83ho86tpi

I got code 43 twice when I stomped on the gas, but not under normal driving conditions. I just started to use WINALDL for the first time with a 10K ohm resistor from A to B and got ZERO spark counts on the program.
SOOOOOOOOO.................
I tested voltage KOEO at the knock sensor wire and got zero to negative -.2volts. I heard it said by someone here that I should get 4-6 volts in this situation (is this correct?)

-So I checked the Knock sensor wire E and it tests out OK for continuity to the esc module harness

-Then I tested B and D on the esc module harness and it gave me 12 volts OK

-I get ok continuity from esc module harness C to B7 at the ecm OK.


SOOOOOO.... Now I am thinking its a bad ESC module that is preventing me from getting 4-6 volts at the knock sensor wire....... because the 12V power makes to the ESC module wire harness but the knock sensor wire E gets no voltage.

Is there a way to test the ESC module before I replace it?

I would hate to wast 75$ and still have this problem.

Is there a way to test the ESC module by itself before I replace it?

Thanks

likeistoleit

I just had the same problem on a vette, turned out to be a bad connection at the esc module.

cdartz

I have a machine at work that I test them with. My company is Advance Auto. Check with your local Advance and see if they have the tester.

83ho86tpi

thanks, I tried the loose wire deal with no luck. I just ordered a new one from advanced auto so I can see if they will test the old one before I pick up the new one.

88TPI406GTA

Just to clarify...

The Spark Module (not ignition module) can be tested at an Advance Auto store? I worked part time for many years at a local auto parts store and didn't think there were any plans for a Spark Module testor...

83ho86tpi

Well its not the ESC module, I am about to go nuts!!!!!!!!!

I still get no voltage at the knock sensor wire, I do get 2.01 when I switch my voltmeter to ohms.

I dont get jack squat from that knock sensor wire but the wire does test out ok for continuity.

Are you guys SURE I should get voltage from the knock sensor wire on my 86????


WTH do I do now?????

88TPI406GTA

What is code 43 for your 86?

There is no voltage going to the knock sensor...just a signal coming from it to the ESC...I wouldn't think that you would see voltage at the knock sensor itself.

Try replacing the knock sensor...and returning the ESC module

83ho86tpi

Thanks, but.....
Several other posts here say there should be 4-6 volts AT the knock sensor wire when you unplug it with KOEO. It makes sense to me, I guess you need juice to the sensor for it to do anything, I just want to confirm that there should be juice there. If this is true then a new KS will not do squat without power. I dont get any knock counts from WINALDL even after multiple attempts.

I still get no voltage at the knock sensor wire and I have tried with every ground, even the battery -. I do get 2.01 when I switch my voltmeter to ohms, whats up with that???

My repair book does not include testing this system. Can anyone confirm for sure that I should have 4-6 volts KOEO on my 86tpi??

How do I get power to that wire????

88TPI406GTA

I am going to go out on a limb here and say that it makes no sense that there should be any voltage at the knock sensor. I just finished a DFI to '730 swap so I really understand the wiring...

The TBI setup originally in the car used a ESC module to filter the signal from the knock sensor and the '730 takes the knock signal straight to the ECM (filtered by the MEMCAL circuitry).

Nowhere did I read that there should be voltage at the knock sensor itself. For the '730 knock sensor, it should ohm out to approx. 3.9K ohms...and I don't know the spec on the earlier knock sensors.

As for voltage measured directly at a sensor, there are other sensors that do not require a reference voltage...including the O2 sensor, MAT and CTS.

You should have 12 volts switched on one of the pins at the ESC module...but not directly at the sensor.

83ho86tpi

Im not sure what to think now, I have read some other posts now and I am lost. Here are some of the other ones, It sounds to me like they are testing the wire for voltage.

https://www.thirdgen.org/techbb2/sho...sensor+voltage

https://www.thirdgen.org/techbb2/sho...sensor+voltage

If your car works ok you could pull your wire off and koeo test it against a ground like the battery terminal. I will owe ya some beers if you can help me figure out whats going on.

88TPI406GTA

What year is your car? Is is a MAF setup?

I have a repair manual for my 88 GTA and can check it out...

