Egr problems
June 17th, 2019, 11:43 AM
#22
Yes. TunerPro and TunerPro RT - Professional Automobile Tuning Software I used these guys for cable and getting going. OBD1 GM: Getting Started « Moates Support
It does help in some things but is not a fix-all. It's good for stuff like verifying what the ECM thinks the sensors are reading, whether it's in closed loop, catching conditions in which a code is triggered, etc. It helped me with the knock sensor and why I was failing emissions @ idle (I didn't realize I was falling out of closed loop in hot idle which turned out to be due to a lazy O2 sensor).
However, it's no substitute for fundamental checks. I had a shifting problem and catalogued the hell out if it for months trying to figure out why. Finally I listened to the experienced guys who were saying check the fuel pressure and sure enough - that was my problem. I had marginal fuel pressure, about 10-11 psi. ECM doesn't measure fuel pressure so assumes it's good and sets pulse width on injectors based on throttle position, rpm, MAP, and ?, not sure what else. Evidentially, the marginal fuel pressure was good enough to drive around but I had to put more throttle into it than would normally be needed for a given speed/acceleration. I think ECM thought I was trying to accelerate hard based on RPM, throttle position so would delay the shift point even though I was just granny driving. Put in the new fuel pump with solid 13psi and shift points magically returned to normal.
It does help in some things but is not a fix-all. It's good for stuff like verifying what the ECM thinks the sensors are reading, whether it's in closed loop, catching conditions in which a code is triggered, etc. It helped me with the knock sensor and why I was failing emissions @ idle (I didn't realize I was falling out of closed loop in hot idle which turned out to be due to a lazy O2 sensor).
However, it's no substitute for fundamental checks. I had a shifting problem and catalogued the hell out if it for months trying to figure out why. Finally I listened to the experienced guys who were saying check the fuel pressure and sure enough - that was my problem. I had marginal fuel pressure, about 10-11 psi. ECM doesn't measure fuel pressure so assumes it's good and sets pulse width on injectors based on throttle position, rpm, MAP, and ?, not sure what else. Evidentially, the marginal fuel pressure was good enough to drive around but I had to put more throttle into it than would normally be needed for a given speed/acceleration. I think ECM thought I was trying to accelerate hard based on RPM, throttle position so would delay the shift point even though I was just granny driving. Put in the new fuel pump with solid 13psi and shift points magically returned to normal.
June 17th, 2019, 12:22 PM
#23
CF Beginner
Thread Starter
Join Date: Jun 2019
Location: Las Vegas
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
I understand
I understand what you mean. That makes allot of sense. I will probably keep this truck, if for nothing else than for my son drive. I think I am gonna look for something with a carb and old school setup. He wants something old for his first truck. Can’t say as I blame him lol. Next year he wants to start a vocacation school for auto tech, not sure if he’ll find any barbs in there, but I can have him tell me what to do on my truck. Lol. Thanks Sabino, it’s a little one but there is light at the end of this problem.
i have a 14 pound spring in my fuel regulator, pump is rated for 14.5 to 23, I am really curious to see what it’s putting out.
i have a 14 pound spring in my fuel regulator, pump is rated for 14.5 to 23, I am really curious to see what it’s putting out.
June 18th, 2019, 7:15 AM
#24
CF Beginner
Thread Starter
Join Date: Jun 2019
Location: Las Vegas
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
Confused
Update, so I drive about 18 miles to work, drives ok, gets a little hot, 220, studders, knock sensor disconnected, drive home, drives ok, but up the hill gets hot, problem duplicates, flush once more, much cleaner, put the 195 stat in clean knock sensor drives like crap knock sensor in or out. Then had bible study so no more time to test. Really perplexed. Need to test knock sensor, and wire again, not sure if I did it correctly, if I did they are toast as they have no continuity. But could the temperature be retarding the timing? Could I have gotten bad info by setting it to 0 tdc? What if the temperature sensor going to computer is way different from one in block? I will be looking into this software and cable, just need more time. Like you said that information would tell me a lot. And of course need to test fuel pressure. I will probably switch back to 180 tstat for now.
June 18th, 2019, 9:16 AM
#25
CF Beginner
Thread Starter
Join Date: Jun 2019
Location: Las Vegas
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
What the hey
So I run the 195 stat to work. Reset computer. No knock sensor connected. Did ok. A couple of hesitation here and there. Ran a little above 210 a couple times, but another flush to get out what I believe is several bottles of stop leak, and a new rad and that’s going to be better. Just weird. I am looking forward to testing fuel pressure. I also thought perhaps the wire bundle was getting hot. It’s not in a place I like. Looks like someone pulled it off brace and set it on top of intake manifold. Found that when doing grounds.
