FJ80 Uphill/High RPM/Heavy Load Power Loss (1 Viewer)

[FranceJohnson]

This has been a pretty tough year for my 1992 3-FE FJ80. Outlined on other threads, the engine has basically been given a complete refresh, new HG, pretty much new ignition system, ect ect. I am not going to bog down the list of parts replaced upfront on this to hopefully reduce the red herrings. I have be chasing gremlins left over after pulling the engine apart for a few months now. I am leaving in 7 days to take a trip to Moab with my family and my stress level with this new issue is really worrying me. This is likely an electrical/sensor issue due to its intermittent behavior.

I live in SLC (4700' above sea level), and we have some pretty serious hills here. On level interstate the truck behaves great, and has zero problems holding 70-75 mph. Silky smooth, all systems normal. Truck gets pretty much 10 mpgs on the nose, which has been that way since I owned it. My issue is under certain instances when going up hill I will completely lose power. Most of the long steep grades around here require to push 3-3500 RPMs for several minutes, which the engine never had an issue with before the rebuild and for the first couple months after. Now, usually when the air is a little warmer (65F+) it will feel like it is slipping and losing power whenever I put the hammer down. It is a very weird feeling, the RPMs don't really drop off like its missing, I am usually at speeds well above 50, which would mean the Torque Converter is locked up and not slipping, but also does it at lower speeds. It is not related to a specific gear (has happened in what should be 2nd and 3rd). It just feels like all the power just vanishes. It happened one time which the engine ran warm (3/4) gauge afterward for the following 10 mins. After sitting for a couple hours, I drove back over the same hill and it rocketed up it with no issues at all and was nice and cool.

I have read some related 3-FE problems, which were:
Dirty/Clogged fuel pump screen (fuel filter is newer)
Throttle Position Sensor adjustment.

I plan to check out the screen tonight. I will test the TPS per the FSM tomorrow. I ordered 2 cans of B&G 44K so see if that will help clean out the system a little. I just want to make sure there is nothing else that might need to be checked since I have such a short time to knock this out. Or if anyone has some tests or ideas to isolate if this is a fuel, ignition, or mechanical (trans/tcase/torque converter) issue. I am not sure if I had an injector that was malfunctioning what that would feel like. I appreciate any leads or things to investigate outside the two listed above.

 

[SUMMIT CRUISERS]

Recommendation: Don't check out the fuel pump screen/sock, just change it. This sounds exactly like your problem. I have experienced what you described on my son's 92 many years back. After about an hour or so of driving hard, engine power would decline and essentially would stutter to the point of almost stalling. Let the truck sit for 30 minutes, and all would be fine for another hour or so. One more recommendation, keep your tank topped off on the trip. Don't let it get below 1/4 while pushing it hard. The ethanol blended fuels you usually will be experiencing on your trip can boil off causing a vapor lock situation in your fuel tank. This is usually seen more in the summer months, not so much now but keep it full for a piece of mind. Enjoy the trip!

 

[FranceJohnson]

Removed the fuel sock. Pretty easy job. Spend more time brushing and blowing away the red desert collected atop the fuel tank so it wouldn't fall into the tank than anything else.

It looks pretty old and in need of replacement.

Fuel Sock P/N: 23217-11010
Rubber Gasket: 77169-60010

Paid about $22 for both from the dealership. Won't be in for a few days, so I need to make a McGuyver replacement or reinstall until then.

 

[SUMMIT CRUISERS]

Definitely bad. Here's my pic on post #23 on the second page. Notice the sucked in screen like yours.
Fuel Pressure Issue

I have had some luck on replacing the screen with a non-Toyota one at a parts store. Just take yours in and check the clearances. The only problem I have seen is that some of the non-Toyota ones have a longer 90 elbow that will raise your whole fuel pump assembly up too high. So look at the 90 and try to get one with a tight turn. The strainer 90 essentially sets on the tank. That's the issue.