I will look at my own knock sensor when I can in the next day or so.

likeistoleit

Ok, here goes. I am having the same code thought I got rid of it last week but now its back. Initially I had no ground to the knock sensor. Repaired that but from what I understand there should be 12 volts going to the KS until it detects knock. Currently the highest I get at idle is 10 volts so now im wondering if I have an overly sensitive KS. So verify ground, I believe it is the brown wire, verify 12 volts switched, think it is pink and black, verify continuity on the ks wire then with KOEO check for voltage on KS wire.

88TPI406GTA

OK...so I was incorrect

With the key on, engine off, I did get 4.2 volts at the knock sensor...so I guess there is supposed to be voltage there.

At the ESC module, my pink switched wire was 12.2 volts while the battery is at 12.6 volts.

83ho86tpi

Thanks bro!!!! I cant believe that I am so happy now to have this problem with my car. I guess its because I had no Idea what was wrong before and now I have a place to start.

Awesome,
I should owe you a 12 pack for checking that out!!!
Have a cold Budweiser on me


Its back to work on the car for me

likeistoleit

Ok just got back from advance, I ohmed a new KS for a 1985 vette and got 99.5-99.8. This is the same as the current one installed. Ive got 9-10 volts going to the KS and my ground on the ESC is good. I drive the car for about a minute as long as the temp is around 198 and the check engine comes on registering a code 43. Any suggestions or a wiring schematic and troubleshooting from GM would be greatly appreciated

83ho86tpi

you got mail




I still get no power to the KS wire and am trying to figure out why.

72LT1VETTE

Go to the link. Find your ECM and associated drawingsECM drawings

firebirdjosh

iTrader: (1)

Theres not much else to the circuit. Its ECM> ESC> KS as far as I see. The Pink/Black wire is directly fused from your 10A gauges fuse. The ESC just encodes whatever signal you need. If it were my car I'd make sure the ESC is good, check to make sure there aren't any pinched wires by checking continuity between all wires in the circuit, and then start looking into a problem on the ECM. They are cheap and easy to replace. There's really not much to go wrong.

Unfortunately the ESC does some form of encoding/scrambling to the signal so I'm not sure if it should have voltage on the black wire going to the ECM or not.

Rebuildman

Here a some troubleshooting tips from a couple manuals I have. This may help you, or not.
Code 43 is set when the ecm sees low voltage at B7 for more than 5 seconds with engine running OR system has failed functional check.
Functional check will advance spark when coolant is above 95 C and a high load is on, WOT. The ecm actually advances the spark to get knock and then looks at the B7 wire for voltage drop. There is another condition for functional testing but suffice to say the ecm is doing its own self test.

Also when checking the KS for voltage disconnect the esc harness, connect a digital volt meter to pins D and E of the wire harness at the esc module, run engine at 2000 rpm and you should see more than 80 millivolts, this is .080 AC volts NOT DC VOLTS.

Apparently the KS is a voltage generator, not unlike the O2 sensor but the book says to measure it in AC volts!

This should be good for 1985-89 MAF systems. ECM 165.

Hope this helps or at least gets the old gray matter shaken up a bit!

83ho86tpi

Wait a minuite... do you mean I should check the KS wire on AC volts? I have not tried ACV because I thought it should be on DCV, what is correct?? ACV or DCV to test the KS wire????
Please confirm Beetlejuice Beetlejuice Beetlejuice!!!!!!!!!
Thanks for all the ideas, STILL need help please!
STILL ZERO DC VOLTAGE AT KS WIRE AND NO KS SIGNAL, but I have not tried the KS tap test on AC Volts because I didnt think it was tested on ACV.

The 2000 rpm test between wire E to wire D gave me 10.1 ACV, my digital volt meter was set to 200 ACV when I got the 10.1 reading I have NO idea what this result means

Possibilities I am left with seem to be:
1) My new ESC is bad OR both ESC's I have are good
2) My new Engine Computer is bad OR it could be OK (it passed KOEO and RUNNUNG votlage check at each terminal)
3) Something could be wrong with the computer chip OR its ok

I have replaced the ESC module and ECM computer but I have not replaced the prom yet. I know the old ECM computer was bad for sure.

What out of these seems like the culprit????



