Topic: 22r carb sputters and stumbles (low rpm's)

[pleasetellmeno]

Hey guys, i'm having an issue with the carb on my 22r. it has an aftermarket National brand carb (supposed to be a direct oem replacement). My issue is when the truck is parked facing downhill after the engine is warm the engine will stumble and sputter and nearly stall out when starting from a stop (low rpms) it idles normally, and accelerates normally once it gets past that point, around 2000 rpms or more is fine. it takes a good stretch of road where you can drive it harder and it will go back to normal. It mostly only happens when parking downhill, sometimes more often on very hot days, and makes it almost impossible to do any sort of slow speed offroading. none of my fuel lines are too close to the engine or anything very hot but when it is happening you can smell fuel, which makes me think the float bowl is flooding, but whenever i check the level, it is always in the middle of the sight glass.

it only happens when starting from a stop or shifting into second, any situation where i might be using the low end rpm, it seems like it is getting far too much fuel, do you think my carb might just need a rebuild? could it be the AAP (auxiliary accerator pump)? or something more?

[Gnarly4X]

Hey guys, i'm having an issue with the carb on my 22r. it has an aftermarket National brand carb (supposed to be a direct oem replacement). My issue is when the truck is parked facing downhill after the engine is warm the engine will stumble and sputter and nearly stall out when starting from a stop (low rpms) it idles normally, and accelerates normally once it gets past that point, around 2000 rpms or more is fine. it takes a good stretch of road where you can drive it harder and it will go back to normal. It mostly only happens when parking downhill, sometimes more often on very hot days, and makes it almost impossible to do any sort of slow speed offroading. none of my fuel lines are too close to the engine or anything very hot but when it is happening you can smell fuel, which makes me think the float bowl is flooding, but whenever i check the level, it is always in the middle of the sight glass.

it only happens when starting from a stop or shifting into second, any situation where i might be using the low end rpm, it seems like it is getting far too much fuel, do you think my carb might just need a rebuild? could it be the AAP (auxiliary accerator pump)? or something more?

Hey kaalsb,

It sounds like it could be the AAP.  As I remember you can carefully remove it with 3 screws. It’s a little tricky to get to. It has a rubber diaphragm that fails because it gets a hole in it and allows excess fuel into the mixture.

http://www.offroadforum.cz/toyota/aarc.epnet.com/application/8578/8578R04_Auxiliary_Acceleration_Pump__AAP.html

https://www.google.com/search?q=22r+carb+rebuild+kit&rlz=1C1AOHY_enUS708US708&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjd-_fJs4LQAhXogVQKHc7aDUAQ_AUICSgC&biw=1024&bih=633#tbm=isch&q=22r+carb+AAP&imgrc=vKa1UZ8O_QZq_M%3A


Check the vacuum hose as well.

http://www.autozone.com/repairguides/Toyota-Pick-ups-Land-Cruiser-4Runner-1989-1996/EMISSION-CONTROLS/Auxiliary-Acceleration-Pump-AAP-System/_/P-0900c15280060d7f

Have you physically checked the float level?

Gnarls.

[pleasetellmeno [OP]]

Hey kaalsb,

It sounds like it could be the AAP.  As I remember you can carefully remove it with 3 screws. It’s a little tricky to get to. It has a rubber diaphragm that fails because it gets a hole in it and allows excess fuel into the mixture.

http://www.offroadforum.cz/toyota/aarc.epnet.com/application/8578/8578R04_Auxiliary_Acceleration_Pump__AAP.html

https://www.google.com/search?q=22r+carb+rebuild+kit&rlz=1C1AOHY_enUS708US708&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjd-_fJs4LQAhXogVQKHc7aDUAQ_AUICSgC&biw=1024&bih=633#tbm=isch&q=22r+carb+AAP&imgrc=vKa1UZ8O_QZq_M%3A


Check the vacuum hose as well.

http://www.autozone.com/repairguides/Toyota-Pick-ups-Land-Cruiser-4Runner-1989-1996/EMISSION-CONTROLS/Auxiliary-Acceleration-Pump-AAP-System/_/P-0900c15280060d7f

Have you physically checked the float level?

Gnarls.

