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engine compression test for backfire

nothinbutroad

Member
Joined
April 29, 2012
Messages
19
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0
City, State
Grand Terrace
Year, Model & Trim Level
1991 ford explorer
my 1991 explorer has been backfiring, so on the advice and the good people on here i did a compession test, the results are as follows
c1=130
c2=130
c3=145
c4=150
c5=140
c6=140
20psi difference between high and low and i didnt see the needle lose pressure so i dont think i have a leak, is that acceptable?

also the neighbor seen me workin on my truck and took a look, he said the map sensor should have a hose on the nipple, the old 1 didnt have a hose on it, and everything i looked up online shows no hose attached to it, just the wiring. should it have a vacuum line or just be open like i have had it?
 




arco777

Elite Explorer
Joined
April 6, 2008
Messages
2,407
Reaction score
55
Year, Model & Trim Level
1994 Explorer 2dr 4x4
There would only be a hose on the MAP sensor if it was a Speed Density setup. The Explorer is Mass Air so no hose required - reference is atmosphere.

Sounds like your compression numbers are fine.
 




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