fuel injectors? need help

**blackonblackws6** · 05-02-2008, 07:59 PM

Hello ls1.com people! its my first post. i've got an issue with my TA and you guys seem to have all the info so i hope someone can help a fellow Fbody guy. My 2002 ws6 has of late been running a bit rough at idle and low rpm. almost stalls if burping the throttle in gear (its an auto) almost a bit of vibration at 2k rpm. its back to completely stock form as far as the engine goes. i had a bunch of bolt on stuff so one by one i removed every thing attempting to pin point the issue. if not then i could bring it back to the dealer and get them to diagnose it if its not modded. any how, it got 16k miles on it now i checked for an intake vac leak, plugs good, wires new 10.5mm, fuel psi 58-60, put a new maf w/screen back on. compression check next. it started last fall before i put it away for the Michigan winter and seemed to be getting worse after i got it out this spring. the dealer thinks its dirty injectors and they want to do a fancy injector cleaning proceedure for $149, i guess i should believe them but find it hard to. find it hard to believe running some chemical through them will fix this running issue with only 16k miles on them. maybe i'm wrong but don't want to piss away $150 for them to guess. if in fact it is the problem i would rather just replace the injectors with ford svo 30lb ers which i hear that they will really be 36lb with LS1 fuel pressure. Right? i'm planning on camming the motor and putting my headers 90mm TB and intake back on and o yeah the ZEX direct NO2 wet injection system. do i need to have the ECU recalibrated for the bigger injectors? if so what can i expect if i put them on and don't recalibrate right away. sorry i wrote a book but it might save some time wrighting back and forth gathering info. thanks in advance for the help. -mike

**0rion** · 05-02-2008, 09:03 PM

did the dealership diagnose the car or did someone tell you that's what it might be? If they actually looked at the car then I'd be tempted to believe them. Have you tried running injector cleaner or seafoam through it yourself? Even though the car only has 16k miles it is 6 years old and with the low miles I'd say it sits alot so a plugged injector isn't out of the question. When you pulled the plugs what did they look like? Any of them look lean compared to the others? Just ideas. It's tough for anyone on here to diagnose a car other than just some educated guessing. That's why I say if they actually looked at the car and diagnosed it properly then a dirty injector wouldn't be completely out of the question. Run cleaner through it on your own first and see what happens. Also, just check around the engine bay for cracked hoses and things like that. The pcv hose that goes into the side of the intake has a habit of cracking on the backside of that hose to where you can't see it unless you feel around the backside of it.

**SandmanWs7** · 05-02-2008, 09:14 PM

Originally Posted by 0rion

did the dealership diagnose the car or did someone tell you that's what it might be? If they actually looked at the car then I'd be tempted to believe them. Have you tried running injector cleaner or seafoam through it yourself? Even though the car only has 16k miles it is 6 years old and with the low miles I'd say it sits alot so a plugged injector isn't out of the question. When you pulled the plugs what did they look like? Any of them look lean compared to the others? Just ideas. It's tough for anyone on here to diagnose a car other than just some educated guessing. That's why I say if they actually looked at the car and diagnosed it properly then a dirty injector wouldn't be completely out of the question. Run cleaner through it on your own first and see what happens. Also, just check around the engine bay for cracked hoses and things like that. The pcv hose that goes into the side of the intake has a habit of cracking on the backside of that hose to where you can't see it unless you feel around the backside of it.

This is true. My car had a cracked hose in that area and it would shut off. Mine is a manual. Do check the pvc hose and pvc itself.

**blackonblackws6** · 05-03-2008, 05:45 AM

yeah the dealer looked at it. they put the tech 2 on it didn't find a code and said it needs injector cleaning. plugs all looked to be burning nicely. thing about the milage is; i bought the car last Feburary with 4k miles on it and it ran awesome until the end of the season, yeah i drove the heck out of it, 12k in 7 months. so it isn't like it sits for months on end. it did until i got it. i did leave out that i got a P0300 random misfire code in my original post. that was before i switched every thing back over to stock config, but doing all that work didn't solve anything. it still runs like ass but hasn't thrown the code again. any input about the the 30lb svo injectors? must i reprogram the ECU? fuel injection is the bomb when its running good. give me a carb and a distributer i could tune it with a hammer

thanks for the reply guys. great forum!

