False knock, or so it seems???

[bbbbaad]

I am in the troubleshooting stages of trying to find the reason for Turbolink showing timing retard while accelerating under no load, in neutral. I can rev the engine slowly to 4200 RPM and get no indication of retard in timing, but get about 30-40 degrees retard when I rev quickly to that range. If I rev quickly and hold it there, the retard goes away after a couple of frames.

I have read so many posts on this subject, compiled a listing of what people say to check and have been eliminating one at a time, testing to see if it clears each time. I am still getting the same indication and these are all of the things I have done to try and fix it so far:

- Replaced ignition module and coil tower – Done with Delco parts
- Replaced spark plugs – Done RJ-42TS @.025 gap
- Replaced plug wires – Done with Delco wires
- Checked down pipe for clearance- Clear from hitting anything while accelerating in neutral but has dent in it from hitting frame, obviously from engine rolling under load and hitting the frame.
- Checked headers and crossover pipes for cracks/leaks – Donut gaskets leaking mildly, tightened all connections on flange except for the PITA connection on passenger side.
- Checked belt tensioner – Hitting nothing, has adequate tension on belt
- Checked torque converter cover for tightness – One bolt broken, removed cover all together and left it off.
- Check motor mounts – Driver side allows engine to rock under acceleration but not broken, new at about 1500 miles ago

It started raining so I needed to stop for the night. Tomorrow I will continue to search for more problems. This is a list of things that I am going to investigate next:

- Check knock sensor for tightness
- Replace knock sensor
- Check torque converter tightness to flywheel
- Check fuel pressure at WOT, currently set at 40 PSI with hose on but can't be affecting knock in neutral, can it?
- Back down the boost, currently 15 psi but doesn't seem to be able to affect this in neutral...not developing any boost
- Check fuel filter
- Replace PCV
- Check harmonic balancer is tight

Something has to be causing this. It isn't happening at constant throttle no matter what speed I hold but does retard the timing when I rev the engine quickly.

Jack Merkel rebuilt the engine 1500 miles ago. The tranny was rebuilt a few weeks ago at a local shop. I have no reference as to whether this was occurring before either of the builds occurred. I only know it is here now.

I am accepting most any challenges on this. I doubt that I will disassemble the engine to find something wrong, I would rather leave the false knock going if that is necessary.

I am thinking that I am going to replace the knock sensor first thing in the morning and see if that fixes it first and go from there.

Thanks for listening and hopefully for a response.

Andy

 

[suicide six]

Your on your way with this problem but its the only way to do it.What chip are you running and what MAF? Is MAF a rebuilt unit if stock type? Check ffor MAF tube if metal type hitting alternator bracket.Replace fuel filter.Any engine noise?

 

[tom robison]

i wpuld not worry about knock while you are in neutral, while there is no load on the motor and wrapping it to 4200 rpm. i would only worry while you are in gear a full throttle.

 

[bbbbaad]

Your on your way with this problem but its the only way to do it.What chip are you running and what MAF? Is MAF a rebuilt unit if stock type? Check ffor MAF tube if metal type hitting alternator bracket.Replace fuel filter.Any engine noise?

I am running an RA93 chip. The MAF was replaced with a Delco part about 3000 miles ago. There is engine noise up until the time I turn the key off but nothing rattling while it's running other than my head. This is tough.

I did find a lull in the rain tonight and pulled the knock sensor. It is all rusty on the outside but I am certain that the appearance has little to do with how it operates. I am still going to replace it since it is relatively cheap and I akready have it out.

If that doesn't fix it, I may take the advice of leaving it alone and work on the WOT to see if there are any problems remaining there.

Thanks for the help. Any additional advice from anyone is very welcome.

Andy

 

[bbbbaad]

and the saga continues

Well, I replaced the knock sensor and it seems to have lessened the problem but not eleiminate it. I did find the upper radiator hose bracket hitting the metal pipe from the MAF sensor and pused that away so it wasn't hitting any more. I am still getting about 23 degrees of timing retard when I rap the engine to 4K.

