LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

:confused: Help plz car is running crappy

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Old Nov 1, 2004 | 07:17 PM
  #1  
chuck95z28's Avatar
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:confused: Help plz car is running crappy

Okay the frist probelm. I think it might be hitting the rev limiter but i am unsure when i am at WOT it runs fine till it has to **** it sounds like it backfires and to shift i gotta take my foot off the gas for a second to allow it to shift. Any help on this would be great. The second probelm is it is running rich cause i can smell gas. Could my 02's be bad or would anything else cause this? If you can help i would owe you for ever
Old Nov 1, 2004 | 09:13 PM
  #2  
5.7LT1Formula's Avatar
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From: Berne, IN
Re: :confused: Help plz car is running crappy

take it to autozone or if u have a friend w/ a laptop and cables and scan for trouble codes.

when i had to let off the gas for my trans to shift from 2nd to 3rd...i bought a new/refurb. trans...check your fluid level..have you ever changed the filter?..just a few cheap things to try before buying a new trans..but i would scan 1st for error and trouble codes.
Old Nov 1, 2004 | 09:21 PM
  #3  
chuck95z28's Avatar
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Re: :confused: Help plz car is running crappy

its a brand new tranny i just checked the fluid but i will recheck it. do any lights have to come on to throw codes?
Old Nov 3, 2004 | 04:55 AM
  #4  
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Re: :confused: Help plz car is running crappy

Yes you could have a code without the SES light on. However, Autozone can not scan OBDI as is your car even though you have the OBDII connector.

If you are running rich at normal speed, your problem gets worse at WOT since the fuel is richened up even more at that point. The very first thing to do is smell your oil for gas. If so, you obviously have to take care of the problem before you drive it any more.

Check the vac line going to the fuel pressure regulator to see if it's wet. If so, you have to change the fuel pressure regulator.

If that appears to be ok, check the fuel pressure (you will need a gage) to see how fast it drops after the car is shut off. Get a gage with a hose so you can tape it to the windshield in the event you have to do troubleshooting while driving. You may also want to check for a dead cylinder by using a variety of methods.

I like to use an infrared thermometer. It will tell me if there is a dead cylinder by viewing a cooler exhaust manifold. Instead of the thermometer, you could use a spray bottle of water and watch how fast the water evaporates from the manifold. Another method is to pull one plug wire at a time and see if one does NOT change the way the engine runs when it is off. But wires are very hard to get too even if you have headers so that method is impractical. The other way to check is pull off an injector plug one at a time and see if the engine does NOT change in the way it's running.

NOTE: Just because you pull the injector plug and the engine does NOT change the way it's running, DOES NOT necessarily mean the injector is the problem. It only indicates the cylinder is not firing. The same goes for plugs.

Once you have that problem taken care of, you can then see if you still have a shifting problem. Take care of the problems you know first then move to the next unknowns.
Old Nov 3, 2004 | 04:06 PM
  #5  
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From: Edmonton, AB, Canada
Re: :confused: Help plz car is running crappy

When it had to let go of the gas to shift, it was cuz i was losing so much power at higher rpms (and backfiring) that i would probably not reach the shift point.

I had a plug wire that was burnt all the way through (causing a dead cylinder). Even after replacing that, i had backfire and shifting issues at WOT. That went away completely after i replaced my plugs.

Misfires were causing unburned gas to ignite in the exhaust. If misfires are happening to you, you should be able to feel them at WOT, you really cant miss it.

I wish I could give you a systematic approach like slowpoke
Old Nov 3, 2004 | 06:58 PM
  #6  
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Re: :confused: Help plz car is running crappy

Just curious what can casue your oil to smell like gas? and how do you go about fixing it? sorry dont mean to hijack the thread.
Old Nov 4, 2004 | 05:33 AM
  #7  
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Re: :confused: Help plz car is running crappy

Gas can get in the oil if an injector leaks, fuel can run past the rings into the crankcase. Or if the cylinder is not firing due to an issue other than fuel, it will also "soup". This is very critical that a "souping" issue be resolved right away. If a cylinder is not firing but still pumping fuel, the unburned fuel will wash the oil film off the cylinder walls and cause scratching of the rings, cylinder wall or even the piston.

The cause of the problem would then have to be found. For example if the cylinder has no spark. Usually a single cylinder with no spark is from plug or wire. If a leaky injector is found, it would have to be cleaned or replaced.

Last edited by slopokrodrigez; Nov 4, 2004 at 05:37 AM.
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