FJ60 Intermittent Stall at Idle
- Thread starter Rzeppa
- Start date
Rzeppa
Rising Sun Member
So I study the plumbing I have. Holy wrong connections batman! Instead of being connected to the PCV circuit, it goes to the port on top of the distributor cap that is normally supposed to connect to the clean side of the air cleaner housing, which ventilates the inside of the distributor cap!
So what is that VCV that is connected to the PCV circuit for? Why does it have that hose connected to itself?
If I knew exactly what that VCV was for I would have a fighting chance of connecting everything back properly. I know the HIC valve is supposed to connect to that PCV circuit. I know the distributor cap is supposed to connect to the clean side of the air cleaner housing. I am not sure where that vacuum line on the right of the VCV connects to at its other end.
So what is that VCV that is connected to the PCV circuit for? Why does it have that hose connected to itself?
If I knew exactly what that VCV was for I would have a fighting chance of connecting everything back properly. I know the HIC valve is supposed to connect to that PCV circuit. I know the distributor cap is supposed to connect to the clean side of the air cleaner housing. I am not sure where that vacuum line on the right of the VCV connects to at its other end.
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Rzeppa
Rising Sun Member
Rzeppa
Rising Sun Member
Oh, and as a follow-up, I did measure the vacuum at the vacuum switch with the engine running. I only got about 9". Note that this isn't raw manifold vacuum, it is just below the throttle plates so is somewhat less than full manifold vacuum. When I reduced the idle by closing the throttle plate some I got it up to about 12". Certainly not enough to activate it. And makes me wonder if a valve adjustment might be in order...
60wag
Rising Sun Member
- Joined
- Aug 23, 2005
- Messages
- 2,596
The VCV on the passenger side is for the distributor ventilation - not mentioned in the emissions manual if I recall. The other VCV is part of the canister purge system. The HIC circuit doesn't have a VCV in it. The connection to the PCV circuit is just a vacuum source I thought.
Is the HIC atmosphere port just a vent to let the door in the air cleaner housing return to its default position?
Is the HIC atmosphere port just a vent to let the door in the air cleaner housing return to its default position?
MDH33
Hard Core 4+
Jeff, you're welcome to park your 60 next to mine and compare the vacuum spaghetti connections. Mine are stock and properly connected.
Rzeppa
Rising Sun Member
Thanks Bruce! That is good to know! It is not mentioned in my manual either. The distributor in my 78 has a much simpler vent system: Hose to the clean side of the air cleaner housing, check valve so gas fumes don't blow up the distributor, hose to the firewall where there is a filter on the inside as inlet for the distributor venting.
I wonder why they would use a VCV instead of a regular check valve like they do on my 78? In any case, clearly this is plumbed wrong, but will correcting it fix my stalling problem? Doubtful IMHO. I still wanna fix it though.
That is what the manual shows. And as I wrote, I traced the lines and figured out what all that was about.
The EVAP system has its own connection to the intake - it is near the top of the carb.
No the HIC has it's own port to the clean side of the air cleaner housing. When open, it bleeds air into the manifold as shown in the table according to the air temperature at the HIC. It appears that the source of temperature for the HIC is from the flow from the HAI. I think...
Again, at the end of the day, I can look at so many things that might be right or wrong with this system, but she used to idle just fine before I dorked around with getting her through emissions. I *thought* I put her back the way she was, but clearly something has still changed. I still haven't tried blowing out the bowl of the carb.
Rzeppa
Rising Sun Member
Thanks Martin, I may take you up on that. Or if you wanted to just snap a couple of pictures that would be helpful?
Air Randy
Hard Core 4+
Try the "shade tree" carb rebuild. Take the air cleaner off, put a glove on your hand, rev the motor up to about 2,500 rpm, then slam your hand over the bowl of the carb and kill the engine. If you have a little piece of crud in there that got introduced when you changed the jets or added all of the methanol, this could suck it through with the vacuum spike it causes. Nothing to lose by trying and it wont hurt anything.
I did it on my 2F and it fixed a rough idle situation instantly.
I did it on my 2F and it fixed a rough idle situation instantly.
Rzeppa
Rising Sun Member
That is a good idea Randy! I am familiar with this, my friends used to call it a Polish carb rebuild
And it would address the question that I keep finding myself going back to: "What has changed"? I may still take off the jet access ports and blow some compressed air into the bowl though. I really don't want to have to take the air horn off the top to access the bowl, there is just so darn much crap on a 60!
Rzeppa
Rising Sun Member
Still have the problem.
