This thread was saved without dates. "Around Mar 2005" is estimated from neighbouring threads.
Hey guys,
When i start my car on a cold start, it backfires alot when i rev it but only for a couple seconds.Then it will idle fine when warm.
I thought it was probably dirty Fuel Injecters so i bought some STP Fuel injector/carburater cleaner. poured it in my tank with a full tank of gas and the problem seems to have gotten worse. it backfires alot more and now when i try to start the car i have to give it some gas.
What can this be? someone plz help?
Tony
I've always heard that STP is the worst thing you can pour in your gas tank.....does more harm than good. Don't know why, but thats what a Nissan tech told me once years ago.
Damn, wish i knew that before i poured that juice of hell down my gas tank.
But, it was doing the backfire even before i poured the stp. any idea why? my a/f gauge read rich always. its always on rich, it never moves. not even at wot. i changed my o2 sensor and nothing! it remains all the way rich.
Could this be caused by a bad temp sensor? ive never replaced that.
could be an internally leaking fuel injector. Cleaning it made it worse because it technically did it's job.
I never heard about not using STP. putting fuel injector cleaner in my car made it run a little better.
one of the green clips that go on the fuel injecter on the rail is cracked.
Could this be a problem? also, can a bad temp sensor be why im so rich...?
The temp sensor is definately a possibility. I'm not exactly sure what clip you're talking about. Is it for the connector side?
I wasn't saying all fuel injector cleaners were bad.............. I was told be my Nissan tech that I use to always use that was there for 20 years and trained at Jaguar in England, not to use STP. I don't remember the reasoning though....I just stay clear of STP products to be safe.
I use the Chervon Tecron injector cleaner every 5000 miles or so, and it seems to work pretty well
Have you checked for codes to see if your temp sensor is bad?
Are you getting a pulse from the injector with the cracked clip? Also, vac leaks can cause you to run rich too.
vac leaks can cause you to run rich too.
No... lean, boost leaks however will cause a rich condition
i do have a nasty boost leak :/
In a turbo car a vacuum leak will be a boost leak too ;)
Sounds to me like your leak is getting worse. I hate to sound like a broken record, but there's no sense in trying to diagnose a car that is not up to snuff.
Fix your boost/vac leaks, then see.
Check codes on the ECU. It's also possible your DET sensor is on the blink.
Is it popping through the pipes or through the exhaust?
whats a det sensor?
The backfire is coming from the exhaust i believe. Also i have 2 1/2 piping coming from teh down pipe straightback to my exhaust. so do i have a det sensor?
I think he means detonation sensor. yea definately fix that boost leak
BG Products are AWESOME for imports... most mechanics I know swear by the stuff. BG 44k and BG MOA (one is for fuel, other for oil, I forget which is which).
Local Nissan dealer stopped selling it, but the local Toyota dealer still does.
The Nissan dealers out here still sell BG and they use it in their service dept. as well.
how high are you revving? I know that my s12 (v6) backfired with the new exhaust when it was COLD (w/in first like 3 min of starting)..its about the exhaust temperature if you ask me..theres no remedy other than DONT rev it when its cold..let your Oil Psi build, and the engine warm before you do that..but thats just me...
Remember that your o2 sensor has to warm up before it works properly, my manual says that can take anywhere from 60 seconds to 3 minutes depending on the temperature. My turbo downpipe doesn't even get hot for like at least a minute. And your car is almost 20 years old too. haha.
cud be an ignition fault rather than fueling. eg coil,ht leads etc