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ECMlink CEL will turn on then disappear when letting off throttle

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SnowmanFD

Proven Member
142
8
Dec 11, 2021
North Seattle, Washington
Before i had ecmlink i had a cel for my egr, after i installed link the cel was gone. Im thinking its related to that but im not completely sure. Basically the cel will turn on, i will let off throttle ever so slightly and it will disappear
- there is no noticeable changes when its on vs when its off
-it never turns on when im completely off throttle
-i can try to find a video or datalog if that helps
 
Check your logs to see if your knocking. It's typical for DSMLink to be configured to turn on the CEL is the car starts knocking.

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That’s a lot of knock/detonation the ecu is picking up. Check the knock sensor. It’s located under the intake manifold on the block. If the goo melted, you’ll want to replace it.

It runs poorly because the ecu will retard timing based on knock count.

Change the knock cel to 2 instead of 5. Detonation kills motors so let off anytime it comes on.
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That’s a lot of knock/detonation the ecu is picking up. Check the knock sensor. It’s located under the intake manifold on the block. If the goo melted, you’ll want to replace it.

It runs poorly because the ecu will retard timing based on knock count.

Change the knock cel to 2 instead of 5. Detonation kills motors so let off anytime it comes on.
So ill plan on replacing the knock sensor, is it hard job? Also if that doesn't fix it where should i go from there?
 
^What Curt said. Inspect the sensor first and it’s not hard to replace as it just unscrews. Don’t over tighten it either. Think is only 18ftlbs iirc. There could be other factory’s causing the knock reading such as loose parts and/or carbon build up in combustion chambers.
 
You can see from the pic that the car is knocking at 3100 rpm at 18% throttle. Likely not detonation.
I'll be able to check the sensor in about an hour.
correct me if I'm wrong but what probably happened is the silicone goo has melted/gone bad, so the microphone (knock sensor) is picking up other noise and reporting it as knock so the ecu then pulls timing.
also, kind of a dumb question, where is it? I know it's on the block and I'm assuming it's near the intake manifold
 
where is it? I know it's on the block and I'm assuming it's near the intake manifold

Here's a diagram that shows where it is relative to the brace that is under the intake manifold.
I think you should take the car to English Racing and let them tune it. Would probably cost about $400 but it might save your engine from being destroyed by knock or whatever else might be wrong in there.
If they think your knock sensor is bad, they might have one that is still ok lying around in an old block or something.
Or they might tell you they can't tune your engine because such-and-such is wrong with it. Then you'd have a better idea what it needs.
I suppose though that you want to wait until you get some more parts put on it before having it tuned? Is that what you have in mind?

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Here's a diagram that shows where it is relative to the brace that is under the intake manifold.
I think you should take the car to English Racing and let them tune it. Would probably cost about $400 but it might save your engine from being destroyed by knock or whatever else might be wrong in there.
If they think your knock sensor is bad, they might have one that is still ok lying around in an old block or something.
Or they might tell you they can't tune your engine because such-and-such is wrong with it. Then you'd have a better idea what it needs.
I suppose though that you want to wait until you get some more parts put on it before having it tuned? Is that what you have in mind?

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I just recently took the car to them and got my timing, waterpump, and a bunch of seals replaced (see pic below) im planning to install all the parts i want before a tune. Right now i have an fp manifold and an injen intake with a 2g maf. I only need to buy fuel components (fpr, pump, injectors) then i was going to bring them the car and get a tune and probably also have them do the fuel stuff because its a little daunting to me. My dream would be 400hp but seeing as i only have a 16g i feel 350hp is more realistic and itll be more reliable. But im currently waiting for my wallet to recover LOL, the previous service costed more then i thought it would. When the car was down there i asked if they could check the knock sensor or do a base tune just so it would run better but they said they would have to be tuning the car and it would cost a ton more. So i decided to pass for the time being. They also did an Allingment and it was out of spec barely a week later, any idea why this would be?

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Putting more parts on first, ok that's what I thought.
The amount of knock shown in your logs above is way way too much if it is real detonation knock. I mean it would cause engine damage to continue driving it that way if it is real.
What I don't know is, can a knock sensor put out high levels of "fake knock" to the ecu if the sensor is bad? I always thought that if a knock sensor goes bad, that its signal output would be less, and that eventually it would just be dead - no signal.
Maybe somebody in here knows about that.

I'm suspecting that's it's not real detonation knock because the Load Factor is so low. It's 0.5 and then 0.65 Load Factor in those screen shots.
At 0.65 Load Factor, 3175 rpm, coolant 186 deg, I don't think 16 deg timing is a problem even on only 92 octane gasoline. So I'm doubting detonation knock.

