LS1 low idle
Now the issue I cant figure out and it really bothers me is after Ive been driving it about an hour or so, usually ONLY a warm start (has never done it cold start I dont think), it will turn over and start, but idles WAY low, like 100 RPMs and works itself up eventually. It did it last year and would take a while to go up, but now it only does it when the engines warm and builds back up to idle pretty quickly.
Im thinking Fuel Issue. What are your thoughts?
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The first thing to check and fairly easy to diagnose fuel pressure issues is to connect a mechanical fuel gauge to the rail to check fuel pressure. Next is the fuel filter if you haven't been changing it regularly.
The fuel pressure should be close to 58 psi at idle. When you turn on the key it should bring the pressure up to 58 psi and stay there after starting. Note, this assumes the filter is clear and not contributing to the low pressure issue.
Your car is nearly 20 years. So can't expect the internal fuel pressure regulator to last forever.
If it is the FPR, you can either replace the internal in tank regulator and/or replace it with the C5 Corvette kit. The C5 filter is a combination filter/regulator. In either case you will have to remove the fuel module to remove the internal FPR.
If you opt for the C5 filter/regulator you still have to remove the internal FPR. You can't use both. Make sure to get a WIX C5 filter/reg kit. A Wix is reported to be more consistent in maintaining 58 psi than some other C5 brand filters.
Search this forum or YouTube for ways to remove the fuel sender module by dropping the tank or by cutting an access hole just above the tank to remove/repair the module internals.
I would consider replacing the pump too, if you replace the FPR, especially if you drop the tank instead of cutting an access hole. It's no fun dropping the tank without a lift and the tank is 1/2 full of gas.
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Also always when trouble shooting items, ALWAYS start with the easiest and obvious things first. NEVER try to reinvent the wheel when 99% of the time its something small, stupid and simple to fix to get the car back in good running and working order.
Good luck with your repairs and I hope some of this information is helpful to you.
Thanks
Jenni








