dpfi running rough

[88CiViC_D-15]

hey'a guys, do most dpfi make a car run kinda rough?? i just did a tune up and checked the timing and everything, but it makes a poping noise out the exauset and the engine rocks a little when it happens?? plus im using a std dpfi on a dx motor. can that be the prob?? please let me know. btw, there is no codes flashing on the ecu ether.

[91civichatch2571]

do you have a modified exhaust? If you do, the backpressure is going to be different, it might backfire or pop occasionally which could cause the motor movement you were talking about. A couple things you might want to check though just to be safe are, timing, maybe have the car hooked up to an osciliscope at a shop, it shows how the engine is running, how strong the cylinders are firing, etc. also, if your motor rocks a lot, you may have a bad motor mount

[88CiViC_D-15]

well, thanxs for replying, it has a stock exaust but with a aftermarket muffeler. the motor doesnt like rock, it shakes a little. but i will get it checked out. my step dad owns a mechanic shop so i can hook it up. but i know the timing is on, so thats not the prob. i think it started after i put the muffeler on if i remember when i had my old engine in it before it went out after 350k miles on it.

[Shaguar47]

kinda sounds like my situation right now, but in a week I'm going to go see the family mechanic so hopefully I know what the hell my car's problem is. But back to the point..... I've heard storys of the popping sound being the 02 sensor. My 02 sensor light is on and I get that popping sound outta the exhaust occasionally, but not all the times.

GL and tell me how it goes.

[civickiller]

i think its just an old motor. your talking about the car is just sitting there and then you hear the motor stumble alittle bit every few seconds. i think its just old motor wear. ive never seen a car with over 200k on it. idle exactly perfect

[amy@af]

Originally Posted by 91civichatch2571

do you have a modified exhaust?

Originally Posted by civickiller

i think its just an old motor. your talking about the car is just sitting there and then you hear the motor stumble alittle bit every few seconds. i think its just old motor wear. ive never seen a car with over 200k on it. idle exactly perfect

what he said, but i have to add that after reading:

Originally Posted by 88CiViC_D-15

i think it started after i put the muffeler on

when you added the aftermarket exhaust you messed with back pressure. i think that + engine wear could be your problem.

after your step dad listens to it, ask him about the exhaust. also ask about a slight misfire. both are common things he should be familiar with

[civickiller]

because he has an exhaust, he can hear it if he had a stock exhaust, he wouldnt hear it.

[88CiViC_D-15]

well, im going to a mpfi swap, its goin in soon, but would that help the idle or would it just be the same?? i dont mind for it doing that. i just wanted to make sure it wasnt just my car doing it and having a prob without knowing it.

[jhmcrx]

i dont think changing a manifold can change the fact thats its an old motor

[jhmcrx]

dude buy another cheap replacment motor on ebay for around 375-400 shipped or just save up for a bigger and better swap

[turtlecrxsi]

All this advice is great! Check your codes if you have any. Don't worry about getting a replacement engine from ebay because you can most likely find one from somebody on here a lot cheaper if you actually had to do that. MPFI would be nice and reading and re-reading everything that it involves (4thgenerationcivic.com) you'll know how things work better.