bogging down issue.

[g-man]

My 2f is bogging down badly while accelerating in second. It only did it 2 times. Coming out of a turn (like turning out onto a main road), shift to 2nd and hard on the accelerator, suddenly bogs down hard like no gas, It almost stalls and I get off the accelerator pedal then back on to feather it a few light pumps ...comes back to life and down the road I go without issues. Besides this it drives well.

Guessing it's a fuel delivery issue, fuel filter recently replaced but didn't help. Possibly trash in the bowl? Accelerator pump issue?

 

[cps432]

Sounds like fuel delivery. How’s your pump doing? Check that out first. It could be on the fritz.

When my pump went out a few days ago it was doing something similar, but I have a digital readout that’s giving me lots of information on air fuel ratio and duty cycle etc. I knew immediately it was pump related. It was fluttering for a little while before it finally went out.

I know an electric pump is completely different from the mechanical pump, but the principles are the same. In fact I’d rather have the mechanical pump after getting stranded on the highway by an electric unit.

 

[OSS]

Definitely fuel starvation.
Don’t rule out debris in the float bowl.
I had a very small piece of crud drifting around inside the float bowl which would occasionally partially block the main jet, making the engine sputter. Driving up hills was almost not possible.

 

[DFXR]

I had similar bogging symptoms a while back. I pulled the two 14mm bolts on the front of the carb (for the jets) and flushed from the top with carb cleaner. It resolved the issue, though obviously it was too messy to truly pinpoint whatever debris was causing the problem.

 

[g-man]

Sounds like fuel delivery. How’s your pump doing? Check that out first. It could be on the fritz.

When my pump went out a few days ago it was doing something similar, but I have a digital readout that’s giving me lots of information on air fuel ratio and duty cycle etc. I knew immediately it was pump related. It was fluttering for a little while before it finally went out.

I know an electric pump is completely different from the mechanical pump, but the principles are the same. In fact I’d rather have the mechanical pump after getting stranded on the highway by an electric unit.

Pump is newish. Replaced with kyosan 12/2018

I had similar bogging symptoms a while back. I pulled the two 14mm bolts on the front of the carb (for the jets) and flushed from the top with carb cleaner. It resolved the issue, though obviously it was too messy to truly pinpoint whatever debris was causing the problem.

I'll probably try this. Seems like a low intensity kind of effort to maybe get some trash out. When you say "flushed from the top", exactly what did you do? I mean if you take off the top plate don't you have to replace a gasket? wonder if I can just spray it out with some carb cleaner from the 14mm bolt hole?

 

[cps432]

You probably want to get any trash in there to go backwards through the system. So going from the top with the bolts open would back-flush the jets. I think…

 

[OSS]

In my case - what I learned- was that disturbing any of the fuel lines (replacing the fuel pump or fuel filter) can dislodge something that might be clinging to the hose/nipple junction and send it into the float bowl past the needle valve strainer.

Me thinks that if the fuel pump gets replaced, it’s outlet hose leading up to carb should be flushed somehow before firing up the engine the first time to prevent a possible chunk of something ending up in the carb.

 

[DFXR]

Pump is newish. Replaced with kyosan 12/2018

I'll probably try this. Seems like a low intensity kind of effort to maybe get some trash out. When you say "flushed from the top", exactly what did you do? I mean if you take off the top plate don't you have to replace a gasket? wonder if I can just spray it out with some carb cleaner from the 14mm bolt hole?

Here’s a step by step from an old post by Jim C. ( It’s for a 40 but is accurate for our 2Fs.) I just removed the bowl drain plugs and sprayed from top as he describes. That fixed it for me. His complete method has a few more steps but is still very basic - carb stays in place and intact. Agree with @cps432 that you should be spraying from above, not below, so you don’t push anything back into the jets or bowl via the drain holes.

From Jim C:

How to (maybe)clean a 2F carb without tearing down.
- disconnect both fuel lines.
- remove fuel inlet fitting and fuel return assembly
- remove bowl drain plugs, placing a rag underneath to catch the spilled fuel.
- using Gumout spray carb cleaner, blast in the fuel inlet and fuel return, alternating. Chase w/ compressed air where avalable. The sand & crap that is piled up at the inlet screen (visible when looking in the inlet hole), can be moved/removed by blasting back & forth w/ the carb cleaner. Also, since the float is fully dropped now, the small bits that made it through the screen will fall through the wide open needle valve, allowing it to control fuel level better when the bowl is refilled.
- using Gumout, spray in the brass vent pipes in the top of the carb throat. The gumout will wash out of the drain holes on the front of the bowl, carrying some of the loose sand & dust out of the float bowl.
- remove idle mixture needle. Spray gumout in mix screw hole, while holding throttle open, so the idle port is uncovered. Put mix screw back in all the way, back out 3.5 turns.

-Place a clean container under fuel feed line. crank engine to get a cup of fuel. By running the fuel line wide open, much more gas is flowed than normal, washing loose junk up & out of the feed line. Junk that just moved around in the line before, but couldn't really get out.

Reconnect lines & install drain plugs, see if it runs any better, check float level.

