Viair 10000 makes Wideband go lean

[geo53PSI]

I've been dealing with this issue for the past 3 days and cant quite seem to figure out the problem.

I recently installed the Viair 10000 ultralight on board compressor to use for boost control and occasionally fill the ET streets with air.

Wired up the Viair as per their instructions with 40 amp relay.

87 - To Air Compressor +
85 - Chassis Ground
86 - To Pressure Switch
30 - To Fuse and battery

Pressure switch to positive toggle switch .

Car is running an LM1 wideband wired up through the A/C.

LM1 is reading fine at idle while driving and in boost however, after the recent install of the Viair compressor and a quick idle test in the drive way; three seconds after the compressor turns on the wideband will go lean past 1.22 on the Lambda scale. Then even after I turn off the compressor it will stay lean until after I turn off the wideband and hit the battery kill switch.

Things I've tried -

Switching the compressor on from the battery as opposed to the toggle switch..Same result - Lean LM1
Checked volts at the battery when compressor comes on - Stays over 13.2 V
Plugged the 12V plug going to the LM1 into another car while the compressor turned on to make sure it was not due to voltage drop - Same result
Checked my wiring for bad grounds or spliced positive wires -all seem good.

Any and all advice is greatly appreciated at this point

LEANLm1.jpg

[matty b]

You say SPLICED wires. Wire your LM1 to the battery. Thats a voltage drop, dont care how good you think the wiring is. Ground and Poistive to the battery directly, nothing else. If you dont wanna do that, take your meter and probe BOTH positive and negative leads AT the LM1. Then turn on the the compressor. Bet you see a decent voltage drop. Checking voltage is once thing, checking it while under load is another. You also need to check the voltage on the ground side meaning you need to hook your positive lead to the battery itself and check the voltage on the ground wire AT the LM1. I've seen way too many instances of guys that think their wiring is okay and its total shit, not wanting to be offensive, but I bet yours is shit.

IF its not and everything is perfect, that compressor may be drawing too much current for your battery or charging system. You mind taking picks of your compressor install, or more importandly the wiring for it? I bet Ill find you the problem.,

[geo53PSI]

No offense taken, quite honestly I just want to find the issue and I do appreciate everyone's time and input.

That is correct, I looked for any wire that may have been spliced somewhere during installation, all the wire that I used is new. I thought that perhaps somewhere from the pressure switch to the grommet to the relay there may have been a spliced or cut wire.

Checked voltage on battery with my digital voltmeter while the compressor was both on and off, the lowest the battery went while the compressor was on is 13.2v, that was after the compressor was on for more than 20 seconds.

I agree with the LM1 needing to be installed straight to the battery, currently I have the plug for the LM1 installed to its dedicated toggle switch that gets 12V from my Quickcar Ignition Control Panel. The Control panel gets 12V from the battery Kill Switch.

However, to leave no doubt about whether or not the Wideband was suffering from voltage drop I did connect the LM1 12V plug to another car while the wideband sensor was still on the Camaro's Downpipe and the car was on. I then proceeded to turn on the compressor while both cars were on, same thing happened, went lean after a few seconds.

I am confident that in this test the LM1 was getting more than enough voltage to prevent the actual wideband from going as lean as it did.

I believe that the problem is not that the actual LM1 is not getting enough voltage, perhaps the compressor is drawing too much current and skewing the injector data?

I will take the wideband off tomorrow and see if it goes to 1.22 in free air while the car and compressor are on. I will also install the LM2 and see if it does the same thing.

Here are a few pics of the compressor wiring.PressureSwitch.jpgViair Wiring.jpg

[matty b]

What are the grounds for that sit right in front of the compressor?

[geo53PSI]

The grounds are for the Compressor and the Relay. I hit that area with the wire brush drill before install so it can make direct contact.

I also thought it was a weak ground initially so I tried running them both to the battery just to make sure and same thing happened. I even tried a different relay thinking the 40 AMP relay that was supplied was bad, but I had the same outcome.

[matty b]

The fact that the compressor is causing the issue makes me stare directly at the, you guessed it, the compressor. Those grounds are shit for a compressor, fyi. I will tell you afterwards, as I have a good idea of where the problem is, could you take a pick of your power distribution terminal? You said Quickcar so Im guessing everything is tied off one spot, actually, Im putting 100:1 odds it is but take a pic of it.

More or less, I dont think your wiring is as good as you think it is, but I wanna see first.

And Im not quite following the part with using anther car to run the compressor, or is it the wiseband? That I dunno about other than to say that you shouldn't use another vehicle to power components in an attempt to diagnose issues..

Assuming EVERYTHING is electrically sound, its a possibility that the compressor is applying air to components that could affect fueling. Other than your wastegate (Im assuming thats what you are controlling boost with), is anything else tied to the compressor tank like fuel pressure regulators or the like? More or less, you are applying air pressure to something or you have electrical issues. Can you run the compressor with nothing hooked to it and see what happens? That will isolate air pressure from electrical and should lead you in the right direction.

[geo53PSI]

Got it figured out! Rookie mistake on my part,was one of those moments.

When you mentioned the possibility that the compressor was applying pressure to anything, it turned on a light bulb.

Before adding the compressor I had a bleed boost control on, it was hooked up to the side port of the gates. As you can imagine when the compressor would turn on and apply positive pressure to the bottom port, the gates would open completely and the wideband on the downpipe would read lean at idle.

I turned on the compressor with the car on and bled the air at the regulator to keep it from sending any air to the wastegates and the A/F stayed correct.

Just have to setup up the pressure lines from the regulator to the wastegates correctly and all should be good.

[matty b]

Got it figured out! Rookie mistake on my part,was one of those moments.

When you mentioned the possibility that the compressor was applying pressure to anything, it turned on a light bulb.

Before adding the compressor I had a bleed boost control on, it was hooked up to the side port of the gates. As you can imagine when the compressor would turn on and apply positive pressure to the bottom port, the gates would open completely and the wideband on the downpipe would read lean at idle.

I turned on the compressor with the car on and bled the air at the regulator to keep it from sending any air to the wastegates and the A/F stayed correct.

Just have to setup up the pressure lines from the regulator to the wastegates correctly and all should be good.

Good to hear. I would still use something better than a self tapping screw for the compressor ground. I have good luck using rivnuts set for a 10/32 screw and use that for smaller grounds and use 1/4 bolts for heavy stuff.