Vacuum leak?? Stalling issues (1 Viewer)

[uwum15]

So I've been working on a stalling issue but haven't had it on the road to test anything of these fixes yet. What originally happened was my '79 FJ40 would occasionally stall slowing down to an idle. When that happened, even pulling the choke didn't effect the RPMs. Then randomly it'll idle and drive fine for a while.

I've replaced the spark plugs (gapped them at about 33) and tried to pinpoint a vacuum leak with carb cleaner sprayed around the intake. I didn't really hear any change in RPMs, I'm not sure what this means in my voyage to figure out why it occasionally stalls out on me when it idles. Could it have just been bad spark plugs? Does the fact that the carb cleaner didn't effect my RPMs a good or bad sign (I'm fearful or needing to replace the carburetor or have a crack in the intake manifold)? Thanks.

 

[91 4runner]

Try to find a pattern, I know you said it stalls randomly but see if it does it more cold or hot, hard hill pulls, or at a cruising speed.

The carb cleaner to detect vac leaks is good, but does take practice to notice the engine sound,

Let us know what you find

 

[Pin_Head]

It could be a sticky EGR valve as mentioned in your other post.

 

[Tools R Us]

The idle cut solenoid can fail, stick, etc.

 

[uwum15]

Is the idle cut solenoid a simple fix? I'll look at my service manual and try that next along with looking at the EGR-I've Sheena. Lot of talk about just blocking off the EGR saying it'll give me better power at the top end range...I have no idea if that is correct or not, but I wanted to check before I went through the hassle of pulling it and cleaning it since I heard it's a real pain. Thanks again as always.

 

[N919HJ]

Read this, it may help.

https://forum.ih8mud.com/40-55-series-tech/798472-idle-mixture-screw.html#post9106462

 

[uwum15]

I haven't been on the forum for about a year (before it got renovated I think) but I have a '79 FJ40 that was having sporadic idling issues and stalled occasionally. The other issue was the choke didn't always seem to influence the idle at all. After months of searching on Google, help from other forum members, and three mechanics, I finally stumbled on the fact that the idle solenoid could fit the bill. I bought a new one for less than $20, replaced it and it hasn't had an issue yet. What was occurring was the pin in the solenoid would occasionally stick so as soon as I took my foot off the throttle it would die. I was close to pulling the carb and going through all of the vacuums and this was my last thing to check before I had a $1000 bill from a mechanic. Thanks for all of the previous help over the past year, now I'm back to driving it and on with the restoration!