So we did the fuel rail mod and installed my new 370cc injectors tonite. Xmax, HectorC and Dave Sz came over tohelp with the install. The install had its hang-ups, but everything went as smoothly as a first time install should (which half the time is scratching your head trying to figure out what to do next.)

Anyway, we go to crank the car and base fuel pressure is a little high (around 44 psi) I turn it down and the idle gets really bad and the engine starts to shutter. I also heard a knock every once and a while near the tb and close to the engine.

We turned the car off, returned the fuel system to stock and tried it again. Same thing happened.

Then we decided to check the seat of the injectors by turning them in the fuel rail. they seem to rotate smoothly. We checked one on the front bank and it looked fine, like there was nothing wrong with the o rings. I now have the base fp set to 24 psi and it goes from idling smoothly to spouts of shaking and sputtering. The intermittent click is still there. There is smoke coming from the crankcase breather filter.

Does anyone have any suggestions about what we can do to solve the problem?
Thanks
Steve

 

Did you install the Z32 MAF as well?

Maybe a vacuum leak since you had the manifold off?

 

That is almost identical to the symptoms I had with my 370's. It would idle at 40psi, but if I turned it down to 24psi, the car would sputter, ping and stall. Turns out I had a cracked injector head that was leaking. The O-rings were good on mine, but there was a minute crack on an injector.

When we put the new injectors in, the car idles now, and the clicking went away.

 

i did not put in the z32 maf.

the injectors were just flow tested and new o-rings were put on. one had to be fixed (with epoxy), but now they seem to be in pristine condition. I did not check the rear bank though.

With the type of idle it has, I know that it isnt a vacuum leak though.

What is the thumping?

 

Are you hearing an actual knock, or just noise from the coils/injectors? I dont see how it could have changed, but check your timing. My car was idling like crap last night, and turned out my timing was way up for some reason, that took care of most of it.

 

try 26 psi. base fp

 

make sure the pintle cap(s) didn't fall off...its sounds harsh, but I've seen it happen before and the motor would run like *** for obvious resons

 

brad, there really isnt a good way for me to change timing.

delos, I have tried many different fuel pressures. 24 seems to have the least amount of bucking and sputtering.

addae, i will check the pintle caps when I get home. it was the same company that did corey's

 

"So we did the fuel rail mod" - Is this the one where you T-off the supply line to the two rails?

I'm wondering if maybe you need a fuel damper or fuel pressure regulator on each rail now. You might do some fuel pressure checks, since you said your base fuel pressure was slightly higher maybe something else changed.

 

yes, that is the fuel rail mod that i was talking about. I have two ports on my fpr that supply the same pressure to both ends. We ended up taking that out and returning the fuel flow to oem.

base fuel pressure might have been a little high because i was adjusting the allen screw to try and set it lower before startup. i must have turned it up. since there was no fuel in the lines, there was not trouble with flooding the motor.

 

I'd try going back to the stock rail configuration and see if that fixes your problem.

 

i did, and it helped a little.

 

Okay, that pretty much narrows it down to the injector install or the injectors additional cc.

You might try the Z32 MAF and bring fuel pressure back up to help atomization which directly affects idle quality. Or an eManage.

 

i think i'm going to reinstall them tonite or tomorrow and see if the pintle caps are intact and i can get the injectors to fit better.

If that doesn't work, then it might be the same problem that Shadow had (but I doubt it since i just got them serviced) and will have to go back to stock injectors, put the 8:1 disc back in and be satisfied with the 3.33 pulley for a little while longer.

 

So what happened? Did you figure it out? Need us to come over tomorrow? We'll be in the neighborhood.

 

Update:

It seems like where one of the injectors was repaired, there is a fracture that doesn't lett the top o-ring seat properly. I need to replace it. I am getting a part number now to try to possibly get one from the dealer at wholesale.

Davey, are you going to be around later, like after you go to the napa warehouse?

 

Update #2.

So I put the stock injectors back in and fire it up and i hear a loud pop out the exhaust and it is idling funny. It threw a code. I have to pull it tomorrow.