20r engine start troubles

[JoeyDeezNutzz]

Picked up a 78 Chinook last week and it started up and ran fine several times. Drove it home and a few days later she doesn't want to turn over. I'm no mechanic but the battery is fine and I jumped it to be sure, almost wants to turn over but then chokes out. I believe it's not getting enough fuel in the carburetor. How can I verify this? There looks like there is a dirty fuel pump which I'm hoping is going to be the cheap fix! Can I just blast it out with my hose or get a new one? I will turn the key on later and listen for the fuel pump which I believe is in the gas any help appreciated!!

[Derek up North]

Ether/Quickstart will confirm that you have spark but no fuel.

[zero]

I don't understand exactly what the problem is since your descripion sort-of contradicts itself. "Turning over" and "starting" usually denote two separate things. "Turning over" is when your engine is . . . well . . turning over (via the starter motor). "Starting" if after it has sucessfully "turned over", combusion takes place, and the engine is running.

You say it "doesn't want to turn over" and "chokes out." "Choking out" would be a reference, in auto-speak, to the engine running and then faltering from running to rich or lacking air - i.e. acting like it was "choking" from a closed choke. You mention a "dirty fuel pump", yet I doubt you can even see the fuel pump inside the tank.

I'm not trying to demean your word choices. I truly do not understand.

If the engine really is not "turning over" as you first stated - it's electrical (usually) and the fuel system has nothing to do with it. Batttery, battery connections, starter switch, starter relay, starter motor. I said "usually" because if the engine was really screwed up inside and turned harder then it should - then it could be mechanical issues other then electrical.

If the engine turns over OK and starts - and THEN runs lousy as if it is "choking" - maybe it is. The choke is automatic. Cold when closed (once triggered by the gas pedal). Once the engine starts - vacuum is supposed to pull it partially open (vacuum break). Then as it warms up - heat and a bi-metal spring allow it to fully open. If in question - hold it open manually.

To check for gas in the carb - just look down into it while operation the the throttle back and forfth. There is a pump that acts on throttle movement (accelerator pump). If working and there is gas - you will see gas squirting like from a water pistol.

[JoeyDeezNutzz]

OK Thanks! Good to know about the vacuum break and how to check the accelerator pump. And t isn't running! I pump the clutch a few times and turn the key.. and it will not "turn over" Tried giving it a little gas and will occasionally sputter as if it is almost going to start and then quickly dies. I will suss this out further tonight, especially checking the accelerator pump

[zero]

OK Thanks! Good to know about the vacuum break and how to check the accelerator pump. And t isn't running! I pump the clutch a few times and turn the key.. and it will not "turn over" Tried giving it a little gas and will occasionally sputter as if it is almost going to start and then quickly dies. I will suss this out further tonight, especially checking the accelerator pump

I assume you mean you pumped the "gas pedal" and not the "clutch?" Unlike a fuel injected vehicle - you must pump the pedal a few times. Once activates the choke. Also every stroke "primes" the engine with a squirt of raw gas. Some are cold-blooded and need to be pumped many times and some only require one or two pumps. Pretty much depends on how well the accelerator pump is working and how it is adjusted.

[waiter]

I assume its cranking, but won't start.

How old is the gas? year old gas may not start.

Try some starter fluid, VERY CAREFUL. as it could backfire.

Have someone crank while you give it a couple squirts of starting fluid. If it starts, then you probably have a fuel related problem.

JOhn Mc

88 Dolphin 4 Auto

[JoeyDeezNutzz]

Yeah starter fluid got her up and running again. Thanks for the assistance.

[Donnie]

Just a thought : the starting fluid may have given the engine enough fuel to fire up & get the oel pressure up to kick in the relay that turns on the electric fuel pump that is located in the tank on many of these old Toyoda's... SOME of these , but not all, need to see oel pressure before the fuel pump will run...IF IT FAILS TO START AGAIN AFTER SITTING A FEW DAY'S---------DIS-CONNECT THE WIRE THAT GOES TO THE OEL SENDING UNIT, A SWITCH THAT IS SCREWED INTO THE BLOCK BELOW THE CARB...with this wire dis-connected, turn on the key & listen for your in the tank fuel pump to be running....if it is running, start the engine & reconnect the wire

It is best if you have a helper when performing this maneuver.........Donnie

[zero]

Yeah starter fluid got her up and running again. Thanks for the assistance.

