m.a.p. sensor question

[smslyguy]

what is the stock m.a.p sensor's supposed to be reading while at cruising speed. Should i be reading around 70 k.p.a on my m.a.p while at cruising speed? Also on my stock 2000 gmc the L.t.f.t. are around 15 to 22%. Is this typical for these trucks?

[joecar]

Post some log files.

[smslyguy]

here is one with the map sensor reading what i thought was high just for cruising speed, observe that even at an idle the map is at around 35 kpa.

[joecar]

35 kPa for idle is normal.

70 kPa is normal for cruising along the highway at 2300-2500 RPM.

The MAP graph should follow the TPS graph, but with the peaks more "intense" (i.e. when you open the throttle an appreciable amount (say 50%) for a sufficient amount of time (a few seconds or more) the MAP will rise up to barometric pressure.

Looks kinda normal to me... but checkt it out with a vacuum hand pump (e.g. Mity-Vac):
[you seem to be at elevation where BARO is about 100kPa...]
0" vac -> MAP should say ~100kPa (~15psi)
10" vac -> MAP should say ~67kPa (~10psi)
20" vac -> MAP should say ~33 kPa (~5psi)
30" vac -> MAP should say ~0 kPa (~0 psi )[this may be hard to with the hand pump].
If you get MAP values that deviate appreciably from those, then the MAP may be faulty, otherwise the MAP is goog, and you may have an airleak...

Hmmm.... (see your other thread).

LTFT's going that much positive is an indication of an airleak between the MAF and the NBO2's (too much air, so PCM has to trim positive)... check the following:
- PCV plumbing leaking;
- Intake manifold leaking (underneath);
- EGR plumbing leaking;
- Exhaust manifold leaking;
- Exhaust/catalytic leaking near O2 sensors (upto 8-12" after the O2's) [check the catalytic's front pipe weld/seam, sometimes it separates].

Could also be an indication of injectors sticking and not spraying properly (not enough fuel, so PCM has to trim positive), or insufficient fuel delivery (clogged filter, crimped/bent fule line (especially the nylon lines), bad voltage/ground connection to pump, worn out pump).

[smslyguy]

35 kPa for idle is normal.

70 kPa is normal for cruising along the highway at 2300-2500 RPM.

The MAP graph should follow the TPS graph, but with the peaks more "intense" (i.e. when you open the throttle an appreciable amount (say 50%) for a sufficient amount of time (a few seconds or more) the MAP will rise up to barometric pressure.

Looks kinda normal to me... but checkt it out with a vacuum hand pump (e.g. Mity-Vac):
[you seem to be at elevation where BARO is about 100kPa...]
0" vac -> MAP should say ~100kPa (~15psi)
10" vac -> MAP should say ~67kPa (~10psi)
20" vac -> MAP should say ~33 kPa (~5psi)
30" vac -> MAP should say ~0 kPa (~0 psi )[this may be hard to with the hand pump].
If you get MAP values that deviate appreciably from those, then the MAP may be faulty, otherwise the MAP is goog, and you may have an airleak...

Hmmm.... (see your other thread).

LTFT's going that much positive is an indication of an airleak between the MAF and the NBO2's (too much air, so PCM has to trim positive)... check the following:
- PCV plumbing leaking;
- Intake manifold leaking (underneath);
- EGR plumbing leaking;
- Exhaust manifold leaking;
- Exhaust/catalytic leaking near O2 sensors (upto 8-12" after the O2's) [check the catalytic's front pipe weld/seam, sometimes it separates].

Could also be an indication of injectors sticking and not spraying properly (not enough fuel, so PCM has to trim positive), or insufficient fuel delivery (clogged filter, crimped/bent fule line (especially the nylon lines), bad voltage/ground connection to pump, worn out pump).

i checked the intake manifold and there was no leak
no leak on the pcv either.
no leak on the egr
no leak on the exhuast manifold.
and no leak on the exhaust or by the cats

I do however have a service engine light on with a code po452 ( fuel tank pressure sensoer condition. the fuel pump as been replaced and so has the sensor. Don't know if this would have anything to do with the fuel trims being so high or not???

[smslyguy]

also cruising speed in this truck is at 1700 rmp with 70 kpa.