I did put sealant on the KS and I read that that can cause problems. I have a spare so I will try to do a quick switcharoo without loosing all my coolant.


PS: DONT tell me its bad wires or bad KS untill you read the following:
ITS PROBABLY NOT THE WIRES BECAUSE:
E) replaced KS wire #496 from KS to ESC module STILL NO DC VOLTS
D) replaced ESC ground wire#486, made special ground just for esc module BOTH WIRES HAD GOOD GROUND CONTINUITY
C) replaced B7 ESC signal wire #485 to computer BOTH WIRES GAVE SAME DC VOLTAGE AT B7 = 9.15 (specs call for 9.2-9.3)
B) tried to replace #439 at ESC 12V power wire but it sets code #43 when I do this, I am guessing #439 needs to be connected to the other stuff it connects to to run OK, so I put it #439 back the way it was.....I think #439 to A6 is good because it gives battery voltage to the ESC and A6 without any interuption or fluctuation. (specs call for battery voltage)
SOOOOOOOOOOO...... I dont think the wiring is a problem unless you see sonething I missed.

PPS: I changed the wire routing to the ESC for fun and found a combination that WORKED till CLOSED LOOP, now it does not work that way anymore. I put it back to original and it still gives me the same problem of 0 DC volts at the KS wire.
HERE IS WHAT I DID
Terminal A normaly not used) switched to ground #486
RAN WITH GOOD GROUND (within specs)

Terminal B (normaly #439 wire to A6) switched to ECM computer wire #485 to B7
RAN WITH 10.6 DC VOLTS (outside of specs, specs call for 9.3V)

Terminal C (normaly #485 ECM wire to B7) switched to #439 B
battery voltage power to A6
RAN AT BATTERY VOLTAGE (within specs)

Terminal D (normaly #486 Ground wire) switched to #496 KS wire
RAN AT 4.4 DC VOLTS (within specs)

I taped on the KS and watched the DC voltage change at the KS wire # 496 and at the voltage ALSO changed at the ECM wire # 485 B7. This means that the KS signal was being sent to the ECM like normal.
It ran good and I got some H2O (water) out of the tailpipe and a clean complete fuel burn exhaust smell like a normal running car.
THEN.... it stoped working shortly after it went to CLOSED LOOP and ran BAD again. I tried the tap test on the KS again and it does not send a signal anymore. I tried it again when the car was cold (open loop) and it did not work then either, not even with a different KS.
Maybe this will mean something to someone else, but I cant figure it out. REMEMBER: this is not the correct wire setup but It worked for a little bit. the normal wire setup NEVER worked since my old ECM computer went bad and I replaced it.

It was an interesting test but it got me nowhere. I still have 0 DC volts and no KS signal when I wire everything up original.

Rebuildman

O.K. bare with me, I know you have tested, retested, rewired, and spent several hours on this problem and as far as I can tell it still does not work. And by does not work I am assuming you do not get any knock counts when you scan your ecm and you are driving, correct?
Lets break this down to simple circuits, and I can try and verify the results on my TPI system which is a 165 ecm.

First we agree that the KS is a voltage generator, yes? I have one manual that says check for AC volts above 80 millivolts with car running at 2000 rpm and meter connected to pins D & E at the esc module, this would be with the connector disconnected!
Personally I have not tried this but if I get a chance today I will give it a go and let you know the results.

Anyway, you mentioned getting 10 volts from the KS, this is something we need to address, did you get this reading with the connector at the esc module connected and by back probing the pins? Or was it disconnected from the esc?
If my manual is correct and we are to check for MV from the KS 10 volts would be WAY TOO much, is it possible you have voltage on wire 496 from the ign system feed to the esc, maybe something is wrong at the plug connection at the esc module.

Another thing to try, if indeed the KS is a voltage generator how about this, with the connector disconnected at esc and volt meter on pins D & E and ignition switch is off. Tapping on the block with a hammer should provide some sort of voltage, it would be small and in the MV range, AC or DC? Try both.

I will try mine and let you know what it does. I know my system works because the knock counts are very active on my motor.

Since this system does a self test everytime you start up the car do you get the check engine light when you go to wide open throttle? I believe you mentioned this once, is it still happening?

