3rd Gen / L98 Engine Tech 1982 - 1992 Engine Related

305 TPI Rough running questions

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Old 06-06-2011, 01:23 PM
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305 TPI Rough running questions

I took the car out of winter storage and drove it around for a bit, perfect idle and lots of power. After sitting for a few hours the car was idling rough and the tach showed no rpm's the engine had reduced power and I can smell raw fuel. After a few minutes of driving the tach started working but still rough idle and reduced power. I pulled the spark plugs and all looked fine, I replaced them anyways. While it was idling I wiggled the wires and nothing changed.

What and how do I check wires and distrubutor for problems. I'm pretty sure it's not a computer problem but I can't rule it out.
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Old 06-06-2011, 10:41 PM
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Re: 305 TPI Rough running questions

First of all more info would be great. What kind of car. Camaro/Firebird or another car that a 305 TPI has been transplanted into it. I'm thinking a firebird based on your user name.
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Old 06-07-2011, 12:27 AM
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Re: 305 TPI Rough running questions

Firebird is sold. It's in the porsche. 1986 305 not sure about what kind of car it was originally intended for.
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Old 06-07-2011, 01:30 AM
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Re: 305 TPI Rough running questions

Bad gas from sitting over winter.
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Old 06-11-2011, 10:30 AM
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Re: 305 TPI Rough running questions

Could be bad gas but I used stabil.
I replaced all the spark plugs and wires with no change. It does sound like it's only 1 cylinder not firing though. The left exhaust sounds fine but the right one sounds rough and smells like raw fuel.

It has a full tank, how much damage am I risking by driving the car til it's empty then filling up again so there is fresh gas in it?
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Old 06-11-2011, 12:57 PM
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Re: 305 TPI Rough running questions

I bought a firebird with a tank of bad gas and I was told by the mechanic to just drive it out. The night I bought it, it ran so weak I popped the hood and one of the manifolds was glowing orange. Sure enough it was just a bad tank of gas.

The gas might be so bad that stabil doesn't even affect it. I'd stay around your neighborhood and drive it there or let it idle in your driveway until its gone. Or syphon it out?

Get that gas out of the tank to eliminate that if its something else.
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Old 06-11-2011, 11:28 PM
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Re: 305 TPI Rough running questions

So I ran a half tank out of the car driving all day, it's just too damn good on the mpg. Once it got up to temp on every shift there was a backfire out the right muffler. I really don't think it's bad gas.
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Old 06-12-2011, 02:39 AM
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Re: 305 TPI Rough running questions

You said its an 86. Does unhooking the maf change the way it drives? Do you have access to a scanner?

What I would do is run the tank dry and fill it up. See if it improves. Then I'd do a full tune up. Wires, coil, distributor cap, MAF relays go bad and are cheap to replace.

Report back when you get a new tank of gas in there.
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Old 06-12-2011, 11:02 AM
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Re: 305 TPI Rough running questions

I don't think it has a maf. here is a picture of the engine, you can't see the whole intake but it's just a tube. https://i.imgur.com/L2V0l.jpg
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Old 06-12-2011, 07:00 PM
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Re: 305 TPI Rough running questions

You can see the Map sensor on the side of the plenum. In Fbodies that would be on the passengerside. I can't tell how the motor is positioned in the porsche. That means its not from an 1986, but from a 1990-1992. MAF cars were 1985-1989. That doesn't point to anything, but if someone gave you a 1986 computer wiring harness with a Speed density motor, that will be a big part of your problem.

I assume the check engine light on your dash works in conjunction with your computer? If not, you need to see what codes are possibly popping up.
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Old 06-12-2011, 07:08 PM
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Re: 305 TPI Rough running questions

If you are talking about the probe sticking out, thats the driver side. The engine is facing the same way it normally would be in a Fbod but it's in the back of the car. Your right shoulder would be where the bend in the intake is. The car has been running fine for years, just now has it started to act funny
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Old 06-12-2011, 07:15 PM
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Re: 305 TPI Rough running questions

Are there any codes that pop up?

No the little black box on the passenger side right behind the back runner tube. That is the MAP sensor. The probe on the driver side is merely there to hold a tie down bracket for the the throttle and TV cable to stay in place. Looks like you had bracket made.

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Old 06-12-2011, 10:18 PM
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Re: 305 TPI Rough running questions

That's not a 1986 motor because of the map sensor as stated above. Unless someone took an 86 motor and a 90-92 plenum and put them together.
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Old 06-12-2011, 11:46 PM
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Re: 305 TPI Rough running questions

I was told it was an 86 motor but it could be just about anything because it was never actually in a car. Lets just say it was supposed to be destroyed but never made it to the dumpster.
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Old 06-13-2011, 10:45 PM
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Re: 305 TPI Rough running questions

Originally Posted by Nick's WS6
I was told it was an 86 motor but it could be just about anything because it was never actually in a car. Lets just say it was supposed to be destroyed but never made it to the dumpster.
Not sure what you mean by was supposed to be destroyed, but who cares, another TPI motor still in service. Put's a smile on my face no matter what car it's in. Sorry no further help at this time.
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