I forgot to post one other item I found last night which was the tranny cooling lines hitting the Y-pipe. I moved them clear of anything hitting and still wasn't any help.

It's raining again this morning. I am going to reinstall the tourque converter cover and try a test ride on the biggest raceway around here, the beltway around DC. Hopefully the knock is gone when I accellerate on the highway.

On we go........

 

[Squid4life]

Did you torque the new knock sensor to spec? 14 ft lbs. Any tighter it is "too sensitive". You said you have the torque converter cover off, did you check the converter bolts? Do you have any exhaust leaks? Crawl around and look for black carbon tracking at joints and flanges.

 

[bbbbaad]

I didn't use a torque wrench but probably should have. I can take it back out and re-do it, but not until this rain lets up a bit. I did check the TC bolts and they were tight.

I looked for carbon traces and found a few at the dougnuts. I wrenched them tighter except for that PITA bolt on the PS where a wrench can't possibly get to. I do hear a ticking sound coming from the floor pan area on the PS, around where the DP connects to the CAT. I don't see any leaks there, though.

I replaced the PCV and the O2 sensor but still have the same problem. The retard of the timing is still occuring when I get into the higher RPMs on the street but seems to be affected very little by load (adding boost).

I am pretty much at a loss right now. I do feel a little vibration on the center console when I rev the engine, so it could be a balance problem with the engine, even though it was supposedly balanced when I had the engine rebuilt. If that is the case, it is just going to have to be this way.

I will still keep searching for that innevitable win over this problem but losing faith that I will ever find it.

Andy

 

[bbbbaad]

The saga continues

I am still looking for the one thing that will stop the knock from occuring. I am getting it in neutral when rapping the engine to 4400 RPM or so as well as when i get on it on the interstate. I can keep 1/2 to 3/4 throttle on the interstate, get 15 psi boost, and not get any knock but kicking it down to bring the revs up and I peg the turnolink at about 60 degrees of retard to the timing.

I tightened the knock sensor down some and no difference. I had left it kinda loose when I installed the new one (no torque wrench to put it in at 14 per spec).

I found a vacuum leak at the base of the injectors. I replaced all of the o rings and now I have a new problem. The BLMs were finally coming in at around 124-128 at idle and now I can't get them to go above 103 at idle. The engine is running very rich and you can smell it. I have run the FP regulator down to about 36 psi with the hose on and it is still not coming back. I still have the knock, which is what started all of this to begin with. If I wasn't afraid of grenading the engine, I might want to pull the sensor wire off and stop the timing retard from the false knock but what if a real knock problem comes through?

Someone wanna buy a car for a buck??? Do I sound frustrated? I will get it, but I am at wits end right now.

Any other help?

Thanks

Andy

 

[jjvites]

Andy,
For a long long time I had a very simialar problem at the same rpm. Even though it seems to you that the belt tensioner is not hitting anything it might be bottoming out BECAUSE your belt is just a tad to long. A shorter belt solved my problem. Remove your belt, draw a line next to the moving part of the arm, reinstall the belt, start it and see how close it comes to where it bottoms out. Hope this helps.
Marty

 

[bbbbaad]

Marty,

Thanks for the reply. My intention was to replace the tensioner pully and belt with the length prescribed in orevious threads on this. I will check it first to see where I stand. I also intend on putting in 108 octane fuel and seeing if the knock dissapears. If it does, then I know it isn't false any more. With my setup, which is fairly mild, I shouldn't be getting knock at all with 93.

I haven't given up yet. I am up to two bucks for it now.

Andy

 

[TurboBuickSix]

It has to be false,real knock usually won't happen without having a load on the motor.First you need to set it exactly at 14 ft lbs with a torque wrench.If you don't have one get one.60 degrees kr is real real bad.

 

[HEATSEEKER]

I am still looking for the one thing that will stop the knock from occuring. I am getting it in neutral when rapping the engine to 4400 RPM or so as well as when i get on it on the interstate. I can keep 1/2 to 3/4 throttle on the interstate, get 15 psi boost, and not get any knock but kicking it down to bring the revs up and I peg the turnolink at about 60 degrees of retard to the timing.

