Original MAP doesn't hold vacuum

I was hoping you'd see the video first.

I tested with a regular $20 digital volt/ohm multi meter with KOEO. (Key in RUN position engine off). No scan tool used.

The MAP sensor was removed from the intake manifold to test it. Engine running would have zero effect since no vacuum would be applied to the MAP from the intake manifold.

I back probed the MAP sensor connector and used a handheld vacuum pump and the multi meter to check just for curiosity. But there's no change in voltage. 5V steady reading.

Before any use of the DVOM, I checked the original MAP with the vacuum pump and saw that it wasn't holding a vacuum. I bought a new MAP and tested vacuum. The new MAP held 29in of vacuum no sweat.

I then tested that new MAP off the engine with the pump for voltage drop by back probing the connector to it with the DVOM and saw no voltage change.

OBDII scanner. No codes. Car runs great! Unfortunately I get about 22 city MPG and since I only drive at or slightly higher than the minimum legal speed limit on the freeways, I get 48 MPG.

Believe it or not, this Saturn is in mint condition. I've kept it perfect since it had 3 miles on it.

I'm at a loss. :-(

Any help would be greatly appreciated.

I'll have to check tomorrow. I can check with engine running and off. I'm sure voltage will remain same and steady.

I remember seeing 19V from one of the connector probes to intake manifold as ground. But 19V is ridiculously impossible, right?

But just before I knock out for tonight, if all other readings are proper by testing with engine ON and engine OFF, other than the improper steady 5V reading under different vacuum testing of 5in, 10in, 15in, and 20in, would you recommend checking the wiring back to the PCM and if so, how would I do that and where is the PCM located?

Thanx in advance. I'll try the engine running tomorrow.

Sorry for the delay.

I got 4.75v at zero vac. 3.88v at 5" vac. 2.97v at 10". 2.04v at 15". 1.20v at 20". 0.30v at 25".

Readings are with key in RUN engine OFF.

Now when I had the engine at idle, I got between 1.30v and 1.40v.

Voltage would decrease by about 0.25v for every 500 RPM increase after 1,000 up to 3,000 RPM.

But, when I rapidly press the accelerator to WOT for 1 second and release, the voltage would hit 4.00v and drop to about 1.20v to 1.30v at idle.

Engine was at normal operating temp.

I never disconnected the battery to reset the computer before I started my quest to figure this out.

After all my tests, I disconnected the + battery cable from the battery post, turned ON the headlight switch and also turned the ignition key to START to eliminate any residual electricity.

I did not perform any tests after the battery disconnect prep.

Should I have tried any tests with the battery cable disconnect prep?

I didn't check the wiring from the MAP connector to the PCM since I saw that there was voltage change when performing my tests.

I did drive the car after my initial inquiry thru this site and I guess the computer started communicating with the MAP. So, no need to check for ohms in the wiring.

Thanx for your help with my MAP questions.

I do have another minor but annoying issue.

Not sure if I was suppose to create another new question. But here it is.

The trans fluid has been flushed (not forced/no machines) I should say, just drained and refilled with the appropriate Castrol Dex/Merc ATF three times since I bought it in '99 with the most recent trans fluid drain May 2013.

I also replaced the exterior canister-type trans filter and also the TTS (Trans Temp Sensor).

Never has the trans been serviced other than what just mentioned.

Anywho, my issue is that REVERSE engages after a slight 2 to 3 second delay when the engine is warm/hot.

REVERSE never fails to engage immediately when cold. And it engages normally, no slams.

When warm/hot, I shift into reverse from Park, Neutral, Drive, etc. And it doesn't do anything for a few seconds. Sometimes I have to increase RPM's to about 1,500 to get it to engage in REVERSE.

By the way, all fluids on the car, other than the gasoline, have been drain/flushed out.

The ECT sensor was replaced I believe 2 to 3 yrs ago.

No delays/slippage occurs in any other gear.

This delay began about 2 yrs ago and since then, there have been numerous times where engaging into reverse resulted in heavy/hard slams from over-revving trying to get it to engage.

I disconnected the connector located on top of the trans valve cover and tested the probes protruding from the valve cover for ohms.

Both the probes and connector show no burnt signs/wear.

As far as resistance, each showed either 6.02 or 6.04 ohms.

I haven't taken the valve body cover off to check for resistance on the actual solenoids themselves.

What would be my next step? The solenoids?

Oh, before I forget, since I've let the reverse slam numerous times, has anything loosened up? All gears sound normal when they're engaged and vehicle is in motion, car/tranny handles very well in all gears any climate. Just the reverse engage delay when car is warm.

I ask that before I decide to dive into the trans.

Thanx again in advance for your help.

:-)

. Climate temp extremes. Referring to Chicago weather.

P.S.

Forgot to ask if I require draining the trans fluid before removing the valve cover and/or valve body top/cover to replace a solenoid should I have to.

Cool. What's the tool that I need to search for on Amazon?

I have an exhaust question. What is the factory exhaust piping diameter?

I thought it was 2.25" but I was told it was under 2". My question is, how big can I go? No mods to the engine. Everything is stock. I'm not upgrading the exhaust for better sound/performance. I'm thinking that by putting a 2.25" or 2.5" piping I'll reduce exhaust back pressure restriction and increase fuel efficiency. I wanna squeeze as many MPG's as possible.

I'll be using the factory stock exhaust manifold and right after the O2 sensor right at the flex pipe I'll be using 18 gauge 304 grade stainless steel piping all thru out.

So, how what's the max diameter piping can I go with for the purpose of increasing fuel economy?

I don't race or anything like that, just normal day-to-day driving. The engine never sees over 2,500 RMP's.

Thanx. :-)

Getting the exhaust installed tomorrow morning.

I bought the CAT, resonator/muffler and an 8.5' stainless steel 2" O.D. Pipe.

I only need to buy the flex pipe but I'm not sure what the specs/dimensions are.
What should I buy if going with the same size factory piece?

Length, O.D. Inlet/outlet, inside diameter center and the flange/gasket size?