Going to research how to test this knock sensor. Never gave a code until I disconnected it. Connect or not does not read to ground. If I put in block it does not either.
Going to research how to test this knock sensor. Never gave a code until I disconnected it. Connect or not does not read to ground. If I put in block it does not either.
Update, so I drive about 18 miles to work, drives ok, gets a little hot, 220, studders, knock sensor disconnected, drive home, drives ok, but up the hill gets hot, problem duplicates, flush once more, much cleaner, put the 195 stat in clean knock sensor drives like crap knock sensor in or out. Then had bible study so no more time to test. Really perplexed. Need to test knock sensor, and wire again, not sure if I did it correctly, if I did they are toast as they have no continuity. But could the temperature be retarding the timing? Could I have gotten bad info by setting it to 0 tdc? What if the temperature sensor going to computer is way different from one in block? I will be looking into this software and cable, just need more time. Like you said that information would tell me a lot. And of course need to test fuel pressure. I will probably switch back to 180 tstat for now.
June 18th, 2019, 11:20 AM
#26
With respect to knock sensor - I don't think you can test it with ohm meter but not sure. I think it's a piezo-electric thing which wiggles voltage with vibration/knocks when biased with some voltage. Maybe someone else here knows for sure.
Are you saying that you have constant code on knock sensor now? whether plugged in or no? If you can verify continuity from connector to somewhere up the wire where you know its good - then it could be the sensor failed. I've read that they can fail with torque on body. again - no experience on that myself.
with respect to timing - here is good link with info on checking timing and fuel pressure https://www.chevytalk.org/fusionbb/s...hp?tid/200181/
with respect to temp - I don't know what ECM does with temp other than decide when to enter closed loop. I'm pretty sure ECM uses sensor on side of block by #1 cylinder. Not the sensor on the tstat. If I'm wrong, somebody will probably correct that.
good luck
Are you saying that you have constant code on knock sensor now? whether plugged in or no? If you can verify continuity from connector to somewhere up the wire where you know its good - then it could be the sensor failed. I've read that they can fail with torque on body. again - no experience on that myself.
with respect to timing - here is good link with info on checking timing and fuel pressure https://www.chevytalk.org/fusionbb/s...hp?tid/200181/
with respect to temp - I don't know what ECM does with temp other than decide when to enter closed loop. I'm pretty sure ECM uses sensor on side of block by #1 cylinder. Not the sensor on the tstat. If I'm wrong, somebody will probably correct that.
good luck
June 18th, 2019, 11:43 AM
#27
CF Beginner
Thread Starter
Join Date: Jun 2019
Location: Las Vegas
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
The saga continues
I watched better video, first I use ohm to test if it’s shorted. Then I use volt meter to see if it produces current off and on vehicle. This is new stuff for me, but learning. Might be a problem, as they go bad they can become more sensitive. Things like a noisy a/c or exuast or other noises can affect it. I gotta go home tomorrow and test it by tapping a wrench on the block while black is on ground red is on sensor.
Code has never came up with it connected, sorry for confusion, but it ran like crap when it was. I’m trying to get ahold of a service manual. Eric the car guy just told me to try a pdf on, lots cheaper.
Your right on torque, they can be very sensitive when older. Ima check that site on timing. One more thing, looks like once knock sensor tells ecm to retard, only reset will make it go back to normal. Explains yesterday.
Code has never came up with it connected, sorry for confusion, but it ran like crap when it was. I’m trying to get ahold of a service manual. Eric the car guy just told me to try a pdf on, lots cheaper.
Your right on torque, they can be very sensitive when older. Ima check that site on timing. One more thing, looks like once knock sensor tells ecm to retard, only reset will make it go back to normal. Explains yesterday.
With respect to knock sensor - I don't think you can test it with ohm meter but not sure. I think it's a piezo-electric thing which wiggles voltage with vibration/knocks when biased with some voltage. Maybe someone else here knows for sure.