I tightened the knock sensor down some and no difference. I had left it kinda loose when I installed the new one (no torque wrench to put it in at 14 per spec).

I found a vacuum leak at the base of the injectors. I replaced all of the o rings and now I have a new problem. The BLMs were finally coming in at around 124-128 at idle and now I can't get them to go above 103 at idle. The engine is running very rich and you can smell it. I have run the FP regulator down to about 36 psi with the hose on and it is still not coming back. I still have the knock, which is what started all of this to begin with. If I wasn't afraid of grenading the engine, I might want to pull the sensor wire off and stop the timing retard from the false knock but what if a real knock problem comes through?

Someone wanna buy a car for a buck??? Do I sound frustrated? I will get it, but I am at wits end right now.

Any other help?

Thanks

Andy

I have the same problem
I am loking for the knock sensor on the engine, how does it looks like??

 

[Squid4life]

Threaded into the engine block behind the intake manifold on a "ledge". It has one wire going to it. It has I believe a 13/16" hex head on it, is about 1.5" round, and has a round plastic connector on top.

HTH

 

[HEATSEEKER]

Threaded into the engine block behind the intake manifold on a "ledge". It has one wire going to it. It has I believe a 13/16" hex head on it, is about 1.5" round, and has a round plastic connector on top.

HTH

Thanks :biggrin:

 

[Squid4life]

Not a problem!

 

[ledzeppac]

umm its 12 lbs of torque.... Dont take it off unless you have checked everything else... I have never heard of a knock sensor going bad...

 

[bbbbaad]

Progress but there are still things that go bump in the night, I still can't find them.

I replaced the tensioner pulley with a new one today, mine was chirping like a little birdie. I also checked the unloaded position of the tensioner and it was indeed at the end of it's travel. I was certain that I finally hit on something and was praising you guys big time. I had a 64 inch belt installed by the guy that rebuilt the motor. A 63 inch belt is actually closer to the OEM size belt and keeps the tensioner up further where it should be. But, after all that, the knock is still there when I rap the engine, but not when I bring up revs slowly. This is in neutral or running down the road.

So, I decided to try some octane boost. I put a full can into a 1/4 tank of gas to see if the knock dissipates. It didn't. I still have the same problem, same levels of Kr. It has to be false knock since it didn't go away with higher octane, nor did it lessen any.

I am running out of things to replace. I have checked everything easy, replaced everything that is moderately priced. Replaced a few costly items. I don't have a spare ECM to replace it with. I am hesitant to buy one on Ebay since I already have one that I have no clue if it is good or not. If someone in the DC area has a spare one for me to try out, that would be greatly appreciated.

The car runs great so long as I don't look at the turbolink scanning it. I know it can be better if I can get the Kr to stop.

Where do I go from here?

Thanks

Andy

 

[jjvites]

Andy,
Take a look at the bolts on the A/C unit, they might be loose and sometimes there is one missing on the bottom position. This can cause a rattle-vibration noise. There is a guy here on the board who sells good used ecm fairly cheap as they can be found in many other makes in the bone yard.
Just wondering , do you feel a drop in performance as you accelorate? Is there audible knock-pinnging noise? Do you have another way of checking for knock besides turbolink? I'm not knocking turbolink as it is a fine product, just maybe something wrong with yours.

Marty

 

[bbbbaad]

I have no indication of loss of performance, no knocking or sound. The car runs great.

I have a lot of trust in the turbolink software, it is at least repetitive. I don't have any other means to check it, though.

Who is the person that lists ECMs cheap?

I will check the AC bolts. I have a full set of wrenches at the ready. When I see a bolt, I tighten it. When I see something running by something else, I make certain it isn't hitting. I am getting very intimate (oops, is this a kid's show?) with my car. I didn't want to, but life happens.

Andy

 

[Squid4life]

http://www.turbobuick.com/forums/showthread.php?t=182486

Red Regal T sells the ECMs, here is a post with info in his sig.