Engine oddness? stalling. Any ideas? (1 Viewer)

[rage]

Less than a week and I've already got some hopefully simple issues/questions.

Here is whats happening,
72 FJ40 with 3 spd. and stock F engine.

Running normally it takes a bit of time to warm up, which seems normal.

Idling seems steady but occasionally stalls even when warm.

When warm I am driving, moreso in 2nd/3rd gears. Say doing 40mph or so, I start to slow down in 3rd gear and all of the sudden I start hearing some pretty harsh noises from the exhaust, I wouldn't say a backfire. But its loud, grumbly, and sounds like some not so loud popping. At that point the engine dies, I end up having to restart on the fly.

Same thing happens pretty much in 2nd gear as well, but the noise thing seems to be new. But it ends up dying on a clutch in deceleration, say when coming to a stop sign.

Is this just a low idle thing that happens to be killing the engine when I clutch in or something worse? Any ideas/suggestions?

Thanks,
Rage

 

[kulangot]

Rage,



When you dial in a race car or high performance, you keep leaning it out until it starts to pop and gurgle on deceleration and then richen it out a bit from there. This is where you make the most power. Too lean makes power, but is bad for the engine because it burns valves. Hard to understand sometimes for a new gear head but more fuel does not mean hotter combustion, the engine can only burn so much fuel.

Very hard to fix a problem like that with out seeing the truck. However, you can check all of your basics and often find the source of the problem by just doing that. Start by looking at the plugs, that will tell you if the truck is running too rich or what I think is happening, too lean. See just about any decent automotive textbook and you'll find plug diagnostic pics. You might even be able to find some on the net. If it's running lean and causing backfires you'll see that in the plugs. If lean, check for vacuum leaks. Land Cruisers are very prone to vacuum leaks at the intake manifold and head. Lots of ways to find leaks, carb clean, pure oxygen, propane, stethoscope, etc.

Always check the basics. So many times a compression check and or vacuum guage reading can save you so much time and effort. Same goes for checking all tune up specs, plugs, etc.

Let us know how it works out.

-Stumbaugh

 

[greytandy]

So many times a compression check and or vacuum guage reading can save you so much time and effort. Same goes for checking all tune up specs, plugs, etc.

John:

What compression and vacuum gauges would you recommend? I've seen compression gauges for as much as $300 and as little as $45. Any guidance for a monetarily-challenged individual appreciated. Okay, semi-hijack over.

 

[rage]

I'll start searching for something on the net for plug diagnostics, and go from there. Know if there is anything in the FSM or Haynes detailing it? I'm still waiting on those to arrive but if I don't see anything on google, I can go find a book on it if there isn't anything in those two manauls.

Thanks again, I'm sure I'll have more questions once I get back into town and start poking at the engine.

Rage

 

[greytandy]

Know if there is anything in the FSM or Haynes detailing it?

One of them, I forget, has a color page of all the spark plug maladies. To the untrained eye (like mine) some of the pics look very similar. It's a good place to start!

 

[Felix]

All Haynes manuals have a full page of color photos of plug problems on the inside back cover.

 

[rage]

Excellent, Amazon prime should have my haynes here today, I can take a look at it on the plane.

 

[kulangot]

Here is a really good one that I found by searing Google for "reading spark plugs"

http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

Another:

http://www.centuryperformance.com/spark2.asp

and a page on lean running:

http://www.classicmotorcycles.biz/mechanics/exhaust/thread73.html

It's MC's but the same principal.


As far as the vac and compression guages, if you don't do it for a living, sears is all good. You need to be carefull about testing your tools on occasion though. I once rebuilt an F motor just because I had a bad timing light. What a bummer.

I have a few extra of these tools that I'd sell. Compression checker, vac guage, timing light, engine analizer (to set dwell on distributor) - all in great shape and what you need to do a tune up.

PM me if your interested.

Look for vacuum leaks!!!

-Stumbaugh