Hey all...

Question on behalf of a friend of mine with a IRL.

His car is "pulsing" at idle. I mean seriously... it sounds like a harley. Stock exhaust... 42lb inj. 3" pulley, custom tune.

Ran fine till a week or so ago. I can put my hand behind his exhaust tip and feel it. Pulse... wait a sec... pulse... wait a sec. It's not like mine where the pulses are almost constant.

It threw a code a few days back... then it dissapeared... haven't gotten it checked yet.

Any suggestions?

 

Is it missing by any chance

 

On the under hood end everything sounds fine. It seems to drive okay just "runs like crap" as my friend put it.

I don't know if it's timing... a fouled plug, or something in the exhaust. Seems to me if it were a serious enough issue the ECU would throw a major code. We all know how testy the damn computers on these things are.

Just wanted to get a few opinions before we take the wrench to it and start pulling things off. Didn't recall anyone having run into this before.

 

if it sounds like a wrx, then hes in trouble.

 

This reminds me of the "blew #4" threads. Is that what you are referring to?

 

either that or its gunna start sounding like that possible #4 going

 

id be interested to know what code it through, if its loud and runs like ass, there could be more of an issue than a fouled plug, do a compression/leak down test.

 

So... worst case scenario here... what would make #4 go on a car that's run just fine for a long time? His tune is plenty safe... he's running the right plugs... just changed them not too long ago actually. I'll guess at 40,000 miles on the car. Lotta track passes... never any major issues.

 

I dont honestly know what could cause it to pulse beside that or a fouled plug check under the hood for oil or signs of leaking oil

 

Will do. Thanks.

 

thx for the suggestions..

No leaking oil. All issues started after I replaced the vacuum line that connects the cover to the air intake with the little air filter. I put the stock vac line back on the next day cause she started to run like ass.

I think im going to reset the battery tomorrow. I'm at 40k miles.....just took a 400 mile trip where a code came on for a few hours, then went away...next day same thing. Code now gone for 3 days.

Really odd....

 

Could it possibly be a short in a sensor if the cel is doing that

 

Pull your spark plugs and do a compression test. I don't want to worry you but exhaust pulsing ,if I'm understanding you as you put it, is a bad thing. Like burned vale bad.

 

i did reset the battery today then went to IonTops and back....still doing it just the same. =(

I'm also going to try to clean the maf tomorrow too. As I looked at it today i noticed that the air intake side of that vac line wasn't on there very well at all. Some how it was really loose and was probably letting in all sorts of goofy air. That would be after the maf though.

I'll get a compression test done asap.... i hate being worried about the car like this. =(

 

dont feel bad.. had my oil changed a while ago.. it pissed out.. well, long story short.. same thing happened to someone else.. my car chatters like a diesel sometimes.. his did it too..

he ended up getting his fixed.. it was the hydraulic tensioner and timing chain.. they have to do mine next..

my exhaust pulses all the damn time on idle.. just an AEM intake.. his did it too.. so check that as well.. timing may play a role..

btw, my car pissed out 5.5L of oil.. but its still alive, somehow..

 

just an update..pics to follow

I checked the #1 and #4 plugs and took pics. The color on the tip was a little odd I think but am not sure. I did clean the maf as well with cleaner. It did look a little dirty...

The big thing though...there was/is a hose that is splitting where it connects at. Its about 1/4 in dia and goes from under the fuel rail and in to the block I think. The other side loops up and towards the back up by the fuse block. It was splitting and hissing/leaking a **** load of air. It sounded like a pissed off snake, lol.

I'll post pics for help since I'm not sure what what this hose does.

 

Sounds like the boost line, goes from the top of the intake(under fuel rail cover) to the boost bypass control valve selinoid, the little block on the right side of the engine with 3 vac lines on it.

 

That is what it sounds like to me.

 

that was/is my guess but I didn't want to assume

 

Well hopefully sounds like a miss-fire due to a vaccum leak. Fix the leak and hopefully it will run ok... if the plugs were dirty, replace them.

 

interesting... I'll be back in town on Thursday there Photo... I may swing your way on friday and we can take a look under the hood and see what's up with this line.

 

i replaced my vacuum lines this weekend [preventative maint] dont ask me why lol i heard vacuum lines rarely need replacing unless they crack

anyway. The line that goes from intake manifold to bypass was loose (very) loose. My car sounded like it had a cam in it pum pum pum then it would sound like baffles wanted to shoot out of the cat lol, i ended up throwing a lean code and tightened down the line with a zip tie....CEL went away 3 minutes later and the car was running a 100% again, crazy how much that one line means to the car!

 

Pulsating tone ahhhhhh yes the famous "wawawawawawa....." from your high performance exhaust can make us crazy. It's a very pricey and simple fix....My integra has done it....my brothers colbolt has done it and it's all the same. Your engine is just fine though.....but your fuel injectors are not. This is caused by a poor delivery of fuel. Pretty sure you're mileage isnt doing the best these days either. Unfortunately you must buy the right injectors and they are 300 for the set for my car with the fixings. However these culprits wreak havoc on your entire fuel delivery setup. If you're in it for 200-300 bucks on injectors, don't make these shiney new performance boosters (and best tune up component) run with dirty surroundings.....Get the fuel filter, fuel pressure regulator, and fuel pump as well. Clean the living .... out of the rail and make sure you have new injector plugs and seals and all the things to ensure proper sealing is intact. It wouldn't hurt to clean the throttle and replace those sensors like TPS, MAP, MAF, and replace the vacuum lines while you're at it. Total price on Ebay will run around 300-400. Cost me 250! And my car now runs at spec without further wonder if my tranny is shot (4th gear was jumpy!) Smooth and the best it's ever driven in the time I've had it....Injectors must be replaced every time the manual states its required. Cleaning them also works and YouTube will save you boatloads of cash if you're handy and want to avoid mechanic costs. A ratchet and pliers carb cleaner and flat / Phillips head will literally save you money. I am a 37 year old woman who hasn't been to a mechanic in years. YouTube taught me everything and my integra type r is always surrounded at the Acura dealership as they never hear a 2000 run as smooth as mine. Careful....You will become OCD quick lol finding yourself pretty much replacing everything in sight.