Vortecs are very sensitive to fuel pressure. Anything less than 60 PSI will give you issues, and you really need 62 PSI for the engine to be happy. With the demands of a 383 stroker, fuel pressure will also be important.
Pls help! Acceleration problem!
- Thread starter Jesusv132
- Start date
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Thanks for the replies! Im going to be doing some work on it tomorrow and see if i can get this issue fixed!
Keep us posted on what you find.
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Don't need OBD-II to verify short- and long-term fuel trim.
1. Connect a fuel pressure gauge, see what the pressure is when you stab the gas pedal.
2. Connect a REAL scan tool, see what's in the data stream, especially when you stab the pedal.
Initial impression is low fuel pressure, or high resistance in the secondary ignition, (I'd like to have a look under the distributor cap!) or a weak ignition coil. But there's other things it could be. Diagnose first, replace parts second.
ArmourofGodEphVIXI
Newbie
After reading the post I'm shocked no one mention the EGR valve if the engine was built with one. If this is something that just showed up I would point at a sensor going somewhere. With the EGR sensor not allowing the valve to open at the correct time the mixture of fuel and air would be screwed up. Possibly allowing the unburned emission gases to mix with the air that is supposed to be going in with the fuel. Thus, choking it out when a lot of fuel is introduced at one time. In a pinch you can take the vacuum line off the ERG valve and plug it with a golf tee. That's how I was running around until I fixed my issue with it. It will smell like you're running rich if you have to do something like that. The description of your issue would make me go after an electrical component before thinking it could be mechanical. Even though I realize it all works in tandem.
There is no EGR sensor.
Exhaust gas is essentially inert as long as the engine isn't misfiring. It doesn't really change the fuel/air mixture, although it does dilute or displace it.
If the valve ISN'T opening, how do the "unburned emission gasses" get into the intake airstream?
RawbDidIt
I'm Awesome
Agreed. EGR would fail one of two ways. Either it's not in the correct position as the ECM engage or disengages the valve. This would throw a code, easily read by a scan we previously recommended. The other option is the diaphragm failing causing a vacuum leak, which would be found in the vacuum test we recommended earlier. The former would only be evident intermittently as during normal operation the EGR valve is supposed to closed during warmup and intermittently after warmup depending on environmental factors and catalytic converter temperature. The description sounds like it's a regular occurrence now, which would point to vacuum leak IF it's EGR related. First things first, test broad, narrow it down to particular systems once you have a direction to go. I agree, it's likely sensor related, but which sensor? The cheapest and quickest way to reliably know is to test and diagnose.
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It was a tps sensor!
Glad you found the problem. Nice sounding 383 by the way.
