cam only tune issues
Thread Starter
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Joined: Dec 2007
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From: Charleston, SC
cam only tune issues this morning i went on a cruise with some buddies, after a few miles my car would spit and sputter while cruising in 5th gear. downshifted to 4th to raise the rpms to around 3k, it quit and began to run good again. after a mile or two of that it began to do it again. so id get in it, sometimes even dropping a gear/punching it and it would quit then once it got back to cruising rpms 2.8k or so it started again. i basically dealt with it for the rest of the morning. once i left to go home it got real bad. even when i would get in it hard it would spit and sputter real bad. almost barely running. but theres no knocking or banging coming from the engine bay. the exhaust note changed quite a bit which makes me believe that its running rich. the exhaust note went from crisp and clean to almost muffled and quiet. all the plug wires are hooked up and it has brand new plugs that are two weeks old. the car has never done this or even ran bad for that matter. does it sound like a fuel issue or somethin else?
mods are:
232/234 on 112 lsa
QTP Lt
TDs dynomax bullets
slp intake
u/d pulley
any ideas guys?
mods are:
232/234 on 112 lsa
QTP Lt
TDs dynomax bullets
slp intake
u/d pulley
any ideas guys?
Teching In
Joined: Jul 2008
Posts: 24
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It could be a heap of different things. Ensure your tune is spot on first then check the mechanical side of things, start with leads,plugs, fuel filter, O2 sensors and cats as well. If its not ones of these then it could be a dodgy injector not flowing enough or the fuel pump not maintaining enough pressure.
JB
Nearly forgot check your pcv hoses and things to make sure you don't have a vacuum leak
JB
Nearly forgot check your pcv hoses and things to make sure you don't have a vacuum leak
Last edited by cosmo vyss; Oct 25, 2008 at 06:16 PM. Reason: more info
Thread Starter
11 Second Club
Joined: Dec 2007
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From: Charleston, SC
yes, twice actually.....the first tune was spot on. i had not one issue for the 2 months that it was on the first post cam tune.
i recently swapped to LTs and now have QTPs with TDs. my tuner just tuned it on the dyno but did not street tune it.
the plugs are brand new, i think two weeks old. im not running cats and the 02 sensors are new but they could be the issue. i have never changed the fuel filter and ive owned it for 8 months. all hoses and lines are hooked up.
i recently swapped to LTs and now have QTPs with TDs. my tuner just tuned it on the dyno but did not street tune it.
It could be a heap of different things. Ensure your tune is spot on first then check the mechanical side of things, start with leads,plugs, fuel filter, O2 sensors and cats as well. If its not ones of these then it could be a dodgy injector not flowing enough or the fuel pump not maintaining enough pressure.
JB
Nearly forgot check your pcv hoses and things to make sure you don't have a vacuum leak
JB
Nearly forgot check your pcv hoses and things to make sure you don't have a vacuum leak
the plugs are brand new, i think two weeks old. im not running cats and the 02 sensors are new but they could be the issue. i have never changed the fuel filter and ive owned it for 8 months. all hoses and lines are hooked up.
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Teching In
Joined: Feb 2007
Posts: 34
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From: Charleston, SC
If you don't find any air leaks, may need to take it back to the tuner. Could be some low RPM fueling and timing issues. Doesn't sound like a fuel pump/pressure issue since it clears at higher RPMs.
unless it has to do with the weather change, its starting to get cold out here, its not going to be a tuning issue. it wouldnt work fine then all of a sudden act up. definately check the fuel filter. i have seen some pretty strange effects from a clogged up filter.
I had that problem tuning a buddies car (cam only). I didn't know to raise the misfire
count cells in the tune. The car would run awesome for a little while, then go to crap.
Turns out, the car was going into open loop because of 'misfires'.
count cells in the tune. The car would run awesome for a little while, then go to crap.
Turns out, the car was going into open loop because of 'misfires'.
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There's a few things that could cause this, I would check these first.
02 Sensor, make sure they didn't start to touch the headers burnt through the wires. Same with the spark plug wires. Check for any missing conections, such as for the IAT, MAF. I've also seen fuel pumps start to go where they'd act like that as well. Only bad thing about that is that you need a Fuel Pressure guage to check for that while driving.
If you're concerned that it might be the tune, pull the plugs, and see if they're fouled out or missing any ground straps. That'd be the first indication that there's something wrong with the tune based on fuel and timing (can't really use those to check for the idle control settings).
02 Sensor, make sure they didn't start to touch the headers burnt through the wires. Same with the spark plug wires. Check for any missing conections, such as for the IAT, MAF. I've also seen fuel pumps start to go where they'd act like that as well. Only bad thing about that is that you need a Fuel Pressure guage to check for that while driving.
If you're concerned that it might be the tune, pull the plugs, and see if they're fouled out or missing any ground straps. That'd be the first indication that there's something wrong with the tune based on fuel and timing (can't really use those to check for the idle control settings).
Thread Starter
11 Second Club
Joined: Dec 2007
Posts: 868
Likes: 0
From: Charleston, SC
correct, i have never had one problem out of the car. then out of the blue one day it slowly transitions into this
im not so much concerned with the tune? the tuner really knows what he is doin, plus my car ran beautifully since day 1 after the cam
the maf was dead since day 1 of owning the car, my tuner said he just tunes them out on all his cars and said that he did the same with my car and ive never had a problem.
ill have to double check the 02s and plugs.
THANX AGAIN GUYS
ill have to double check the 02s and plugs.
There's a few things that could cause this, I would check these first.
02 Sensor, make sure they didn't start to touch the headers burnt through the wires. Same with the spark plug wires. Check for any missing conections, such as for the IAT, MAF. I've also seen fuel pumps start to go where they'd act like that as well. Only bad thing about that is that you need a Fuel Pressure guage to check for that while driving.
If you're concerned that it might be the tune, pull the plugs, and see if they're fouled out or missing any ground straps. That'd be the first indication that there's something wrong with the tune based on fuel and timing (can't really use those to check for the idle control settings).
02 Sensor, make sure they didn't start to touch the headers burnt through the wires. Same with the spark plug wires. Check for any missing conections, such as for the IAT, MAF. I've also seen fuel pumps start to go where they'd act like that as well. Only bad thing about that is that you need a Fuel Pressure guage to check for that while driving.
If you're concerned that it might be the tune, pull the plugs, and see if they're fouled out or missing any ground straps. That'd be the first indication that there's something wrong with the tune based on fuel and timing (can't really use those to check for the idle control settings).
THANX AGAIN GUYS
