puck

And I'm not talking about me!

Okay, first off I have an '84 Corvette, automatic to be exact. I just replaced the fuel filter earlier today, it was a little clogged. I took it out for a spin afterwords, as I was sure it would fix the problem, but the car still bogs upon acceleration. At light acceleration it'll bog/hesitate. Anybody know where I should look? I pulled a few of the plugs, and they're fine.

Thanks,
-Steve

Red94Vette

Sticks his big nose in the post.

Ok here's the triangle rule here, you need all three to run smoothly "fuel, air, and spark". Too much or to little of any of those and it runs bad.

One or all of those is not right if it falls on it's face.

You need to pick one and go after it.

If you think it's spark, try new cap, rotor, plugs, wires

If you think it's fuel try fuel filter, clogged injectors (try the cleaner you screw on to your shradder valve and pull the fuel pump fues and vacuum line to FPR), You can hook up a gauge and watch your fuel pressure. Make sure there isn't any fuel leaking by your fuel regulator through the vaccum line, mine did this and it ran like crap. Maybe your fuel pump is going out, my brothers 96 Z28 just crapped out and it would fall on it's face and barely run. Pressure up your fuel rail with the engine off and see if your injectors hold pressure. If it falls then you have leaky injectors or a leak somewhere.

Air: You could have a vacuum leak, maybe a lobe went flat on your cam. :eek:

Just start eliminating what it could be.

Then you can have problems with sensors that will fall back to a fuel problem. If you have a bad O2 sensor, or bad TPS sensor. Check your TPS sensor voltage.

Check your base timing, make sure the dist. didn't move.

:smash:


[Modified by Red94Vette, 8:47 PM 5/30/2002]

bogus

fuel pump?

puck

I cleaned the throttle bodies today, and that seemed to help quite a bit. Now here's the question, when in park, if the car is given gas should the throttle body plates open? Maybe it was just because it was dark out, but I had my friend give it gas and I looked at the TBP [the plates] and they didn't move.

Thanks
-Steve

98NYFINESTVETTE

I would first check fuel pressure while the car is idling and then leave the gauge hanging out of the hood to watch while driving to see if drops. This I choose since it is to do and could be the problem. If this is not the problem I would check spark as mentioned by another member. You need three things to run (Fuel, Air and Spark). Good Luck

puck

Okay, latest update:

I took the car to work, and the car was running fine. It had a little hesitation upon acceleration just once, but the rest of the time was fine. I was getting good gas mileage too. However, on the ride home, I drove her back to my house and I parked her. My friend was leaving, so I pulled my car out of the driveway so he could get out. When I started her up, it idled about 700 then dropped to 400, tried to regain itself back to 600 and then died. I started it up again and it died immediately. Finally, after a hard start she started up idled a little goofy and then idled fine. I backed the car out and let my friend pull his car out, and then I put her in the driveway. I started the car again and it did the same dying bit.

Now here's a question, I just changed the fuel filter as well as cleaned the throttle bodies, they helped the bog/hesitation upon acceleration, but it now dies upon startup [I think it just wants to die upon startup when the engine is warm, but I can't confirm that until tomorrow when the engine is cool]. Is there anything that comes right to mind that might be responsible for the hesitation as well as it dying upon startup? It starts up after a couple of times and then runs fine. But then it'll bog a bit. I replaced the TPS about 4,000 miles ago. The plugs are fine, I just replaced the fuel filter and cleaned the throttle bodies. What else comes to mind?

Thanks
-Steve

ol,RJ

sounds like the fuel pump to me. If you've got over 80,000 miles its about due for a fuel pump anyway.
our vettes have to be one of the easiest fuel pumps around to replace.
RJ

kenfusion

Try the following:

1. Check the fuel pump. If you end up replacing go with one from an 85 and run full voltage (there is an inline resistor on the 84). If you decide to go with a better intake down the road you would nees to do this anyhow.

2. Check the distributer, especially thre Ignition Module. Also check the distributer for excessive play.

3. Check for vacuum leaks.

Feel free to e-mail me at kenm@austin.rr.com if you have any questions or need some advice.

Good luck!


:cheers:

puck

Thanks for the replies RJ and Ken. I'll probably be doing the '85 fuel pump sometime next week when I get paid [I'm a college kid, I live from paycheck to paycheck :)]. As far as the car goes, I started it up this morning no problem. Hmm, I wonder if it was just a bad batch of fuel. I'm going to do a fuel system clean and then get a new batch of gas and see how that does in the meantime. But that'll have to wait when I get back from work.

-Steve

Blueyednd

My 84 was doing the same thing. It was a combination of all the above listed items: not enough psi from the fuel pump, timing was off, TPS was off, throttle bodies dirty and needed to be reworked and a leaky fuel injector. It is in the shop right now having these items corrected. I should have it back in a couple of days. Luckily the shop I use also suggested the 85 fuel pump to help out with more flow. :chevy