I got the car boosting a little but I seem to hear a rattling sound coming from the engine. I'm letting it cool down some and I am going to pull the plugs to see what they look like.

I don't hear the rattling out of boost, but it is there as soon as I begin to boost. It is pretty loud, so I am thinking it could be the WG opening up? All I have controlling it is an MBC, so I am hoping the WG is opening before getting to full boost and that is the noise I am hearing. I hit maybe 5 psi.

Fuel setup as follows.

450cc injectors
AEM fuel rail and FPR
Untuned Hondata 3b with a program that was tuned for another car. (Fmax, 440cc injectors, b16)
Walbro High pressure intank
Base fuel pressure at 50psi.

Oil is leaking, so I'm not going to drive it too much. Othen then those two problems it seems great!

 

rattling noise from engine bay and no loose bolts = detenation.

How loud is it and does it go away with higher rpms? What grade gas are you using? Try some octane booster or and maybe bring your timing back a bit.

 

It is pretty loud, easy to hear. I was afraid to bring the rpms up high.....I got into the throttle at around 3000 rpms and let them go up. I didn't give it full throttle, but once it started to boost it seemed like it was making that noise. I have 93 octane in there.

Oh, how can I bring back my timing?

 

more than likely its the wastegate

when you hear the noise does the engine hesitate or act funny?

 

Nope, seems to act fine.

Thought I would add some color to this thread.



[Modified by HXMan, 4:20 PM 6/10/2002]

 

Wow Steve you have a crazy # of posts!

 

if not wastegate or loose bolts... it might be a little pre-ignition? that would follow your descrip of starting when you get boost.

 

does it sound like someone is dropin marbells in your engine???

 

Hmmmm....what could fix this? Colder plugs? Different plug gap??


Its hard to tell....wish there was someone around here that really knew....

 

prolly the wastegate. are you using the turbo for your vac source to the wastegate?

 

Yes.....

 

I might as well ad to this post. Sometimes if I just start to get into boost I hear one quick "knock". Only thing is its VERY infrequent.. seems like it only happened mabye 4 times total..... Doesn't sound like marbles more like when a big rock hits the bottom of your car or something, and it only happens once in blue moon... Its possible its something moving in my trunk hitting something else mabye? I just wanna be sure its not detonation...

Also no hesitation or otherwise weird engine response when its heard.

 

I am hearing it everytime. Here is a pic of my plugs...they look good. I couldn't see any metal flakes on them.....

 

How long have those plugs been in the car? they look like they have been a little hot!

This is a pick of a normal plug!


[Modified by -=TWITCH=-, 4:39 PM 6/10/2002]

 

yeah, looks like you ran lean on the plugs.

also, tee your wastegate actuator line into the fpr vac line. my deltagate always opened up @ 0psi until I did that.

 

Mine have that flaky crumby look just a tad... but I know I'm leaning out a bit at high rpms due to crappy stock injectors.. even with a 12:1 fmu the stocks just can't last long or put out with the stress of 100+psi of fuel pressure....

 

Here is a close up...maybe I am running a little lean. Doug at hondata told me what fuel pressure the program was tuned for......but I can't remember if it was 50 or 60 psi! I was running 50, guess I will jack it up.

Oh, here is a closeup.

 

That plug looks good to me. That's how mine looked with my JRSC @ 8psi, dyno tuned, and safety tuned with the J&S to remove all detonation.

Sonny

 

Here's a good project, let's you know for sure if it's knocking...it seems cheesy at first, but is apparently BETTER than a J&S, if you know what you're listening for...I'm going to build one real soon, hopefully.
http://www.autospeed.com/A_0353/page1.html

 

Cool, but I'll stick with the tried and true, J&S.

Besides, once that boost kicks in, you'll be too busy listening to that burning rubber to hear anything in those headphones.

Sonny

 

detonation can sound different depending on the type...

When I had my car running lean on an hold Hondata map, I'd hear audible pinging from the motor and out the exhaust (easier to hear right when letting off the throttle to quiet exhaust noise but motor was still under load..) This sort of detonation sounded like a literal "PING PING" sound. Just like they say, dropping BBs in a coffee can.

Yesterday I had my car running on the AEM EMS b18c5 ignition map. Car was running crazy rich at full boost -- around 10.0:1 @ 7psi and about 12:1 @ 3-4psi.
When merging on the freeway at moderate throttle in 5th gear, I heard some decent detonation. However, it wasn't ping ping sound detonation. It was a ticking. Under accel I would hear random 'tick tick tick' sounds from the motor, only in boost. Sort of sounded like I was kicking small rocks up, but the sound was very clear and obvious.

I got the car home and checked the ignition map I had blindly installed. It was running about 32 degrees ignition advance @ 4psi heheh. Crazy. I guess this map is for a b18c5 w/ 9.2:1 compression as compared to my 10:1. I pulled a bunch of on-boost timing out of the map and the detonation is gone now. The knock sensor is only picking up light activity since the change....

So, yes, there is a good chance you are hearing detonation. You should be able to tell the difference between the wastegate opening and detonation...

HTH.

Dustin

 

Well, sounds definitly like detonation to me. But hey, you don't have to take my word for it.

Sounds like bolts ratteling in your engine bay, but no bolts are loose=detenation and if it's loud=serious detenation

 

Hmmm....anyone know where to get a JS knock meter or anything like that?

 

Hope I didn't blow it up yet!

 

long shot here but you running 50 psi fp w/ hose off? thats the correct way to read it, if not on me if you already knew this, cuase if your @ 50psi fp w/ the hose onyour really at about 40psi.