:Pumping the gas pedal should of accomplished the same thing as spraying it with stater fluid. Either something is mechanically amiss - or you're not pumping the pedal.

[fred heath]

Just a thought : the starting fluid may have given the engine enough fuel to fire up & get the oel pressure up to kick in the relay that turns on the electric fuel pump that is located in the tank on many of these old Toyoda's... SOME of these , but not all, need to see oel pressure before the fuel pump will run...IF IT FAILS TO START AGAIN AFTER SITTING A FEW DAY'S---------DIS-CONNECT THE WIRE THAT GOES TO THE OEL SENDING UNIT, A SWITCH THAT IS SCREWED INTO THE BLOCK BELOW THE CARB...with this wire dis-connected, turn on the key & listen for your in the tank fuel pump to be running....if it is running, start the engine & reconnect the wire

It is best if you have a helper when performing this maneuver.........Donnie [/quot

Donnie,

I have the same year and engine. During the crank cycle the fuel pump should run even with no oil pressure.

That safety sensor only works if the engine looses oil pressure while running. You should be able to here the fuel pump run when starting. If not sure, remove the fuel hose at the carburetor and place in an old water bottle. Crank the engine and see if gas comes out. If it does, the fuel pump is fine. If no gas, remove the fuel filter and do the same test again. A blocked or partially blocked filter will give the same symptoms.

Remember to have an extinguisher nearby.

[waiter]

As JD says, The carb should have an accelerator pump, and pressing down on the gas pedal three or four times (slowly, all the way to the floor) before cranking should give it a few good squirts, and set the choke. If you smell the gas, it may have a varnish odor to it, its definantly bad.

Starting procedure for Carb is just the opposite of an EFI. On EFI, don't touch the gas pedal. The clear flooded procedure for carb and EFI are the same, hold the gas to the floor while cranking. On a carb, this generally opens the choke to allow more air. On an EFI, it generally turns off the fuel injectors while cranking.

Anyway. My thoughts were about bad gas, If the gas were old, it may not be able to start the car, but once its running, it may be able to keep running.

John Mc

88 Dolphin 4 Auto

[zero]

Just a thought : the starting fluid may have given the engine enough fuel to fire up & get the oel pressure up to kick in the relay that turns on the electric fuel pump that is located in the tank on many of these old Toyoda's... SOME of these , but not all, need to see oel pressure before the fuel pump will run...IF IT FAILS TO START AGAIN AFTER SITTING A FEW DAY'S---------DIS-CONNECT THE WIRE THAT GOES TO THE OEL SENDING UNIT, A SWITCH THAT IS SCREWED INTO THE BLOCK BELOW THE CARB...with this wire dis-connected, turn on the key & listen for your in the tank fuel pump to be running....if it is running, start the engine & reconnect the wire

It is best if you have a helper when performing this maneuver.........Donnie [/quot

I don't know of any vehicle that needs the oil-pressure switch to work in order to start. All cars and trucks that I know of with electric fuel pumps have a over-ride system when you turn the key and gives 8-10 seconds of fuel pump operation - regardless of oil pressure. Or in some cars -alternator charging.

[zero]

As JD says, The carb should have an accelerator pump, and pressing down on the gas pedal three or four times (slowly, all the way to the floor) before cranking should give it a few good squirts, and set the choke. If you smell the gas, it may have a varnish odor to it, its definantly bad.

Starting procedure for Carb is just the opposite of an EFI. On EFI, don't touch the gas pedal. The clear flooded procedure for carb and EFI are the same, hold the gas to the floor while cranking. On a carb, this generally opens the choke to allow more air. On an EFI, it generally turns off the fuel injectors while cranking.

