94NDTA

I've been battling this for a while, I'm trying to figure out what might be causing this issue. Car is a stock bottom end lt1, LE2 set up (cam is the 227/235 with 110 LSA)new ac delco vented opti, 37# racetronix injectors, stock in modified tb, Walbro 255 pump. Plugs are autolite 104 copper gapped at .035, Taylor 8mm spark plug wires, MSD coil (did this as well with stock coil). O2 sensors are original.

I really don't believe it is leaking fuel, I feel like it is not being burned completely (at least not at idle/part throttle). I did a fuel pressure test, the original regulator had plenty of pressure and only dropped very slightly after a half hour). I pulled the fuel rail and primed the fuel pump to see if the injectors were leaking and they did not. Still the spark plugs will be wet, and when I changed the oil (which I am doing often) it has a slight gas smell to it, more so than any of my either cars.

The car will start just fine after it has sat over night, but if I have been driving it, and I need to start it, half the time I need to put the gas pedal to the floor to shut off the injectors for it to start. Sometimes it does stumble to life. I have had the car to two different tuners, neither say it is an issue with tuning.

The suggestions I have been told are as follows.

it is not getting enough spark to burn completely. I have a set of MSD plug wires waiting to go in as we speak. This issue was present with the original coil and MSD coil. I replaced with the MSD because I believed the original to be damaged.

The stock tb needs to have the blade opened slightly or drilled. With the cam I have, there is not enough air at start up/idle. On the dyno, at WOT with a wide band and it read a great a/f. I do not have read outs at idle/cruising. I am in the middle of trying this right now.

Original O2 sensors are either giving false readings and dumping too much fuel.

Any suggestions or ideas? Let me know if you have any questions. I do have plenty of scans, nothing really showing out of the ordinary. I have a constant false knock I have been battling, but at leaning towards it may be real knock from too much fuel now.

craby

have you had it tuned yet? if not get er done. pcmforless or lt1pcmtuning are good mailorder tune places. pull the 02s and see if they are fouled. could be getting acceptable false readings and dumping fuel. the injectors seem a little much. have you thought about using 30lb'ers.

94NDTA

Two different tuners. Lt1pcmtuning did the initial tunes then TPiS did a dyno tune. I didn't really think much about this issue when getting it tuned because I thought it was tune related. The car got easier to start after warmed up after the last tune, but I still needed to shut off the injectors, and still wet when I pull the plugs.

I will check to see if the o2 sensors are fouled, but to be honest, I don't know how one would tell.

Lloyd, Solomon and Jim at TPiS didn't make any mention of 37lbers being too big, but I will look into this.

97lt1camaro

iTrader: (3)

I was told that because there is no available spec/data for the racetronix 37# injectors that it will be hard to
Tune because of it.

I habe them in my car and have issues with my tune

94NDTA

Similar issues? What did you replace them with? Do we have a racetronix rep on this board?

pantera_efi

iTrader: (1)

Hi, yes the air door may need to be drilled OR IAC is not operating ?

The MORE common cause is fuel leaking past the injectors into the cylinders.

This is not common but your report states a fuel leak into the engine.
This could ALSO be caused by a bad Pressure Regulator Diaphragm.
Would the FPR be ported to the manifold ?

Lance

craby

02 sensor will foul just like a plug. gets covered with black coating that can effect the 02 reading. i had my injectors flow tested and adjusted to match. solomon tuned mine as well. i did have same issue as you but mine was a couple bad injectors spraying to much and to high fuel pressure.

94NDTA

IAC is working to the best of my knowledge. I have the stock TB on right now, no longer have the holly. TPS reading at .60volts. I will recheck though as I checked it when I first put the set up together.

I tested FPR, and it was right on spec and held pressure really well. I also pulled the entire fuel rail to test if the injectors were leaking, with 43 psi behind them they held for 15 minutes, no leaks from the injector or past the injector.

As far as the FPR being ported to the manifold, I don't know what that means. It's the stocker in the stock location (to the best of my knowledge)

94NDTA

They are super black, but assumed that was due to the fuel issue.

craby

yah it can get into a cycle, fouled 02 sees a little less fuel than there is so pcm adds more fuel, 02 fouls more see's less fuel so pcm adds more fuel. that may be a side effect of your problem though, if your still going to get to much fuel then the new 02's will foul as well. i have used actyline torch to clean mine while i was searching for issue. clean blue flame did a pretty good job of cleaning. dont get it to hot or will melt wires inside.

94NDTA

Either way, I'm sure I need to replace them by now. If it stil persists, I will know right away anyways.

craby

lol i have at least 2 sets of injectors around here, i think one set is 32lbs and a stock set and another i dont know what they are. had the 30lb set all flow matched with the numbers for solomon so we went with them.

94NDTA

I really hope that it isn't the injectors. I wonder if I can send them to racetronix to test them, or if it is even worth it. I didn't think 37# was too big at all for my set up.

craby

it can be tuned for that size, just need fairly consistant numbers. might try having them flow tested at an injector shop. stay clear of the cheap china injectors. i think it was 25 bucks an injector for the last set i had cleaned and flow tested.

94NDTA

They should be tuned for this size. I bought them brand new, who did you have test them?

All of my plugs have fuel on them (I believe, I'm pulling them again) but last time I checked it was all of them. How would flow testing them help my situation? Determine if they are flowing too much or if one or more is flowing too much?

craby

the set in the lt1 were new too. two of them was off. doctor injector in tacoma. sent em in us mail and got them back three days later.

shbox

What is missing is info about what your IAC counts are. That will help tell you if it is not getting enough air at idle. You will want to know this well before making any kind of changes to the TB blade angle or drilling anything in the TB.

94NDTA

I will go over the scans and provide them. Both tuners made no mention of any issue with IAC counts.

94NDTA

IAC counts 105-115 at initial start up at idle. 48-60 at idle when at operating temp. Average would be around 51 counts. TPS volts at .59.

BALLSS

your IAC counts are on the high side but as long as the car is not stalling when you turn wheel at idle or when AC kicks on at idle you are OK

They want to be 32 (30-35) at idle when motor is at operating temp

you are running rich and will kill 02's quickly then CATS if you don't find out why. gas in oil is not good and hard on bearings

the 37 lb injectors are on the high side for your build but a "good" tuner cam tame them....if they are familiar with the specifics of the 37 lb racetronix ones

exhaust leak pre-02 will make 02 read lean and command PCM to dump fuel so confirm you have no exhaust leak at exhaust manifold flange or where it bolts to CATs

On injector service I use www.cruzinperformance.com Rich knows his stuff and you get a B & A printout on injector performance