False knock driving me crazy, help please

[Flyin Brian]

I agree, I think Rick is correct. That flatline KR is very strange, don't think I've ever seen that before. And like Rick mentioned it's just hanging around even after you let off. Strong possibility of an electrical gremlin. Ground issue, corroded pin/terminal at ECM connector, etc etc... Might even be an issue with the chip.

Thanks for all the responses. I am starting to think electrical gremlin as well. Chip is new and I have tried some others with previous combos and still had the problem. Grounds are done right and ECM is new. Got to be old wiring harness or ESC module. I never hear of ESC modules going out though. Is this common?

 

[Mr.Spool]

have you clearenced the downpipe yet or put the stocker back on?

 

[Flyin Brian]

have you clearenced the downpipe yet or put the stocker back on?

I have close to half an inch between the downpipe and the frame rail. I may try the stocker today. About to hit the garage and tear into it.

 

[Jerryl]

Thanks. I have gone through most of this list. Almost everything in this car is new and has less than 1500 miles on it except for the ESC module and the wiring harness. Electrical problems suck

Yes they do!!
Probably not the ESC module.
Never seen one go bad . . . and . . . ask me how I know. LOL!


Oh . . check the driveshaft for conctact with the exhaust.

 

[TurboBuRick]

Do you have any other devices attached the esc circuit? Knock gauge? Alarm? etc.

Do you also have another chip you can try? Chip could have a bug.

RL

 

[Flyin Brian]

Yes they do!!
Probably not the ESC module.
Never seen one go bad . . . and . . . ask me how I know. LOL!


Oh . . check the driveshaft for conctact with the exhaust.

Got the car about half way apart now. Looking at wiring harness etc. Not in great shape. Driveshaft not hitting exhaust but sway bara link close at one point.

 

[Flyin Brian]

Do you have any other devices attached the esc circuit? Knock gauge? Alarm? etc.

Do you also have another chip you can try? Chip could have a bug.

RL

I do have an old school Larry Fisher black box knock gauge attached to the ESC circuit. It is carefully soldered to the appropriate wire going to the ECM. No alarm attached to ESC circuit unless the factory alarm is. Could the knock gauge be causing the false knock signal?? I had not thought of that.
I am running a volt booster but I have tried unhooking it and I get the same problem. I don't have another chip to try that would work with my 80 lb injectors but when I had 60 lb injectors and matching chip I was having the same problem. I went to the 80 lb injectors and chip because I thought I was not getting enough fuel and that might be causing the knock. My fuel problems are all solved now but the crazy false knock signal still happens. I am checking out the wiring harness now.

 

[TurboBuRick]

I was referring to a knock alarm.

Anything attached to the esc circuit could reap havoc. Disconnect the aftermarket knock gauge.

RL

 

[Flyin Brian]

I was referring to a knock alarm.

Anything attached to the esc circuit could reap havoc. Disconnect the aftermarket knock gauge.

RL

Ok, I will try that thanks. Makes sense. I am checking through the rest of the engine harness and it is not in the best of shape. Looks like the previous owner messed with it alot.

 

[Fast4Ward]

hmm berry berry phishy...u got problem .....gl

 

[Flyin Brian]

hmm berry berry phishy...u got problem .....gl

Well, I have half of the car taken apart now. Wiring harness looks like hell. Going to keep working on it. Almost got the entire harness out of the car. Got several miles of electrical tape to unwrap to inspect the wires. Connectors not in great shape. May look into getting the Caspers replacement harness. Anyone install one of those? Looks like alot of work but I am half way there already.

 

[ThikStik]

Have you looked at pins going into ecm female/male...you know, the water on top of ecm issue that has been known to occur? Also, you can look at motor with hood open while stalling it up in D and R to see how much its moving. Could get someone to do it whilst looking at dp.

 

[Flyin Brian]

Have you looked at pins going into ecm female/male...you know, the water on top of ecm issue that has been known to occur? Also, you can look at motor with hood open while stalling it up in D and R to see how much its moving. Could get someone to do it whilst looking at dp.

I got the entire harness out now. Connector pins at ECM look good. C100 connector does not look so good. Found alot of butt splice connectors under all of the freaking electrical tape. Lots of bad work under the tape. I was about 1 strand of wire away from losing my brakes. Downpipe has been hitting the frame. Crossover pipe has been hitting the rear upper control arm bushing. I need the HR motor mounts.

 

[captflash]

subscribed

 

[ThikStik]

Sounds like your close. best to solder those wire with butt splices, if u recrimp, put some electrical grease on splices to keep corrosion out. Brakes were what?/?

 

[Flyin Brian]

Sounds like your close. best to solder those wire with butt splices, if u recrimp, put some electrical grease on splices to keep corrosion out. Brakes were what?/?

I just ordered a new engine harness from Caspers. Everything about my old one looked bad. I hate crimp butt connectors, i prefer crimping in un-insulated connectors and soldering and heat shrinking. At some point in the past the previous owner had done a vacuum brake conversion and just cut off the powermaster part of the harness. I guess they then put the powermaster back in and used butt connectors to re-connect the harness. When I took all the electrical tape off, some of the butt connectors just fell apart. While I am waiting for the new harness I am going to check out all the wiring behind the dash at the fuse box, ECM power feeds, and anything else that looks suspect.

 

[Flyin Brian]

Ok, I have now done the following. Replaced engine wiring harness, installed HR parts motor mounts, welded up crack in downpipe, checked every nut and bolt, removed and re-installed knock sensor carefully, replaced ac compressor (needed one), checked all wiring and grounds that I could find, replaced every vacuum line, installed EGT probe in # 6 pipe, removed old knock alarm and did not re-install, checked and tied up anything that could be banging around near the motor, and drank alot of beer. The downpipe and crossover pipe are now nowhere near hitting anything thanks to the HR parts motor mounts raising the engine up. I drove it today and it seemed to run much smoother. When I statred hammering it the false knock returned however. It was not nearly as severe with the plateau shape like my previous powerlogger screenshot but it is still pulling 15 degrees all at once when I hammer it going slow. Rolling into it in 3rd still gets me no knock like before. EGT was around 1500 F after standing on it in 3rd for a while. Is this a little warm for E85? My wideband was jacked up for that run and I am working on that now but what could still be causing this false knock? I still have the stock ESC but everyone says these never go bad.

Thanks for the help thus far. Brian

 

[ThikStik]

So your very sure engine/dp isnt torking too much to pass side?

 

[Flyin Brian]

So your very sure engine/dp isnt torking too much to pass side?

I am pretty sure. With the new motor mounts the motor is nearly solid mounted. I have half an inch betweeen the downpipe and the frame rail and also between the crossover pipe and the rear upper control arm bushing. I have half an inch between the downpipe and the firewall too. I could verify by hitting the close areas with a paint pen and driving it and then checking for visual contact. I am going to keep looking. I noticed I do have the problem people have talked about with the belt tensioner being all the way extended and that causing false knock somehow. Could that be it?

 

[larrym]

I don't get any knock counts at all since polished the crank and changed the bearings .............

They where rattling