I seem to have a lack of power? (1 Viewer)

[70 FJ40]

Ok. So I know that 2Fs are not fast or super powerful but i'm wondering if my new '77 needs some help or if its just the way it is. It seems to run really well but it does not have the power I think it should. It has the hard top and 141k. It is in really good shape mechanically. And its all stock except for a safari roof rack and a 3" lift from SOR with 33x10.50 mud terrains and a vintage air system. The PO said he had the carb rebuilt by the toyota dealer in town and like I said it does idle and function quite well. But 50 to 55 mph is about all it will do comfortably and getting it to 60 is not easy. it also fades real fast when I hit a hill of any sort. Milage is also terrible at only 8 or 9 mpg. The reason I feel there may be an issue is that my '70 got 14 or 15 mpg and would easily go 60 and I still had plenty of room to go more. I just rarely did because it didn't feel safe. It also pulled itself up hills without too much slowing. It was also stock with a rebuilt f motor, vacuum advance distributor, a similar lift and 32x11.50 mud terrains. It did not have a hardtop or roof rack.

Is the extra weight and wind resistance of the top and rack and all the other little things like vacuum advance adding up here or should I try to give it a tune up? I hesitate to do this because like I said other then low on top end power it runs and functions great. In the past I have made things worse by trying to fix what isn't really broke. I'm not the best mechanic and its hard to find a good one that will spend the time on a carbed rig. They usually just say things like "Hey its old" or "It wasn't meant to go fast".

I doubt its anything serious or it would be much worse. It shouldn't need rebuilt at only 141k right? And I don't expect to run it at 70 to 75 down the freeway all day but it seems like it should do at least 60 comfortably.

Any advice or experience would be great.

Thanks

 

[edwjmcgrath]

My 78 with hard top (same color) will go 65+ (faster than I feel safe going) with no problem.
Gas mileage on all cruisers is terrible, so I wouldn't go by that.

I would start with three things. All are simple tests that you or any mechanic can do.
The first one is to see if the carburetor's secondary is working. Your carb has a vacuum operated secondary. There's a diaphragm on the carb with a rod to the linkage that opens the secondary. Search here for the paper clip test. You put a paper clip on the rod and then drive it at high speed under load, then see if the paper clip moved indicating that the secondary opened.
The second one is a compression test. This will tell you a lot about what kind of shape your engine is in.
The third is to check the ignition timing with a timing light.

 

[sggoat]

x-2

 

[Rustic76]

I would also check to see that the vacuum advance on your distributor is functional. If it isn't working it can feel gutless like you are describing. Good luck.

 

[71FJ40]

Also run a vacuum test to check for vacuum leaks

 

[70 FJ40]

It was my '70 that had a vacuum advance distributer that I got from SOR. Does my '77 have one from the factory because otherwise it is probably still a retard system. How would I check to see if it is functioning? Hopefully I don't sound too ignorant here.

 

[70 FJ40]

How would I do a vacuum test? How can I tell if my Cruiser is de-smogged. Sorry again if the questions sound dumb but I would like to learn how to work on my own Cruiser and I guess that might require asking a few dumb questions.

 

[70 FJ40]

Well I just took my Cruiser for a short drive and it failed the paper clip test. I got it all the way up to 60 mph and went up a slight hill two of them actually one at about 55 and the other at about 40. So what now?

 

[Solace in Solitude]

What edwjmcgrath said, in post #2, above, compression test and check timing.

 

[Coolerman]

We all had to learn sometime so ask away! However if you really want to learn, I'll suggest nicely what some here will suggest rudely: Obtain the FSM (Factory Service Manual) for your truck. This is available on E-Bay or if you Google Toyota Factory Service Manual, you will find many places to order it. Next you will need a good set of metric tools to do the standard jobs, and as you get better you can add the tools like a vacuum gauge to test engine vacuum.

All the procedures mentioned in the posts above can be found in the FSM, in the FAQ section (link at top of home page), or by using the search function. Someone has done every job you can imagine before and probably posted a 10 page howto showing exactly how to do it and what tools you will need.

Last suggestion: Post some pics of your engine compartment. Many can tell if your de-smogged just by looking and some can even tell if the de-smog was done correctly. A de-smog done wrong could be the cause of your exact problem: Lack of power.

Edit: Never fails, I post a long response and in the meantime the original poster finds the problem! Good job on not only finding, but actually doing the paper clip test!

 

[Coolerman]

Oh forgot to add that is a nice looking truck!

Is this the thread you read about testing your secondary? https://forum.ih8mud.com/threads/how-to-troubleshoot-the-secondary-on-my-carb.812685/#post-9286758

 

[Pin_Head]

Try increasing the mechanical opening of the secondary: There is a tab on the primary linkage that contacts a cam on the secondary linkage to kick open the secondary by a few degrees. If you bend the tab upwards so it contacts the cam eariler, you will get more mechanical opening and hence more vacuum at the ports for the vacuum secondary actuator.

Also check the linkage to make sure that the primary is opening 100% all the way.

 

[70 FJ40]

Thanks, thats a great video. I will check the linkage. Just wondering though if this could also be the source of my poor fuel milage? Doesn't seem like it would be.

 

[edwjmcgrath]

Here's a link to my experience in tuning the vacuum secondary. I had to kick it open much more than the FSM would indicate.

https://forum.ih8mud.com/threads/tuning-vacuum-operated-secondary.612961/

That said, just because your secondary isn't opening doesn't mean that's the only problem you have.

 

[sggoat]

Check to make sure the secondary diaphragm is ok before going further.

 

[Pin_Head]

Just wondering though if this could also be the source of my poor fuel milage? Doesn't seem like it would be.

No. The more power you make, the more fuel you burn.

 

[70 FJ40]

So the everything seems to move and open as it should but I need to check to make sure that when the gas pedal is pressed all the way it is moving the linkage far enough to kick the secondary open a little. I will do this next time I have a few minutes to work on it. If it looks like its working properly I will pull the secondary diaphragm and make sure its working like it should. Just before coming in for the night I noticed that the orange hose going from the air cleaner down to the valve cover was not connected properly and it is in pretty bad shape as well. I reconnected it and I will try the paper clip test again before doing anything else. Could this be my problem?

Also here are some pics of my engine compartment. Can someone tell me if it has been de-smogged and if it was done properly?

Another question. Is my Cruiser vacuum advance? if not is it wort changing?

Thanks for all the help guys. I have learned a lot about my carburetor today.

 

[Rustic76]

Take a pic of the engine bay from the passenger side and get a close up of the distributor, someone here will be able to tell you if it's mechanical, vacuum advance, or vacuum retard. No telling what the previous owner was running without getting a look.

Or take a look at the setup and then head to coolerman's website and do some studying .

 

[Pin_Head]

The air cleaner hose has nothing to do with it.

 

[Downey]

The 1970-76 had a vacuum retard distributor, the 1977 had points, and went back to vacuum advance. 1978 distributors went to electronic breakerless, odds are you do have the 1977 distributor. I'm a Holley 350 man in an Aisan world, so I've never tried to figure out how to use the Aisan smog device controlled carburetor when aborting the smog device??? Seems to me the smog device vacuum system controlled the secondaries, etc. Someone school me on how you properly desmog the Aisan carburetor???