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View Full Version : Does 195 psi in all 4 cylinders mean engine was rebuilt? 220k on the van



Headhunter38
08-29-2021, 04:20 PM
Like the title says, all 4 measured 195 psi with a compression test. The previous owner seemed to think it had been rebuilt by one of the other previous owners because it did not leak or burn any oil even with 220k on it. he didnt know for sure and just thought it might have been rebuilt because of that. My van failed CA smog test twice, high nox and hc. We decided to do a compression test just to see where the engine health was at since we were checking the spark plugs gap. I was surprised to see that it measured so high since the service manual said 175psi was the normal.

Hammervan
08-31-2021, 10:28 AM
195 seems suspiciously high; I think even a new engine of this type would typically be more like 185. Was the engine warm when it was checked? My van's compression (with 280+ miles on original engine) runs around 160.

I'd check your ignition timing. I have to retard my ignition timing a few degrees to pass emissions these days. Last time I failed on HC at 251 but passed with 62 just by changing timing. It has no power in its retarded state and can't even get up to freeway speeds so I have to reset it to spec after I get through emissions.

MarkH
08-31-2021, 05:49 PM
I think the only way of having high pressure other than a defective gauge is lots of carbon build-up on the piston top and head, reducing the volume in the cylinder.

boogieman
09-02-2021, 11:21 AM
ive never had two air pressure gauges read the same, but if it was rebuilt, maybe the head was shaved a bit too much..the higher compression could be causing the high nox and hc figures....make sure the egr is clean and working properly too. theres a good thread 'passing cali smog' on this site...good luck