This will often make an improvement on an old FJ40 w/ dirty tank that is blocking the trail for everybody else

 

[65swb45]

/\ all of which begs the question of a possible restriction at the pickup screen in the tank.

 

[g-man]

Ok, Thanks everyone for pitching in and giving me plenty of ideas!

 

[g-man]

I flushed my carb as suggested. Didn't see any debris come out though. Can't really tell a difference. Hasn't bogged down on me though. But I found I have another problem that may be related. I had a hesitation that I felt mostly while not accelerating but trying to stay at a steady speed. Like a huck a buck or herky jerky. disconnected the fuel line and ran fuel into a mason jar. Nothing ...clean gas. Then test drive and it ran great but idled high when i came back to park it. I opened the hood to check for a loose vacuum line and low and behold ...the big vacuum line from egr modulator to egr was not connected. So I started checking my egr modulator and it failed the first test. This one:

Then I checked my egr vsv and it doesn't click or open when 12 volts applied. So, now I'm at a cross road. I've found some toyota type modulator and vsv ...of course they are not land cruiser as these are NLA.

Amazon product ASIN B08K747Z58
and

Amazon product ASIN B0814MPNFB
cheap like $36 US for both, but then still need to check my EGR valve itself. OR, do I get some lighter springs for the dizzy and just remove and plug the vacuum line that controls the EGR basically disabling it?

And ....could the bogging down be related to the egr modulator problem?

 

[OSS]

Hesitation at light throttle is classic EGR malfunction. - opening too soon and too far.
It’s easy to rule out if the hesitation is caused by the EGR system by just removing the vac hose from the EGR valve and taking a test ride.
Likely you’ll be shocked at how nice the engine accelerates (until it eventually pings at certain loads, throttle position and RPM).

If the bogging is gone when EGR is off, then you know what’s causing it.

The FZJ80 Land Cruiser EGR vacuum modulator is still available new and it works exactly the same as the FJ60 EGR modulator… and it’s the same dimensions. Clips right in. Only difference is one or two of the pipes are oriented differently- but that’s easy to fix with a longer piece of vacuum hose.

Below is a picture of the FZJ80 modulator on a FJ60. Works perfectly.


(TPD link below)

25870-66011 Genuine Toyota EGR Vacuum Modulator Valve Assembly

ToyotaPartsDeal.com offers the great deal for genuine Toyota parts 25870-66011 (2587066011) EGR Vacuum Modulator Valve Assembly for $103.24. All parts are backed by the Toyota's warranty.

www.toyotapartsdeal.com

 

[g-man]

Ended up my EGR vsv was bad and the new one got my truck running right. Even though it looks different it really is the same. I was able to remove the old VSV from the metal housing and put the new one inside the metal housing so I could bolt it back to the same spot. The air filter (black cylinderical thing) pulls right off the back of the new VSV and you can see the metal vacuum line port ...same as the land cruiser one that goes to the air cleaner. Cut the electrical wires and connector plug from the old vsv and crimped on some 2.8 female spade connectors and fit them in the new VSV.

 

[cps432]

Ended up my EGR vsv was bad and the new one got my truck running right. Even though it looks different it really is the same. I was able to remove the old VSV from the metal housing and put the new one inside the metal housing so I could bolt it back to the same spot. The air filter (black cylinderical thing) pulls right off the back of the new VSV and you can see the metal vacuum line port ...same as the land cruiser one that goes to the air cleaner. Cut the electrical wires and connector plug from the old vsv and crimped on some 2.8 female spade connectors and fit them in the new VSV.

Very cool

 

[g-man]

Pics of the new EGR VSV. There are 4 tabs on the front that need to be squeezed together with pliers to remove the plastic switch from the metal housing...both old and new ...once the switches are loose the rear piping comes out of the hole and the plastic switch comes out. The new switch had two plastic tabs on the front at the sides that I ground off so it would fit in the old metal housing. I could have just cut two slots in the old metal housing to accommodate the tabs. They are there to hold the switch from moving around inside the housing. There is no plug on the old switch itself but the rubber boot that goes on top of the switch was slid back onto the wires and kept as a cover but it doesn't exactly fit. Once the new switch and front plate are in position on the old metal housing the 4 metal tabs at the front are spread apart again to hold it tight. I used a flat head screwdriver and worked it down inbetween the tabs.

 

[g-man]

and images of the terminals and the boot:

 

[65swb45]

Pics of the new EGR VSV. There are 4 tabs on the front that need to be squeezed together with pliers to remove the plastic switch from the metal housing...both old and new ...once the switches are loose the rear piping comes out of the hole and the plastic switch comes out. The new switch had two plastic tabs on the front at the sides that I grinded off so it would fit in the old metal housing. I could have just cut two slots in the old metal housing to accommodate the tabs. They are there to hold the switch from moving around inside the housing. There is no plug on the old switch itself but the rubber boot that goes on top of the switch was slid back onto the wires and kept as a cover but it doesn't exactly fit. Once the new switch and front plate are in position on the old metal housing the 4 metal tabs at the front are spread apart again to hold it tight. I used a flat head screwdriver and worked it down inbetween the tabs.

View attachment 3005917

View attachment 3005918

Dude that is first-class tech! on you.