FJ40 2F Engine Idle Issue, not the usual fix, ideas? (1 Viewer)

[outwestjim]

I like your technical and practical approach step by steps ,


Your on target with your first 2 u mention above …

Timing being out will affect your vacuum in the most drastic ways possible so make darn sure u set it to the stainless steel BB per the FSM

And only then final finite adjust via a high quality vacuum guage hooked up directly to your intake manifold

Not the carb base or any other source to be klear here

This the prescribed recipe for sucses

Then once you have dialed the timing and base idle and fast idle also don’t forget …

Transition to the FCS , and confirm and properly diagnose that ..

I have personally had more then one original fcs provide a solid clicking sound a touchy freely click sensation when hand held , yet still be a failed faulty part at the end of the day …

Good luck your on the right path here I feel …


Matt

Thank you Matt,
I appreciate the encouragement!
Going back to how the problem started, we were on a short drive and the idle issue surfaced as we neared home.
Keeps me wondering what could have changed in a short amount of time.
I think we'll proceed with another FCS and also an emissions computer since ours has the low voltage issue to the FCS.
We'll also share the vacuum readings (I have good gauge) once the tachometer arrives.

 

[outwestjim]

If you are suspecting intermittent electrical issues, I have seen problems with the fuse holders and connectors on the back of the fuse panel get high resistance.

thank you, we'll check them out!

 

[outwestjim]

The 81+ computer controls the EGR VSV, FCS, and two air Injection VSVs depending on the inputs. I'm not sure the AI or EGR can cause the idle issue and you took the FCS out of the picture. One thing that comes to mind tho is the computer switching VSVs, maybe it is switching in a vacuum leak?

It's been a while since we've had time to work on the FJ, but want to get back to it. I'd like to order an emissions computer and another FCS. Who do you recommend we purchase from? I'd like to support vendors here, if possible.

 

[Engineer8000]

I recapped this one and tested earlier this year. It may be more cost effective for you to send yours in for refurb and testing.

 

[65swb45]

Did you try blocking the EGR from the intake yet?

 

[outwestjim]

Did you try blocking the EGR from the intake yet?

Yes, we removed the EGR completely, and checked it with a vacuum pump. It seems to be working normally.

 

[outwestjim]

I recapped this one and tested earlier this year. It may be more cost effective for you to send yours in for refurb and testing.

View attachment 3073131

How would I go about purchasing this unit from you? I trust a unit you stand by more than a unit pulled from a vehicle...

 

[outwestjim]

An update: We finally had some time to devote to the FJ and our idle issue. The good news: The replacement Emissions Computer arrived from Engineer8000, it looks really good and did solve the low voltage going to the FCS. A really great job with communication and the quality of the unit, plus fast shipping.

We still have the idle issue and have some vacuum readings to share:

900 rpm (the lowest it will idle) 8 inches vacuum
1,000 rpm 13 inches
1,200 rpm 15 inches
1,400 rpm 15 inches
The vacuum doesn't really go up after that, except when letting off the accelerator from fast idle (temporarily goes to 20 inches).
This seems low, but I'd like to hear your opinions please.
Many Thanks!

 

[Pighead]

An update: We finally had some time to devote to the FJ and our idle issue. The good news: The replacement Emissions Computer arrived from Engineer8000, it looks really good and did solve the low voltage going to the FCS. A really great job with communication and the quality of the unit, plus fast shipping.

We still have the idle issue and have some vacuum readings to share:

900 rpm (the lowest it will idle) 8 inches vacuum
1,000 rpm 13 inches
1,200 rpm 15 inches
1,400 rpm 15 inches
The vacuum doesn't really go up after that, except when letting off the accelerator from fast idle (temporarily goes to 20 inches).
This seems low, but I'd like to hear your opinions please.
Many Thanks!

Yes, that is a very low vacuum reading. Where are you taking the vacuum from? What is your timing at, and your altitude? (Not that that really matters)
Does your vacuum increase if you advance the timing?
Please stop calling it an FJ

 

[outwestjim]

Yes, that is a very low vacuum reading. Where are you taking the vacuum from? What is your timing at, and your altitude? (Not that that really matters)
Does your vacuum increase if you advance the timing?
Please stop calling it an FJ

Sorry if I offended, I started calling them FJ's sometime after my first 1969 Landcruiser FJ40 with 3 on the tree.
The timing is dead on the marks, set per the manual, but I have not tried advancing the timing to see if the vacuum changes.
Altitude is ~4,200'

 

[Pighead]

Are you measuring the vacuum from the intake manifold or elsewhere?
When did you last adjust your valves?

 

[outwestjim]

Are you measuring the vacuum from the intake manifold or elsewhere?
When did you last adjust your valves?

Right off the intake manifold, just below the carburetor. Valves were adjusted at the time of the rebuild, then rechecked after a warmup.
To recap, the engine idled perfectly after the rebuild, drove it on several short trips. On the way back home from the last trip of maybe 20 minutes, it would no longer idle.

 

[Silver City Cruiser]

I think your problem is not your carburetor or idle circuit.
I think you may have a sticking egr valve. It opens when driving under certain conditions and needs to close fully to have good idle quality and prevent stalling. I have seen many 2F exhibit this condition even with lower miles.
When it is idling good, disconnect egr hose and plug the hose Test drive a few days. Replace valve if stalling is gone. Bill

 

[outwestjim]

Update: The idle problem with our FJ40 Landcruiser seems to be fixed!
First, thank you for all the suggestions!!!
ToyotaMatt and Spike Strip mentioned the FCS could still be an issue, even if replaced.
I ordered another one from SOR, we installed it this afternoon and now have a fairly smooth idle at 800 rpm and no choke.
The interesting thing is, both of the previous FCS's would 'click' when energized, but were apparently still the problem.
This includes when they were wired directly to the battery.

 

[outwestjim]

If the ICS you used is one of those $20 CCP units, they don't always work so well. Some do, some don't. If you have the original ICS test it for clicking. If it's working, you might try and swap it back in.

Also, something that I've seen a few times in FJ60s (you have the same carburetor), is when the 35 year old ICS is removed, the bits of the old brittle O-ring from the tip of the nozzle get stuck in the bore, and clog the circuit when the new ICS is threaded in.

You could remove the ICS and try spraying come carb cleaner into the hole, sticking the pipe in to try and dislodge any crap. If the circuit is clear, I think you should see some discharge out the idle circuit port looking down the throat of the primary barrel.

This was good advice, thank you!

 

[Spike Strip]

What did you find?

 

[outwestjim]

What did you find?

2nd replacement FCS fixed it