90 Renix Running Real Rich

Hey y'all I got a 90 4.0L 5speed xj that is running super rich, I just got it about a week ago so I don't know much. It seems to be idling fine and drives what seems to be great but I noticed inside the exhaust is black.. and I mean black. If idling and I give it some throttle it'll blow a bit of black slightly blue smoke out of it. Also I put my hand up to the exhaust and small black specks end up on my hand. I put some sea foam in her today so we'll see how it goes tomorrow.. but till then what do y'all think? Its EGR Valve is deleted, has MSD Ignition, MSD coil blaster and MSD distributor&plugs also has a Edelbrock cowl intake. Oh and previous owner removed the vac canister and went from closed to open coolant system. Thanks everyone


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Start with the basics. Is there a misfire? Is the o2 sensor working? It may be fowled.


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I haven't noticed misfire symptoms but the o2 sensor could be a culprit. This is my first vehicle so I don't happen to know all the quirks like y'all do.. I've seen a website on how to test multiple sensors on the renix's one including the o2's so I will try to test that tomorrow..


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Can you post up some pictures or picture links of various sides of the engine bay? Check your PMs here too. I wonder what else the PO changed and is missing?

90renixxj said:

I haven't noticed misfire symptoms but the o2 sensor could be a culprit. This is my first vehicle so I don't happen to know all the quirks like y'all do.. I've seen a website on how to test multiple sensors on the renix's one including the o2's so I will try to test that tomorrow..


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Renix uses an air charge sensor mounted on the intake just to the rear of the throttle body. They can cause it to run way rich, as can a bad MAP. Either one can be checked with a multimeter.

old_man said:

Renix uses an air charge sensor mounted on the intake just to the rear of the throttle body. They can cause it to run way rich, as can a bad MAP. Either one can be checked with a multimeter.

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That is the 3rd or 4th name of that sensor I forgot. How many names does it have?

MAT, IAT, ACS and I think there may be a fourth LOL

Hey y'all sorry just got off work. I will post a engine bay pic and test that in the morning as it's dark here in Canada now


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