95 LT1 rough idle
Thread Starter
Race Director
Joined: Jul 2000
Posts: 16,508
Likes: 2,399
From: Out Where the Buses Don't Run, Eglin AFB/ Niceville FL
2025 C8 Z06/7/E-Ray of the Year Finalist - Unmodified
2022 Corvette of the Year Finalist -- Modified
2021 C6 of the Year Winner - Modified
2020 C7 of the Year Finalist -- Modified
2020 C6 of the Year Finalist - Modified
95 LT1 rough idle
Need your help again. LT1 with new opti, plugs, crank position sensor, and starter. Car starts but will not idle. Will stay running if throttled up and sounds like its on all 8 but still rough. Could I be looking at bad injectors or possible fuel pump. I have not checked fuel pressure yet. I don't have much if any hands on with the LT1/4 cars. I went from L98 to LS1. Thanks for any and all help.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Make sure your ECT sensor in the water pump is connected and does not have any broken wires. This will cause engine to run to rich. This feeds the digital temperature indicator on the speedo and the PCM for fuel management. If your digital temperature shows a reasonable reading it's probably OK.
Bad idle can also be caused by a dirty throttle body or a bad IAC (idle speed motor). But would probably not cause a rough engine.
Check the EGR to make sure it's moving properly and closing.
And just on a wild hair, unplug the MAF connector and see if anything gets better.
Bad idle can also be caused by a dirty throttle body or a bad IAC (idle speed motor). But would probably not cause a rough engine.
Check the EGR to make sure it's moving properly and closing.
And just on a wild hair, unplug the MAF connector and see if anything gets better.
Last edited by pcolt94; Jul 14, 2019 at 10:11 AM.
Thread Starter
Race Director
Joined: Jul 2000
Posts: 16,508
Likes: 2,399
From: Out Where the Buses Don't Run, Eglin AFB/ Niceville FL
2025 C8 Z06/7/E-Ray of the Year Finalist - Unmodified
2022 Corvette of the Year Finalist -- Modified
2021 C6 of the Year Winner - Modified
2020 C7 of the Year Finalist -- Modified
2020 C6 of the Year Finalist - Modified
No codes surprisingly enough. Did find a bad fuel pressure regulator and bad EGR valve. The TB was pretty dirty so cleaned that was well. Won't get the new EGR until tomorrow as it was not in stock at any of the chain parts stores. More to follow.
UPDATE
Replaced the fuel pressure regulator and the car fires right up and idles perfectly. The new EGR valve will be delivered and installed today. Thanks for all the inputs.
UPDATE
Replaced the fuel pressure regulator and the car fires right up and idles perfectly. The new EGR valve will be delivered and installed today. Thanks for all the inputs.
Last edited by Tally Ho; Jul 15, 2019 at 12:06 PM.
Thread Starter
Race Director
Joined: Jul 2000
Posts: 16,508
Likes: 2,399
From: Out Where the Buses Don't Run, Eglin AFB/ Niceville FL
2025 C8 Z06/7/E-Ray of the Year Finalist - Unmodified
2022 Corvette of the Year Finalist -- Modified
2021 C6 of the Year Winner - Modified
2020 C7 of the Year Finalist -- Modified
2020 C6 of the Year Finalist - Modified