Good luck, I will post my results when I get them.

Rebuildman

O.K. here is what happens on my TPI.
1. Engine off, key off, esc connector off, ohm check on pins D & E (to knock sensor) 99K. I know some say this is not correct, but I also have a new sensor and it is the same, my knock system works so I am going with this as correct for me.

2. Same setup as above, meter selected to 4 cyl. rpm scale. tapping on block gives me readings, no tapping meter at zero, the harder I tap the larger the reading on meter, interesting. Knock sensor appears to be doing something which is what I am looking for.

3. Start engine, meter still hooked up, now reading 65 -70K ohms, when engine gets hotter its up to 165K ohms, I don't think temp has anything to do with it because if I turn off engine reading goes back to 99K so its doing something with the noise from running motor!

4. Engine running, change meter to 2V DC scale have about 60 MV, increase RPMS reading goes higher had up to 105 MV, which is over the 80 MV the book was looking for and since my meter does not have the AC scale for volts DC was what I checked and it compares with the book except it is DC not AC. I will have to assume the book is wrong! Should be DC.
When you said you seen 10.5 Volts are you sure it wasn't .105 volts?

Anyway the results are that I can get the sensor to do something different when tapping on block or changing engine rpm's, sensor is working.
Does your car do this? Can we rule out a bad knock sensor? And the wiring going to it?

83ho86tpi

Thanks, I will try those tests and report back on my day off weds.
I am going to replace it with a new KS and put it on without any sealant, I had a lot on the old one because I didnt want leaks.

my 2000 rpm test from D to E was with the ESC disconnected. I got the 10.1 ACV on the 200ACV setting. I will try it again to see what happens, my digital volt meter only has settings for 200 ACV or 750 ACV.

I used WINALD (scantool program) and it did read a few knocks with the new ESC module. But it only shows them when I turn the car off and on again, not when it is running.

The ESC system is retarding my timing to approx 18*BTDC at idle, it is off the chart with the ESC timing wire connected. Timing is dialed in at 6*btdc with the ESC timing wire disconnected, I dont think my balancer or timing marker is off either since they are new OEM for 86tpi.
Im not sure but 18* btdc seems way off to me for idle at 900rpm.


I do not get a check engine light unless I go WOT after closed loop, that was the only time I got a #43.

88TPI406GTA

I wouldn't forgo the sealant because then you have a coolant leak...

Just use regular teflon tape and make sure it is torqued to the right setting for your car.

Good luck,

Rebuildman

The ESC system is retarding my timing to approx 18*BTDC at idle, it is off the chart with the ESC timing wire connected. Timing is dialed in at 6*btdc with the ESC timing wire disconnected, I dont think my balancer or timing marker is off either since they are new OEM for 86tpi

This statement needs some clarification.
With the brown timing wire disconnected that goes to the distributor, your timing should be 6 degs BTDC. With the wire connected it should ADVANCE to the setting on your chip for the given rpm and load, stock settings are around 20 degs at 900 rpm. I can't remember if the 20 is added to the 6 or not, I will have to check that, but you will have at least 18 deg advanced, of course depending on the chip setting. And it bounces around alot! This is normal.
Does your timing advance or retard when the timing wire is hooked up?
The code 43 is due to a failure of the self test for the esc/knock.
Check the sensor first and see what happens before you change it and after just to compare the two.

83ho86tpi

with the esc tan/black wire at the passengers side firewall unhooked I have it set to 6*btdc (stock)

it changes to approx 18*btdc (more twoards the passengers side of the block) when the esc tan/black wire is hooked back up.

both of these readings are in park at idle.

I will check again tomorrow

kevinc

The right term for what the ESC/ECM is doing is "advancing" your timing, and the numbers you're seeing sound right for a properly functioning system...with the ESC connected the timing should bounce around a few degrees in each direction at idle.

83ho86tpi

no code 43 yet, so thats good.
I put in a new clean KS. I do get milivolt readings from the KS and they do change when I tap on the block. I tested the wire #485 to B7 (the computer wire) and it also reads the taps I made on the block. That means that I got the system to send signal to the computer.

