MAF sensor - is it the same thing as a ' Air Intake / Charge Temperature' Sensor?

[JCH13]

Ta da! How's it doing today?

 

[Pick2]

Yea , Don't just leave Us dying at a stop light

 

[mrblotto]

Update:
After I got it all together, I just let it idle for a while. The next morning (Sunday), I decided to drive over to the grocery store for some food/beer. Didn't stall once

Today, I got in to go to work. Come to the 2nd stop light - stalls! sonsabitches! Back to '2 feet driving'.....ugh.....

There's still no CEL, and my reader said 0 codes.

The reader DID pick up a code after I re-assembled everything - a P0110 (Intake Air Sensor) but I can't remember if I reinstalled the sensor into the airbox before or after.

In other words, I may have forgotten to put the sensor into the airbox, thus causing the code.

Took a look at the reader today, nada.

So, pretty much, I went around the block and came back to my house lol

 

[JCH13]

Could be a bum IAC valve.

Edit: is there an idle adjustment screw or hose you can pull to get your engine more air to see if the stalling continues?

 

[boomerang]

The reader DID pick up a code after I re-assembled everything - a P0110 (Intake Air Sensor) but I can't remember if I reinstalled the sensor into the airbox before or after.

In other words, I may have forgotten to put the sensor into the airbox, thus causing the code.

I don't think that the computer cares where the sensor is. It could be in place, hanging out of place or connected through a long jumper harness sitting on the workbench. It senses the temperature of the air regardless of where it is. It's just a thermistor.

Now, is it the sensor, the wiring or the computer that is the problem? Without a manual and a DVOM, it's a guess. Might as well replace the sensor. It appears to be pretty cheap. Although I just don't see that causing the stalling.

I'm back to oil pressure and I'll throw in fuel pressure and just for grins, EGR. Yes, you had the EGR valve replaced but that doesn't mean that it hasn't failed or that the EGR solenoid isn't on the fritz. There is an EGR temperature sensor that should set a code if EGR is happening when it shouldn't but many things are timing issues. If the EGR is putting in too much exhaust gas (or at the wrong time) and the time it's doing so is brief, the sensor and or the computer may not reach the threshold to throw a code. The sensor could be lazy and reporting erroneous readings. I will add that it can be difficult to find aftermarket parts that last. OEM is oftentimes the best but in older cars they are not always available.

I got corralled a month back into replacing the coil pack on a friends car. I had given up working on cars many moons ago but... It corrected the misfire for all of three minutes before the replacement coil pack took a shit. He ended up taking it somewhere and the coil pack put on was exponentially more expensive that the one from Advance Auto Parts but it fixed the issue and more importantly, the car is still running and running well.

A fuel pressure problem would require a FP gauge attached that could be observed when the vehicle stalls to properly diagnose.

How much fuel do you typically keep in the car?

 

[bruceb]

If it was the EGR it should be setting an OBDII code for it.

 

[NutBucket]

Unless the EGR passages are plugged with carbon?

 

[mrblotto]

Before I left work, I unfastened the air filter 'top' to let a wee bit more air in. It didn't make a difference. Stalled about 2 miles down the road at a light. Maybe that was at the point that the car was 'warmed up'? and things change a little bit. Sensors turn off/on/whatever *shrugs*

I dont know if it merits mentioning, but it WONT stall if I put it in Neutral while traveling at speed. Like going down a slight hill on the freeway. I'll put it in Neutral, the RPM's stay at about 1000, and it runs just fine. Of course I can't do that all the time (like I could anyhow lol). Maybe something about the 'widget' just sensing air passing along makes it 'happy' or something.

@boomerang:
Good to know it really doesn't matter where the hell the sensor is, only that it's connected. I would speculate (oh no!) if it were the wiring, the condition would either be 'off' or 'on', not 'random'. Kind of like a SSD, it either bricks or it doesn't. Then again, the engine shakes/vibrates a bit under operation, so maybe not......

Yes, I had the EGR replaced maybe 5 years ago. It was spitting CEL's. I had my guy clean it first, then replace it when the CEL's didn't stop. He uses OEM parts as well, but only charges maybe half in labor. Still, it's all a part of the whole ball of wax.

I'm fairly certain I thoroughly cleaned the ......dammit....so many acronyms flying around.......uhhh.....the IAC? The thing where I had to take off the throttle body to get to. It was stoopid dirty. Also, I didn't know the valve was 'magnetic'. That is to say, it sits between 2 magnets that have something to do with it's operation.

