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Discussion Starter · #1 ·
I just finished My hsr installation but i idles rough not running on all cylinders.
I changed Maf but nothing and iac and nothing , No trubble codes set. When logging i cant really see anything wrong.

Timing set at 6 dregres with est disconnected , all the plugs are working i tested everyone.

It seems to be à ingnition related problem, no vacumm leaks ,tested everything with starter gas and nothing.
Could there be something wrong with the distributor ( cleaned the cap inside and rotor)
or Did i install the camshaft sligty wrong?

I hope you got some suggestions
 

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Discussion Starter · #2 ·
I also tested all the injectors and they all showed 14,3 ohm so that sounds fine.
We adjusted the valves a second time just to be sure and the timing, its dead on 6 degres.
I also changed the prom to a custom made for this setup (used in a z28 with the same setup) still the same problem.
 

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This is how I cured the rough idle on my '88 coupe:

I had pulled the inlet manifold to re-do the leaky gasket and ditch all emissions fittings including cats. While the rocker covers were removed I adjusted the valves as per the Haynes manual, which says to take all lash out of the lifter and then tighten the nut holding the rocker arm another 360 degrees.
When I finally had the engine back together it would'nt idle below 1200 rpm. There was also a percussive detonation sound and I'd end up wearing ear protection as I vainly attemped to find the problem.

Replaced: CTS, Injectors, O2 sensor, plugs, checked and rechecked all circuits and timing.

Finally, at a total loss, I rotated the engine to TDC and then re-adjusted the rocker arms my way as I wound the engine around by hand and each valve set came up to TDC for the corresponding cylinder.

My adjustment was to back the nut holding the rocker arm right off, then re-tighten it untill all lash was taken out of the lifter. Then I would give the nut another 20 degrees tightening - not 360 degrees as per the Haynes manual.

So ofcourse when I had it all back together it started right up and idled beautifully.
 

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Discussion Starter · #4 ·
Im going to do à compression test, i guess that will show if any valves are not closing properly. I hope anyway.
 
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