only pulling 19"

[bigcrunch]

So my new to me 97 v8 AWD started with only 12" of vacuum, the cam position sensor was chewed up replaced it from my parts 96, new sparks, wires and Accel coil pack(used but check OHMs). Also replaced the PCV valve and did a smoke test to find intake leaks, none. Sucked a half of B12 chem cleaner thru intake vacuum port (small amount at a time) rest in tank. With the fresh tune up it pulls 19", with the AC on it goes to 17.5" at idle no codes but have not driven it faster than 5 mph.

Anyone have a suggestions were else to look?

 

[deweyville65]

Depends on where you live. At high elevation, 19" isn't too bad. My 96, 4.0 OHV with 150,000 on it would pull 20-21" in Omaha, Ne. I haven"t checked it here, at 4700 ft. If you live at sea level, 19" is a bit low.

 

[bigcrunch]

Near Atlanta Ga. GPS says 1100ft elevation. my 2000 mountaineer V8 does 21" sitting 5' from my 97.

Also checked fuel pressure it is 35lbs and timming chain has no slack check via rotating crank back and forth and finger on the cam position drive.

Just looking for some ideas,,,

 

[deweyville65]

Near Atlanta Ga. GPS says 1100ft elevation. my 2000 mountaineer V8 does 21" sitting 5' from my 97.

Also checked fuel pressure it is 35lbs and timming chain has no slack check via rotating crank back and forth and finger on the cam position drive.

Just looking for some ideas,,,

How many miles on the engine? I honestly would not be concerned about 19" vacuum at Idle.And the drop with the a/c on would not concern me either, after all the engine is working harder. If the engine runs smooth and drives without problems, I would just drive it. If I can remember, I will go check my 96 and see what it pulls at this elevation, and post what I find.

 

[rs2k]

Same issue here.

I was pulling 17, 15 with ac on before replacing the lower and upper intake gaskets egr gasket and a few vacuum lines. Recently (within a year) replaced cam sensor, plugs and wires. Now running at 19, 17 with AC on:

Truck runs just fine. Pulls just as well as my 2000 Mounty with a vacuum in the 21 - 23 range. (Don't remember exactly and don't have it here to test)

I think anything above 17 when warm with the AC off is considered healthy. The 19 reading might just be because the engine is showing little wear. How many miles do you have?

 

[bigcrunch]

the 97 v8 has 165k idles smooth in park and gear(after tune up), hardly any blowby check with PVC pulled and plugged warm. No leak down check, compression test 150-160 lbs.

the 00 v8 has 158k

 

[rs2k]

I think everything is fine then. I assume the vacuum gauge is steady? What kind of vacuum does the 00 pull?

 

[deweyville65]

How many miles on the engine? I honestly would not be concerned about 19" vacuum at Idle.And the drop with the a/c on would not concern me either, after all the engine is working harder. If the engine runs smooth and drives without problems, I would just drive it. If I can remember, I will go check my 96 and see what it pulls at this elevation, and post what I find.

So I checked my 96, 4.0 OHV with 160+k on the clock. Needs new rocker arms and push rods on the right bank. Pulls steady 17" at idle. Measured at the brake booster hose.

 

[bigcrunch]

the 97 v8 has 165k idles smooth in park and gear(after tune up), hardly any blowby check with PVC pulled and plugged warm. No leak down check, compression test 150-160 lbs.

the 00 v8 has 158k

2000 mountaineer V8 does 21"