advice needed diagnostics

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srplus

srplus

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well, although i have viewed this site for a while, i thought it would be better to read than spew. however, after owning MANY cruisers, i have come upon something with my brand new '86 FJ60 that i could use some advice on.

since i am getting old (or lazy) i let a mechanic do some work for me and i do not believe his diagnosis. also, he makes money on every replacement part wheter it solves the problem or not...
PROBLEM: cruiser cranks and runs fine - that is, until it gets warmed up. everything sounds perfect when just getting rolling. after about 20 miles, or so (sometimes more, sometimes less), the engine sounds like it might be missing on one cylinder (intermittently) and the engine can stall when stopped or even when driving along if foot is off the accelerator pedal.

now, we are not juniors, have done frame off restores on fj55's and 40's and have done much of regular stuff one would do with a new old car: including since the vehicle sat up for about 6 months, draining the gas tank and adding new fuel, changing fuel filter, new plugs and wires, distr. cap and rotor, etc... you get the picture. of course since it is a TLC it has the usual exhaust manifold leak.

what i was looking for (and i think this would be very helpful to others) is an actual checklist / procedure and itinerary to go down for identifying and solving this problem to eliminate the guess factor, before i end up changing every good part under the hood.

since a stock TLC carb is $904.00 from my friendly local Toyota dealer and the rodchester and other carbs are still not cheap... before i get to that or a distributor replacement, or even make it a Chevota, i would like to isolate what the problem actually is. and YES, i have heard of Ebay... and was buying from Man-A-Fre back in the 70's...

i have reviewed / searched the site and suspect it could be a vacuum leak that doesn't show until the engine is warm, since, on start up and for quite a few miles, it does not rear it's ugly head. i guess i am gonna start turning wrenches and rachets again (those ones with MM stamped on them) since i don't have enuf scarred knuckles and the mechanic so dearly likes to work on warm motors. if you have any specific ideas chime in... but the procedure to follow when i pull over in the walmart parking lot or the shoulder on the interstate after it finally stalls would be most useful.


thanx in advance. and sorry for the long post.
 
Well Steven, its too early in the morning for my brain to start diagnostics; however, I'll concentrate on the electronics, since I'm pretty good at that discipline.

Assuming that the ignition system is stock, I would start here:

How old is the battery?

Check all battery cables, especially the frame ground. Grounding cables from the engine bloc to the firewall to the right fender.

Look for corrosion on the coil leads right at the coil. If the connections on the positive and negative leads have not been touched in years; the connection could have corrosion and be intermittent. I have had this happen to me on my FJ40.

Intermittent (corrosion again) at/or in the ignition switch &/or the fuse link. My fuse link connectors were corroded.

And lastly; it may be possible that the coil is old and has an intermittent failure showing up as the engine bay warms up.


Chew on this for a while as I get some more coffee.


...
 
thanx but need more

appreciate that... but since this only happens after the warm up and no matter what the car starts immediately if i either let out the clutch in gear while rolling or when stopped - if i pull the choke out and turn the key; i do not think on the '86 it is electric or electronic... could be and i will check that stuff.

the fellow that owned the crusier before me was the second owner and not as good as the original owner. he fixed only what he had to to keep it running... e.g. he had to replace the clutch and the master cylinder... i checked and he did not replace the hydraulic hose to the slave, the slave, the rear seal or the throw-out bearing... all of which i have done since i got the thing. could not believe the slave was not replaced or if he had the tranny out - the throw-out bearing and the rear seal! just glad he did not own it for too long.

love cruisers and don't want to always be fixing 'that one more thing' that should have been included in the repair to start with, especially when off road and a long way to the parts house or AAA.
 
maybe the choke? i know it will run fine at half way but maybe its sticking closed
 
been thinking to do that but the mission right now is not to replace every little thing or check every little thing but rather to try to develop a diagnostics procedure for eliminating one thing at a time in some kind of logical order... i do electrical repairs in signs and it usually takes a little more time to diagnose and fix a problem if you go through a routine... if you don't and immediately jump to the 'i thought it might be solution' it's great if you hit the nail on the head... if you don't you have wasted a bunch of time and possibly parts that were unnecessary.

i really do appreciate every imput though... i have pondered fuel problem as one of the possibles... the mechanic wants me to replace the carb but i am thinking i may be lucky and it is something else... his second recommendation follows his first to do the tune up... and i am sure that if the second recommendation does not work then he will recommend changing the distributor... you know how it goes.
 
the main thing is that the idle runs fine and the engine purrs when cold... only after running up the road (just too far to walk home) that the engine starts to run a little rough and then starts the stalling routine... if it sits for a while after doing the stalling and i crank it up again it sounds and runs great.

i will eventually go thru the whole chilton's manual to get to and resolve it but was hoping for some do this as # 1 and this as # 2 - etc. to eliminate all of the 'it sure sounds like'...
 
If it only happens when vehicle is warm, I think of a vacuum leak (manifold).
A vacuum gauge makes a fine diagnostic tool, do you have one?
This is the first thing I would rule out before buying new parts, since it is such a common problem with our engines.
 