Thanks for the reply Gnarls. i haven't physically checked the float level, just peeked at it through the wee sight glass. i will source a new AAP diaphragm and pop it in and report back.

[pleasetellmeno [OP]]

Thanks for the reply Gnarls. i haven't physically checked the float level, just peeked at it through the wee sight glass. i will source a new AAP diaphragm and pop it in and report back.

well, i got the new diaphram in, the old AAP looked to be intact. it looked like it may have had a tiny pinhole in it, but i couldn't tell. i parked the truck facing downawards in my driveway for 15 minutes and took it out for a drive and it seems to be operating correctly, but it will take a week of driving to tell for sure.

[Gnarly4X]

well, i got the new diaphram in, the old AAP looked to be intact. it looked like it may have had a tiny pinhole in it, but i couldn't tell. i parked the truck facing downawards in my driveway for 15 minutes and took it out for a drive and it seems to be operating correctly, but it will take a week of driving to tell for sure.

 

[pleasetellmeno [OP]]

Whelp, week of driving down and the issue re-appeared today. i was stopped on a steep downhill at a red light for a minute or so, and about 2 blocks later my truck starts to sputter at low rpms again, I parked the truck for about 15 minutes and went to start it again and it was tough to start, issue persisted until I got out for a short stint on the highway and it went back to normal.

i guess i'll check the vacuum line next. what was it about checking the float level again?

maybe a carb cleaning is in order.

[Gnarly4X]

Whelp, week of driving down and the issue re-appeared today. i was stopped on a steep downhill at a red light for a minute or so, and about 2 blocks later my truck starts to sputter at low rpms again, I parked the truck for about 15 minutes and went to start it again and it was tough to start, issue persisted until I got out for a short stint on the highway and it went back to normal.

i guess i'll check the vacuum line next. what was it about checking the float level again?

maybe a carb cleaning is in order.

This sounds like the carb is flooding?  Does it act like the choke is on and blowing black smoke?

Gnarls.

[pleasetellmeno [OP]]

This sounds like the carb is flooding?  Does it act like the choke is on and blowing black smoke?

Gnarls.

i can't see any black smoke behind me when i'm driving, nothing while idling.

[79coyotefrg]

sounds like the float might be too high.

[Gnarly4X]

http://board.marlincrawler.com/index.php?topic=81651.0

Gnarls.

[pleasetellmeno [OP]]

http://board.marlincrawler.com/index.php?topic=81651.0

Gnarls.

Thank coyote, and again gnarls. i'll pull the top of the carb off and take a look. my fuel level sits dead in the middle of the glass, but i've heard of people lowering the level so i'll try that.

[pleasetellmeno [OP]]

Alright guys, same issue.

I broke down and ordered another carburetor, a National. same brand that the previous owner had on the truck when i bought it, and it's giving me the same issue.
It's really making me wonder if it's just these junky National carbs (both have had the fuel cut solenoid go out on them, the solenoid goes wacky even when bench tested on both) or if it's another problem.

i put in a 1-4 psi fuel regulator with no noticable change today, still going to try and adjust the pressure a little bit lower to see if that can fix anything.

I can smell excess fuel when it happens, could possibly be weak spark? I don't know how to test for that besides just replacing the coil. I've jumped out when it starts to show it's symptoms and checked the float level, but it always seems right in the middle of the glass, or just below (seems normal as ever). I would love to get my hands on a factory carb just to see if that changes anything.


update on the problem:

the issue happens on and offroad. on the street it only ever happens when we have hot weather, I run the engine till its warm, park the truck for about 10 miniutes or so, start the engine, normal idle. go to take off in 1st and engine sputters, lurches and wants to die at low low rpms. i get the engine up at higher rpms for a mile or so and the problem goes away completely.

The problem happens most of the time offroad, when i'm just crusing around on trails, doing low speed crawling it does the same thing. seems like a lot of bumpy terrain accompanied by slow lower rpm driving causes the problem. Again, the problem does not go away until i hold 25+ mph/ 2600 rpm ~ for a mile or so. I've tried to sit in neutral at a stop and just hold the throttle open thinking it needs to burn extra fuel out of the carb to no avail.

i'm gonna continue to play with the adjustment on the fuel pressure regulator, but would love some more input from you guys.


