I have read many posts about this problem and have tried all. My knock sensor wire is routed away from exaust and in good condition. Timing is currently at 6 deg. BTC. have tried 0 - 12 deg. Replaced knock sensor and ESC module with new parts. Ways I produce the code
Start engine and bring to 2500 rpm, engine starts surging between
1800 and 2500 and then light comes on. This happens when it is cold or hot. Once I start driving light will go away and then back on again intermitaly. It seems to go off when I am on the gas hard and back on when cruising. I am using the painless performance wiring harness 61010. Since I have a manual NV4500 I had to twist 2 wires together to override the neutral saftey switch, they said that might be a problem if the computer limited Rpm in park but i have not experienceD that. The engine has been recently rebuilt and is completly stock. I did put headers on it. When I disconect the wire to adjust the timing I am at 6 deg. If I have the light on it and rev the engine the timing jumps to about 15 deg. BTC when I rev engine to
2000 rpm with the wire still disconnected. Any ideas would be greatly appriciated. Tests to rule out individual componets would be helpfull. Thanks, Jacob
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G
GMC Gremlin
What vehicle is this in? I have a 1990 GM factory service manual and the knock sensor is the same (wireing wise) in anything that doesn't have a 2.5L engine or the 4L80-E transmission. I just want to make sure that you have a TH700R4 (K5/Jimmy) or the 4L60-E (I think they had these in the K10/20's, IE pickups).
GMC Gremlin
"
"Doc"
The only AT's offered behind a TBI 350 that year were the TH400 and the TH700R4.
Doc
G
GMC Gremlin
Ya... just noticed that my manual is for 1991. My jimmy is the '90
GMC Gremlin
G
GMC Gremlin
Do you still use MSN IM? Never see you there...
GMC Gremlin
"
"Doc"
Yeah I do, just not too much the last few months. Hella busy at work.
Doc
G
GMC Gremlin
Well I guess no one else has help, so here is one of the first things that looks applicable out of the manual: Can you cause a knock code by tapping on the right exhaust manifold with a hammer?
GMC Gremlin
G
GMC Gremlin
Jeze doc. Sounds like you used toe be a hellion!
formatting link
GMC Gremlin
J
Jacob
When should I try that? Will it get a knock code before it does it's self test? I think as soon as it fails it's self test the light comes on but then it will go off again, should I try tapping on the block then? One other thing, when I changed out my knock sensor there was no coolant fluid pouring out of the block like I read there would be. Does the knock sensor need that fluid to work, I would think it would just need to be tight in the block, just thought I would metion that.. Then engine is in a Jeep CJ7 infront of a nv4500 trans. The engine came out of a 90 chevy blazer with an auto tranny. I got the painless wiring harness and have triple checked all connections. Would the fact that I bypassed the neutral saftey switch have anything to do with this?
Jacob
G
GMC Gremlin
The self test is supposed to happen at WOT at speed, not at idle. When the ECM suspects that the knock sensor is faulty, it advances the timing, and if it can't get a knock signal - it throws a code. The same code as if it was knocking (not my idea of a good system, but they fixed it with the OBD II system). At idle, when there is no code, you should be able to set the code with a hammer on the exhaust manifold. Also, I would find the program "WIN ALDL" so you can read the "real time" data instead of looking for a trouble light. This will be able to read everything from the O2 senor voltage to WHEN it get's (or doesn't get) knock signals. MUCH more informative. It's free, and the cable is easy enough to make with parts from rat shack. I don't know if the park/neutral switch would do anything. It isn't mentioned in the knock sensor schem (which is very simple) so my guess would be no, but computers are frikken weird.
GMC Gremlin
J
Jacob
I have now built a cable to use with WINALDL and have logged a complete driving session to a file on my laptop. When I look at it I can see what all my sensors are doing but really don't know what it means. Is there anyone out there that can figure out a code 43 and why it is happening from looking at a WINALDL file? Thanks for all you help so far, looking forward to closing this thread.
Thanks, Jacob
G
GMC Gremlin
Can you post it in a text format here?
GMC Gremlin
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Jacob
Here it is.. It seems that the data kept it's format but the column headers will need to be formated. Let me know what you think.
