runs rough, code 24 and 52

[Mjcsupra]

Hey, im at a loss with whats going on here and i have a couple of questions that i hoped to get answered. io have a 7mgte, metal head gasket, arp bolts. i had thought that i had a vacume leak from my egr valve on the head. i have since removed the entire egr and replaced all my intake manifold gaskets. i now have an issue where the car runs rough (sounds like a subaru if you know what they sound like). and i have 2 codes one is a 24(IAT) and the other is a 52 (knock sensor) i dont have any idea if there is a problem that will cause both. i checked the wireing on both knock sensors and they look good. let me know if you have any ideas. thanks

 

[bioskyline]

im going to guess you plugged off all the egr ports? also what shape is the iac hose in? it still soft or has it gone to hockey puck rubber?

 

[Mjcsupra]

Yeah i made plates and sealed off the ports, the idle air control is what i think you are talking about and yeah it seems to be in good condition but i am not sure if it is the right size for the tube. it does seal up. i thought it might have been that also but it runs like this up through the rpms also.

 

[shaeff]

Hey, im at a loss with whats going on here and i have a couple of questions that i hoped to get answered. io have a 7mgte, metal head gasket, arp bolts. i had thought that i had a vacume leak from my egr valve on the head. i have since removed the entire egr and replaced all my intake manifold gaskets. i now have an issue where the car runs rough (sounds like a subaru if you know what they sound like). and i have 2 codes one is a 24(IAT) and the other is a 52 (knock sensor) i dont have any idea if there is a problem that will cause both. i checked the wireing on both knock sensors and they look good. let me know if you have any ideas. thanks

For future reference, check the TSRM for what the error codes mean, it will make finding the actual problem a breeze: http://www.cygnusx1.net/Supra/TechTips/engine_error_codes.aspx


We will start with the code 24.

24 Intake air Temp Sensor Signal

Diagnosis
* Open or short circuit in intake air temp sensor signal (THA).

Trouble Area
* Intake air temp sensor circuit
* Intake air temp sensor
* ECU

The intake air temperature sensor is in the AFM. Check the connection at the AFM, test it per the TSRM: http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=96

Make sure it tests within spec. If so, trace your wiring and make sure it's in good shape. I can almost guarantee it's not the ECU causing the problem. 7M ECUs rarely fail.




Then there's your code 52:

52 Knock Sensor Signal

Diagnosis
* Open or short circuit in knock sensor signal.

Trouble Area
* Knock sensor circuit
* Knock sensor
* ECU

Most of the time the problem with this is old wiring, however first check to make sure that both knock sensors are plugged in. They're located below the intake manifold, on under runners 2-3, and one back near the starter. They could be green or gray, with green or gray circular connectors. If they're plugged in, verify that the wiring is intact and conducting properly. Grab your DVOM and set it to continuity check. Place one lead on the center pin of the connector, and the other on a good ground. If you get a tone for either wire, do the knock sensor rewire: http://www.supramania.com/forums/content.php?135-Knock-Sensor-Rewire-Write-up-(code-52)

Most code 52s are caused by bum wiring. It's not a bad idea to rewire regardless of the condition, but certainly not needed if your wires in good shape.

If your wiring checks out, you have a bad knock sensor. You can test them with an oscilloscope. I recommend checking/replacing the front knock sensor first, as it's easy to get to. The rear one is sortof blocked by the starter (depending on year of car) and thus more difficult to get to. No matter what you do, if you replace the sensor(s), test them beforehand to verify that they operate properly.

 

[Mjcsupra]

Yeah ... i know what your saying but i dont have a toyota maf, i am using a GM 3" so the TSRM will not help with this issue. i am using a MAF translator with the gm mass air. i was not getting a problem code before i took apart the intake so i dont think it is the sensors them selfs. i do think i will comb through the wiring with a DVOM and take a look for some crap wireing. also the codes do not set until i have the car rpm past around 4000 and am in boost. i have a idle and a rev sound similer to a subaru with no codes thrown, so if you could help a bit with this.

 

[shaeff]

Yeah ... i know what your saying but i dont have a toyota maf, i am using a GM 3" so the TSRM will not help with this issue. i am using a MAF translator with the gm mass air. i was not getting a problem code before i took apart the intake so i dont think it is the sensors them selfs. i do think i will comb through the wiring with a DVOM and take a look for some crap wireing. also the codes do not set until i have the car rpm past around 4000 and am in boost. i have a idle and a rev sound similer to a subaru with no codes thrown, so if you could help a bit with this.

The code 24 is most definitely due to the wiring at your MAFt unit. Double check everything there to verify that it is set up properly.

The "Subaru" sound you hear is due to the code 52. When code 52 is set, it will retard the timing a max of 10°, which will make the car sound terrible, and generally hate boost. The two problems are unrelated. Do as I said above with the knock sensor circuit, and check that AFM/MAF wiring.

 

[Mjcsupra]

I know its been a while but i finally go t around to messing with the car again and i rewired both knock sensors and both my codes stoped coming up. the miss i was having was due to a injector clip not being fully connected, thus causing a consistant lean condition and making the car run like dog crap (obviously), thanks for all the help. got the car back legal and on the road (been since 07 due to east coast emission laws, and mechanical issues).