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So, since the car failed smog I decided to run through the L-Jetronics completely from start to finish. All going well up to the VVT testing.

Checking Function, engine off: the VVT engages

Checking function, engine on: VVT does not engage. (see included pics)
 

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86 Veloce
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If the VVT is not advancing it will not adversely affect your smog report.
 

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But Mad North-Northwest
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Actually the opposite. Emissions will be okay without the VVT engaging but you'll lose power.

But I don't know the answer to Mike's question. If it works not running it should work while running, right?
 

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Hmmm. Maybe you should re read my answer.....
 

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It is activated by throttle position anyway. Probably would never even get to that point during a CA smog check....
 

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You could look in the VVT inspection hole while the car is running and pull up on the throttle linkage quickly to see if it engages. I think the butterfly has to open to 45-55 degrees or something like that. Dont do it slowly or you will hit redline before it has a chance to engage...
 

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pulling on the throttle to see if the solenoid pops in/out, does just that, it tests the solenoid is operating....it doesn not test if the VVT operation.

to test the VVT itself is working, you remove that white plastic cap (on S3s), then, with engine idling, apply 12V to the two spade terminals on the solenoid (doesn't matter which way round) and hold it a few seconds....
if the car idle goes really rough and the engine almost stalls.....your VVT is working.
if it doesn't, it isn't.

(on the S4, which doesn't have that white plastic electronic gizmo on the end, you just remove the 2 wires, and test the same way)
 

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I guess that did need to be clarified.... now, what if the solenoid engages but the timing does not advance, what then?
 

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I guess that did need to be clarified.... now, what if the solenoid engages but the timing does not advance, what then?
then you look at the VVT on the end of the camshaft

some people have had luck cleaning oilway blockage with compressed air.
couple of diagrams (all from BB) here
VVT-3.jpg

VVT diagram colored.jpg

Mike (mcola) did us nice write up here
(good pics too of various parts) to finally get his working again...in fact it should be placed in the FAQ
how do you test the vvt mechanicals
 

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Nice info! Always wondered how the VVT worked, that sectional view speaks volumes. I have been thinking of just deleting the VVT function but I will check out these options. I may take it apart when I adjust lash in a few hundred more miles.
Thanks Dom, could never seem to get any info or answers on this magical device....
 

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The CO has to be adjusted at the airflow box.
 

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But Mad North-Northwest
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There is an idle carbon monoxide (CO) adjustment screw on the AFM. It's typically covered by a plug because you're Not Supposed To Fark With It.

It has nothing to do with the VVT, and unless you really, really know what you're doing you should Absolutely Not Fark With It.
 

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Yes. You are suppose to Fark with it. The CO is not self adjusting on these cars. Like it is on later ones.

It is covered with an aluminum plug to protect the adjusting screw from dirt and water.

Here are the pages from the shop manual.

Back in the day we used a Sun 75 CO tester. I now use an older innovate AFR to set the CO. You can get a conversion chart from AFR numbers to CO numbers.
 

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To really give you good advice on here. We need to know the numbers from the test. Also what state are you in.
 

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But Mad North-Northwest
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Jim, you know what you're doing, and you have access to a CO meter. For 99% of the people out there that's not the case, and that screw is not something that should be regularly touched. I mean, they used an aluminum plug that you need to drill out: that's sort of a clue! If it were just a dust seal they could've used a plastic plug like on the S4 AFM.

CO on the L-jetronic cars is in fact self-adjusting during closed loop running. You can verify this on an L-jet car by watching the sensor output at idle with a DVM. That's why you need to disconnect the lambda sensor to set CO per the procedure you posted, otherwise adjusting the screw probably won't do much until you hit the trim limits.
 
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