Are you saying that you have constant code on knock sensor now? whether plugged in or no? If you can verify continuity from connector to somewhere up the wire where you know its good - then it could be the sensor failed. I've read that they can fail with torque on body. again - no experience on that myself.
with respect to timing - here is good link with info on checking timing and fuel pressure https://www.chevytalk.org/fusionbb/s...hp?tid/200181/
with respect to temp - I don't know what ECM does with temp other than decide when to enter closed loop. I'm pretty sure ECM uses sensor on side of block by #1 cylinder. Not the sensor on the tstat. If I'm wrong, somebody will probably correct that.
good luck
Are you saying that you have constant code on knock sensor now? whether plugged in or no? If you can verify continuity from connector to somewhere up the wire where you know its good - then it could be the sensor failed. I've read that they can fail with torque on body. again - no experience on that myself.
with respect to timing - here is good link with info on checking timing and fuel pressure https://www.chevytalk.org/fusionbb/s...hp?tid/200181/
with respect to temp - I don't know what ECM does with temp other than decide when to enter closed loop. I'm pretty sure ECM uses sensor on side of block by #1 cylinder. Not the sensor on the tstat. If I'm wrong, somebody will probably correct that.
good luck
June 18th, 2019, 9:54 PM
#28
I'm here for the party
you can test the knock sensor. Troubleshooting sensors and how to test
ive never done it at home and i know autozone has the tester Wells talks about using. supposedly you can test it with a/c tester if it can read HZ.
the knock sensor produces its own electric currant. its very small but you can test for it. Set you tester to A/C probe the center of the sensor with the red lead and ground the black lead. now tap on the sensor it will produce 6-12 K hz
but again ive never done it so i cant say for sure if it works or not
ive never done it at home and i know autozone has the tester Wells talks about using. supposedly you can test it with a/c tester if it can read HZ.
the knock sensor produces its own electric currant. its very small but you can test for it. Set you tester to A/C probe the center of the sensor with the red lead and ground the black lead. now tap on the sensor it will produce 6-12 K hz
but again ive never done it so i cant say for sure if it works or not
June 19th, 2019, 12:09 AM
#29
CF Beginner
Thread Starter
Join Date: Jun 2019
Location: Las Vegas
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
Good info
Ok so I tested it on the truck tonight, no time to take it off. There is no continuity between sensor and ground. Read no voltage. I will test it when I remove it, but it looks like it’s shot.
Thanks Irish alley! I will reread and try and duplicate results.
QUOTE=Irish_alley;430193]you can test the knock sensor. Troubleshooting sensors and how to test
ive never done it at home and i know autozone has the tester Wells talks about using. supposedly you can test it with a/c tester if it can read HZ.
the knock sensor produces its own electric currant. its very small but you can test for it. Set you tester to A/C probe the center of the sensor with the red lead and ground the black lead. now tap on the sensor it will produce 6-12 K hz
but again ive never done it so i cant say for sure if it works or not[/QUOTE]
Thanks Irish alley! I will reread and try and duplicate results.
QUOTE=Irish_alley;430193]you can test the knock sensor. Troubleshooting sensors and how to test
ive never done it at home and i know autozone has the tester Wells talks about using. supposedly you can test it with a/c tester if it can read HZ.
the knock sensor produces its own electric currant. its very small but you can test for it. Set you tester to A/C probe the center of the sensor with the red lead and ground the black lead. now tap on the sensor it will produce 6-12 K hz
but again ive never done it so i cant say for sure if it works or not[/QUOTE]
June 21st, 2019, 6:54 PM
#30
CF Beginner
Thread Starter
Join Date: Jun 2019
Location: Las Vegas
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
Update
Replaced knock sensor, new one seems to hit like 5 or 6 volts, old one 1 or two. Flushed so much crap out of cooling system again. Used a hose t with two hoses going into drain plugs. Hooked that to my hot water heater. Need to flush again and replace radiator, maybe water pump the way it looks. Good news is keeping cooler. Put old air cleaner on to humor my son. Reset computer, ran all day, except for a very small hesitation in mid range. Went to go smog and register, put my air intake on, goes right back to crap. Good news is I passed. Worse news, guy in the Ford lighting behind me blew his ac, scared the crap outta me and the smog tech. However I thought I heard it knocking, but when I went over, it was the injectors in the plenum. Sounded just like it. Gonna experiment with old air cleaner. Need to check fuel pressure. There are two different injectors in the tbi, need to verify same part #. Other than that I can only think pcm, but without a way to read figures yet, it’s tough. Whenever I reset the ecm pcm it works for a period of time. Also got a used Haynes manual for $7 so I’ll be pouring over that when I have time this weekend.