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scan tool map vacuum reading

Posted: January 2nd, 2015, 5:55 pm
by rammit11
Hi, I was running a live data scan on my engine today and I have a question on what the value of hg. should be when on scan tool . I get a reading of 29.5 koeo and with the live data I see 10.5 with engine idling and does show a drop when revved, is this normal or should I be seeing more when running? I did a check on engine vacuum when I first started the engine at break in and was around 20".

Re: scan tool map vacuum reading

Posted: January 2nd, 2015, 9:11 pm
by IH 392
When I looked at my stock 4.0, '97, it showed about 12" with two different MAP sensors.