65 Sportwagon

Here is my story... Ive installed a 91 Trans Am 305 TPI in my wifes 65 Sportwagon.. It is very Cool but Im having problems with the knock sensor..
Ive hooked up a Scanner and with the key on, there is no Knock sensor being seen.. But when you start the car, The scanner says Knock YES.. The Car runs great in open loop then is goes to Close loop and it sees the Knock Sensor and runs like a turd... Ive tryed to hook a new knock sensor to the wire and Ground the sensor and raped a rag around it to try to trick the ecm. That didnt work for me.. I was just try to see if the motor had a Knock that I didnt hear.. Motor only has 66,000 Miles..
Ive checked the Wire at the knock sensor I Have 4.93 Volt.. That is Good
Ive Ohmed the sensor out it was 3.9K That is Good
Ive ohmed the wire from sensor to ECM... That is Good.
Ive replaced the ECM That didnt Help
Ive replaced the MEMCAL Chip... That didnt Help
Battery voltage at ECM with Car running is 14.3
The motor has a Good Ground...
With car running and wire on I read 2.425 volts I dont know what it should be
I Feel I've done everything I can Im very upset that I can Fix this.. If anyone has a idea Please Let me know...

DENN_SHAH

iTrader: (1)

there is a TSB for the problem your having which may be the fix for you.
check the code on the MEMCAL & post it up, its normally 4 letters & looks something like AXYB.

Kevin91Z

iTrader: (1)

Are you sure you have the correct knock sensor for a 91? There are different types. One style for 85-89 engines and a different style for 90-92 engines, because of the ECM differences.

RBob

iTrader: (1)

65 Sportwagon, what makes you think that there is a problem with the knock sensor? Code 43? Excess spark retard? As you posted your checks of the ESC system show it is correct (even the "wire on I read 2.425 volts" is correct).

Once the ECM goes closed loop what does the scan tool show for INT & BLM?

RBob.

65 Sportwagon

The 3.9k knock is the right one for a 5.0.. I have two memcal chips.. The first one is a AXXF and a new one of AXXB.. Ive try them both.. I think I have a knock sensor problem because the scanner with key on not running will say NO... Then I start the engine and Knock Sensor goes to Yes.. Car will run great in open loop then it changes to closed and looks at all sensors and retards tons of timing...
INT is 119-123
BLM is 128 This was in close loop

DENN_SHAH

iTrader: (1)

the chip shouldn't be the problem.
AXXB shows to be the latest update for ARZC & AWFU.
AXXF shows to be the latest update for ARZU & AWFY.
both show to be fixes for driveability and/or check engine light code 43
both show to be for LB9 & auto trans, AXXB for P214/60R16 or P215/65R15
AXXF for P245/50ZR16
i show no designation for Federal or California emissions on either one.

make sure the knock sensor wire isn't near any of the plug wires. with the knock sensor disconnected, set your volt meter on the 2 volt AC scale & start the motor up & see what you get.
what is the timing set to? did you unplug the timing set connector when you set the timing?

65 Sportwagon

The wire is ran under the manifold and up the firewall than inside..
I set the timing at 0 with plug off and then reconnected wire..
I disconnected Knock sensor and started engine, With a meter on wire in AC mode I have .001
I have never had a 43 Code or and codes....
Im hoping someone can HELP Im will to do anything..

RBob

iTrader: (1)

Half of your replies do not make any sense.

However, this one does:

I set the timing at 0 with plug off and then reconnected wire.

The base distributor timing is 6 deg BTDC.

RBob.

65 Sportwagon

I sorry, I checked timing tonight and it is at 6 BTDC with wire unpluged..
Any other suggestions

RBob

iTrader: (1)

So the issue is excess retard on the SA. Double check that the scan tool is also showing the knock counts increasing on a steady basis. They should be as this is what triggers the SA retard.

Couple of things that can cause this:

The Fan switch and Knock sensor connectors are switched. IOW, the fan switch connector is plugged into the knock sensor and vice-versa (this is the fan switch in the passenger cylinder head).

