Knocking sound and disconnected hose, Help! - ZR-1 Net Registry Forums

MLC ZR1 · 2 Weeks Ago

90Z with 62k miles

Need expert help and insight after a plenum pull for a manifold vacuum line repair and fuel injector inspection. Once I got the car back it immediately developed a loud knock at idle (will attach audio) along with a bunch of other symptoms I'll list below. While inspecting the engine I noticed the Fuel regulator hose was disconnected from the regulator. Luckily, I took a video of the knock immediately after I got the car back and in the clip you can see its disconnected. I have images of it connected days before drop off. I just didn't catch it until now. Can this be the cause of all the issues im having with the car, I feel like the regulator has now gone bad as a result.

VIDEO - https://youtu.be/IFdDZnwwwf8

Since getting the car back while hose was disconnected:
-Strong fuel smell out exhaust after cold and hot starts
-Long start times, most of starts I have to hold for 5+ seconds before it starts, struggles to hold but doesn't die just sputters till RPMs rise enough, spits out large puffs of white smoke that smells like fuel from exhaust. RPMs shoot up to 2500-3000 then levels at 8-900 after about 10 sec.
- Knocking sound heard at idle, Knock subsides when giving it gas, but has died on me when doing this while the car is parked. The whole car shakes when the knock is present.
-Drives very sluggish and feels lean at times and rich at others (coming out exhaust)
-multiple backfires
-Poor fuel economy

Recent Work
All fluids and plugs changed to Marc's recs.
Original Injectors but all checked out ok and flow and ohm tested good.
Plenum pull with manifold vacuum line repaired and some gaskets changed.
Fuel pressure was normal during inspection at rail and held.
Fuel Pump and filter replaced in 2021 at 60k.
Battery replaced.
Transmission and clutch replaced 2021 at 60K, not sure if flywheel was done.

2 Weeks Ago	#1
MLC ZR1 Join Date: Aug 2024 Location: Florida Posts: 5	Knocking sound and disconnected hose, Help! 90Z with 62k miles Need expert help and insight after a plenum pull for a manifold vacuum line repair and fuel injector inspection. Once I got the car back it immediately developed a loud knock at idle (will attach audio) along with a bunch of other symptoms I'll list below. While inspecting the engine I noticed the Fuel regulator hose was disconnected from the regulator. Luckily, I took a video of the knock immediately after I got the car back and in the clip you can see its disconnected. I have images of it connected days before drop off. I just didn't catch it until now. Can this be the cause of all the issues im having with the car, I feel like the regulator has now gone bad as a result. VIDEO - https://youtu.be/IFdDZnwwwf8 Since getting the car back while hose was disconnected: -Strong fuel smell out exhaust after cold and hot starts -Long start times, most of starts I have to hold for 5+ seconds before it starts, struggles to hold but doesn't die just sputters till RPMs rise enough, spits out large puffs of white smoke that smells like fuel from exhaust. RPMs shoot up to 2500-3000 then levels at 8-900 after about 10 sec. - Knocking sound heard at idle, Knock subsides when giving it gas, but has died on me when doing this while the car is parked. The whole car shakes when the knock is present. -Drives very sluggish and feels lean at times and rich at others (coming out exhaust) -multiple backfires -Poor fuel economy Recent Work All fluids and plugs changed to Marc's recs. Original Injectors but all checked out ok and flow and ohm tested good. Plenum pull with manifold vacuum line repaired and some gaskets changed. Fuel pressure was normal during inspection at rail and held. Fuel Pump and filter replaced in 2021 at 60k. Battery replaced. Transmission and clutch replaced 2021 at 60K, not sure if flywheel was done.