# Air Zenith Ob2 Relay Problems



## 03_uni-B (Sep 6, 2005)

So I am having some troubles with my system.

Installed just prior to SoWo and we problem free till just about 2 weeks ago. The AZ relay is causing some problems, first the compressor will stay on, running past my preset of 150psi, then the Elevel will go crazy kicking on and off. So for temporary measures I only plug the relay in when I need to fill the tank.


Also I have noticed this doesn't seem to happen all the time, I thought I had the problem fixed when I replaced the relay and went 3-4 days without issue then it happened again and the compressor kicked on randomly, the elevel restarted etc. 


Any ideas of the problem?


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## 03_uni-B (Sep 6, 2005)

I have it wired exactly like this. 










Only difference is I am only running 1 ob2.


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## Buck Russell (Feb 24, 2003)

How are your grounds wired?


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## 03_uni-B (Sep 6, 2005)

Buck Russell said:


> How are your grounds wired?


I'll give you a shout today if work doesnt get too out of hand.


But the one off the manifold harness and the on off the ECU both ground off the manifold like in that picture. Then the compressor and relay ground both go to that body ground on the inside of the rear quarter.


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## MechEngg (Jan 13, 2009)

Did you ground the manifold block itself to the frame?
Low voltage sometimes causes the ecu to start tripping out and will act like you just hooked up the battery (short compressor on stint for half second)


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## 03_uni-B (Sep 6, 2005)

MechEngg said:


> Did you ground the manifold block itself to the frame?
> Low voltage sometimes causes the ecu to start tripping out and will act like you just hooked up the battery (short compressor on stint for half second)


Thinking through it the manifold is mounted to the EXO mount which is mounted to the rear parcel shelf. Interestingly enough I pull the relay and operate normally without the compressor and havent had a problem with Elevel. So that's why I keep coming back to the compressor and relay.


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## MechEngg (Jan 13, 2009)

03_uni-B said:


> Thinking through it the manifold is mounted to the EXO mount which is mounted to the rear parcel shelf. Interestingly enough I pull the relay and operate normally without the compressor and havent had a problem with Elevel. So that's why I keep coming back to the compressor and relay.


Did you scratch the paint off of both the EXO mount and the parcel shelf? That might be causing the glitching and the de-powering of the ECU circuit which could in turn be turning the ECU on and off. Intermittent grounding is one of the hardest things to find


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## 03_uni-B (Sep 6, 2005)

MechEngg said:


> Did you scratch the paint off of both the EXO mount and the parcel shelf? That might be causing the glitching and the de-powering of the ECU circuit which could in turn be turning the ECU on and off. Intermittent grounding is one of the hardest things to find


I am going to just lengthen those grounds and run them to that body ground. If that fixes the problem with the compressor/relay I'll be perplexed. But worth a try for sure. Just strange because without the relay (disconnecting the compressor basically) I haven't had any troubles with Elevel. And I ran for ~3 months without issue, until now.


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## VirginiaBeachA4 (Mar 15, 2009)

If the ground is not strong enough, it acts as a resistance. Think of it like traffic on a four lane highway, then just becomes a two lane highway. Unplugging the compressor reduces the load on the circuit and the elevel doesn't need much amperage to operate.


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