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Car vomits oily stuff out the exhaust


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'73 240 with stroker l28 running efi

Whenever I start the car and as it warms up, it sprays out black oil-like stuff onto the ground. Think of if you shot some black spray paint parallel to the ground, thats what it looks like. I'll have pics up later. I have the stock hose from the valve cover to the intake, all the smog stuff is removed. I don't know what the substance is. Of the friends I asked, they said water/condensation to fuel. It doesn't evaporate and it looks to thick and black to be water. Also, if some of you happend to see my post in the non tech section, yull understand the importance of getting this fixed ASAP. Thank you much folks.

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I would agree, water/condensation being mixed with exhaust gasses...my guess is you dont have a catalytic converter (I dont). Mine does the same thing after its been sitting for a while and I start her up.

 

Here's a test. Start your car, get it fully warmed up, and drive it somewhere like a parking lot or something. Give it a couple healthy revs and see if spits out any tail pipe soot. You could probably even hold a piece of paper behind the tail pipe if that helps you see it any better. If all you get is exhaust gasses after its fully warmed up, and dont have any noticeable exhaust spray on the piece of paper, then you can pretty much assume its just condensation in your exhaust getting sprayed out during start up. After its warmed up, it should go away. If not, then time to investigate further.

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Great minds T-Bone, I already tried that (against a wall, not with paper), and it is just gases, no solid-ish stuff. And yes I don't have a cat. So, in essence if I installed a cat it -should- dissapear? Or at least not paint the driveway black?

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Great minds T-Bone, I already tried that (against a wall, not with paper), and it is just gases, no solid-ish stuff. And yes I don't have a cat. So, in essence if I installed a cat it -should- dissapear? Or at least not paint the driveway black?

 

Sounds like it is running pretty rich. Are you using the choke for cold start? If so try and start without that. Also don't rev the engine while sitting there. Crank up and move along.

 

Does your tail pipe extension point straight out or down. Don't point it down.

 

Hope that helps.

 

Alan

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...I didn't know there was a choke for EFI. And yes, I start it, let it sit for about a minute or 2 and go, and the exhaust is straight.

 

 

Whoops, didn't the FI, just the '73 in your sig. It still sounds overly rich. FI engines do have cold start devices. You might look at the function of those items and check general state of tune.

 

Don't sit. Just go. It can warm up away from your "spot".

 

Alan

Edited by DrSideways
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I'll take a look into it. The mechanic I got the motor from said he was looking into a old style fuel controller. He described it as a small box with a few dials, for example dial 1 would be 2k rpm to adjust rich-lean. He said that would help with the richeness, but I'll see what I can do without that.

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My old '76 280z did the same thing. I also removed all the cold start and emissions stuff (what there was of it). The stuff out the exhuast appeared to be a mixture of water and soot from the exhaust pipe. My engine ran rich causing soot to build up in the pipe. I suspect yours is doing the same thing.

 

If it's really bad it could be a blown head gasket causing coolant to enter the combusion chamber, vaproize then condense in your exhaust. In that case your exhaust will smell like antifreeze.

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I don't smell coolant, but what you described sounds almost exactly like what my car is doing. I don't know if the cold start is on or not. It doesn't look to bad , but considering I havn't had this motor for a month yet I'm realllyyy hoping its not a head gasket.

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