Symptoms of a bent valve?

**GottaHaveLS1** · 07-14-2008, 08:21 AM

what kind of symptoms would i experience from a bent valve? my car ticks a little but drives almost perfectly everytime. i'm asking because my tuner said it could be the cause of why i'm not getting enough fuel.

**gtoguy3** · 07-14-2008, 11:01 AM

you would have an engine miss with a bent valve. Tick is probably a lifter. Not really serious. Bent valves are pretty rare. jerry

**gtoguy3** · 07-14-2008, 11:03 AM

Also, why do you say you're not getting enough fuel? Fuel has nothing to do with a ticking lifter.

**Spaz** · 07-14-2008, 11:31 AM

Originally Posted by GottaHaveLS1

what kind of symptoms would i experience from a bent valve? my car ticks a little but drives almost perfectly everytime. i'm asking because my tuner said it could be the cause of why i'm not getting enough fuel.

if your car isn't getting enough fuel change the fuel filter... it's probably clogged...

**GottaHaveLS1** · 07-14-2008, 11:52 AM

Originally Posted by gtoguy3

you would have an engine miss with a bent valve. Tick is probably a lifter. Not really serious. Bent valves are pretty rare. jerry

that's good to hear i suppose. it started ticking last summer after i got long tube headers on her. i can only hear it at idle... u can't here it when u drive and it doesn't get worse (louder/faster) when i rev it.

for the other guy, i replaced the fuel filter, fuel pump, etc. still not enough fuel so probably the injectors.

**Spaz** · 07-14-2008, 12:43 PM

Originally Posted by GottaHaveLS1

that's good to hear i suppose. it started ticking last summer after i got long tube headers on her. i can only hear it at idle... u can't here it when u drive and it doesn't get worse (louder/faster) when i rev it.

for the other guy, i replaced the fuel filter, fuel pump, etc. still not enough fuel so probably the injectors.

how many miles are on the car??? also what octane fuel are you running???

**GottaHaveLS1** · 07-14-2008, 03:15 PM

Originally Posted by Spaz

how many miles are on the car??? also what octane fuel are you running???

72K miles and i always run 91+
i used to run 93 all the time but now its 5 cents more per gallon than 91

**gtoguy3** · 07-15-2008, 03:13 AM

I'm wondering how do you know you are not getting enough fuel? Has the performance degraded? Did someone tell you? If the car doesn't seem to go like it used to, then, try some injector cleaner. If that doesn't work, you may need to get a programmer and tweak the computer. New injectors will help if you use a larger size, but your fuel consumption will go right up with them. The headers should have helped with the breathing. Are you racing the car? I can't think of anything that would 'slow the car down', unless the timing has changed. If the timing has changed, we're talking crank position sensors and other cans of worms. You do have a lot of miles on it. Jerry gtoguy3

**gtoguy3** · 07-15-2008, 03:16 AM

Another thing I forgot to mention is that if you are using lower octane gas, the computer automatically retards the timing to protect the engine, so that will decrease your performance. gtoguy3

**GottaHaveLS1** · 07-15-2008, 03:58 AM

Originally Posted by gtoguy3

Another thing I forgot to mention is that if you are using lower octane gas, the computer automatically retards the timing to protect the engine, so that will decrease your performance. gtoguy3

good idea, i'll prally just go with 93 from now on. its not a dd anymore either. i dont race it at all.. just the occassional street race. i've run injector cleaner thru it twice. my tuner told me it's not getting enough fuel to tune it for WOT or put it on the dyno. i've replaced the fuel filter twice in last 5K miles and just put in a new fuel pump with a clean sock. (walbro 255lph)

**Spaz** · 07-15-2008, 04:48 AM

Originally Posted by gtoguy3

Another thing I forgot to mention is that if you are using lower octane gas, the computer automatically retards the timing to protect the engine, so that will decrease your performance. gtoguy3

you woldn't notice the difference from 93 - 91...

gotta... have you gone to the front of the fuel rail and checked it you're getting good fuel pressure??? try getting some injector cleaner... when your tuner said you're not getting enough fuel were you on a dyno and do you have a print out of thte A/F ratio???

**GottaHaveLS1** · 07-15-2008, 12:02 PM

Originally Posted by Spaz

you woldn't notice the difference from 93 - 91...

gotta... have you gone to the front of the fuel rail and checked it you're getting good fuel pressure??? try getting some injector cleaner... when your tuner said you're not getting enough fuel were you on a dyno and do you have a print out of thte A/F ratio???

i haven't checked the pressure yet. i've put injector cleaner through it twice. he saw that i wasn't getting enough fuel when he tried to tune it for WOT when he was driving it on the street... it never got on the dyno. he said my a/f ratio would drop to 12 something when the car was at WOT. there is no print out we only saw it on his laptop.

**tims02** · 07-15-2008, 12:20 PM

Well if you had a bent valve the performance would be real shitty.. You can do a leakdown test on each cylinder and that would tell ya what it is. As far as fuel pressure goes I'm right around 60 psi at the front of the fuel rail.

**GottaHaveLS1** · 07-15-2008, 04:35 PM

Originally Posted by tims02

Well if you had a bent valve the performance would be real shitty.. You can do a leakdown test on each cylinder and that would tell ya what it is. As far as fuel pressure goes I'm right around 60 psi at the front of the fuel rail.

well my car performs pretty well actually... it should pull stronger though. it backfires occassionally after WOT and it's running lean... other than that she drives very well. so i guess i can rule out the bent valve for my lack of fuel