1978 FJ40 2F Idles ok, stalls when trying to accelerate unless high revs (7 Viewers)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

C

cmcmill01

Joined
Oct 8, 2013
Threads
5
Messages
45
So, my 1978 FJ40 2F with an Aisan H3662 carb and oil bath air filter (weird) starts with the choke on and then idles ok. See the video below. (The rpm looks a little high.) I let it warm up, and as soon as I drive it out and have to accelerate to get up a slight incline in my drive, it really wants to stall unless the revs are very high and I have multiple goes (clutch in and high revs again) at it.

I have replaced the fuel filter and cleaned the oil bath air filter, but no difference.
I can't see any cracks or splits in the pipes, but the PCV valve and rubber washer don't look in the best of shape.

Having read a few posts, it seems good to check the vacuum and the RPM (this is the first time using either of these tools!), which I have done in the video. Does this show anything that needs to be corrected/ changed?

IMG_0476.jpeg
IMG_0472.jpeg
IMG_0475.jpeg
IMG_0454.jpeg




 
How old is the fuel? Put a bottle of gas dryer in it anyway. Let it run for 1/2 hour to suck up any water. Start a cold engine and get it idling. Take a can of WD40 with a peetube - quickly and lightly spray along the intake manifold gasket. If/when the rpm's kick up there is your leak. Do the same at the gasket joints of the carb. Try a big hemostat on the vacuum booster hose and see if it runs better.

Check your valve lash and compression both dry and then wet.
 
charliemeyer007 said:
How old is the fuel? Put a bottle of gas dryer in it anyway. Let it run for 1/2 hour to suck up any water. Start a cold engine and get it idling. Take a can of WD40 with a peetube - quickly and lightly spray along the intake manifold gasket. If/when the rpm's kick up there is your leak. Do the same at the gasket joints of the carb. Try a big hemostat on the vacuum booster hose and see if it runs better.

Check your valve lash and compression both dry and then wet.
Click to expand...
I did get some carb cleaner and sprayed the pipes to check for leaks, and will use this on the areas you mentioned.
The fuel is relatively new and I did add some Redex System Cleaner to the Petrol not that long ago.

I have a pipe clamp and will give that a go on the vacum booster hose, is this the same one that runs to the PCV valve?
 
cmcmill01 said:
Not a clue, need to read up on how to check those items
Click to expand...
Start by checking that the vacuum hose to the distributor is connected - suck on it and check that the points rotate freely.
I've had this before now - runs perfectly without load, but apply a load and it dies.
Could also be just a weak or leaky ignition - worth looking in there when it's dark for blue flashes around the HT leads
 
45Dougal said:
Start by checking that the vacuum hose to the distributor is connected - suck on it and check that the points rotate freely.
I've had this before now - runs perfectly without load, but apply a load and it dies.
Could also be just a weak or leaky ignition - worth looking in there when it's dark for blue flashes around the HT leads
Click to expand...
Will do, have a timing light turn up later so will check that as well.
The points! So I take the Distributor cap off to see these? and suck on the vacuum hose once I disconnect from the carb???
 
So opened the dizzy and looked ok, I started the car and had it sitting at idle sucked and blow into the vacuum line going into the dizzy and nothing happened, I think that's not correct!!
Also tried the timing light but could not see the bb at all! Does that mean the timing is way off??
IMG_0486.jpeg
IMG_0485.jpeg
 
Last edited:
Set the points to make certain they're not frozen. Confirm you're hooked up to cylinder No. 1 with the timing light. Lightly loosen the distributor clamp so that you can just barely turn it by hand. Start the vehicle and, with the timing light aimed at the bellhousing window, slightly rotate the distributor CW and CCW until you spot the ball. Be very careful to avoid any moving engine parts like the fan blade, pulleys, or fan belt. Keep your body, hands, and any loose clothing well around to the passenger side of the engine. Put something non-conductive over the battery like cardboard, etc. You've got to be somewhat close with the timing to get it to run well at all. Don't worry about the vacuum advance issue yet.
 
