SR20DET multiple problems (misfiring,bad idle...)

Thread in 'Technical Questions' started by DanielzZz, Aug 1, 2020.

  1. DanielzZz

    DanielzZz Member

    Apr 27, 2011
    Likes Received:
    Hi,everyone !
    I did a rebuild on my S14's engine couple of months ago.The engine had low compression on 3rd cylinder,turned out to be a cracked sleeve.Sent the block to a machine shop for new sleeves,crank polishing etc.The car had some problems before the rebuild,which are still present.
    First of all - if I let it idle for more than a minute,it won't rev past 3k rpm.I suspect it's the MAF,self-diagnostics didn't show any codes though.

    Second - engine is idling like it has some pretty aggressive cams.I didn't find any vacuum leaks.Before the rebuild I thought it was due to the low compression.Now I think it's something to do with spark,although engine runs good in higher revs.Again,self-diagnostics show no codes.I've tested the TPS and it's ok.

    Third problem started showing up after the rebuild.When I drive for a while (let's say 20kms),car starts misfiring(not bogging down,just sounds like it's running on 3 cylinders).I suspect this is a coil.Spark plugs are new OEM-spec NGKs,I haven't touched the gap.
    Engine is stock - I have an mbc,intercooler,air filter and an exhaust.I doubt there's even a remap.I run very low boost pressure(0.6bar),so I can see how the engine goes through the revs without going too fast.
    Only thing I haven't done is setting up the CAS with a timing gun.But I've left it on the old marks,so it shouldn't be causing those problems.
    Other things I've noticed - car had additional ground wires,which I didn't use.Judging by the work done by the previous owner/owner's mechanic,I don't think it's a good idea to put unnecessary sh*t.I prefer to solve the problem(if it even had one,car had some sort of "backfiring button",maybe he used them for that).All grounds are bolted on their stock places,except for the coil pack harness and the other one,that mount to a plate on the back of the head.I'm not sure,but I think I've bolted them on the back of the head,as the plate isn't present.

    Fourth problem is a mechanical one - sometimes when I start the engine there's a loud clicking noise.Sounds like a stuck lifter,but I've bled them all(twice on top of that),and I think I would've noticed if one of them was problematic.Could that be the famous VCT rattle ?
    Only mechanical alternation I did was dual guide shims,which are of course height adjusted.
    #1 DanielzZz, Aug 1, 2020
    Last edited: Aug 1, 2020

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