Alfa Romeo Forums banner

1 - 20 of 23 Posts

·
Registered
Joined
·
264 Posts
Discussion Starter #1
Hi All,

The last couple of times I took my 88 Grad out I had problems with a lumpy idle. It seemed to appear only after the car warmed up, when I first drove the car it was fine.

Tonight it was idling poorly, on the verge of stalling and on a lark I unscrewed the red VVT fuse near the coolant recovery bottle. Bingo - perfect idle returned.

So I started some testing, here is what I did and found:

1) I tested the TPS switch per the instructions in the sticky, everything checked out perfect.

2) I did the VVT check with the engine off per the sticky. I turned on the ignition and opened and closed the throttle. I could clearly hear the VVT solenoid click - both open and closed. I repeated this many, many times and it worked every time.

3) I started the car and blipped the throttle with my hand just past the point where the VVT engages - back to the lumpy idle. Unscrewing the red fuse to break the circuit returned idle to normal. I also did this many, many times.

So, why does the VVT reset when the engine isn't running, but will not reset while running unless I unscrew the VVT fuse ?
 

·
Registered
Joined
·
264 Posts
Discussion Starter #2
Hmmm, No ideas ?

That scares me because if the gurus on this board don't know what the problem is, it is going to be tough to fix.

If I want to drive the car for a while until this is corrected, is there any problem (other than reduced performance) with me removing the VVT fuse to stop VVT from activating ?

Thanks !!
 

·
Registered
Joined
·
264 Posts
Discussion Starter #4
Eric,

Thanks for the advise on driving w/o the fuse.

I'm confused about one thing. You state that your spider has solenoid controlled VVT, so does mine, aren't they the same ?

Or was it simply a typo and you have the centrifugal controlled VVT ?

Thanks again,

-Steve
 

·
Premium Member
Joined
·
1,709 Posts
Can you look through the small hole on the VVT solenoid mount to see if the solenoid is retracting all the way when the throttle is disengaged? I wouldn't think that disconnecting the fuse would have any effect on idle under normal operation, as the solenoid should be retracted fully at idle.
 

·
Registered
Joined
·
264 Posts
Discussion Starter #6
I didn't specifically look at the plunger, but my assumption was that disconnecting the fuse broke the circuit which then allowed the plunger to retract.

I agree that the plunger should be retracted at idle, but it seems that is not happening, therefore causing my rough idle

If I drive conservatively, and never open the throttle enough to activate VVT there is not problem, but once I activate VVT, it will not reset.

After looking over the schematic, it appears to me that the TPS, solenoid and ECU are the only electrical components that effect VVT
 

·
Trained (ex)Professional, , 1953-2018 RIP,
Joined
·
16,232 Posts
With the solenoid engaged and a rough idle, will the VVT retract if the TPS connector is disconnected?
 

·
Registered
Joined
·
264 Posts
Discussion Starter #8
With the solenoid engaged and a rough idle, will the VVT retract if the TPS connector is disconnected?
Jim, I don't know, but I will certainly test and report back. Thanks for the tip.

I'm wondering if there is any chance that the TPS is "weak" and there is something about the engine running that causes it to fail. Heck I'm just grasping at straws right now :) :)
 

·
Registered
Joined
·
759 Posts
It may seem basic but my vvt had alot of gummed up junk on the plunger and was not moving well in either direction I sprayed carb cleaner in the sight hole and got rid of all the oily grime and it moved freely after that. It should be easy to see if it activates and retracts when you work the throttle linkage. Prior to engine rebuild I had oil leaks that attracted dirt and built up grime onto the plunger. I also has to tighten up the connectors on the wiring harness but since have not had any issues with it.
 

·
But Mad North-Northwest
Joined
·
10,002 Posts
It may seem basic but my vvt had alot of gummed up junk on the plunger and was not moving well in either direction I sprayed carb cleaner in the sight hole and got rid of all the oily grime and it moved freely after that.
There's actually a TSB on that (01.90.01: Intermittent Erratic Idle) but Alfa suggests using a spray lubricant like WD40, not solvent. I spray some TriFlow through the little hole while working the throttle to make the plunger move in and out.

From Steve's description it *sounds* like it's more of an electrical problem??? But lubing the plunger certainly can't hurt to try. The TSB is for the S4 Spiders but I'd assume it applies to all the electrically actuated VVTs.
 