It rat awesome untill it went into closed loop. It took normal time to warm up and the exhaust was clean with some water coming from the tailpipes. Then when It was warm enough for closed loop it sounded a like it ran a little different, the water stoped coming out of the tailpipe and the exhaust smelled rich with a tiny bit of white smoke when I rev it hard.

In short, it runs like crap in closed loop.

I might guess that it is getting bad readings from the sensor(s) or that the closed loop info on the computer chip is messed up, or something inbetween the sensors and the computer is messing the signal up.
What would cause it to run ok in open loop (cold motor) only?

Oh, I still have the EGR and Canister hoses unhooked and plugged off and the solenoids unhooked. But I dont think that would cause it.

88TPI406GTA

You really need to do some datalogging on your car...if you could see the data together in a graph, I bet the answer would be more clear.

How is your o2 sensor? In closed loop, the ECM uses the signal from the O2 sensor to help control fueling...and if you have a bad O2 sensor, that could be contributing to the problem.

Also, I have seen leaky injectors or other fuel delivery problems impact the car in closed loop. If the engine is running rich, it might not be noticable in open loop, but when the engine is warm and it drops into closed loop, it could show up.

Good luck.

Rebuildman

Looks like the ESC problem is corrected, except the self test I read about in the manuals does not appear to use the KS for testing at WOT which is when you received the code 43 before.
But if it's working don't sweat it! Do some data logging and see if you can log some knock counts, and check the o2 sensor readings, if you have done some mods to the engine and still are running the stock chip you will need to do some tweaking. I have tried running without the EGR and have determined that I like it better with it hooked up, I am able to run more advance timing without knock and you can also set when the EGR comes on.
I actualy ran without it on my 90 vette and it caused a rich error code at part throttle cruise, so I hooked it back up and tweaked the chip in regards to EGR and it runs great!

I also added a WB sensor to my toolbox and it has been a great help, something to consider if you plan on doing this for awhile.

83ho86tpi

Cool thing is it is faster than the old motor and it isnt even running correctly. Bad thing is I can only run it for a few miles or it gets too hot and it sucks down lots of gas.

I have a new O2 sensor in already, it did not help. My average O2 reading is around .56. It jumps up to .8 and down to .2 my old O2 acted the same way. I think the car is trying to get it around .45 but it just cant and it winds up being rich.


I hope my injectors are still good, I had them cleaned and tested by Cruzin performance last year and they have worked fine for the 5k miles I put on them after that.

I hooked up my new charcoal canister, purge valve and solenoid with all the egr stuff, it did not help on my test drive. But the good news is that it did not hurt. No gas leaked out of the bottom of the canister this time (i think a busted purge valve caused this to happen on the old one).

I am running a mild 305 with comp cams tpi engine combo kit, comp says it should still run ok with stock chip, Im not so sure how acurate that claim is.

I tried some datalogging before it got too hot, I am not used to what the numbers mean though.
Here is a link to the results I got from WINALDL so far

https://www.thirdgen.org/techbb2/sho...hreadid=311416

83ho86tpi

I went to 2 shops and neither one will work on it. They said They dont know where to start since I did so much work on the car and since I built the motor I think they are just lazy, but I do understand thet they are in a buisness where they want to turnover easy repair jobs faster than the flatrate to earn as much $ as possible.

They both agreed that my comp TPI kit was making the car run rich and they said I need a different computer / chip to run it. I called comp and the guy admitted that I should try a custom burned chip.

So far everyone has agreed that it would not overheat from running rich.

The shops did look over my cooling system and told me it looks fine (DUHHH!! I only replaced all the cooling parts twice), so they started to blame my heads or gaskets and my workmanship.

I took off my intake and heads and the gaskets and heads look fine (those mechanics almost had me thinking I had the gaskets on upsidedown or the wrong ones on). Of course I didnt put them on wrong and it all checks out. I will take my heads back to my machine shop monday to have them pressure checked and tested.

I am planning on putting my old shortblock in since it ran great. I checked it and it only needs $100 for bearings, timing chain, and gaskets, everything else looks great on it, the rings are still well within service specs and the bores look great.

The old block should run cool like it did before, and it should not run as rich since it has the regular GM tpi cam in it. At least I wil be able to run my car again while I work on the new motor.