Joshg

Has anyone heard of this problem where the DME will not activate varicam?

On my car bank 2 varicam is not working when tested with PST2, solenoid replaced and still not working.

logray

Someone had this problem with a turbo that the DME would not activate it. I can't remember what the outcome was but I think his issue might have been a bad solenoid.

As a sanity check, one of the things he tried was manually applying 12 volts to the solenoid, that might be a place to start to see if perhaps you have installed a bad replacement or to isolate wiring as the culprit. You should hear the car idle very differently if it is working, with the timing advance, and you should also be able to see the actual angle for the camshaft in bank 2 change whilst monitoring with the PST2.

dcdrechsel

What year is the car ? Are there any codes (cel) ?If I remember correctly -non US cars with DME 5.2 don't report bank 2 .If you have the workshop manuals please refer to setpoints .

logray

1998-9 5.2.2 Motronic does not report actual angles, only deviation values.

You need a DME 7.2 or later (MY2000) to monitor actual angles.

Joshg

Ok, yesterday I did some electrical checks as follows;

I checked for voltage at the DME between pins 25 (bank 1 variocam earth) and pin 54 (voltage supply to solenoids) and I get 12 volts when above 2000rpm which must be when vario cam actuates?

I also checked between pins 52 (bank 2 solenoid earth) and 54 (voltage supply) and i get the same 12 volts above 2000 rpm.

Next I disconnected both solenoid plugs and took the end that goes to the DME and wired up a simply circuit with a bulb between the 2 pins, I dis this for both sides bank 1 and 2. I started the car and proceeded to increase revs and at around 2000+ rpm both light bulbs were coming on at the same time.

Another test I did which is basically the same as above was to connect my old solenoid and rise the revs and watch the solenoid pin pop out. I did this for both sides bank 1 and 2.

For my next test I took the plug that comes out the solenoid and connected a motorbike battery to one pin then started the car. I then earthed the other pin which then actuated the solenoid as I could hear the revs change and the car idle funny. I then did the same for the other solenoid and exactly the same thing happened.

So I now think my variocams are both working ok so I have no idea why when my car is connected to PST2 bank 2 variocam wont activate?

Do these tests I have done actually confirm my variocam is working correctly?

logray

It sounds like it is working properly based on your description.

Going back to what year your car is, if it is 2000 or later I would use the PST2 to monitor actual angles.

Then rev the car and around 1500 to 2000 RPM you should see both banks rise to 24 degrees ish IIRC.

Here is a good post about the Variocam operation:

http://www.6speedonline.com/forums/996/205309-how-variocam-variocamplus-works-primer.html

Joshg

Its a 1998 so probably wont have those options on PST2.
Also as stated above non U.S cars don't have a camshaft sensor on bank 2 for some reason.

logray

Just curious not related to your problem, when you tested your old solenoid out of the car, did the pin come completely out of it or did it stop before that?

Joshg

The pin comes out about 1/4" when 12 volts is applied

logray

1/4" really??? I only got 1/16" (about 1.5 mm) when I just tested mine.

I've been meaning to do so since I've got my 3.4L apart for a valve job.

dcdrechsel

I don't know if this will help..........The Durametric doesn't report Bank 2 camshaft deviation with the dme 5.2 .I was concerned(having replaced lifters ,chains etc and retimed the engine) and checked with several very knowledgeable dme individuals .They all said that if bank 2 isn't working in very short order the cel will be on with codes .
Based on your other tests -no cel and I'll bet good power -it's working .

Joshg

sorry for the inaccurate measurement my solenoid pin does only come out about 1/16" just like your picture shows, I'm used to working to metric

Joshg

Problem is non U.S cars don't have a cam position sensor on bank 2 only bank 1 so if there was a problem with bank 2 I wouldn't get a cel.
Also my car isn't making good power its running about 25hp down.

Macster

While the CEL (DTC) for a non-existent bank 2 sensor would not appear likely another DTC would be recorded because the DME would attempt to compensate for the lack of proper cam timing by playing with the fuel injector pulse widths on that bank's injectors and it would likely reach some DTC triggering threshold.

When my 02 Boxster's passenger side VarioCam solenoid failed not only did I get a CEL with a DTC that pointed to the VarioCam solenoid but the short and long term fuel trims were widely separated with IIRC the passenger side bank short term fuel trim running around +6% while the driver's side bank running a bit on either side of 0% which based on my observations over time is something I've never seen before.

Later when I told the tech about this he confirmed it was the DME attempting to compensate for the failed solenoid.

BTW, if the solenoid is bad chances are high the actuator is too. The techs tell me their experience is almost always both are bad. This proved to be the case with my car. After the solenoid was replaced a short while after I picked up the car (in under 30 miles of driving) the CEL came back on again and IIRC the same error code appeared. The car went back and this is when I learned both items are replaced. But why I was not asked to ok this (which I woud have done based on the fact I trust the techs) I don't know. I do know I was not charged for the duplicate labor/parts/supplies required to replace the actuator. I was charged only for the parts and extra labor required to replace the actuator.

Anyhow, what I think happens is the solenid starts acting up and triggers either partially or completely the actuator over and over again which wears it out. Because the failure is intermittent and has a short event duration no CEL appears until the solenoid fails hard enough.

PST2 or PIWIS diagnostics are done which finds the solenoid bad but with a bad solenoid there is no way to verify the function of the actuator. It is only after the solenoid is replaced and the engine is buttoned up that the bad actuator (with a good solenoid now present) makes itself known.

Sincerely,

Macster.

Joshg

Thanks for your input macster. I never thought about the Dme adjusting fuel injection.

I don't think I understand why the cam timing would be out with a failed variocam though, doesn't variocam just retard ignition at certain revs for performance gains?

I would like to know what actually fails in the actuator.