·
Registered
Joined
·
759 Posts
There's actually a TSB on that (01.90.01: Intermittent Erratic Idle) but Alfa suggests using a spray lubricant like WD40, not solvent. I spray some TriFlow through the little hole while working the throttle to make the plunger move in and out.

From Steve's description it *sounds* like it's more of an electrical problem??? But lubing the plunger certainly can't hurt to try. The TSB is for the S4 Spiders but I'd assume it applies to all the electrically actuated VVTs.
WD40 would probably have been better for pure lubrication but mine was covered in thick black goo so it took me a while to realize there was even a plunger in there at all! I agree with sloboy that the plunger should retract at idle or below the activation point if not gummed up. BUT if it is staying on not just hanging up could that be an issue with the little circuit board in the VVT plug? or tps continuing to send the signal to the vvt that throttle is still open? We need to hear back from steve as to what is the plunger doing after the vvt activates and then back to idle. I have not had to mess with mine but can the tps be unplugged while the engine is running/ideling or will it die? If the plunger does not retract after returning to idle and the tps is unplugged would that reset things as happens when the vvt fuse is pulled? I am anxious to hear the answer when steve has a chance to check.
 

·
Registered
Joined
·
113 Posts
There's actually a TSB on that (01.90.01: Intermittent Erratic Idle) but Alfa suggests using a spray lubricant like WD40, not solvent. I spray some TriFlow through the little hole while working the throttle to make the plunger move in and out.
Tom,
Do you have a link for that TSB on the BB?
Thanks
David
 

·
But Mad North-Northwest
Joined
·
10,002 Posts
No, but it's available on the Cardisc.

It's pretty simple though. If you look the through the little hole in the passenger side of the VVT housing you can see he plunger extend and retract as you blip the throttle with the engine running. Spray the plunger with lube as it moves in and out.
 

·
Registered
Joined
·
448 Posts
I'm not sure this is relevant to your problem, but several folks have eluded to the presence of thick black goo.

When I removed my VVT a few years ago, my VVT bushing was turning into black goo that covered everything.

VVT-3.jpg

VVT-4.jpg

AlfaBB member Duke58 sent me instructions for building a brass replacement bushing which I had a local machine shop fabricate and install.

I never had problems with my VVT before, but I've never had any problems since either.

Just a thought.

VVT new brass bushing-2.jpg
 

·
Registered
Joined
·
264 Posts
Discussion Starter #17
With the solenoid engaged and a rough idle, will the VVT retract if the TPS connector is disconnected?
papajam,

I drove the Alfa to work this morning. Once it was warm I opened it up and then pulled into a parking lot. The lumpy idle was present.

I pulled the connector off the TPS and nothing changed. I unscrewed the VVT fuse by the coolant bottle and bingo - perfect idle.

I took the fuse out and drove the rest of the way into the office with out incident.

What are your thoughts on that ?

Thanks,

-Steve
 

·
Trained (ex)Professional, , 1953-2018 RIP,
Joined
·
16,232 Posts
It appears that the electronics in the 'power relay' at the VVT solenoid may be the problem (assuming that the yellow trigger wire is not somehow compromised). Your relay is acting (sort of) like a latching relay which requires a mechanical or electrical reset as opposed to the normal non-latching relay which resets automatically when the trigger is removed. I think I have a good working unit I could send you to test it out if you'd like.
 

·
Registered
Joined
·
7,563 Posts
Could the connector on the VVT is wired the wrong way?...that even possible?...so the plunger is effectively "out" on tickover (hence rough idle) and pops back in without the fuse connected?

......maybe I'd better keep quiet till Jim replies:)

Oops sorry, he just did!!
 

·
Registered
Joined
·
264 Posts
Discussion Starter #20
It appears that the electronics in the 'power relay' at the VVT solenoid may be the problem (assuming that the yellow trigger wire is not somehow compromised). Your relay is acting (sort of) like a latching relay which requires a mechanical or electrical reset as opposed to the normal non-latching relay which resets automatically when the trigger is removed. I think I have a good working unit I could send you to test it out if you'd like.
papajam,

Thank you for your extraordinarily generous offer. I will send you a PM.

-Steve
 
1 - 20 of 23 Posts
Top