I did test today as suggested in Kirby’s Book. Each solenoid clicks and also air bellows retracts when I suck air when both solenoids are activated. From what I can see, both plungers have rubber disc on.
So - what next? i guess I will clean the connector that actuator is attached to, check the vacuum hose and…there my knowledge ends. What about that blue (safety) valve on the right side of the engine? That could probably cause problems, too? How should I check that blue thing - I guess that is another valve or solenoid?
Hi, Aristides! Yeah, I read guy named Dave have had similar problems…the system worked for a while and stopped. Next drive the same…after all check he found the problem - it was dirty and corroded connector.
Hope that will solve my problem, too.
Have any idea how to check that blue safety valve?
It’s a three way valve, but same as the any other, apply voltage and see if it opens/closes the ports.
IIRC, one state is vacuum to bellows, the other is Bellows to atmosphere
I will, Robert - it was little loose, but anyway I did the bypass to check and still did not work last time.
Now the actuator is checked and works…put bellows back on and is waiting for silicone to harden a little. Connectors to and in the actuator cleaned…
I started the car and tried the hose that is normally connected to solenoid. i can feel very gentle vacuum on my finger…but if I put small piece of paper it stands on the hose. Is that OK and enough - such gentle vaccum?
Which hose to which solenoid?
If its the one at the bellow you shouldn’t have any vacuum, even if the CC is on…
The car has to be rolling faster than the low speed limit and the speed set for the bellows solenoids to see vacuum, otherwise the safety valve will be closed.
The fact that you have a slight vacuum would mean that the safety valve is leaking.
hose that is normally connected to bellows, you know, to valve A on the photo above. I thought that hose supposed to produce suction always with engine running, and the bellows valve opens only when CC engaged??
So what does that mean - if there supposed to be no suction at all at that hose with engine running? I thought I read somewhere testing at the engine running there should be suction on that hose itself…?
Aristides, please help me understand this…so, with engine on, the hose that goes from blue safety valve (EAC 7905) to the actuator valve A (but not connected to it) should not produce vacuum at all? But what about cars without that blue safety valve - or bypassed - directly from intake manifold to valve A - don’t they have constant vaccum and actuators solenoids control the game, allowing or not, the vacuum to retract (or not) the bellows?
Anyway - if there should not be vacuum in the hose attached to blue valve at engine running idle, at all - does that mean the blue valve does not do the work - part EAC 7905 is available and I could buy one.
Would that explain my problem with CC working only for few miles each drive?
Thank you,
Cene
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
31
The sealing properly was an issue on my '83. Each plunger had a little rubber baby buggy bumper on the end that got smoooshed up against a port to close it, but the rubber buttons had fallen off and were rattling around inside the module. I punched new buttons out of a bicycle inner tube with a hole punch and superglued them in place.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
32
The problem with my stalk switch was that the entire stalk was not grounded. It was supposed to be, but the little black wire snapped off. I just attached the wire directly to the stalk – toward the inner end where it’d be hidden within the clamshell around the steering column – and it worked fine from then on.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
33
Easiest way to test it is to remove it. It was added via recall, probably in response to a lawsuit. How this system ever failed in the on mode, giving throttle when off, I dunno. In any case, if you remove the thing and the system works perfectly, you know it was that add-on thing that was causing problems. Then you can decide for yourself if you wanna waste money getting a new one.
Thanks, Kirbert. So I should bypass blue valve and connect hose from vacuum manifold directly to valve A of the actuator, right?
As you see above discussion now the hose that goes from blue safety valve towards valve A on the bellows produce vacuum with engine on and I am not sure if that is OK or that indicates bad blue valve as Aristides wrote, it I understand him correctly…
No, should be strong vacuum. May have to energize the blue solenoid for full vacuum at the servo. My ‘88 does not have the solenoid and has manifold vacuum at the servo. Bypass the solenoid to verify if that is your issue.
My ‘88 doesn’t have the solenoid; if you just tap the brakes, the cruise sometimes resumes by itself. Maybe vacuum is holding the solenoid closed? Used to it so doesn’t bother me.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
37
If it resumes without the solenoid, it’d resume with the solenoid. The controls aren’t changed at all. It just adds redundancy to the valves.
**
I quite agree with Kirbert, Cene; omit the safety valve - and connect the ‘inlet’ valve directly to manifold vacuum…
Like others, it was not fitted to mine - and the issues that caused it to be added later never arose. It is a bit uncertain how it is activated - and it may also fail on its own accord. If the problem disappears, leave it out - and then you can, if you like, muse on the cause of its malfunctions…
If this doesn’t fix the problem; removal is the quickest way to verify that the problem is elsewhere - to be pursued…
The Safety valve is a master solenoid, (NC) and third port (NO) vents to the atmosphere. When it’s OFF there should be no vacuum at the other solenoids.
Solenoid a (NC) applies vacuum to the bellows
Solenoid b (NO) bleeds vacuum from the bellows.
Solenoid a ON, solenoid b ON - car accelerates
Solenoid a OFF, solenoid b ON - steady speed
Solenoid a OFF, solenoid b OFF- car decelerates
When you apply the brakes, or when the CC is OFF, or the car is bellow the minimum set speed, all solenoids will turn OFF, including the safety solenoid and bleed all vacuum from the system.
You could run the system without the safety valve as suggested and see.
If I was you I would take it apart and inspect it.
It’s redundant but a good safety feature. I had once the CC stuck on me (for an entirely different reason) and the car would not decelerate, believe you me it was terrifying…
An other thing you can see it in the diagram is that both the CC brake switch (NC) and the brake light switch (NO) can cancel the CC, an other safety redundancy, so check them both.
If all solenoids are working correctly and still you have a problem then it would be an electrical fault.
