90 Camaro running terrible
#1
90 Camaro running terrible
Hey guys I've been reading through these forums a lot and finally decided to post something. I need help! What happened to me is a few days ago I was sitting at a stop light when suddenly my car died and wouldn't start back up. So a few days later I got it towed back to my apartment and withing 5 minutes figured out that the kill switch went bad. (I bought the car that way..) So now thats fixed but the car is running absolutely terrible now and I just don't know why. I did notice however that one of the jets in the carburetor is just trickling while the other is spraying normally. My engine is a 305 thats been converted to a carb. I was thinking it was the fuel pump but now I'm not sure. Any suggestions as to what to look for would be greatly appreciated.
#2
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Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
Re: 90 Camaro running terrible
1st off, I'm betting your car is not carburated, it's a TBI unit - Throttle Body Unit - looks like a carb, but has 2 fuel injectors inside it.
2nd, the "jet" that is dribbling is actually a fuel injector, and it's bad - needs cleaned or replaced.
3rd - make sure you replace the fuel filter as well - it's time you did that.
2nd, the "jet" that is dribbling is actually a fuel injector, and it's bad - needs cleaned or replaced.
3rd - make sure you replace the fuel filter as well - it's time you did that.
#3
Re: 90 Camaro running terrible
No its an edelbrock 4 barrel carb, i know what I'm looking at.. My fuel filter was just replaced only 3 weeks ago. The guy i bought the car from converted it to carb when the fuel injector wires from the computer shorted out and he opted to take them out. Did a terrible job as well because he took to many shortcuts and now there is pretty much a rats nest of wires under my hood. But before the kill switch malfunctioned the car was running great now this..
#4
Supreme Member
Re: 90 Camaro running terrible
What circuit is the kill switch wired into? Is it possible that there is a poor connection in that circuit? How did the old switch fail? Did it burn up? maybe there is a short. If the PO did a carb swap, he also had to swap distributors from an EST unit to an early style HEI or some sort of non computer controlled unit. Check the wiring to the distributor. It may be hacked up and shorting out or not making a good connection.
As far as carburetion goes, the venturies shouldn't spray fuel at all with the throttle plates closed. All fuel should be coming from the idle jets below the throttle plates. If fuel is coming out of the venturies at idle, it points to a stuck float or excessive fuel pressure forcing fuel past the closed fuel inlet valves. Check fuel pressure with a gauge and verify it's between 4 and 7psi.
Just some ideas.
Edit: One more thing to check. The power valve in the Holley is rather delicate. If the engine backfired when it died, it's possible your power valve ruptured. Again, just a thought.
As far as carburetion goes, the venturies shouldn't spray fuel at all with the throttle plates closed. All fuel should be coming from the idle jets below the throttle plates. If fuel is coming out of the venturies at idle, it points to a stuck float or excessive fuel pressure forcing fuel past the closed fuel inlet valves. Check fuel pressure with a gauge and verify it's between 4 and 7psi.
Just some ideas.
Edit: One more thing to check. The power valve in the Holley is rather delicate. If the engine backfired when it died, it's possible your power valve ruptured. Again, just a thought.
Last edited by ASE doc; 04-15-2011 at 10:57 PM.
#5
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Car: '78 GMC Sierra Heavy 1/2
Engine: GMPP ZZ4 Q-Jet
Transmission: 700R4 Stage 2 w/Race Internals
Axle/Gears: 10 Bolt 3:42 Eaton
Re: 90 Camaro running terrible
I'd suggest you pull the airhorn and inspect the float bowl for debris
You can get replacement airhorn gaskets in a set of 5
I think the part # is 1499
You can get replacement airhorn gaskets in a set of 5
I think the part # is 1499
#6
Re: 90 Camaro running terrible
hey thanks ASE and yes the switch is wired directly to the distributor which is an accel HEI one. i checked those wires which go directly from the battery to the switch to the distributor. however the venturies you were talking about are dribbling when i pump the gas pedal with the car off. this is why I'm having trouble diagnosing because all the wires seem to be ok and I replaced the switch
#7
Supreme Member
Re: 90 Camaro running terrible
Okay, the fuel you see dribbling when you pump the throttle is from the accelerator pump. It should be a fairly good stream from both sides. The pump discharge will vary in strength and in length of time according to adjustment of the pump cam and the size of the discharge nozzles. I always start with the last thing done. Since the car ran well before the switch was changed, we have to assume that this is the cause of the problem. If it were the carb, it would be a real coincidence.
What year is this car? Did the PO use the original electric in tank fuel pump? Is it possible that the fuel pump was run off the same "kill switch" as the distributor?
What year is this car? Did the PO use the original electric in tank fuel pump? Is it possible that the fuel pump was run off the same "kill switch" as the distributor?
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#8
Re: 90 Camaro running terrible
No the PO switched over to a mechanical fuel pump. Today I had to drive my car anyways and it runs but still bogs down when the engine is cold and I give it throttle. It's also idling incredibly rough plus some lost power.. But today my toggle switch for my electric fan just fried. It started smoking out of no where so I'm starting to think I posted this in the wrong forum.. But I'm starting to think your right and when the kill switch shorted out this started all the problems..
Last edited by dmonsts550; 04-16-2011 at 03:47 PM.
#9
Supreme Member
Re: 90 Camaro running terrible
Check power to the electric choke. As soon as you can, switch control of the cooling fan(s) to an automatic fan control. Flexilite makes a universal controller that's inexpensive and works well.
#10
Re: 90 Camaro running terrible
Hey guys just thought I would update. I took the intake off the car because it was leaking a little bit and I thought coolant was getting into the engine but nope. It turns out that I have a leaking head gasket... There is so much sludge in my engine its not funny so I figured it would be best to just get another engine for my car. I was thinking of dropping a 350 in it this time.
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