The scan tool is putting a 10K resistor across the ALDL A & B terminals. The ECM will ADD 8 to 10 degrees of SA to force knock to occur.

There is something that is attached to the engine that is making noise (such as a bad bearing in an accessory). Or something attached to the engine is hitting a frame or suspension member.

RBob.

65 Sportwagon

HUMM

65 Sportwagon

Couple of things that can cause this:

The Fan switch and Knock sensor connectors are switched. IOW, the fan switch connector is plugged into the knock sensor and vice-versa (this is the fan switch in the passenger cylinder head).

There is something that is attached to the engine that is making noise (such as a bad bearing in an accessory). Or something attached to the engine is hitting a frame or suspension member[/quote]

Its not the wire being switched.. Ive traced the wire from the knock sensor to the ecm and it is going to the right stud.

I took off the belt so no acc. were spinning and It still detards timing.
I don't know it this would work, But I installed a new sensor to the plug and grounded the sensor (sensor not in motor) and raped the sensor in a rag to dampen and shock(sensor on wheelwell) and I still can't make it not see the knock sensor. My thinking on this is. If the motor dos have a knock, This should make the ECM not see it.. MY THINKING IS NO GOOD.
It still retard timing. I fell Ive done everything..

Can I have a new chip burned to not see the knock sensor..

RBob

iTrader: (1)

To eliminate the knock sensor and still have the ECM see it (no DTC 43), replace it with a 3.9K resistor.

Note that there are some other reasons for a knock sensor to alert the ECM. But it gets ugly.

You just may want to pull some plugs and look for signs of detonation. Would not be good if there is and you disable the knock sensor.

RBob.

65 Sportwagon

I try a 3.9K resistor in place of the Knock sensor and it still retarts timing..
Is there any other reason timing will be pulled out.

DENN_SHAH

iTrader: (1)

this is kind of strange, you shouldn't see any knock counts with the resistor in place of the knock sensor. it sounds like your getting AC voltage induced into the knock sensor wire.
with the 3.9K resistor still in place, ground the negative lead of your DVMM & with the positive lead tap into the knock sensor wire, set the DVMM on the 2 volt AC scale & start the motor and see what the AC voltage looks like. let it run long enough to go into closed loop & watch your scanner for knock counts. when you see knock counts, look at the DVMM.

65 Sportwagon

Ok, I installed a 3.9 resistor were the knock sensor goes and hooked up a DVMM (on AC volt) to the resistor and grounded other meter end. I ran car in closed loop and it still pulls timing and I show no AC volts on wire..
If you do a brake stand (just off idle 900rpm) It pulls 10 Deg timing out..

With the resistor installed scan still says Yes to knock..
It also pulls timing, I saw Knock retard Jumping for 8 to 12 well in gear and foot on brake around 900RPM.
I did see the INT go down to 80 well this was going on..
I thought it was to stay at 128.. I dont know why it was doing this.
There got to be something retarding timing besides the knock sensor..
I'm REAL GREATFUL for the help trying to fix my problem.. I will try anything...

RBob

iTrader: (1)

With the 3.9K resistor and no A/C on the knock line, then it is either:

1) the ECM is bad

2) the scan tool is bad

3) there are bad grounds between the ECM & engine block


Note that having the INT drop to 80 isn't good either. That is pulling a lot of fuel out. Did the engine start to stumble or want to die when the INT went that low?

RBob.

cmgrinn

How did you make out with the knock sensor problem? I'm having very similiar problems in my 91 Z28 L98. I tried putting the knock sensor in insulation, but still have same problem. Just started diagnosing recently, but seems to happen more often under hot conditions, and I lose all advance, and timing goes into retard under accel. The more I accel, the more it retards. Is there an Electronic spark module like the older tpi's or is it built into ECM? Please let me know if you fixed it or not. Thanks.