PH - would the exhaust manifold leak cause this type of prob? since i gave up doing all my own repairs a few years ago when i got the fj80 i let go most of my fix the fj 40's and 60's stuff and am down to a few wrenches and rachets... i will prolly go down to the parts house and start replacing guages etc.
 
I will certainly be following this thread as I am having the same problem. I have a rebuilt motor, new distributor and no vacuum leaks that I know of. I believe my carb is suspect...it is a Holley. I would give my left nut to see how it would do with a Jim Chenoweth carb.
 
No, an exhaust leak will not cause stalling, it would run fine, just sound awful, but an exhaust leak can be an indicator of an intake leak...a warped manifold or head may seal OK when cold but leak when warm.
Also, some intake manifolds develop a crack directly under the carb where the exhaust manifold bolts to the intake manifold...impossible to see without pulling the carb off or dropping the exhaust manifold. The crack may be small when cold but expand and leak more when warm...





srplus said:
PH - would the exhaust manifold leak cause this type of prob? since i gave up doing all my own repairs a few years ago when i got the fj80 i let go most of my fix the fj 40's and 60's stuff and am down to a few wrenches and rachets... i will prolly go down to the parts house and start replacing guages etc.
Click to expand...
 
toyman 317:

if you need a carb i have had the best luck with a Weber 32/36 from these good folks (about 1/2 the price of stock TLC carb from dealer) and available at this url:

http://www.man-a-fre.com/pa/webercarburetorkits.htm

not to offer advertising but it is a great product and these have been great folks to me. i switched out the carb and put in their headers in an fj40 i did a frame off on and it got WAY BETTER gas milage and gave superior performance.

AS USUAL PH: thanx for that pointer on possible location of leak... will check that also.

so for diagnostics for this kind of problem:
1) use vacuum gauge to determine that there are no leaks
2) ? if it is not # 1

(not shooting for my avatar in one day of posting, LOL)

ALSO FORGOT TO MENTION PREVIOUSLY... WHEN IT IS READY TO STALL THE RPM'S DROP VERY LOW AND PULLING OUT THE CHOKE A LITTLE WILL KEEP IT RUNNING BUT STILL SOUNDS LIKE IT COULD HAVE A SKIP OR NOT FIRING ON ALL 6.
 
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Another important clue!
If the engine runs better with a little choke...BINGO! vacuum leak! (choke compensates for unmetered air).
Get an idle vacuum reading while cold, get one while hot, report back to us with the numbers. I'll have more ideas by then...
 
When it is starting to go into the stalling mode try spraying the ignightor with cool water and see if that is it. I have chased that down a few times. When cold do a vac reding then do it again when you get into stalling mode (if ya can) this can help isolate a vac leak, the crack mentioned under the carb sounds like a good choice.
 
Srplus-
While this may not be very helpful in forming the diagnostic checklist you seek, I can add a couple things helpful to the thread. I experienced this same problem back in September, both before and after a carburetor rebuild that I had to do to pass emissions (I was living in WA at the time). The old carb was dumping far too much fuel, clearly failing and the problem persisted after the rebuild. Strike carburetion from your list.

When I moved from WA to IL shortly thereafter, the 60 was laden with a trailered motorcycle and several hundred pounds of goods. My engine would idle at approximately 800 and drop to about 450 when it stalled, so I adjusted the idle RPMs to 1200 for my trip so I didn't have to mess with engine stalls. It would still dip occasionally to 750 or so, but if it's your daily driver that's a quick and dirty way of handling the problem until you come up with a more permanent fix.

I replaced all my vacuum lines a couple months back and the stalling has not reemerged, that's all I can add to the story.
 
crunch time

the search begins... will hunt down and trace out this leak if that is what it is... several of the suggestions are great but... is there a step # 2 if step # 1 is not successful? sure are a lot of step # 1's. LOL. i also do not think that this is a carb problem. after all, the exhaust manifolds don't glow in the dark yet.

but one more quick question... let's suppose it is the crack in the intake manifold somewhere... wouldn't a 'sniffer' find it with out disassembling the entire top of the engine? just a thought before i get even more cuts on my hands after i throw the gloves down in disgust.

thanx BTW
 
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I swapped carbs last week with the Holley in my 40. Truck runs better than ever. No more idle crash. Good luck in finding the problem. Let us know what you determine to be the problem.
 
will update

got my vacuum guage (finally) and my can of carb cleaner... after reviewing every post i could find here re: vacuum leaks, carb problems, no idle, etc. it seems that the absolute first thing with this kind of problem is to do the vacuum leak test first and also insure that there is no blockage in any of the vacuum hoses or in the carb.

had used propane instead of carb cleaner before but my mechanic friend uses the carb cleaner and swears by it... if there is a leak after the engine has warmed it will most definitely show up by higher revs when the carb cleaner is sprayed around the suspect areas.

will post findings.
 
Got to agree with the thermal problem vacume leak and the use of carb cleaner. Secondarily, if no vacume leak, you may want to disconnect one plug wire at a time to isolate the cylinder affected or cylinders. If you cannot isolate it to a single cylinder, then you must look further into common denominators. You may also have a valve that it to tight causing a loss of compression in one or more cylinders or a sticking valve. This should be shown during the cylinder isolation test.
 
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