ok heres the deal, i have an 89 camaro with multiple sensor problems. these are the codes that have come up

23. Low temperature at manifold air temperature sensor OR Throttle position sensor error

33. High voltage (low vacuum) at mass air flow sensor (or MAP sensor)

43. Low voltage at electronic spark timing circuit

51. PROM error

i am not sure if all these are bad or if one thing is triggering another causing a chain reaction. and why the prom error is coming up, i removed the prom to get some number off the chip to see if that could be causing a problem to see if it wasnt the right one. is there anything that could cause a low temperature at the manifold, or high voltage (low vacuum) at the map or maf, or low voltage at the esc? thanks in advance for all your help.

 

All at once? Where you working on something in a certain area?

Here's a link to a pdf of TPI trouble codes and how to dianose them. When it opens save a copy to your computer for future use or off line.

http://www.eagle-mark.com/Fuel-Injection/TPIcodes.pdf

 

I do not have a tpi. It is a 305 tbi. and i have rebuilt the engine and transmission about 2800 miles ago but there sensors popping up before the rebuild.

 

With so many codes check that the harness grounds at the engine block are OK.

Code 51, PROM, means that the PROM in the ECM is bad or going bad, or that the ECM was powered up without the PROM in it. It can also be caused by the PROM socket getting dirty, re-seating the PROM can sometimes clear this code up.

When code 51 is active the SES/CEL will blink/flash rapidly.

> 23. Low temperature at manifold air temperature sensor

Check that the IAT sensor is plugged in. It is located in the air cleaner housing with the connector on the outside. If not present or not connected a low IAT code is set.

> 33. High voltage (low vacuum) at MAP sensor

Check that the MAP sensor is correctly plumbed to the TBI. Vacuum line is from the MAP sensor to the center rear port on the TBI. A cracked or missing vacuum line will also cause this code.

> 43. Low voltage at electronic spark control circuit

Knock detection and reporting system error. This can be caused by the forced knock test failing to detect knock. It can also be caused by the knock filter either missing or not getting +12 volts at ignition on.

RBob.

 

ok code 51, you say could come from the car running without the prom, which it did. so i have recently reset the computer and re inserted the prom while the computer was being reset. so i will see if it helps it.

code 23.......there isnt a iat on this car, only a tps, and all wires going to it seem to be fine. and it is connected solid.

code 33. the vacuum line and wires are fine to the sensor and to the tbi. i pulled off the vacuum line and tested just now and everything with it is ok.

code 43. from looking up pictures of the knock sensor i can see that i believe it goes to the side of the block, there is one on each side of the block, not sure if each are knock sensors but i do no that neither have ever been connected since i bought the car, the wires that go to that area do not look like anything that could connect to those sensors either. i do not no if something at the end of the sensor has been ripped or torn, or anything else.

so what should i do about that, if that knock sensor is not hooked up, could that be setting off the esc? is there anyway to bypass that?
if not, what can i do to re wire and get knew knock sensors put in?
if that knock sensor is setting off the esc, could it also set off the tps and map sensors as well?
thank you for your help.

 

Code 51 is explained, so no real issue with it.

Code 23 is from not having an IAT. Without the intake air temperature sensor that code will always be set. Best bet is to get one and install it. Note that this code has nothing to do with the TPS.

Code 33, a scan tool will tell you more about this error. Need to see what the ECM is seeing. It may be that the sensor is bad, or the wiring is bad. It may also be that the wrong sensor has been installed.

However, a poorly running engine will also cause code 33 to be set. As the engine stumbles and the RPM drops the MAP reading goes up (low vacuum), this can set code 33. And as such the code will go away once the engine tune up is OK and the engine runs properly.

Code 43. Knock sensor is on passenger side of block right above the pan rail in front of the starter. If not connected that will cause the forced knock test to fail which will set code 43.

The connector for the knock sensor is similar to the one for the fan switch (passenger head between 6 & 8). Best bet is to look to see if the wire is there (goes to the knock filter on the firewall by the brake booster). And get a new connector for it.

Can't bypass it with resistors or such as the forced knock test will fail. Although I posted a patch for the ECM firmware to bypass it on the DIY_PROM board.

RBob.