I think maybe I'll replace the (again...damn acronymns) Intake Air Sensor that goes into the airbox. It'd be nice if I could plug something into the OBDC port and drive around for a bit. I guess that's what you mean by 'DVOM' (Digital something something Meter). Wonder if they have something like that for an iphone......

Edit: sorry....I usually fill up when the tank gets around 1/4 tank or a little below. I HATE it when the light comes on! I hope it's not the fuel pump.......then again, I think I saw something about pulling out the back seat to get to it.....so maybe it's not as bad as dropping the tank....

 

[boomerang]

I dont know if it merits mentioning, but it WONT stall if I put it in Neutral while traveling at speed. Like going down a slight hill on the freeway. I'll put it in Neutral, the RPM's stay at about 1000, and it runs just fine. Of course I can't do that all the time (like I could anyhow lol). Maybe something about the 'widget' just sensing air passing along makes it 'happy' or something.

Stick or automatic? I'm guessing automatic.

Google if there is a connector that can be unplugged at the transmission that will prevent the lockup of the torque convertor. bruceb reminded me that this is an OBDII car so a code will probably be set and mileage will suffer a bit but only if you drive a long ways with it unplugged. Regardless, ignore the CEL and see if the stalling stops. If the torque convertor is staying locked up, the car will stall when stopped.



The following is not relevant to your issue, it's just me trying to jog my brain and anyone that knows, please chime in. My recollection was that '98 was the first year for OBDII but now my brain is kicking in and I seem to recollect that '98 was when it was mandated. Some manufacturers, on some vehicle lines, implemented it ahead of the mandate. I recall that about two years prior was the start which would be why your '97 is OBDII. I forgot all this in my reply related to the EGR. I should have realized my error when I was talking about the EGR temp sensor.

 

[JCH13]

Before I left work, I unfastened the air filter 'top' to let a wee bit more air in. It didn't make a difference. Stalled about 2 miles down the road at a light. Maybe that was at the point that the car was 'warmed up'? and things change a little bit. Sensors turn off/on/whatever *shrugs*

I dont know if it merits mentioning, but it WONT stall if I put it in Neutral while traveling at speed. Like going down a slight hill on the freeway. I'll put it in Neutral, the RPM's stay at about 1000, and it runs just fine. Of course I can't do that all the time (like I could anyhow lol). Maybe something about the 'widget' just sensing air passing along makes it 'happy' or something.

@boomerang:
Good to know it really doesn't matter where the hell the sensor is, only that it's connected. I would speculate (oh no!) if it were the wiring, the condition would either be 'off' or 'on', not 'random'. Kind of like a SSD, it either bricks or it doesn't. Then again, the engine shakes/vibrates a bit under operation, so maybe not......

Yes, I had the EGR replaced maybe 5 years ago. It was spitting CEL's. I had my guy clean it first, then replace it when the CEL's didn't stop. He uses OEM parts as well, but only charges maybe half in labor. Still, it's all a part of the whole ball of wax.

I'm fairly certain I thoroughly cleaned the ......dammit....so many acronyms flying around.......uhhh.....the IAC? The thing where I had to take off the throttle body to get to. It was stoopid dirty. Also, I didn't know the valve was 'magnetic'. That is to say, it sits between 2 magnets that have something to do with it's operation.

I think maybe I'll replace the (again...damn acronymns) Intake Air Sensor that goes into the airbox. It'd be nice if I could plug something into the OBDC port and drive around for a bit. I guess that's what you mean by 'DVOM' (Digital something something Meter). Wonder if they have something like that for an iphone......

Edit: sorry....I usually fill up when the tank gets around 1/4 tank or a little below. I HATE it when the light comes on! I hope it's not the fuel pump.......then again, I think I saw something about pulling out the back seat to get to it.....so maybe it's not as bad as dropping the tank....

Opening up the air filter won't fix anything unless your air filter is completely plugged. You need to let air in DOWNSTREAM of the throttle plate and IAC, not upstream.

Does it stall in park/neutral when stopped? Or just in drive?

 

[bruceb]

You really need an OBDII scanner that can read real time data streams to find this problem. Also check for vacuum leaks as they will affect the car idle speed. A dirty fuel injector or one that does not work all the time can also do it.

 

[mrblotto]

Stick or automatic? I'm guessing automatic.

Google if there is a connector that can be unplugged at the transmission that will prevent the lockup of the torque convertor. bruceb reminded me that this is an OBDII car so a code will probably be set and mileage will suffer a bit but only if you drive a long ways with it unplugged. Regardless, ignore the CEL and see if the stalling stops. If the torque convertor is staying locked up, the car will stall when stopped.

