My downpipe flex section has a ton of holes in it and it's right up against the transfer case, probably what's contributing to my oh-so-fun phantom knock.

I've got a replacement flex coming from Ziggy, but it's not going to be here for a little over a week.

I would like to wrap my flex with something to keep the exhaust in and buffer any vibrations that may be triggering the knock sensor. I'm thinking of picking up a bicycle tire tube or blown up trailer tire tube, cutting it, wrapping it around the flex and using worm clamps to hold it.

Any other ideas that may work? Has anyone used anything similar?

Won't it melt?
How about some foil tape?

How about just removing your downpipe and seeing if that's even your problem?

I would also consider forcing it away from the xfercase by getting some steel strapping (you know that sh!t with the holes in it) wrap it around the dp and bolt or screw it to something to keep it away from the xfercase.

I'm not sure if it will melt, does the downpipe get that hot?

The only problem with removing my downpipe is that it's LOUD and I live in a very quiet neighbourhood right across from a hospital, where the cops live there most of the time. I'll give it a shot maybe this weekend.

meh its not that loud unless you get on it.

Yeah, well I need to get on it to see if I get knock right?

Things get loud at 4K RPMs.

None the less, I'll give that a shot on Saturday.

Wow what a thoughtful citizen you are!

Not like you'll be pushing the rpms in your neighbourhood anyway. I say give it a try without the downpipe like Adam said. You might as well eliminate a possibility the easy way.

That's true.

Yeah, I'll give it a shot.

So, lets say it is the problem, what could I wrap it with temporarily so I can at least enjoy the car until the new flex gets here?

I doubt that is the problem. Do you get phanton knock just reving the car without moving ?

Got a Chunky Soup can? Might fit.

Yup. Free revving, I get it EXACTLY between 2500-3500 every single time, I can set my watch by it.

there is a muffler bandage tape that may work.

It might just be that then. What about at WOT only above 4500 rpm ? What if you use the stutterbox ? It should not knock if that is the case. Maybe a simple phantom knock code will do the trick.
If your still getting it at WOT without inducing it first, it might just be your air flow metering device, or fuel settings.

get a flex from crappy tire and get someone to weld it for you

Yuri,
Did you read Ryans initial post or did you just read the last reply and throw in your idea. He clearly states that he has a new flex section coming from Ziggy, had already looked in Sudbury for one, and is looking for a temporary solution for the leak and the vibration issue he is plagued with.

I get it if I stutterbox, not as bad.

WOT over 4500 I get little/no knock. I am very sure it's this... why?? Because I can't even hear my damned lifters this engine's so quiet! Loud freaking exhaust leak though, and one of the holes is pressed up against the transfer case.

I've got a peckerhead chip in there with an 11:1 A/F ratio and set for 780cc injectors. My base is bang on and I probably have a few small leaks, can't test for it as I don't have a BLT.

Also on order is a new intake mani gasket and new upper/lower seals for my PTE 780cc's.

I'm HATING not being able to get onto this thing!!

Ryan from my experience, going WOT from over 4500rpm, should eliminate phantom knock. Knock up there is usually from improper tuning. It could be a combination of that and the exhaust leak.
That big exhaust leak can definately do it alone, if the knock sensor is picking up the right vibes to set it off.

A good way to elimiate this theory is to unscrew your knock sensor from the block so it is freely hanging, and ground it.
Your knock should go away and you'll be more than happy to install that new flex section, and the knock sensor back into the block

Yeah, my tuning is fine, logger shows everything being ok and I can't really adjust anything due to not having a piggyback other than the MAF-T, where I can adjust fuel, however I'm rich as it is.

I'm kind of uncomfortable taking the knock sensor out of the picture here, I'd rather keep it in. I only drive the car for a total of about 15 minutes a day, seeing as I live 1.5 k's from work. Hell I could walk it in 15 minutes one way if I wanted to.

I'm heading down to Crappy tonight, I'll see what I can't put together. Hopefully it doesn't melt.

But, your not taking it out of the picture, you are taking it out of the block with it still connected and grounded like it should be.
Free reving like you said picked up knock, so you don't even have to drive it. If your exhaust leak is causing the knock, it will go away if you try this. Just my 2 cents as you seem to be trying everything. Nonetheless, I hope you get it fixed.

