what would make a fully modded rx7 3rd gen idle like a harley vtwin rumble or a v8 with straight pipes? the timing is on.vacuum is -400mmhg on the power fc and i dont have a shitload of smoke resembling a blown seal.but i do have an exhuast leak between the turbo exhuast housing and downpipe.i know at idle this can screw with the o2 sensor but it quits as u accelerate just like if it was the o2 sensor. it has a strong and steady idle.

 

bump

 

Define "fully modified" Ported? stock coils? ???????????????

 

My car had a V8 rumble to it (93 w/haltech, single, streetport). Turned out it was a blown seal. Get the compression checked. Perpare for bad gnus.

 

it was just fine b4 i put another intercooler in.

no stock port.

it only does it at idle,when u start to accelerate after 2000 rpms it is completely smooth.

but also if it is a blown seal wouldnt i have a bunch of smoke?or other symbols?

 

oh yeah im sorry it rides smooth as hell and pulls really hard.

but like i said it has a steady and strong idle not bouncy like with a blown seal.and vacuum stays between -400 and -450....-600 when letting off gas completely.

 

well?

 

Make sure you have good fuel pressure, and your injectors are clean and connected. I had a similar problem which turned out to be a broken connector going to a primary injector. Oh yeah, be patient. It takes a while to get answers, and impatients bothers some people.

 

so do u think im not getting fuel at idle?but wouldnt i get fuel cut since the secinds dont come online till 4000?

 

bump

pleez help

 

see if it is to rich at the rpm range that sounds badly it could be that simple, or not .

 

i do not know how to read pfc maps maybe u could help and explain?i know from what some guys have said i have symptoms of a blown seal and then again i dont.this forum can be so confusing sometime.can someone help with this as far as the knowing how to read the map?
also i havent heard no grinding like throwing a seal out the exhuast.can anyone tell me how to do the timing real quick to make sure it is not preignition?i have no power loss either.i hope it is just an exhuast leak messin with the 02 sensor.if so i think kinda like the sound of it.but if not i hate the sound very much so.

 

Is it a "whacking" sound? It sounds like you have the same problem I had right before it decided to throw the corner seal. Mine was rough at idle because the seal would float out and hit the intake port. At higher RPMs the seal did not have time to float out. It was still pulling strong too. The bad thing is that a compression test will not indicate a corner seal failure until it is too late. Then about 2 weeks later driving down the road I felt it lost some power. It was still making full boost but it would die if I pushed the clutch in. I tried to make it home but I didn't.

If you think this is happening to you and you plan to have your motor rebuilt I would stop driving now. If you are going to get a reman I would drive it until it fails.

 

You need to be specific about your motor in order to get any reasonable diagnosis. You say it happened when you put in a new intercooler? Check for a vacuum leak.

 

ive had vacuum leaks man that is what i just cured.even with the vacuum leak it was sounding normal.

but what would make the corner seal go all of a sudden?

 

I had 103,000 miles on the engine when the corner seal went and my compression was 6's almost all around.

 

i went over it completely with brian at rotorsports racing in kannapolis.he said i am gettin good vacuum at idle.i let him listen to the rotors with the leading plugs out and just like i thought it is very smooth and sounds very strong compression wise.and it was just like i thought ,the exhuast leak b4 the 02 sensor is screwing with it by letting all this outside air hitting it.just like if u pulled the 02 sensor out of the downpipe.he said his race car has the same rumble on his n/a.

thanx again brian