Will take a look-see

Does it stall in park/neutral when stopped? Or just in drive?

I wanna say when it's just in drive, but I could be wrong. Guess I'll test that by stopping at a light when I have it in Neutral.

You really need an OBDII scanner that can read real time data streams to find this problem. Also check for vacuum leaks as they will affect the car idle speed. A dirty fuel injector or one that does not work all the time can also do it.

Yeah, whatever those things are called - I should take a look at getting one. I think it's a good thing to have anyhow. I was under the impression that a vacuum leak would raise the idle? Also, can't hurt to put in some fuel-injector cleaner stuff the next fill up. Oh, and yeah, I should replace the fuel filter too. I looked again. It's DEFINITELY easier getting to via the top!

 

[bruceb]

Vacuum leaks will lower the idle. If you spray carb cleaner on the vacuum hose and the speed increases, you have found the leak.
http://procarmechanics.com/problems-caused-by-an-engine-vacuum-leak/

 

[JCH13]

Vacuum leaks will lower the idle. If you spray carb cleaner on the vacuum hose and the speed increases, you have found the leak.
http://procarmechanics.com/problems-caused-by-an-engine-vacuum-leak/

Since this car runs with a MAP sensor a vacuum leak will cause a higher idle, the added air is being measured by the ECU. On AFM cars stalling is common with vacuum leaks because the added air bypasses the AFM and the ECU cannot measure it.

I would be surprised if a vacuum leak caused this stalling issue. However, I have been surprised before.

 

[freeskier93]

The following is not relevant to your issue, it's just me trying to jog my brain and anyone that knows, please chime in. My recollection was that '98 was the first year for OBDII but now my brain is kicking in and I seem to recollect that '98 was when it was mandated. Some manufacturers, on some vehicle lines, implemented it ahead of the mandate. I recall that about two years prior was the start which would be why your '97 is OBDII. I forgot all this in my reply related to the EGR. I should have realized my error when I was talking about the EGR temp sensor.

OBD2 became mandated in the US in 1996. Takes all of 15 seconds to find it on Wikipedia.

 

[boomerang]

OBD2 became mandated in the US in 1996. Takes all of 15 seconds to find it on Wikipedia.

Just so you know, you can be an ass and it rolls right off my back.

 

[mrblotto]

OK Update time!

Going to to work this morning, I remembered what *scrolls up* JCH13 mentioned (...Does it stall in park/neutral when stopped? Or just in drive?...)

Getting up to the stop light, I put it in neutral and came to a stop.......was fine for a few seconds, then stalled. So I guess it stalls in either N or D. Does that rule out the torque converter then?

I went a googling last night looking for real time data gathering software (there HAS to be an acronym for that lol). I came across a couple. You load the software on your lappy, then plug it into your car (dont know if you use the OBD port under the dash or the 'diagnostic' port for the ECU under the hood), then drive around and gather data. There's a quite a few of 'em out there.

My plan for this weekend is to replace the fuel filter, and get a full tank of gas and dump some injector cleaner in there as well.

I did text my mechanic guy as to where/if there is a plug/sensor thing connecting to the transmission, he said he'd look it up. But I'm hesitant to keep asking him for free info. It's his livelihood, not his hobby lol.

Much appreciative of y'alls responses. I think bruceb is the closest one, so I'll buy you a beer and/or invite you to dinner! (Bonus points if you look like your av lol)

 

[JCH13]

Most likely not the torque converter. I'd still look for a vacuum line that you can pull or an idle air adjustment screw to give the engine more air. This will help determine if things are clean enough or if perhaps if the IAC valve is bad in some way.

 

[herm0016]

i use the torque app and an elm 27 Bluetooth adapter. works great and has saved us a costly tow by being able to clear codes while driving.

 

[boomerang]

Does that rule out the torque converter then?

Yes

I'd go the route herm0016 has suggested before putting any more money into the project. You can throw sensors at a car all day and not fix a thing.

I would especially like the bluetooth adapter/torque app route if you can take a snapshot or put it into a recording mode for x number of seconds with the press of a button. That's what's really going to tell you something IMO.