Time SENSOR:PROMID SENSOR:IAC SENSOR:Coolant Temp SENSOR:SPEED SENSOR:MAP SENSOR:RPM SENSOR:TPS SENSOR:INT SENSOR:O2 SENSOR:Battery Voltage SENSOR:Knock counter SENSOR:BLM SENSOR:rich / lean counter MW2:Vss Pulse Occured MW2:ESC 43B Ready for second Pwr Enrich MW2:DRP Occured MW2:Factory Test Mode (3.9k Ohms MW2:Diagnostic Mode (0 Ohms) MW2:ALDL Mode (10k Ohms) MW2:1st time Idle Flag / High Bat Voltage MW2:Idle / Cool Flag MWAF1:Clear Flood Flag / Not Closed Loop MWAF1:BLM Enable Flag MWAF1:Low Battery (IAC Inhibited) MWAF1:4-3 Downshift for TCC unlock MWAF1:Asynchronous Fuel Flag MWAF1:Old High Gear Flag MWAF1:Rich Flag MWAF1:Closed Loop Flag MCU2IO:AIR Divert Solenoid ON MCU2IO:AIR Divert Solenoid ON MCU2IO:A/C Disabled MCU2IO:TCC Locked MCU2IO:Park/Neutral MCU2IO:No High Gear MCU2IO:Not Used MCU2IO:No A/C Requested MALFFLG1:24 VSS (Vehicle Speed Sensor) MALFFLG1:23 IAT / MAT low (Air Temperature) MALFFLG1:22 TPS low (Throttle Position Sensor) MALFFLG1:21 TPS high (Throttle Position Sensor) MALFFLG1:15 CT low (Coolant Temperature) MALFFLG1:14 CT high (Coolant Temperature) MALFFLG1:13 Oxygen sensor MALFFLG1:12 Engine not running MALFFLG2:42 EST (Electronic Spark Timing) MALFFLG2:41 Not Used MALFFLG2:35 Not Used MALFFLG2:34 MAP low (Manifold Air Pressure) MALFFLG2:33 MAP high (Manifold Air Pressure) MALFFLG2:32 EGR (Exhaust Gas Recirculation) MALFFLG2:31 Governor Fail MALFFLG2:25 IAT / MAT high (Air Temperature) MALFFLG3:52 CAL Pack missing MALFFLG3:53 Not Used MALFFLG3:54 Fuel Pump Relay Faliure MALFFLG3:55 ADU error MALFFLG3:51 PROM error MALFFLG3:45 O2 rich (Oxygen sensor) MALFFLG3:44 O2 lean (Oxygen sensor) MALFFLG3:43 Knock ESC
You will be able to read it better if you click "Original Format" on the top right and then select all the text and paste it into notepad. Once you save it in notepad you can open use Excel and do a file open and choose the text file so you can work better with the data. You may not need this info but I thought it may help.
Thanks again, Jacob
G
GMC Gremlin
I can't make head's nor tails of it. It would make sense that maybe this is what the computer "sees" as it does it's start up routine? Are all the numbers at the end supposed to be voltage readings?
WIN ALDL is a new one on me. I had always been under the impression you would be able to watch the knock sensor circuit and see when it triggers, or doesn't trigger, etc.
I had originally intended to say "Fix this first and you're done. The problem will likely be gone."
I edited it to this.
When it should have been this.
Fix this first and your problem will likely be gone.
Yes, I'm probably anal, but I believe inaccurate spelling or grammar suggests inaccurate content.
Bob
J
Jacob
Do you know where I might start to fix the low voltage problem? I have a new battery and a good ground.
Thanks, Jacob
N
noone
The drop may be long enough and frequent enough to see it with a voltmeter connected to battery. In this case banging, wiggling and disconnecting circuits should narrow it down.
Remember though, it is the ECM that is detecting that voltage. So if the above testing doesn't show anything, the problem may be between the battery and the ECM. You might have to connect the meter at the ECM connections.
This could be a very, very ugly problem to find if you can't reproduce it.
Or you could use the SWAG method. My Scientific Wild Ass Guess would be battery cables. GM side post terminals can corrode inside the rubber covering. The ground has to go to the block, not just the body. And the 'new battery' or its connections top my list.
Bob
M
Marsh Monster
Or you could use the SWAG method. My Scientific Wild Ass Guess would be battery cables.
======= =======
lmao......
I will be changing the Signs in the shop now, and the work orders.
SWAG fee $10.00
SWAG fee when symptom is cured $85.00
(the above fees only apply when all other diagnostic resources have failed to intended results)
~:~ Marsh ~:~
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