 

From all the research i have done, there never was a iat on this model. i have the original intake manifold on the car, there is not a spot on it for a iat. it is a 305 tbi. and i look up the iat for this exact model it keeps giving me the coolant temp sensor. so if there is one, could you please me what it looks like and where it is suppose to go? also, when reading codes this is what is says for code 23 in every manual i have found

23. Low temperature at manifold air temperature sensor OR Throttle position sensor error

 

The IAT is not in the manifold, as I posted it is in the air cleaner housing. Code 23 with the '8746 ECM has nothing to do with the TPS. I don't care what the manuals you are reading states, they are general purpose only. Not specific to your car.

From Rock Auto:

AIRTEX / WELLS Part # 5S1009 More Information About this Part {Click Info Link for Alternate/OEM Part Numbers 12110320, 25037229, 25037313, 25037357, SU1195} (In Air Cleaner)

And the picture is attached, also from Rock Auto.

RBob.

 

ok i see what your saying. i do not have the air cleaner house. i have a stack on my tbi unit. i am not sure what i can do about that. idk if i can find a way to bypass the need for that sensor, or i can rig something on the stack. any ideas?
could a dealership make it to where the computer doesnt need to read it?

also another code popped up today while i was driving around:
13. Oxygen sensor signal stays lean during warm engine cruise.

the other codes: 23, 33, 43. all popped up again as well.
but 51 never came on. also the car started to drive like **** like the timing was bad?

could the computer be bad itself? because after my first post, i rechecked all of the wires going to the sensors and the only problem i found was the wire going to the knock sensor and that the place where the knock sensor itself goes has got a regular bolt in it which it why it became so difficult to find where it actually went until i looked up pictures. the other side of the block where the engine temp sensor goes also has a bolt in it that looks like factory but im sure isnt. the grounds for everything on the engine and car good. the car is 22 years old, could the sensors just be bad and all need replaced?

sorry for the million questions but i dont have the funds to go through and replace a bunch of could bes and might bes. i need to pin point the issue and solve it. thank you.

 

forgot to mention that i replaced the o2 sensor and the wire for it already and it is still saying its bad.

 

sorry for the million questions but i dont have the funds to go through and replace a bunch of could bes and might bes. i need to pin point the issue and solve it.

Well, many of the error codes you already know why they are there. And have the fixes for them listed, such as installing/connecting the proper sensors.

could a dealership make it to where the computer doesnt need to read it?

No, they can't. Just get an IAT in the air path someplace. Doesn't even need to be at the air cleaner. I've installed them behind the front grille. Just as long as it reads ambient air temperature you are good to go.

13. Oxygen sensor signal stays lean during warm engine cruise.

Good possibility the fuel pressure is dropping off. Get/borrow a gauge and check it.

the other codes: 23, 33, 43. all popped up again as well.

And we know why code 23 & 43 popped up again. Code 33 is still up in the air. Fix the easy ones and get them out of the way, then tackle code 33.

but 51 never came on. also the car started to drive like **** like the timing was bad?

Code 51, that was because you ran the ECM without the PROM in it. Unless you do that again code 51 won't get set.

When code 43 is active the ECM pulls spark timing, so yes it will run poorly. Get the knock sense hooked up.

The engine temperature sensor for the dash gauge is in the drivers side cylinder head, between 1 & 3. The cooling fan switch is in the other cylinder head between 6 & 8. The coolant temperature sensor for the ECM is in the front of the intake manifold.

There are no locations in the block for engine coolant reading/sensing.

The knock sensor goes into the block drain hole. Which is a tapered thread (NPT, pipe). If a regular bolt has been jammed in there, then someone in the past really didn't know what there were doing.

RBob.

 

Ok, Thank you for all you help. I am going to order the knock sensor and iat and wires for both today, and order a map sensor just in case it is bad. once i get everything and install i will update it on here how it is acting afterwards. Thank you once again for all your help RBob.

 

I have put on the knock sensor, connected new wires. put on a new map sensor. i am still waiting for the connector for the iat sensor so i can hook that up. reset the computer and went for a drive. took it easy and goosed the peddle here and there. the cel came back on and i got 23, and 33 again. no 13, or 43. thank you for your help RBob.

now code 23 coming back on was expected since i havent put the iat in yet.

33, i am unsure what is causing that now since i have replaced that sensor. any ideas as to what is causing it and how to fix it?

 

I'd first check it with a scan tool, just to see what the ECM is seeing. Some time ago I pulled a new MAP sensor from a Chevy van in the JY. I appeared to be a GM unit and was new, so figured it was a good grab.