Anyway. My thoughts were about bad gas, If the gas were old, it may not be able to start the car, but once its running, it may be able to keep running.

John Mc

88 Dolphin 4 Auto

Yes - bad gas (low volatility) or no gas sounds like the issue. Usually when ether works and normal cranking does not - it's no/bad gas or low compression.

On a side-note - anyone noticed how weak starting fluid is these days? It is no where near as explosive as it was a few years ago. We used to seat problematic tires onto rims with it. The new stuff doesn't work. Maybe they weakened it due to so many engine being ruined by it?

[fred heath]

I don't know of any vehicle that needs the oil-pressure switch to work in order to start. All cars and trucks that I know of with electric fuel pumps have a over-ride system when you turn the key and gives 8-10 seconds of fuel pump operation - regardless of oil pressure. Or in some cars -alternator charging.

JD,

Reread my post and show where I said you need oil pressure to start.

[zero]

JD,

Reread my post and show where I said you need oil pressure to start.

I wasn't inferring that that was your take on the matter. It was "Donnie." But his comments were within your post - so when I "replied", it came out looking like it does.

[Donnie]

I would like to hear from other mid 70's truck owners : Trucks with carbed engines & fuel pumps in the tank...CARBED ENGINES ONLY.... I would like for you to turn on the ign, but DO NOT START the truck, just turn on the ign & listen for the fuel pump...post back if you hear the pump running or not....just to clear up my thought process.........thanks Donnie

[zero]

I would like to hear from other mid 70's truck owners : Trucks with carbed engines & fuel pumps in the tank...CARBED ENGINES ONLY.... I would like for you to turn on the ign, but DO NOT START the truck, just turn on the ign & listen for the fuel pump...post back if you hear the pump running or not....just to clear up my thought process.........thanks Donnie

The ;pump is not supposed to run with the key in "IGN" position. When the key is put into "START", i.e. when the engine is cranking - the fuel pump is energized. Most cars/trucks I know of with electric fuel pumps - carbed and EFI - work with 8-10 second timers. Every time you crank the engine, the electric fuel pump gets 8-10 seconds of power.

[zero]

My comments were general ones. I just pulled out the factory wiring diagrams for 1977 and 78 trucks with 20R engines. No timer. The electric fuel pump is energized whenver the engine is cranking. If you crank for 30 seconds, the fuel pump runs for 30 seconds.

A fuel pump relay is used to do this. Power feed to the fuel pump is from one of two sources. One is the "start/crank" position on the key switch. The other is directly from the fuse-box as long as there is engine oil pressure. If no oil pressure and the key is in "run" position, the signal turns the relay off.

The one thing NOT shown in the diagram is what kind of relay Toyota uses. From the description elsewhere in the manual, it sounds like it is a "latching" relay. That means it locks in place and is not momentary. Needs a signal to change positions. When in "run" position to provide power to the fuel pump - it stays that way until it gets a ground-signal from the oil pressure switch.

Any fuel system I know of with either an electric pump and some with gravity-feed fuel tanks - have over-rides to allow fuel to flow when trying to start. Some e.g. Toyota use oil pressure for a signal and others like Subaru use an alternator charge sensor. If voltage drops below 13 volts, the fuel pump stops.

[Donnie]

That's the point that I am trying to make. A faulty oel sender switch can cause the fuel pump relay not to close...

If I can figure how to get this info. from the manual to this forum, I will prove my point.. You surely understand that oel pressure is created when cranking the engine & also there is supposed to be enough fuel in the carb to start the engine......this thread started when the poster was trying to start an engine that

had sat a while...fuel evaporates or leaks down/ & now we have to deal with fuel losing it's volatile nature.