Edit: with the new carb the truck isn't sputtering on downhills like it was previously, so it did fix something

[H8PVMNT]

Maybe check the BVSV deal that runs the AAP? It's in the middle of the intake side of the head.  I was looking for a good one for a guy and I went through 3 or 4 before I found a good one.  They can go bad and not shut the vac off when they at supposed to causing your AAP to be  on when it should be off.

Other than that the symptom sounds just like when I have had a bad fuel cut solenoid or bad supply to the fuel cut solenoid.  Check the solenoid for a click on battery 12V and check the lead that sends power to it.

Definitely worth pulling the top off your carb and checking the float level with a ruler and setting to spec just in case.

One other thing, your fuel pump might be slightly gimpy or your fuel filter plugged up.  All the aftermarket mechanical fuel pumps are garbage these days.

Check for vac leaks with a can of carb cleaner, starting fluid or propane.

That's about all I got and I think the other fellas all ready touched on all that.

I would certainly encourage you to stop buying the national carbs though and find an aisan to rebuild or get a weber.  I have dealt with both the 22r aisan carb and the 32/36 weber and I like them both.  You mod the aisan to work better for street performance and you mod the weber to work better off road.

[pleasetellmeno [OP]]

Wow, i forgot to check back for a few days. Thanks for the response.  the BVSV for the AAP is a good sugestion, i'll have to look at the fsm for testing procedure on that one.

Fuel cut solenoid has been ruled out. ive hot wired it, tested for a click on the solenoid, and even just plugged the hole with a stubby bolt. the only change i can get from testing that is when the solenoid is closed, the engine will not run on idle. sort of the opposite of my problem.

float level i have played with but not entirely ruled out. i will continue to adjust it.

fuel filter has been changed out a few times, i would love to find one with a clear housing so i can see if it's dirty. im just blindly swapping out the frosted white filters.

fuel pump has also come across as a possible fault. but in testing the pump pushes a lot of gasoline out while the engine is running and can fill a water bottle before the carb runs out of fuel, also I smell excess fuel when having the problem which leads me to believe it is running fat. can't tell if it has ever been changed, you have any reccomendations on a replacement? would the LCE pump be a good option?

Vac leaks have been ruled out. i replaced all vacuum hoses, and compared my setup to multiple diagrams for my year and california emmisions stuff. tested with brake clean sprayed around all the vacuum hoses.

Would love to get my hands on an aisin carb. just hard to come by. im in central cali, suprisingly not a lot of these toyotas around here.

I know weber makes a smog legal carb, but it's quite expensive. not a move i'm looking to make at the moment. certainly an option if it gets to that point.


Edit: I forgot to mention, i took the truck out on a short little rock garden trail we have in town, problem still persists even with the fuel regulator at about 4psi, but i'm convinced that it has gotten a little better. i'm going to try and drop the pressure down a bit more. i dont have a guage on the system, so i'm kind of just blindly adjusting it.

[H8PVMNT]

On the fuel pump:  https://22reperformance.com/22r-fuel-delivery/fuel-pump-mechanical-for-carbureted

You can get them from a few different places but you want the OEM Kyosan pump.  I burned through 4 or 5 of the after market brands before I finally bit the bullet and bought a good one.  It would have been cheaper to buy the right one on the first place.  Last aftermarket pump I ran stranded us with the top off on the way to church next to a marsh with the most vicious swarm of mosquitos I have ever encountered in my life.

On the BVSV, you want it to switch over from one port to the other when it heats up.  You can test this by blowing through some vac lines into a jar of water.  You blow on the port where the manifold vac hooks up and see if the other two will switch over when the temp changes.  The bubble should switch from one line to the other.  Pretty simple really.

[pleasetellmeno [OP]]

Sweet, thanks. I'll have a go on the BVSV tomorrow. Fuel pump will have to wait until I rule out all the cheaper options 

[pleasetellmeno [OP]]

Well gentlemen, After over a year of frustration i have finally solved the wild sputtering issue.

while charging down Interstate 15 on my way home from Utah, just after passing through Vegas, my engine died out. I pulled over to discover the float bowl completely drained, after pulling the fuel line from my regulator and putting it into a can and cranking the engine, I confirmed that my fuel pump gave out.