**juiced99ws6** · 05-03-2008, 07:57 AM

Yes if you do injectors you would need a tune. If you have a local tuner they could probrably just do a "street tune" for you instead of a full out dyno tune. Doing a tune for just injectors and some minor bolt ons wouldnt be to big a deal for an experienced tune.

As stated previously I would definatly recommend cleaning your injectors yourself first and see if that will improve anything for you. Unless you plan on alot more mods I wouldnt recommend replacing your injectors.

**blackonblackws6** · 05-03-2008, 07:04 PM

thanks, i'll try your advice. i'll do a dyno tune when i get my bolt ons back on and get the cam in, i'll do new injectors then if needed. i tried a F.A.S.T. / Comp Cams tune and yet to get it the way i want it after a few time sending it back to them. great guys but the Hyper Tech plug in tuner has run better for me. there tune puked a crank senser learn code. i gave up on them $130 in the toilet. any recomendation for injector cleaner. i heard seafoam, is that some thing that goes in the fuel rail and runs directly into the injectors? pouring some STP in the tank never fixed anything in my experience. thanks again people.

**SteveC** · 05-04-2008, 05:18 AM

You state you put a new maf with screen back on, did you have a ported maf ends with no screen before? if so this would have changed the air fuel ratio to the point that the pcm could not compensate.

I went to ported maf ends with the stock maf, and needed adjustments to the a/f settings in the pcm during a dyno tune, before adjustments (to 13.2 wot), I was running lean @ 15.4 wot.

SteveC

**blackonblackws6** · 05-04-2008, 07:30 AM

no, the maf sensor was stock with the screen punched out. i just had a new one un-modded to put back on for the dealer. my dealer would evn look at it for diagnoses with out it being totaly stock. that helped me eliminate any bolt on problems as well. i'm gonna try the injector cleaning today and see what happens. if that doesn't make it better i'll do a comp check. probly a good thing to do any how after running no2 all last season. mybe i bent a rod or bad valve(s).

**blackonblackws6** · 05-04-2008, 07:32 AM

it was a nice running car unlit i started beating on it. part of the game i guess.

**sic2001** · 05-09-2008, 11:42 PM

did you ever find out what this was? Im having the same issue

**blackonblackws6** · 05-10-2008, 01:50 PM

i hope i got it figured out. i have a set of OE 28lb injectors coming in monday. man i hope its the problem. i still find it hard to believe its the injectors with 15k miles but maybe i got some moisture in the fuel and it sat long enough to f*#k em up. i've looked at EVERY thing they are the only thing left and thats what the dealer says it is. i'll tip the tech when i see him next or call him a ass depending on the out come. i've done a ton of t&d before i let the dealer look at it. its totaly back to the way it came from the dealer. so i know it nothing bolt on failing or uncallibrated. i did a compression check before i ordered the injectors, they were all within a couple psi. if it fixes the problem i will for sure post it and let you know who services the injectors and flow test them, they also give you a print out of the flow test. it a load cheaper than buying new or A/M and retuning.

**blackonblackws6** · 06-10-2008, 08:54 AM

well i installed the new GM injectors, guess what? it didn't change anything as i suspected. now what? who knows, i'm really frustrated now. i took it back to the GM dealer the same MASTER tech looked at it again and said" i told you the injectors were dirty or plugged last time you were here." I said yeah i know and i replaced them and the fuel filter for good measure. plenty of fresh 93 oct. fuel through it as well before the injectors. he says "huh i guess you got some bad injectors". what a jackoff!

he's dead set on the injectors causing the problem. if the antilizer doesn't tell them what to replace they can't fix it

. anyone can replace parts, i need a good driveability guy to diagnose this car. i really need some help now, anyone?

. i'll try a new dealer i guess.

**sic2001** · 06-11-2008, 09:35 AM

Well for me, i seem to have found a partial answer, My ICS (idle sensor) was FILTHY and I cleaned it off real good, alot of black stuff came off it. Car idles great now and even the stagger is ALMOST gone.