Not so good once I got it home and on the bench (testing it). It turned out it was a Standard brand, and, the output was inverse. At barometric the output was low, and went higher as the pressure was reduced. Had the correct green connector insert and all. No wonder the van was in the JY.

If the sensor is OK, a MAP high can be caused by a bad ground to the sensor, the vacuum line missing, cracked or otherwise not providing the proper vacuum to the sensor. The ECM may be bad, but that would be my last choice.

You can measure the voltage at the center pin of the MAP. At key-on, engine-off should be about 4.5 to 4.75 volts (elevation dependent). Then with the engine running go lower (probably around 2 volts).

Pin A on the MAP is ground, pin C is +5 volts. According to the '92 wiring, the MAP ground goes to the ECM, pin D2. The signal goes to ECM pin C11.

RBob.

 

Ok, I am unsure where to get a scan tool and what kind i should be looking for.

 

If you have a laptop or PC can use WinALDL, it is free software. Still need a cable though.

If you have a DVM it would be faster & easier to check the voltage and ground for the MAP.

RBob.

 

ok well once again i am sick of this car. i got the connector in for iat sensor and put it behind the grill like you suggested. reset the computer and went for a drive, after about 10 minz the cel came on again, and the timing went all out of wack. so i decided to just keep driving for about 50 miles both hwy and city to get all the codes that were gonna show to show up. this is what i got

both 13 and 43.

im pretty pissed with this car since i bout a knock sensor and connector and ran it yesterday with it and everything was fine and that code never popped up when it use to pop up after running for 5 minz every single time i started the car then yesterday i put in the knock sensor and connect everything up and there are no problems. today all **** decides to hit the fan. any ideas before i blow this pos up?

 

Code 13 means the O2 sensor isn't doing anything. Just like it was disconnected.

The code 43 again, maybe the connector fell off? It may also be that the forced knock test failed. Did you notice a SES light shortly after a WOT or near WOT pull? This is when the ECM attempts to force knock.

The forced knock test can fail if you are using premium fuel, which can prevent it from knocking. Not having the base distributor timing set correctly can also cause this test to fail.

RBob.

 

Ok, so what spot on the ecm is the o2 sensor and I can run a whole new wire there.

When the code comes on it normally happens near a WOT. Ill do a WOT and let go and itll be fine but when i only do it half way it will pop up and sometimes the CEL will go off and sometimes it wont. i only run 87 octane in it. the timing is at TDC and was put at 8 degrees by a timing light.

 

Any idea what could be causing that with the knock sensor. Still only does it when i go half way on the throttle, and sometimes the CEL will go off while im driving after it comes on.

 

O2 signal goes to ECM pin D7 (PPL), O2 sensor ground goes to pin D6 (TAN). The ground is tied to the engine block. Both are required for proper O2 operation.

Note that I said code 13 is like the O2 sensor is disconnected. Not that it is. The sensor may be bad.

RBob.

 

The o2 sensor was replaced after engine rebuild and the code was popping up before that. so ill re wire it and see what i get.

And for the knock sensor problem?

Update for the knock sensor problem on top of the half throttle. I had to take the car on a 4 hour trip(4 hours there and 4 back). Really took a tole on it but that code would pop up randomly and go on and off periodically with no real reason behind it while i was driving on the interstate cruising. It would come on, then go off. Main problem i had with the car besides it taking me 2 and 3/4 tanks of gas to travel 300 miles, was that at the end of the first 4 hour run, the car would not stay running. It would stall on me constantly while i was driving it through the city to get to where i was going. I didnt do anything to it, took the 4 hour drive back and it never stalled me even to the point when i got home. I dont know if it just got so hot from running so long that it just gave up on me or what? Any ideas on that as well? As always RBob thank you for all your help. I've been able to get almost all of my problems taken care of thanks to you!

 

oif0709, there is additional info on code 43 in this thread/post:

https://www.thirdgen.org/forums/tbi/...ml#post4952263

RBob.

 

I had a 305 konck sensor in a 350 (they are different and year specific) and the ses would come on and go off like yours is. Maybe you got the wrong knock sensor. Also I know some cars have 2 one on each side depending on year, might check to see if you have 2. If you do it will be a blue wire with the same connector as the pass. side. I'm not sure which years have 2 but it will be pre-wired even if you dont have 2.