There is a page somewhere that illustrates my point....A FAULTY OEL SENDER in these CARBED / pump in the TANK trucks can cause a NO START CONDITION

I have experienced this condition only a few times, years ago, as I am not a Toyota Specialist......My field has been for most of my adult life....automatic transmission's., not Toyota's, & obviously not computers...Auto computers/ processors, what ever you want to call the automobile control box , yes I understand the feedback, sensor operated systems on later model's.........since their arrival in 1980.or 78 if you want to count Chry. lean burn a computer controlled system.........BIG LAUGH

I will find the diagnostic source & refer you to the page as I my scanner took the BIG one....give me a day or two

[Donnie]

Ok, had to hit the books, I am not fortunate enough to have a FACTORY manual for these trucks, but I do have & I would hope anyone owning a Toyota Chinook would have some sort of reference manual..... I have an old Clymer, somewhere, perhaps packed in with my manuals that are going to Carlisle....I am keeping the Haynes manual now that I own two of these babies

I have in my hand a Haynes Manual...........Toyota HI-LUX pickup..........1969 thru 1978.....some of you may have this book, if not, you should be able to find one on Amazon, used for a few bux.

This book has wiring schematics, but you only need to go to the trouble shooting charts to see what I am talking about.>>>

Trouble shooting tip # 4 on page 65 will explain my point, clearly.( oel pressure switch relationship to no fuel pump activity )

If ANYONE has this manual, possibly you can scan that page & post it, so I don't sound like a fool, thanks in advance...Donnie

no I don't have a I phone either

[fred heath]

Donnie,

My toy is a 1978 with the 20R motor (carburetor).

The manual says "it is possible" regarding the fuel pump/oil sender. Keep in mind this manual was printed in the UK. The 20R came out in 1975. Some info could relate to earlier engine types.

On the fuel issue; As I stated earlier, pull the hose at the carb, crank the engine and see if you got fuel. Also check the fuse for your fuel pump in the fuse block. Many times it just process of elimination.

[5Toyota]

did you check the glass sight window on the carb gas level should be in the middle of the glass at all times if i rember it is on the front of the carb

[fred heath]

I would like to hear from other mid 70's truck owners : Trucks with carbed engines & fuel pumps in the tank...CARBED ENGINES ONLY.... I would like for you to turn on the ign, but DO NOT START the truck, just turn on the ign & listen for the fuel pump...post back if you hear the pump running or not....just to clear up my thought process.........thanks Donnie

With the pigtail from the oil pressure switch DISCONNECTED turn the ignition switch to ON and either listen for the fuel pump running or pull the hose at the filter and check for fuel flow. The oil pressure safety only becomes active if a running engine should loose oil pressure. If you disconnect the pigtail you will know for sure if the pump is working.

[zero]

That's the point that I am trying to make. A faulty oel sender switch can cause the fuel pump relay not to close...

Lack of oil pressure will cause the fuel-pump relay to shut the electric pump off when in "run" position. When in "start" and cranking - the electric pump gets power regardless. I'm not sure what your point is.

If an engine has a low oil pressure problem (or a bad OP switch) the engine will start and die. Over and over. Just like having a bad ignition ballast resistor.

[Donnie]

If you disconnect the oel pressure sender wire & GROUND it. Does the fuel pump run ?

[zero]

If you disconnect the oel pressure sender wire & GROUND it. Does the fuel pump run ?

No . That would stop it from running. The oil pressure switch is normally closed which stops the fuel pump from working. When engine oil pressure gets over 6 PSI the switch opens and allows the fuel pump to run continously as long as the key is "on."

[zero]

Three quick things you can try. Just unhook the oil-pressure switch. Also you can pull the harness plug off of the fuel pump resistor and put a jumper wire in it (eliminating the resistor). Also you might try running a ground wire directly to the top of the fuel tank cover.

[zero]

That's the point that I am trying to make. A faulty oel sender switch can cause the fuel pump relay not to close...

Yes - and if that happens the engine will still start. Just won't stay running once you stop cranking. It will run for a minute or so and then die.

[zero]

Donnie,

My toy is a 1978 with the 20R motor (carburetor).