Shadygrady

iTrader: (3)

subscribe.I`m having similar problem.On acceleration getting alot of retard.20 degrees is not uncommon.Pulling out most of my advance.Sensor is new,was installed with new engine which has about 11,000 miles on it.No knocking or pinging heard.Plugs look perfect.No signs of detenation.I`m going to try to insulate the sensor and see what that does.I was running lean and thought that was the problem,but had that fixed and no change in retard.I know I prolly shouldnt have done this but I kinda had to see.I disconnected the knock sensor and went for a drive,only differance I noticed was the car seemed to have a good bit more power.I wasnt dattalogging when I did this.Will do soon.Gonna pull sensor and check part number and get a new one.That things a PITA to get at.

ninetyone

iTrader: (2)

Ok, i know this may be late, but did any of you guys ever figure out a solution to your knock sensor problems? I own an 91 TPI trans am 350 . I have a similar issue. Not sure if it is my knock sensor. My car runs great in open loop .Gets warm and runs like crap. When i try to accelerate it just kind of falls on it's face. Feels like my timing is really being retarded. Almost feels like a wet distributor cap. The car does not run like this all of the time though. Now the car DOES run GREAT when it is driven normally. Try to floor it and forget it! 98 percent of the time it acts up like this. I have no codes. My injectors are new and ohmed. No vacum leaks. Idles great. Yet, the problem seems to go away when i am about to and eighth of a tank or lower.??? What the hell is going on here? My trans am is just not a Trans am anymore!! I have been trying to figure this out for six months now. I cant help but feel this is related to the knock sensor. Also i would like to add that somebody looked at my engine and told me that i may possibly have a bad engine ground. Look, something is limiting my acceleration like a mother f @!!#$. Somebody please help.

Dennis-Z28

iTrader: (1)

Does anyone know what the differences are? Is it just thresholds or is functional as well?

I replaced my stock knock sensor with a new one and now it throws code 43. the stock one has ~1500 Ohms across the pin to the threads; the new one has no conection between the two (open circuit). Im just not sure which is right. Both measured with engine off.

RBob

iTrader: (1)

Either you are measuring the knock sensor incorrectly or they are both bad. From center terminal to body the ohms reading should be in the 3.9K to 4.0 K range.

Note that this is for a '90-'92 TPI f-body.

RBob.

Dennis-Z28

iTrader: (1)

You're right, jumps between 3.9 and 4.0 kOhms. (I had it on the audible setting which read 1500 for some reason)


Looked into my part numbers:
existing has stamped: DR019-3140
new one is: BWD brand S8003

Still have to figure why the new one is an open circuit. Maybe if I loosen/tighten it a few times to get a better contact to the block.

RBob

iTrader: (1)

If the new one that is in the block measures 100K ohm then it is the wrong sensor. That would be for a TBI car or a '85-'89 MAF car (f-body cars).

RBob.

lonestar7

iTrader: (1)

I would like to know the answer to this problem too. A 1992 RS (B4C, 1LE code car) that I'm looking at as a possible buy has a similar problem. Has new ECU and knock sensor, giving code "43" and runs like crap. Owner thinks it could be caused by bent oil pan hitting crank, but I'm not sure the slight bend there is enough to do that.

ninetyone

iTrader: (2)

Turned out my timing was retarted, injectors were too big and i also took out the hypercrap chip and now it runs much better.

Dennis-Z28

iTrader: (1)

the new one is 104k Ohm. those knock sensors are not cheap either, I have no luck with parts stores. especially Lordco.

RBob

iTrader: (1)

Yes, that will do it. Time to carry the DVM into the store for the right knock sensor.

Many times stuff is just mis-boxed. Was with sometime while trying to get a TPS for a crossfire car. Parts store books showed a picture of the TPS that was correct. But in the box was a TPS for a q-jet carb, not even close to being correct.

RBob.

jetsziarnick1

Looking for a knock sensor for a 1982 Camaro with the crossfire injection v8 - 5.0 - vin#7 -


Help