Former DIL's car had an intermittent sag/hesitation when accelerating from a stop. This was back before OBDII days. I had a scanner that could connect to a printer. I put the scanner in snapshot mode and afterwards was able to scroll though the data incrementally and print out a specific 'frame'. The screen on the scanner only showed three lines so it was difficult to get a real picture of the problem but the printer put everything there right in front of you. It pointed to out of spec data from the MAF that was too brief to set a code. Close inspection revealed a bunch of 'wooly' buildup on the sensing wire in the MAF. Cleaning it not only corrected the intermittent problem, it made it run much, much better across the whole RPM range.

GM had put the MAF forward of the air cleaner on that car so everything that got sucked into the snorkel had to pass through the MAF unfiltered in any way.

 

[mrblotto]

I looked up that torque app....it appears mainly geared towards Android phones.......of course, I have an iphone, but still looking..........

I'll pull a vacuum line as well and see if anything changes 'edelweiss'

 

[mrblotto]

OK...prolly the final update:

Went out today. I took out the EGR valve and gave it a cleaning. Then I turned the screw for the idle a bit, it now idles around 1k.....argh.

Anyhow, I had it started, so I removed all the tubes from the EGR valve......and nothing happened.....hmmmmm

I removed another hose, it went down below somewhere, and the idle went up, so I guess whatever it is was working ok lol

Finally, I decided to try the fuel filter. It accessible from the top. It's NOT accessible from underneath because it's right above the .....uhhhh....some big piece of frame that the shock/strut sits on. Anyhow, I loosed the screw/bolt for the C-clamp it's held in. No way I was gonna get it out without bending the clamp out of the way, which I did. With the filter free, I could now see it's connected from the top and the bottom - Fuel in and Fuel out.....how nice.

I started undoing the top 17mm fitting, only to find out the WHOLE thing was moving as well......gah! So, I had to improvise: I got Ye Olde Visegrips and firmly latched onto the filter so I could undo the top fitting. Voila - done!.

Now for the bottom fitting. I saw/felt that it was hard metal tubing that went into it, so I gently moved it around some so I could get a 17mm crescent wrench on the bottom fitting, while still having the Visegrips attached to the top part. Slowly....ever so slowly, it loosened. Finally it gave way with a stream of gasoline!

After that had stopped dripping, I went ahead and turned the old filter upside down, in order to drain the contents of the 'before the filter material' part. OMG it was like gray/black water! Nasty nasty nasty..........."You know Blotto, that HAS to be the problem!" I thought to myself.

So I went about installing the new filter. I was able to hand tighten the bottom fitting, then with both the Visegrips up top and the crescent on the bottom fitting, I was able to tighten it maybe 1/8 of a turn each time.......it was horrible!

Once it was sufficiently tightened, I attached the top fuel line. It was tough, but I managed to get it pretty good. Then I gently moved the whole magilla back into the clamp and was attempting to hold the clamp closed whilst at the same time getting the bolt started......when I noticed it.....

A drip........then another......and another......about 1 every 2 or 3 seconds..........oh hell!

I felt around the underside of metal tubing...and I dont believe I felt any cracks from me moving it around.....so I felt up ( lol ) further. It seemed to be coming from the bottom fitting..........but how? I thought I had tightened that thing down good!

So, undo the top fitting again.....monkey around some more with the bottom fitting. I managed to maybe get it 1/4 to 1/2 turn tighter. Then I moved it back up into the clamp and saw no more drips...hooray! I put the top fitting on, tightened it down, then jumped in and started it up.

It took a couple tries.....obviously the filter was empty and needed to fill. On the 2nd try, it started right up...victory was mine! I got out to admire my work.

Then I noticed gasoline spraying out from the bottom fitting of the filter, much like a loose or ill-fitting garden hose......oh sonofabitch!

I quickly turned it off...put the airbox top back on, and called my mechanic guy........the end :/

TLDR

-made it worse...now have to have it towed to my mechanic

 

[boomerang]

There are usually O-rings that seal the inlet and outlet lines at the filter on older cars. In your case the O-ring for the line on the bottom probably stayed in the old filter. It's a pretty common situation. Sometimes reusing the O-rings still results in a leak and you have to get new ones.

 

[bruceb]

Agree about the O rings on the metal lines connecting to the fuel filter. And if it was as dirty as you say, I would have manually run the fuel pump into a container to be sure you have clean gasoline coming from the tank and through the lines, before installing the new filter.

 

[mrblotto]

Final update (again lol)

Took the car up to my guy. Turns out I hadn't tightened the fuel filter enough.....go figure. I swear.....I tightened that thing as hard as I could......but the mechanic had the tools to do the job better.

So far, so good. No stalling on the way to work today either