I stopped off at Joe Calleja's because I was nearby, and borrowed his emissions FSM to figure out the correct way to connect the HIC system and the distributor cap ventilation system. I did that right there.
Joe strongly suspected a fault in the emissions computer which might be intermittently ungrounding the idle fuel cut solenoid. I reminded him that he had "repaired" this particular computer and the receipt I got from the PO showed he had charged $300 for it. He said there might still be a problem and that I should take a look at it.
His tech Gary thought there might be an obstruction in the idle circuit passages. I told him of my plan to blow compressed air into the bowl through the jet access ports. He said if it were him, he would remove the idle solenoid and the idle mixture screw and spray carb cleaner though the idle circuit passage.
So I have taken the computer out and examined it under very high magnification. There were no obvious problems but I could see which solder joints Joe had apparently simply reflowed and added more solder, and the flux was still there. They were all for the connector itself. So I removed the excess solder with solder wick, resoldered the joints properly, cleaned the flux and reinstalled the computer. Then, just to be sure I built a pigtail and hardwired the negative connection for the solenoid straight to ground at the computer connector.
That didn't fix the stalling problem, but it completely eliminated the computer as the cause.
Next I tried gloved hand over the carb throat trick.
That didn't fix the stalling problem but at least I tried.
Today, I drove her to the store and a bunch of errands and had no stalling issues at all. This thing is maddeningly intermittent!
I stopped off at Joe Calleja's because I was nearby, and borrowed his emissions FSM to figure out the correct way to connect the HIC system and the distributor cap ventilation system. I did that right there.
Joe strongly suspected a fault in the emissions computer which might be intermittently ungrounding the idle fuel cut solenoid. I reminded him that he had "repaired" this particular computer and the receipt I got from the PO showed he had charged $300 for it. He said there might still be a problem and that I should take a look at it.
His tech Gary thought there might be an obstruction in the idle circuit passages. I told him of my plan to blow compressed air into the bowl through the jet access ports. He said if it were him, he would remove the idle solenoid and the idle mixture screw and spray carb cleaner though the idle circuit passage.
So I have taken the computer out and examined it under very high magnification. There were no obvious problems but I could see which solder joints Joe had apparently simply reflowed and added more solder, and the flux was still there. They were all for the connector itself. So I removed the excess solder with solder wick, resoldered the joints properly, cleaned the flux and reinstalled the computer. Then, just to be sure I built a pigtail and hardwired the negative connection for the solenoid straight to ground at the computer connector.
That didn't fix the stalling problem, but it completely eliminated the computer as the cause.
Next I tried gloved hand over the carb throat trick.
That didn't fix the stalling problem but at least I tried.
Today, I drove her to the store and a bunch of errands and had no stalling issues at all. This thing is maddeningly intermittent!
Rzeppa
Rising Sun Member
So, any helpful ideas fellas?
MDH33
Hard Core 4+
So, any helpful ideas fellas?
Hey Jeff, sorry I didn't reply sooner, I was away all last week. If you have time this week, feel free to bring it by and we can park it next to my 60 and do a comparison of emissions gear. If it all checks out, my thought would be to pop the carb off and rebuild it.
Good News: I have a spare Emissions computer if you want to plug it in and see if it helps the issue...
Bad News: I am in Vail/Breck until the 5th...
let me know if you want to try it out and I will bring it down with me..
K
Bad News: I am in Vail/Breck until the 5th...
let me know if you want to try it out and I will bring it down with me..
K
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Rzeppa
Rising Sun Member
Visual side-by-side will probably be helpful to verify that I have now got everything plumbed properly. The carb was rebuilt about 2,000 miles ago so it should not need an overhaul, but it is possible that I introduced some crud while changing the jet 2x.
Rzeppa
Rising Sun Member
Thanks Kraig, that might be helpful. I know that I have eliminated the computer's control of the idle fuel cut solenoid, however there are a few other functions that the computer does which might be the culprit.
I'll get it out of the shed and bring it back down with me after the weekend...
K
K
Anxiously awaiting a solution to your problem. please post when you get it nailed down.
Cheers
Cheers
Rzeppa
Rising Sun Member
I am too!
I am pretty close to wits end. I am going to email Robbie in his official capacity as TT Tech Editor and see if he has any additional suggestions. Each remaining course of action seems more and more time-consuming and laborious!
It's gotta be something simple (I hope!). And I have to keep asking myself, what has changed? It used to be fine before I made a couple simple changes to pass smog, then when I un-made those changes the stalling didn't go away!