Stall After Valve Adjustment (Page 1/1) ANAM427 DEC 28, 10:15 PM Just completed a valve adjustment on a 3.4 (re-manufactured engine) and now it will not idle and stalls. It fires right up but as the RPMs come down to normal idle, it just dies. If I flutter the throttle, it takes a lot of effort to keep it running. If I put the ALDL connection in diagnostic mode, if won't even start. To set zero lash, I use the rotation method, determining zero lash at the point I begin to feel resistance (with each valve in the correct position for doing this). After zero lash, I turned the nut 1 3/8 of a turn for each. I decided on 1 3/8 of turn as there seems to be no consensus on whether 3/4 turn or 1 1/2 is correct so I choose in the middle. Though there is the possibility that I did not connect something while reassembling the top end, what could cause this idle issue? Perhaps 1 1/2 is correct and my cylinders are not getting enough air with the current 1 3/8 turn? As always, thanks Fiero community! Patrick DEC 28, 11:55 PM quote Originally posted by ANAM427: After zero lash, I turned the nut 1 3/8 of a turn for each. I decided on 1 3/8 of turn as there seems to be no consensus on whether 3/4 turn or 1 1/2 is correct so I choose in the middle. Though there is the possibility that I did not connect something while reassembling the top end, what could cause this idle issue? Perhaps 1 1/2 is correct and my cylinders are not getting enough air with the current 1 3/8 turn? I posted the method I used for setting 2.8/3.4 valve lash Here. I researched it quite a bit beforehand, and 1-1/2 turns of the rocker nut past zero lash is correct for this engine (and not to be confused with the different setting for a small block Chevy). Having said that, if you found zero lash properly for each valve, then the 1/8 turn extra you didn't do wouldn't cause any of the issues you're experiencing. I suspect something hasn't been re-connected during the re-assembly after the lash setting. Was this engine running smoothly prior to the lash adjustment? Any codes stored? pmbrunelle DEC 29, 12:01 AM quote Originally posted by ANAM427: To set zero lash, I use the rotation method, determining zero lash at the point I begin to feel resistance (with each valve in the correct position for doing this). The increase in resistance is very minimal when the lash is taken up. A lot of folks tighten past zero lash without realizing it. The rotation method isn't reliable for me. Instead, I wiggle the pushrod end-to-end, and I find zero lash that way. Are you experienced at finding zero lash using the rotation method? quote Originally posted by ANAM427: After zero lash, I turned the nut 1 3/8 of a turn for each. I decided on 1 3/8 of turn as there seems to be no consensus on whether 3/4 turn or 1 1/2 is correct so I choose in the middle. The real answer is that it depends on the specification of the lifter. The lifter's plunger is supposed to be pushed in a certain amount (specified by the lifter manufacturer). Then, knowing the rocker ratio, and the pitch of the adjusting stud thread, the correct number of turns is determined. On my own Fiero, the adjustment works out to 5/8 turns of rotation after zero lash. But I would not say that it should apply to all. Since your engine is remanufactured, it seems like the engine remanufacturer should have the information. lou_dias DEC 29, 01:25 PM If you disconnected the battery, it's probably not idling because the IAC needs to be calibrated again. Take it for a drive over 35mph and then shut it off and start it up again. It should idle fine. Pyrthian JAN 02, 02:02 PM quote Originally posted by lou_dias: If you disconnected the battery, it's probably not idling because the IAC needs to be calibrated again. Take it for a drive over 35mph and then shut it off and start it up again. It should idle fine. yup. start with the easy ones. IAC, Timing, Fuel Pressure as to the lash - endless answers. but - thats why hydraulic lifters are used - they take up the slack. as long as what you did was consistent, you'll likely be OK. finding zero lash is all feel, and things feel different on the first one vs the last one. you kinda get used to it. but, if its not sounding like a sewing machine, or loosing compression due to not fully closing valves - usually accompanied by shooting flames out intake or exhaust. also, to be fancy - you can get the finger gauges, and actually measure the amount the piston gets pushed in.