Post Cat Delete Tuning Advice Needed

Not sure if any single tool. But I'd recommend a CIS pressure gauge kit and a 5-gas analyzer, the last one will be pricey but it'll let you know exactly how combustion is going. A good vacuum gauge doesn't hurt.

CIS runs on pressure deferentials so it's critical that they are correct. Beyond that there's no specialty tools. WSM and the Bosch CIS Ferrari booklet.. good to go.

 

One readily available tool is your finger . On a US 1985, the first thing you should do is confirm/deny if the frequency valve is vibrating when the engine is running -- it should -- warm or cold. Your report of a low and lumpy cold RPM may be an indication that it isn't operating and someone (wrongly) tweaked it up warm with it not working -- so easy to rule this in or out.

Also, do you still have the O2 sensor mounted in the exhaust stream?

 

Once the control pressures are set and if the fuel distributor unit is properly set (even flow from all ports), then setting the mixture is down to the single screw. For that, I use an Innovate LM-2 wideband reader, with a wideband O2 sensor stuffed in each exhaust side. Image Unavailable, Please Login

In previous years I datalogged through the Innovate unit to watch the air-fuel ratios at cruising steady-state and accelerating, aiming for steady state to be just under 14.7:1 (Green box #1) and under full throttle acceleration to be around 12:1 (green box #2)

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This past winter I installed a new ignition system (Electromotive XDI from Nicks Forza Ferrari), as the original Digiplex boxes were not functioning properly, so afterwards I checked the A/F ratios quickly by hooking up the two O2 sensors in the tail pipes and holding rpm at a steady 4,000 rpm or so, simulating steady cruise rpm. A/F ratios on both sensors were about 14.6:1 that way. The LM-2 isn't good for reading A/F ratios at idle rpms because there's not enough exhaust flow to ensure the sensors in the exhaust tips are reading exhaust gas exclusively, there will be air mixed with the exhaust gas in the exhaust tips at idle speeds. At higher rpm, there's enough exhaust gas flow to ensure that the O2 sensors are only reading exhaust gas.

A single O2 sensor kit for the Innovate LM-2 unit is $479, the dual sensor complete kit is $669: https://www.innovatemotorsports.com/products/lm2.php

Cheers,
Gordon

 

All that sounds good for the FV.

Do you have a specific reason for disconnecting the CSI? Have you tried doing a cold start with it connected?

One other thing to check here is that the throttle idle microswitch is working correctly. When the throttle is released to idle, this idle microswitch switch (when closed) "tells" the injection ECU to limit the excursions of the A/F ratio that the FV is doing -- with such little airflow in a hard deceleration condition, the system would undershoot to too lean (if still in the "normal" operating closed-loop mode). Pin 2 of the throttle microswitch should be electrically connected to pin 18 of the throttle microswitch when the throttle is at idle:

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Do you have a copy of Service Bulletin 10-13 (Ferrari's written explanation of how their K-Jet with Lambda works)? If not, you can get a copy here:

https://www.dropbox.com/s/hk5gupwre678a5q/Service Bulletin 10-13 Bosch K-Jet with Lambda.pdf?dl=0

 

No, but you need to hold the housing and rotate the "D" center shaft section until you hear the "click" of the idle microswitch -- then measure the 2-to-18 resistance.

 

No. If you're sure that the FV and idle throttle microswitch are working correctly, you're up to confirming/denying if the mixture and airflows are correct. Things you can check:

1. At warm 1000 RPM idle, measure the voltage on the unplugged single wire of the O2 sensor = should be something like ~0.7V DC relative to ground (i.e., a little richer than stoichiometric). As you turn the mixture screw, you should be able to "swing" the voltage from ~0.2V (lean CCW) to ~0.9V (rich CW). These are very small adjustments -- 1/8 turn is a huge adjustment. And the access hole to the adjustment screw has to be blocked (like with a fingertip) to get a valid reading (i.e., you'd make an adjustment, remove the tool, block the access hole, then take the voltage reading).

2. At warm 1000 RPM idle, fully close the air bypass screw (note how many turns it was open) = the idle RPM should drop to something like 600~700 RPM. If it does, just reopen it to give the 1000 RPM warm idle again. If the idle RPM doesn't drop, the throttle plate at idle is too open. If it drops more than that, the throttle plate at idle is too closed.

3. At warm 1000 RPM idle with the O2 sensor plugged in, the voltage on the single wire should be "wandering" every couple/few seconds between the boundaries of ~0.2V (lean) to ~0.8V (rich) if things are working correctly closed-loop.

Good Hunting!

 

What exactly does this mean??????

 

It means somebody lost the small screw that seals the adjustment access port and just grabbed something out of a drawer. Pretty cheesy workmanship

 

It means that the car is not running closed-loop at warm idle (as it should). What does the voltage measure (on the O2 sensor side) when you unplug the O2 sensor (just unplug the single wire, not the 2-pin heater cable)?

 

On the O2 sensor side or on the injection ECU side?

Also, what happens to the voltage when you plug it in? Does it "wander" as it should between rich and lean?

 

The adjustment screw hole must be sealed to properly adjust the idle mixture.