If the alignment goes bad right away after it's been done, usually it means there is a bad ball joint or bushing somewhere. Those are things they are supposed to check for first before they even do an alignment. So that's kind of disappointing. But I did have a problem like that with another good body/alignment shop, in Kirkland, on a 2006 Pontiac GTO. They fixed some collision damage, got the car aligned, and the car did not drive right. Took the car to a different body/alignment shop and they figured out pretty fast that it was the steering rack. On our DSMs you can get reman steering racks that are good, if that's what it is.
By the way, alignment is something that can be done on our cars by a normal alignment shop - doesn't have to be a "tuner" shop. It just has to be a good alignment shop.

Back on the knock sensor, maybe you've noticed, there have been several threads in here ever since about 2019 about the fact that the 1g DSM knock sensor has been discontinued by Mitsubishi. English Racing doesn't keep up with that kind of info very well. So if you make arrangements to do anything there that involves possibly replacing the knock sensor, they might come back to you saying that they can't get one. It would be best to tell them that you've heard that the sensor has been discontinued by Mitsubishi and see what they say about what they could maybe do about that. The threads in here have come up with a few solutions, one which seems pretty solid, which involves buying an aftermarket sensor that has the right sensor on it but the wires from it are too short. You can buy it from RTM Racing and they have the explanation for it on their web page, here:
https://www.rtmracing.com/xcart/product.php?productid=20950&cat=0&page=1&featured=Y

Good luck with recovering your wallet!
 
His leak down test in one cylinder is 38% Crank Case. That's a lot, and "Crank Case" means it's mostly the rings that are leaking, as far as I know. So apparently there's a lot of wear on the rings, and probably also on the piston and wall in that cylinder.

So, question for everyone: Can a lot of wear in a cylinder cause a big knock signal like what the OP is getting? I'm thinking, maybe a lot of piston slap from increased piston to wall clearance, or something like that?
 
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There is one other aftermarket knock sensor I know of - Autozone sells one that they say "Fit's your car" (1990 Talon turbo 2 liter).
They call it a Santech KS0120. It costs a few bucks more than the RTM one, and it doesn't have the nice metal gripper on the wire that comes out the back of it. They give the wire length as 9.5 inches and that might be the correct length, I don't know what it should be. That page is here:

Whatever you do with your knock sensor, hang on to the old one! It might still be good. If you have English Racing change the knock sensor, tell them you want the old one back! Don't lose that thing.
 
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There is one other aftermarket knock sensor I know of - Autozone sells one that they say "Fit's your car" (1990 Talon turbo 2 liter).
They call it a Santech KS0120. It costs a few bucks more than the RTM one, and it doesn't have the nice metal gripper on the wire that comes out the back of it. They give the wire length as 9.5 inches and that might be the correct length, I don't know what it should be. That page is here:

Whatever you do with your knock sensor, hang on to the old one! It might still be good. If you have English Racing change the knock sensor, tell them you want the old one back! Don't lose that thing.
Good to know ill make sure to hold onto it. Would you reccomend i have them do it or should i just do it myself?
 
Well, I'm not so sure your knock sensor is bad. But if you did put a new one in, it would be kind of a "second opinion" on the numbers you log.
It's hard for me to say what would be best between you doing it or ER doing it. But if I were doing it on my car, if I was pretty sure I needed a new sensor, I would buy the sensor that RTM sells, and lengthen the wires if they need to be longer. "Need" might just be making sure there's enough wire on there so that it isn't pulled tight, and that you can attach the connector to something like it's shown up in post #12 so it isn't flailing around yanking on the wire.

One of the wires in there has shielding, or is supposed to have. Since those wires are right near the coil and power transistor, the shielding might actually be kind of important to keep the signal clean. I don't know. I do know that when my car was more stock, the knock sensor output was only about 0.4 volts just before the point where it would all of a sudden jump and get recorded as knock. So it's not a real strong signal. There are ways to add shielding back on over your new wire that you would have to insert in there, but I've never done that and wouldn't know what to suggest for doing that.

I don't see a tightening torque given for the 1g, but on the 2g it is 23 newton-meters which is 17 foot-pounds. I would just go with that for torque when putting the sensor in.

Here's something I think you should try though. You should try this first before taking your old sensor out.
Try drastically reducing the timing in the 3,000 rpm cells in "ECU Direct Access". Do this in both maxoct and minoct tables.
What I'm noticing is that your knock is always at around 3,000 rpm, and at that rpm it is knocking even at light throttle and low load factor. At higher rpms I'm not seeing knock.
In these screen shots of your maxoct and minoct tables, I've drawn loops around some cells in the 3,000 rpm column.
Change the values in those circled areas to 15 on the maxoct table, and 14 on minoct table. That is a lot lower than what is in there now.
Then log a drive.
If the knock is still there, then I think it's not detonation knock. It is probably some other noise your engine is making due to mechanical issues that hit at a certain frequency. Like maybe that one cylinder that is going bad, or something else.
Maybe the knock will be gone.
Anyway, we'll see what the results are and it will help with knowing what's going on with it.

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