As a temp fix you can try silver (aluminium) insulation tape - you can get it at home depot. I've used it before to patch a muffler in a beater to get it through an emission test. It lasted a few days - although the DP will be hotter than the muffler, so your mileage will vary.

Well guess what, I wrapped it with a trailer tire inner tube and 4 worm clamps. Car is a lot quieter... but did it fix the knock?


NO!!

Next step: Blow car up.

I'm telling you try another ECU I mean you have one there.

Just tried that, car runs like sh!t and I don't have time to frack with it now as I have to go to work.

My ECU looks like crap, just a lot of brown under the board, and it's dirty, an electronic dirty if you get what I mean.

Malcolm Harris, if you're reading this, check your PM's.

Ryan what about the idea now of swapping in a stock ECU and the 450's out of the other car.
Zero out the maft-t or even better put in the piping and such from your other 1G and see what comes about. it may seem drastic, but hey it's an issue that's plagued yo for a long time. If it goes away it's ecu/tuning based if it's stil there with the other ecu/450's and such well there's your answer.

Ryan, not related to the knocking issue but just an FYI, you might want to remove that tire inner-tube before driving much with it. Since I know you are waiting on a new flex section, if that tube melts to the pipe you're going to have to wire wheel (or whatever) the DP clean if you want to get a good weld on it, making more work for yourself in the end. Just a tip since I deal with welding every damn day!

Tim: I'm thinking of throwing the 390cc injectors in, I may do that tonight (It's an auto).

Steve: The rubber is wrapped around the flex only, it's not touching the rest of the downpipe and FWIW, I've felt that flex with the car running and didn't burn myself.

Your flex should heat up more than that, I can't even touch my muffler tip after a short drive. I'll come visit with ECU's, sensors, mounts and a couple different sized injectors.

Check your PM.

Well, I got home, tried screwing with the automatic ECU, and the car runs like sh!t. I can't even get it to idle anymore, even with playing with the MAF-T, however, something weird happened.

I set the MAF-T to 780cc injectors, as per the manual (Aux 2 Base 5), idled like crap, like lumpy at 500RPM crap. Adjusting the BISS did nothing, wouldn't even change the idle.

Then, I completely zeroed out the MAF-T, idled fine. It was obviously lean, however it idled fine.

So, in saying that, here's a question. Has anyone ever experienced a MAF-T box going on the fritz and causing this? I highly doubt it, however I've never seen or heard of knock this bad before, so for all I know, it could be a sway bar bushing causing it!!

Anyway, Malcolm, I hope to God you can come out this weekend, I need a fellow DSMer on site with a fresh look at the damned thing as my friends are good for holding a wrench and that's about it.

I need someone to understand what I say when I've checked base timing and retarded it quite a bit with the CAS, can't do a BLT as I don't have a compressor, the TPS is bang on and so is the ISC, but the CTPS may be giving me trouble. My #4 PTE 780cc injector insulator is cracked possibly causing the knock, however it could be the lifters in the head.

Yeah, my friends go "Ok, you and your CAtS want to make a BLT sandwich?? What??"

Yeah... again.

I'm having a hard time following what you've done, but I'd start by putting in a stock MAS. I imagine that means putting in the stock injectors / stock ECU chip at the same time.

That shouldn't take more than a few hours and you'll know if it's one of those parts.

Yeah, that's a Saturday thing.

I'm an idiot.

Apparently, you have to disconnect the logger to set base timing, just found that out.

So for shits and giggles, I ran out and did it. Wouldn't you know it, but my base timing was 5 deg ATDC, so I reset it.

Free revving, I still get knock.

Thought I fixed it, but now I know my base timing is set!

Isn't it the other way around?
I thought you need the logger plugged in to set the timing..
You'd be close to 10* ATDC at idle with the ECU controlling it (literally whatever you see on the logger without the pin grounded), and it will depend on what it was actually set at to begin with.
It was probably set close to 5* BTDC before you messed with it tonight.