Remembering what i've read in the past, regarding the 22r fuel pump I quickly noticed I was missing the 1/4" spacer between the pump and the head. after a $45 fuel pump, a $4 spacer and a pair of longer bolts, I was right back on the road. AND!! with no more sputter!!!!  It sounds like the pump was absorbing heat from the head and boiling/ vapor locking my fuel system. Problem solved!! and so much more fun driving off-road now!!!  Thanks again for your suggestions guys, hopefully this cheapo fuel pump doesn't give out too soon!

[Gnarly4X]

Hey kaalsb,

Glad you got your issue figured out. 

I replaced the fuel pump on my 22R twice in about 7 years.  I believe that some of the aftermarket, non-OEM fuel pumps are not as good as the factory stock.   It seems the ethanol-additive fuel is harder on the rubber diaphram inside the pump.  The good news is it's a low cost replacement.  The phenolic (I think it was from factory?  but aftermarket ones are other material) block is a spacer to position the pump arm on the cam, but it is interesting that it also acts as an insulator. 

Gnarls. 

[Lewis Hein]

...hopefully this cheapo fuel pump doesn't give out too soon!

Great to hear that you got the sputtering solved.

If I were you, I'd get a Kyosan pump on ASAP. If your luck is like mine, the cheap one will quit at the worst possible time.

[H8PVMNT]

Yeah I might have mentioned it before but I went through 4 $40 aftermarket fuel pumps before finally relenting and buying the Kyosan.  It now has more miles on it than the others combined.

[pleasetellmeno [OP]]

Where do i find a kyosan pump? The link gnarls left me for 22reperformance only lisys it as a "OE part" having a tough time finding an actual kyosan pump

[OVRAROK]

Where do i find a kyosan pump? The link gnarls left me for 22reperformance only lisys it as a "OE part" having a tough time finding an actual kyosan pump

http://www.partsgeek.com/catalog/1986/toyota/pickup/fuel_delivery/fuel_pump.html  scroll down a bit

[pleasetellmeno [OP]]

Right on, thanks!

[Lewis Hein]

I believe "OEM" implies Kyosan, as they are (I think) the OEM supplier. It just costs more from 22re performance..

[pleasetellmeno [OP]]

I agree, but OEM and OE can mean different things. OE can stand for original equivilent (likely junk), or original equiptment. hard to say, i know 22re performance is a pretty reputable source, but, Parts geek (which i haven't ordered from before) is listing the pump as a kyosan for a bit cheaper.

[Gnarly4X]

I agree, but OEM and OE can mean different things. OE can stand for original equivilent (likely junk), or original equiptment. hard to say, i know 22re performance is a pretty reputable source, but, Parts geek (which i haven't ordered from before) is listing the pump as a kyosan for a bit cheaper.

True…

Typically, if you go to a car dealership, they say “OE”… Original Equipment - that’s what came on the vehicle from the factory.

Just because some part is designated as OEM - Original Equipment Manufacturer - doesn’t necessarily mean you are buying the part that was manufactured by the same manufacturer as the “original” part.  There can be different OEMs – produced in two different manufacturing facilities supposedly to the same specifications, but with possibly different quality assurance and quality control. The specs may or may not be exactly the same, although that is assumed.

If you buy a part in 2017 that was an OEM part in 2010, it may be the same exact part and part number.  But… if that part had a “revision”, possibly because the original design had a flaw, so the factory revised the specification to correct the design flaw, and typically will assign it a different part number.  Both parts are still designated as OEM.

The OEM part does not always guarantee it is better quality than an aftermarket part, although it is generally assumed OEM parts meet and maintain the same specifications.

Small niche specialty suppliers like Marlin Crawler, 22RE Performance, LCE, or engbldr sell quality parts because that is their business, and their consumer perceived reputation can make or break them quickly.  You may pay more for their parts, but if you have a question or want to consult with them about the application, they answer their phone and provide quality technical support – how much is that worth?  If you buy the same part brand from a large online distributor like RockAuto, PartsGeek, or Randys Worldwide and you have an issue or question, when you call them will they answer their phone and will you get the same quality support?

Buying a quality part, at a fair market price, and getting good customer support is always a challenge for the average consumer.

Gnarls.