaction score
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Age
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Location
Los Angeles
Vehicle Year
1988
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Automatic
2WD / 4WD
2WD
I'm going to throw out really annoying and probably overly obvious suggestions that you've already considered, fair warning. Discard these as you see fit.
- It almost sounds like you have a bad tank of gas. Is it possible water got into fuel lines while you guys were pressure washing? I know the fuel tank vent gasket was nearly dissolved in my 88 and contributed to clogged filters and vacuum leaks. I also think some precipitation may have found its way in there as there was a window of time with really rough, chuggy performance. I replaced gaskets and cleaned tank to some improvement. Were you guys able to check fuel pressure while truck is running?
- I installed fuel injectors whose spray were too much aerosol, and never quite got deep enough into combustion chamber. It ran an awful lot like you're describing. I replaced them with rebuilt OEM injectors and regained a lot of performance. Which is why I wonder about fuel delivery and it being of sufficient volume and quality.
- Maybe the computer is cooked? I know even less about reprogramming or the myriad fusible links along electrical lines, but I know they cause major headaches. I wonder if there is a smoking gun along wiring paths or connectors. Even if your grounds are solid, maybe theres a kink or fault that's not allowing a good 12v to find its destination.

Best of luck, will be watching to see how it resolves.
 

rang-a-stang

Active Member
U.S. Military - Veteran
Joined
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Messages
106
Reaction score
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Location
Camarillo, CA
Vehicle Year
1986
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
Total Lift
3"
Tire Size
31x10.50R15
It could be! It drove great up into the driveway, we did the washing, and it has run like crap ever since. We have already verified all the EVAP fittings are good and had removed the bed to (among other things) inspect the gas tank and fill neck (both potential smog failure points). I am not going to say we did not get water in but I don't know a good way to check.

Maybe I cooked my computer. I hope not. Again, hopefully the mechanic will be able to check. If this was a GM OBD 1, I have everything to read it's data stream and write MAPs for those but this is my first Ford EEC in years and all I have is the code scanner.

I also suspect fueling. I can see my timing adjusting with a timing light so I assume it is working correctly. I tried hooking up my Farbor Height fuel pressure gauge on the fuel rail but I cannot get it to read. I assume compression is good because it idles nicely when warm. To me that sounds like fueling. I have an appointment with the mechanic on Thursday, maybe I'll mess with my fuel pressure gauge and see if I can check it again.

My understanding is we should have about 45psi on the rail at idle and cruise. right?
 

rang-a-stang

Active Member
U.S. Military - Veteran
Joined
Sep 7, 2021
Messages
106
Reaction score
41
Points
28
Location
Camarillo, CA
Vehicle Year
1986
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
Total Lift
3"
Tire Size
31x10.50R15
SOOoooooo.....

Mechanic called today and said it was the fuel pump, wanted $450 to drop the tank and replace it. I said "No, the pump is on the chassis, under the driver seat." He said "My parts book says it's in the tank." So I said I would take it home and figure it out. I paid his $110 diagnostic and drove it home (sputtering, kicking, running like crap).

I looked up fuel pumps at McParts and saw two part numbers. Interesting. Posted this thread:
Asked if I had 2 pumps
Sure enough, I have two pumps. Both the Mechanic and I were right AND wrong!

Brought my truck home and started tinkering. I turn the key to on and I hear a pump start. I feel the fuel tank while cycling the key and can hear/feel it buzzing. Then I check the pump in the chassis rail and sure enough it is not buzzing. As I investigate, I notice the positive lead is loose. I pull the cover off and its unhooked! I bet I hit it with the pressure washer and knocked it loose! Woooo hooo! Runs like a champ again!

When I would turn the key and hear the pump, I thought my pump was good! Woo hoo! Smog check next!
 

JerrySab

Member
Supporting Member
Joined
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Messages
117
Reaction score
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Points
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Age
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Location
Los Angeles
Vehicle Year
1988
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Automatic
2WD / 4WD
2WD
GREATEST OUTCOME!!! That's amazing! Just plug the thing back in:LOL:
 

Jazzer

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Indianapolis
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2007
Make / Model
Ranger
Engine Type
2.3 (4 Cylinder)
Transmission
Manual
2WD / 4WD
2WD
Good on you!

-Jazzer
 

rang-a-stang

Active Member
U.S. Military - Veteran
Joined
Sep 7, 2021
Messages
106
Reaction score
41
Points
28
Location
Camarillo, CA
Vehicle Year
1986
Make / Model
Ford Ranger
Engine Type
2.9 V6
Transmission
Manual
2WD / 4WD
4WD
Total Lift
3"
Tire Size
31x10.50R15

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