 

[jonheld]

An old, clogged fuel pump pre-filter will collapse on itself when the fuel in the tank heats up and RPMs and engine load go up. This is one of those "100K mile" parts that should be replaced periodically along with the inline fuel filter.

 

[Rifleman]

An old, clogged fuel pump pre-filter will collapse on itself when the fuel in the tank heats up and RPMs and engine load go up. This is one of those "100K mile" parts that should be replaced periodically along with the inline fuel filter.

Is this a 100,000 mile item on the 93-97 trucks too, or is it just for the 91-92 trucks?

 

[jonheld]

Is this a 100,000 mile item on the 93-97 trucks too, or is it just for the 91-92 trucks?

All 80 Series have them, albeit different part numbers. I have a new one for my LX450 along with a new inline filter sitting in a parts box waiting. Just need the time to work on the truck.

 

[FranceJohnson]

I picked up the fuel sock, installed it, and mixed with the 2 cans of BG 44K, it has a bunch more pep in it's step....but this did not resolve the issue.

It drives great on flat ground, again holds 70+mph on the highway. Yesterday I drove up a steep canyon, which has a speed limit at 40 mph, it powered up the canyon without issue. Today, I was driving along I80 at 70 mph, at it near the mountains to go up the pass, all the power just disappeared again. The RPMs stay pretty much the same, and it definitely has to be something drivetrain related. I can hear and feel what feels like slippage, or like when a gear hunts. Though unlike hunting, the RPMs aren't necessarily revving up before it slams into gear, it just feels like power from the motor is no longer going where is supposed to. All the fluids are fresh, I change 4qts of AFT DEXII every other oil change. The fluid when checked on level ground, at operating temp, with engine running is full, if not slightly above.

If I am going 60-70 mph, shouldn't the torque converter be locked up/unable to slip? Will the trans slip while in gear? This happens in 3rd and 2nd gear, so it is not really unique to a gear. And again, only seems to happen when going at a high speed, into a incline. If I start from stop, and drive up a pass, it doesn't seem to have this issue. I am at a loss.

 

[FranceJohnson]

After doing some reading on the 60 Series side about the A440F transmission, has led me to a similar thread. The "solution" was called "Rodney's Party Trick" which is the most terrifying thing I have ever read on this forum. I am not sure I have the balls to try it.

 

[SUMMIT CRUISERS]

After doing some reading on the 60 Series side about the A440F transmission, has led me to a similar thread. The "solution" was called "Rodney's Party Trick" which is the most terrifying thing I have ever read on this forum. I am not sure I have the balls to try it.

Crazy symptoms, I wouldn't do the party trick either but how about the Rodney's Flush? If your tranny fluid has never been completely changed, I would completely flush the system. Takes about 22 qts more or less. I do it to all my vehicles when I first purchase them. Granted these vehicles always have over 150K on them and probably need the tranny serviced.
Here's the instructions I provided earlier on a different thread (post #10):
Need FJ80 tranny advice

 

[jonheld]

The A440F is very sensitive to fluid level. It should just touch the HOT line at normal operating temperature with the engine running.
Many years ago, I overfilled the transmission by about a quart. It was fine when cool or getting warmed up, but when she got hot I lost power.
If you're reading over HOT on the dipstick, then you have too much fluid in the pan.

 

[FranceJohnson]

then you have too much fluid in the pan

I will pull the plug and bleed off maybe a quart? see how she looks? Have you ever tried the Party Trick? Reading through some 60 series A440F threads shows some similarities of the running warm issues I was having this summer. I would say the truck is running 95% perfect, then is just has 5% total nonsense quarks.