At this point you really should be looking at the ECU.
Either do Reza's test (removing/grounding/isolating the knock sensor, and test it in neutral), or swap ECU with a known good one.

Well Rob, when I disconnected the logger, warmed the car up and grounded timing, the mark was past the TDC mark (not towards the 10, the OTHER way).

I've swapped with a known working ECU, however it's an auto and I have a MAF-T, I was having difficulty in dialing in the injectors, it wouldn't idle at all.

I've got a shopping list of things to try this weekend.

Maybe someone can explain this whole isolating the knock sensor thing. What I'm getting is I have to take it out of the block, ground it and rev the car to see if I get knock?

The logger has to be disconnected when adjusting the ignition timing, you only want to have the ignition timing connector grounded. Simply having the logger off won't do it, I atleast pull the ground wire out of the diagnostic port.

Grounding both, the ECU diagnostic port and Ignition timing connector is only for setting the ISC.

When you pull your knock sensor out of the block, it won't be picking up vibrations anymore. See if it still knocks like this. If not then you know that some noise/vibration is causing it.
I would even go as far as throwing some race gas in it, and see if the knock goes away at WOT and good boost. If it does then it pretty much points to phantom knock, and a bad tune up top.

If not, somethings up with your air flow metering device/ECU, settings etc.....

I had phantom knock, but I would never get it going WOT and lots of boost. The phantom knock code cured that part throttle crap.

Ahhh, I see Reza.

I have NO access to race gas up here, most we have is 91.

I'll give that a shot tomorrow. I'm kind of on the same setup as you, except no VPC. What I mean by that is my chip does the work, with no added tuning. Did before, no problems.

So, what's changed. Front mount makes no difference, piping is the same route.

Exhaust, well I've isolated that, not causing the issue.

Timing, hmmm... I can't get more bang on than I am.

Tune: Steve is the man, I trust his chips, they work wonders.

Reza, I think, wait, should say know, you're probably onto something. Gotta isolate from the ECU or something rattling. And to do that, I have to take the knock sensor out of the block, ground it and free rev the engine. This will tell me whether or not my knock is coming from the ECU or from the engine right?

If I don't get any knock from removing the knock sensor, I can be certain it's mechanical or my tune.

If I am, it's the ECU that's toast, right?

Ok... so it's late, I'm tired... I'm gonna go have me some sex, go to bed and look at this in the morning.

Sorry for the rambling, you guys are awesome.

Cheers.

sh!t. Now I wonder WTF my timing was set at

Well don't think my chip does all the work Ryan. I ordered a target AFR and customer timing maps, and a few other things particular to my setup. The target AFR is just an estimate, and I knew it would not be dead on. I still tune with the VPC gain, and I can manipulate that signal across the board with the AFC. I also have a fuel pressure regulator. You will be surprised to know that my VPC and AFC setting are no where near zero'd out, I'm still adding upto 15 to 17% more fuel in some areas with the AFC. I haven't even seen 60% IDC's yet, they are always in the high 50's. My chip is a very aggressive race tune

The way the VPC and timing maps work with an AFC, is totally different than just having an AFC and no VPC.

My chip has injector compensation, target AFR and target timing map.

When I sell my other car, I'm getting DSMLink, end of story.

The only fuel adjustment I can make is with the MAF-T, however I haven't been able to do a WOT pull or cruise around enough to be able to fiddle with it. My trims look ok, however I haven't driven it enough to get them stablized.

I'll report back tomorrow. I'm going to dive into this car and get some sh!t figured out.

I thought you had DSMlink in your car before, why did you get rid of it ?

It may not be the case with you, but I have seen many guys getting rid of their DSMLINK for a chip, to keep it more simple

I think that is just retarded. They obviously don't know how to use DSMlink or tune!

I would still give my chip up for a DSMlink anyday, but I'm too cheap to get one. I had a pretty good baseline of what I wanted in the chip, and its working well, just as I thought it would

I got rid of it to keep it more simple. At one time, I was almost forced to sell the car when I was moving to New Brunswick. I had sold the DSMLink setup and switched to a peckerhead chip.

Now I want it back as I've learned a lot more how to tune with DSMLink through the board.