Cold idle poor

I had a similar problem on my 86.
It turned out to be the air sliders.
Not sure if your 87 has the same set up as mine is mechanical fuel injection.

 

When you say:

Does that also mean that you:

1. Adjusted the mixture screws at warm idle with the O2 sensors unplugged (with the new working Protection Relay in place) to values of about 0.6~0.7 VDC (slightly rich) relative to ground? You should also be able to manually "swing" the unplugged O2 sensor outputs from lean (0.1~0.2VDC) to rich (0.8~0.9VDC) by turning the mixture screws. Not being able to do this is a clear sign of a serious problem somewhere.

and

2. Confirmed that the O2 sensor output voltages (after the step 1 adjustment), when plugged in at warm idle, both do "drunkenly wander" every second or two from/between the lean boundary (0.1~0.2 VDC) to the rich boundary (0.8~0.9 VDC) relative to ground? This is an important check that the EHAs are working, as the EHAs are what are used to add enrichment for cold-running.

PS That better be inches of Hg (Mercury) vacuum

 

Yes, at warm idle with the O2 sensor single output wire unplugged but connected to your DC voltmeter. Leave the molded 2-pin connectors for the O2 sensor heaters plugged in. The single wire from each O2 sensor is the output wire (label everything carefully -- do not get things swapped).

 

@bpcurtis
https://www.ferrarichat.com/forum/threads/wurs-for-86-euro.660782/

 

1/2 to 1 turn is a huge adjustment of the mixture screws -- something like +/- 1/8 turn (or even less) should go from full lean to full rich. If those O2 sensors are working, the 0.035V is very lean, but the 0.60-0.64V value isn't bad. However, even if the injection ECUs are dead, turning the mixture screws should swing the output voltages of the unplugged O2 sensors. Also, when the O2 sensors are unplugged at warm idle, the injection ECUs will do nothing -- they will just set their EHA current to a constant 10mA (at/near sea level) regardless of where the mixture screw is set.

Are you able to turn the mixture screw of a bank CCW (lean) until that bank obviously stops running, or runs super badly, then turn the mixture screw back CW until it starts to run well? And the air hole to the mixture screw always needs to be plugged, like with a finger tip, when making an O2 sensor voltage measurement or judging the engine's operation.

 

That large, male hex screw is the air bypass screw. The mixture screw (a 3mm female hex) is inside the airflow metering device and has a threaded screw cover that must be removed to access it, and the threaded screw cover has a security (anti-tamper) cap that isn't easy to remove (typically need to drill a short, blind hole into it, drive a sheet metal screw into the blind hole and then pull on the added sheet metal screw to remove the security cover -- maybe you will be lucky and the security caps will have already been removed).

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A cross-section (of a K-Jet, but KE-Jet is the same for the mixture screw -- the note in the figure is from another thread where the OP was missing the threaded cover screw) showing how the mixture screw is down inside the airflow metering device:

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When you remove the threaded cover screw to get access to the mixture screw, that is the "access hole" that needs to be plugged to get a meaningful measurement from the O2 sensor.

Have you read (and looked at the figures) in Chapter D of the TR WSM? Especially pages D61-D016 that cover the US "with Lambda" system.

 

That make things easier. Probably aren't many TR out there now with the anti-tamper plugs still in place.

This link:

https://www.dropbox.com/s/18bidr3sgbofytb/Workshop Manual Testarossa Supplement Catalytic Converter D61-D106.pdf?dl=0

will get you a copy of TR WSM pages D61-D106 covering the TR KE-Jet with Lambda system.

As far a physically making the mixture adjustment, K-Jet and KE-Jet are about the same -- just, on K-Jet, you need to make sure the WUR is working correctly before doing the mixture adjustment; whereas, on KE-Jet, you need to make sure the Protection Relay is working correctly before doing the mixture adjustment.

 

+12V being present on the red wire at the Y-pipe water thermoswitch during starter motor cranking and engine running (you initially wrote that you had already confirmed this is OK).

It's just the preliminary check before attempting mixture adjustments -- i.e., if no +12V there, you've got to fix that first. If there is +12V there, that doesn't confirm that everything is working. The final check is to measure the O2 sensor voltages when plugged in at warm idle (after you get all done with the mixture adjustments with the O2 sensors unplugged):

If the O2 sensor voltages are properly wandering drunkenly between the lean and rich limits = that confirms the Protection Relay, the injection ECUs, and the EHAs are working.

If the O2 sensor voltages just stay quasi-constant like when unplugged = some problem elsewhere.

 

Never heard of that. AFAIK, the stock screw plug is a slotted-head, steel screw:

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I'd add that any fastener with a 6mm female hex drive is going to have a much larger thread size than the stock screw plug (so seems like someone's done some serious changes). The good news is that, worst case, you could use a simple rubber plug to close the hole if things go really bad getting the existing plug out. Can you post a photo of it similar to the one in post #14?

 

As you indicated, a new O2 sensor isn't expensive to try, but you should be able (with the O2 sensor unplugged) to go CCW (too lean) to obvious bad idle running and then CW (too rich) to obvious bad running -- if you can't do that = I'd think that that bank isn't even running at all at idle. (Do keep track of amount of turns so you can know where you were and where you've been.)

 

i'd swap o2 sensors and see if the sensor gets a reading on the bank.

 

When this happened to me, it was caused by a broken wiper arm inside the air metering unit.

Here’s the thread: https://www.ferrarichat.com/forum/threads/ke-jetronic-potentiometer-trouble.657524/
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