 

[FranceJohnson]

If your tranny fluid has never been completely changed,

I did a 16 quart change when I bought it, and it needed it. The drain, fill, run through the gears, repeat method. It was nice and red afterwards. I have since drained the pan and refilled every other oil change. The fluid looks nice and clear, I would have a hard time buying a fluid change only would knock this out. I am going to try and drain off a quart as jonheld suggested. I watched video of the Party Trick (http://vid177.photobucket.com/albums/w219/wjb4000/Rodney Party Trick_zpshkugdtfg.mp4), doesn't seem as scary as I was envisioning.

 

[Rivman1243]

I did a 16 quart change when I bought it, and it needed it. The drain, fill, run through the gears, repeat method. It was nice and red afterwards. I have since drained the pan and refilled every other oil change. The fluid looks nice and clear, I would have a hard time buying a fluid change only would knock this out. I am going to try and drain off a quart as jonheld suggested. I watched video of the Party Trick (http://vid177.photobucket.com/albums/w219/wjb4000/Rodney Party Trick_zpshkugdtfg.mp4), doesn't seem as scary as I was envisioning.

Dear god! I don't know if I could do that

 

[FranceJohnson]

Dear god! I don't know if I could do that

We should probably make clear that this is ONLY for 3-FE/ 1991-92 FJ80s with the A440F. I don't think the electronic magic in the A442 would even let you do it. The reason you have to go 50mph is to keep the parking pin from engaging. If you did it going slower, it would probably end differently.

 

[BILT4ME]

In the newer ones A442, doesn't the computer kill the engine if it senses forward motion and the trans huts reverse? I know my 96 will due at low speed, but I'm not gonna try it any faster.

 

[jonheld]

I will pull the plug and bleed off maybe a quart? see how she looks? Have you ever tried the Party Trick? Reading through some 60 series A440F threads shows some similarities of the running warm issues I was having this summer. I would say the truck is running 95% perfect, then is just has 5% total nonsense quarks.

I have never done the party trick and never had a reason to think about it in the 25 years I've owned the truck. I have never had any issues with the transmission other than the one time I overfilled it . She has always had regular drain/refills since new.
Since this happens in different gears, I'm inclined to think that it's not transmission related . If the trans was slipping , the engine would rev. This sounds more like a loss of power rather than transmission slip.
How old is the inline fuel filter on the frame rail? Are any of the hard lines to/from the tank pinched? You'll see these right by the fuel filter .
I had an issue years ago with a crushed hard breather line that would cause a power loss after an hour or so of highway driving . It was causing all sorts of strange behavior from difficult starts to power loss. Once I bypassed the damage it was like a new truck.

 

[chap79]

Catalytic converters?

 

[FranceJohnson]

Fuel filter is probably 2 years old now. I run 2 cans of 44K through it each year. The fuel tank was clean as a whistle when I did the fuel sock. The fuel dampner and regulator are 3 months old. The charcoal canister is about a year old. I replaced most of the vacuum lines this past summer, I did not noticed any fuel lines that looked damaged but I can check again.

The cats and oxygen sensors are 1 year old. The truck has an egr delete. I might just have to take a video. I read multiple threads on the 60 section with the same problem, but one of my big frustrations is that they never post what the solution was.

 

[FranceJohnson]

Whatever demon living in my transmission was in full force today. The issue even happened at a stop light. The truck could barely accelerate with full throttle from a stoplight. My father-in-law was riding in the car with me and said it almost seemed like the transmission was trying to go into 2 gears at the same time. Even when trying to shift using the lever made pretty much no difference. I drained out a little over a quart of AFT to get it level with the first notch, warm, running, on the dipstick. Prior to this.

Sooooo, I decided the smart thing to do 24 hours before leaving for Moab would be to throw my truck into Park, at 55 mph for 5 seconds. Twice.

The result was really just some ticking from below the shift lever, which I assume was caused by the parking pawl skipping along the teeth. It drove really well on the way home, but it was flat land so the true test will not be until tomorrow morning when I give a run at some hills. I will probably do another 4qt fluid swap in the morning in case anything got kicked out during the Party Trick.