numby said:
Set the points to make certain they're not frozen. Confirm you're hooked up to cylinder No. 1 with the timing light. Lightly loosen the distributor clamp so that you can just barely turn it by hand. Start the vehicle and, with the timing light aimed at the bellhousing window, slightly rotate the distributor CW and CCW until you spot the ball. Be very careful to avoid any moving engine parts like the fan blade, pulleys, or fan belt. Keep your body, hands, and any loose clothing well around to the passenger side of the engine. Put something non-conductive over the battery like cardboard, etc. You've got to be somewhat close with the timing to get it to run well at all. Don't worry about the vacuum advance issue yet.
Click to expand...
Yep going to give that a go, thanks for the info
 
So, some further investigation.
I did the timing light check again and I think the BB wasn't that far away from 7 degrees, I think I just did it correctly this time.
If I have connected the meter correctly, the dwell is 46. I think it's meant to be 41. How do you change this?

Also looking at my dizzy cap it seems something has broken off or worn down where it is connected to the rotor, does this llook incorrect?
Also the dizzy didn't have a dust cap inside, do they all have one?

IMG_0524.jpeg
IMG_0522.jpeg
IMG_0521.jpeg
IMG_0527.jpeg
 
The roughness of the rotor bug has sanded off the spring loaded carbon electrode in the center of your cap. Polish the area on the bug and get a new cap. I have used the carbon electrode from the inside of an old zinc D cell battery - PIA good trail fix - see if you can do it after you get a new cap. I like ones with brass contacts; aluminium oxides form quickly and its an insulator.
I view dwell as really accurate point gap.
 
charliemeyer007 said:
The roughness of the rotor bug has sanded off the spring loaded carbon electrode in the center of your cap. Polish the area on the bug and get a new cap. I have used the carbon electrode from the inside of an old zinc D cell battery - PIA good trail fix - see if you can do it after you get a new cap. I like ones with brass contacts; aluminium oxides form quickly and its an insulator.
I view dwell as really accurate point gap.
Click to expand...
Just ordered a new cap, doesnt look like the dust cover is available anymore. So the points gap needs to be fixed to achieve the correct dwell??
 
Last edited:
AFAIK dwell is not adjustable. 40s are ham-fisted when it comes to some things. Set your gap to the FSM with a feeler gauge, get a new cap and send it.

Couple other things to check - valve adjustment and check your jetting unless you trust your carb has been rebuilt by a knowledgeable rebuilder for your year and spec.
 
cmcmill01 said:
So for the new dizzy cap and fitted it, waiting on new rotor. Also took out the spark plugs, any thing look strange here, to much oil?? The engine is knocking so still must like the timing is off!!
Click to expand...

Looks like you're mostly running too rich or misfiring but there is some wetness. Decide if it's fuel or oil. Oil can come from several places like bad rings or bad valve stem seals, etc. Maybe you've over oiled the filter? Plug no. 2 is worn oddly but doesn't appear to be misfiring as bad as some others do. Definitely get a new cap (and rotor) before proceeding. You're close enough with dwell to run well for now.

'78s have resistance in the hot wire to the coil from the ignition switch because they ran an electronic ignition. Spark wasn't supplied through the points. If your coil has too much internal resistance and you were told to add a ballast resistor in line then you may be over-resisted and suppressing spark strength. If that's the case you will run rough. I don't know what the correct total number of ohms you need to not burn up your points is. Maybe someone can supply that?
 
You must log in or register to reply here.

Similar threads

C
1978 2F starter
2
Replies
20
Views
1K
Grayscale
Grayscale
L
What weight oil for 1978 FJ40 2F
2
Replies
35
Views
3K
Malleus
Malleus
L
Best oil filter for a 1978 fj40 2F
2
Replies
29
Views
2K
ace10
ace10
V
Trying to get 4spd transmission dropped from a 2f - stuck
2
Replies
32
Views
2K
visike
V

Users who are viewing this thread

Total: 8 (members: 3, guests: 5)

Share this page

Back
Top Bottom