The manual says "it is possible" regarding the fuel pump/oil sender. Keep in mind this manual was printed in the UK. The 20R came out in 1975. Some info could relate to earlier engine types.

On the fuel issue; As I stated earlier, pull the hose at the carb, crank the engine and see if you got fuel. Also check the fuse for your fuel pump in the fuse block. Many times it just process of elimination.

My Clymer -Strasman Toyota manual printed in England covers 1969 to 1978 Hi-Ace and Hi-Lux trucks with 8RC, 18RC, 12R, 18R and 20R engines including Canada and USA versions. The electric fuel pump diagram they give says it is for all models with the electric fuel pump setup.

[Donnie]

No . That would stop it from running. The oil pressure switch is normally closed which stops the fuel pump from working. When engine oil pressure gets over 6 PSI the switch opens and allows the fuel pump to run continously as long as the key is "on."

jde, I'm glad you finally understand, (my original post) at the beginning of this thread.. All I was trying to convey to the original poster to pull the wire OFF the sender & see if it would run,,,,,,,,,,,no priming with gas or ether JUST SEE IF IT WOULD RUN......I'm out,,Donnie

I sent you a pm about a vehicle 4 sale that I thought you may like..It was in the Ithaca Craig's............................

[zero]

I have in my hand a Haynes Manual...........Toyota HI-LUX pickup..........1969 thru 1978.....some of you may have this book, if not, you should be able to find one on Amazon, used for a few bux.

This book has wiring schematics, but you only need to go to the trouble shooting charts to see what I am talking about.>>>

Trouble shooting tip # 4 on page 65 will explain my point, clearly.( oel pressure switch relationship to no fuel pump activity )

If ANYONE has this manual, possibly you can scan that page & post it, so I don't sound like a fool, thanks in advance...Donnie

no I don't have a I phone either

My USA version Clymer manual for 86-81 Toyota trucks has a good write up on electric fuel pump diagnosis and also has full wiring diagrams. It shows the value of the fuel-pump resistor as 1.4 ohms. I've checked two and they read 2.2 ohms. A minor point I guess and they might be variable resistance according to heat and load. I've got two new resistors from NAPA and they don't check out as their specs say. ICR11 is rated at 1.35 ohms rated. I checked and it reads 2.8 ohms. ICR13 is rated for 1.82 ohms rated. I checked and it reads 3.2 ohms. I'm sure either one would work fine with the electric fuel pump in the Toyota.

[zero]

jde, I'm glad you finally understand, (my original post) at the beginning of this thread.. All I was trying to convey to the original poster to pull the wire OFF the sender & see if it would run,,,,,,,,,,,no priming with gas or ether JUST SEE IF IT WOULD RUN......I'm out,,Donnie

I sent you a pm about a vehicle 4 sale that I thought you may like..It was in the Ithaca Craig's............................

Donnie -thanks for the info on the Mercedes Hanamog for sale near me (kind of). I get a kick out of seeing them but cannot imagine trying to drive one on a USA highway. They use a tiny British diesel engine and front wheel drive. Since the engine is a British BMC - I'm not sure what part of those things have anything to do with Mercedes. It has the same size diesel as the Volkswagen Rabbits used to have! Pretty small.

I already have one foreign RV that is miserable to find parts for. A Winnebago Phasar built on a French Renault Chassis. Also front wheel drive but if it was diesel, it would be a 2.2 turbo. Not a 1.6 non-turbo like that Hanamog has.

http://ithaca.craigs...4051826783.html

[fred heath]

My Clymer -Strasman Toyota manual printed in England covers 1969 to 1978 Hi-Ace and Hi-Lux trucks with 8RC, 18RC, 12R, 18R and 20R engines including Canada and USA versions. The electric fuel pump diagram they give says it is for all models with the electric fuel pump setup.

The key phrase here: "is possible" as stated in the Haynes manual. By disconnecting the oil pressure pigtail you effectively remove it from the equation. A defective oil pressure switch should still allow the pump to run in the "start" position.

It "is possible" I may win the lottery.