Stalling out issues

[willisjefferyl]

Thanks everyone! Im hoping the MAF replacement does the trick....

[TomsSVX]

Sorry there is a lot of stuff wrong with what is being said here..


If the MAF is causing a stall it is because it drops voltage.... This will not cause any other codes.

If the knock sensors are bad, it will retard timing slightly and run RICH to avoid getting into a det. state

The 02 sensors are likely bad, these codes come up when the ECU sees a reading outside of what it is expecting or if there is an open circuit in the heater. If the car was running rich because of the knock sensors it does not run outside of the expected value that the ECM is expecting to see

Tom

[SoCal LS-L]

Originally Posted by TomsSVX

Sorry there is a lot of stuff wrong with what is being said here..


If the MAF is causing a stall it is because it drops voltage.... This will not cause any other codes.

If the knock sensors are bad, it will retard timing slightly and run RICH to avoid getting into a det. state

The 02 sensors are likely bad, these codes come up when the ECU sees a reading outside of what it is expecting or if there is an open circuit in the heater. If the car was running rich because of the knock sensors it does not run outside of the expected value that the ECM is expecting to see

Tom

Agreed, but do you think he should try the MAF first re: the stalling issue... ?
I have never seen an 02 sensor fault completely stall out a car. Apparently even in open loop the OP is stalling out.... which along with the MAF code would seem that replacing the MAF with a known good one would seem a reasonable course of action. Your opinion counts, especially since hes dropping $70 for me to expedite ship it to him!

[TomsSVX]

Originally Posted by SoCal LS-L

Agreed, but do you think he should try the MAF first re: the stalling issue... ?
I have never seen an 02 sensor fault completely stall out a car. Apparently even in open loop the OP is stalling out.... which along with the MAF code would seem that replacing the MAF with a known good one would seem a reasonable course of action. Your opinion counts, especially since hes dropping $70 for me to expedite ship it to him!

I said the MAF is causing the stall... Indicating that if he wants the stalling to stop the MAF will need to be replaced

He will also need new knock sensors and 02 sensors if he wants it to run properly afterward

Tom

[SoCal LS-L]

I must have misunderstood, you stated "if" on everything except the 02's. I just wanted to make sure someone else concurred before taking his money for my spare MAF.

[SoCal LS-L]

Oops, double post.

Postcount +1 anyways

[willisjefferyl]

Thanks tom for the extra input. I feel confident that the MAF is my problem. heres my thing, Im kinda strapped for cash after this week, replacing half the fuel system. I dont plan on driving the car hard or at high speeds for a while. I just need the stalling stopped. How long can I get by driving with the knock and o2 sensors bad? For all I know they have been bad since I purchased the car? What kinds of issues can these bad sensors lead to?

[SoCal LS-L]

If I may interject, they arent an emergency situation.... the only thing to suffer is optimal fuel mileage. You can get new NGK O2 sensors for $49 each from Advance auto parts.

The knock sensors, if they get really bad, can retard the timing enough to keep it from starting, but im pretty confident you will be ok until you have the cash to get them replaced.

If your shipping total is any less than $20, ill refund that portion back to your paypal, I know how it is on the cash thing.

Hope the MAF gets you going again!

[Wikedjuggalo]

make sure you fix it as soon as possible not when **** gets worse.

[sowise]

I agree that the MAF would be the cause of the stalling but I guess my logic was more that the stalling condition might have been inducing situations and it was a potential trickle effect.

If the stall causes the knock sensor to pick it up it causes it to run rich, running rich would then be picked up by the O2 sensors, though the O2 sensors were likely in the Open loop so that would not necessarily be the case, plus the ECM would know those expected values as Tom pointed out.

That was pretty much my initial thought on it, just was odd to me that Both knock sensors and both O2 sensors plus the MAF were all coming up faulty. I hoped he could step through the diagnostics. First clean MAF see if he gets improvement, then if no improvement replace MAF, clear and recheck codes. If the knocks and O2 still present then do the knock sensors, clear and recheck codes..etc. I guess Tom wanted to clear up any confusion. SoCal's price on the MAF is a steal though.

Also is our ECM smart enough to know 1.) O2 sensor heaters are bad (specifically) 2.) will it then use the coolant temp sensor to go to closed loop or just say sensor is bad default to open loop?

[sowise]

Originally Posted by willisjefferyl

Thanks tom for the extra input. I feel confident that the MAF is my problem. heres my thing, Im kinda strapped for cash after this week, replacing half the fuel system. I dont plan on driving the car hard or at high speeds for a while. I just need the stalling stopped. How long can I get by driving with the knock and o2 sensors bad? For all I know they have been bad since I purchased the car? What kinds of issues can these bad sensors lead to?

Just noticed your other post, did you ever get the alternator situation figured out?

[TomsSVX]

Originally Posted by sowise

I agree that the MAF would be the cause of the stalling but I guess my logic was more that the stalling condition might have been inducing situations and it was a potential trickle effect.

If the stall causes the knock sensor to pick it up it causes it to run rich, running rich would then be picked up by the O2 sensors, though the O2 sensors were likely in the Open loop so that would not necessarily be the case, plus the ECM would know those expected values as Tom pointed out.

That was pretty much my initial thought on it, just was odd to me that Both knock sensors and both O2 sensors plus the MAF were all coming up faulty. I hoped he could step through the diagnostics. First clean MAF see if he gets improvement, then if no improvement replace MAF, clear and recheck codes. If the knocks and O2 still present then do the knock sensors, clear and recheck codes..etc. I guess Tom wanted to clear up any confusion. SoCal's price on the MAF is a steal though.

Also is our ECM smart enough to know 1.) O2 sensor heaters are bad (specifically) 2.) will it then use the coolant temp sensor to go to closed loop or just say sensor is bad default to open loop?

The OBDI ECM does not detect what is wrong with the 02 sensor whether it be a bad heater circuit or a bad signal... Just throws a generic code. When the 02 sensor does go, it will default to a richer mixture based on the MAF reading hence running in closed loop. Poor gas mileage will accompany this.

Knock sensors and 02 sensors are regular maintenance items... People tend to let them go if they are bad and they are planning the sell the car.

Tom

[willisjefferyl]

So I just put on the MAF from SoCal. Thanks for the sensor btw. Heres the thing though, after I took the other sensor off I tried to start the car a few times to confirm the MAF was bad. It satarted but sputtered out and died almost everytime. I then confirmed it was bad by tapping on the MAF and it killed the motor. Now with the other one on, the car is not firing back up. It cranks, I smell fuel, but seems like Im not getting a spark. Any Ideas/suggestions?

[willisjefferyl]

So scratch the last post, I got it started and about to take off for a test drive to see what happens. My fingers are still crossed. So now, assuming everything goes well, I just reset the codes and test again for the other sensors?

[sowise]

Originally Posted by willisjefferyl

So scratch the last post, I got it started and about to take off for a test drive to see what happens. My fingers are still crossed. So now, assuming everything goes well, I just reset the codes and test again for the other sensors?

Sounds right but reset before your test drive. That way any issues during your drive aren't added to old codes. Hope it goes well though.