Fuel injector problem...

[kwkshift]

The last time I had my car on the dyno, it was lean while on the motor. So, I decided to start trying to figure out why that was.

I put a fuel pressure gauge on the rail to see if the regulator and or pump were weak or bad. Fuel pressure would hold at just under 60 psi. I let the car sit and came back after a break and the pressure was still about 55 psi.

I replaced the fuel filter, thinking that maybe the original one was still on there with 40k miles.

I replaced the plugs last week with a set of SRT-10 plugs. I drove the car around for about 100 miles or so and never sprayed the nitrous. I decided to pull the plugs yesterday to see if there were and signs of detonation on any of the plugs and there was. Cylinder #1 looks like it was covered in pepper. There were a couple of others that had some detonation but not like #1. #7 plugs was starting to turn toasty brown, so I figured that I may have a weak injector. I swapped #1 and #7 injectors and tried to restart it. That didn't go very well. The car ran on 9 cylinders and was making some serious racket. I shut it off immediately and pulled the #7 plug. It was soaked in gas. I thought that maybe I didn't oil the o-rings well enough and maybe I damaged one. I pulled the injector again and the o-rings were fine.

I let the car sit over night to help evaporate all of the fuel and I reinstalled that injector again. I started the car again and the same thing happened.

I then tried swapping the injectors back to their original locations. Now #1 plug is soaked in gas after starting the car for a couple of seconds.

This is driving me nuts. Could the injector have gone bad just from me handling it? Has anyone else seen a problem like this? The dealer doesn't have any injectors and they would be ordered in from Detroit in 3-5 days.

 

[Ulysses]

THe injector is pretty sturdy so I doubt that just handling it would make it go bad.

 

[kcobean]

So the facts are these:

- Cylinder/Plug #1 looks like it has been peppered.
- Upon swapping injectors 1 and 7, the #7 plug was soaked in gas and the car would only run on 9 cyl's (presumably without #7)
- Upon swapping inj 1 and 7 back, the car ran again on 9 cyl's (presumably without #1) and the #1 plug is gas soaked.

It sounds to me like you have a stuck/sticking injector on cyl #1 that's causing some serious carbon buildup.

Not familiar with the cylinder numbering on the Viper yet, but assuming that 1 and 7 are in the same bank (odds/evens), could it be that you're running the odd bank's rail lean because of the injector's increased flow? That would explain the #7 cylinder looking lean, the pepper in the #1 cylinder and the presence of raw fuel following that injector between cylinders. Do you have a way to check pressure on each individual rail?

 

[kwkshift]

Well, I have some more information.

My buddy brought over his super kick-ass, $5000 Snap-On scanner and hooked it up to the car. We were able to test fire individual injectors and we can hear them click, but who knows if #1 is sticking or there is another problem.

There is also a knocking sound coming from the engine. This started immediately after swaping the injectors the first time. That's the part that is worrying me.

 

[Jack B]

As was already asked - how are controlling (limiting) the larger injector duty cycle or do you have stock injectors?

 

[AZTVR]

If you are willing to send your injectors out of town, you could have the injectors cleaned and tested. I've used this guy after seeing him recommended on some Hot Rod forums: http://www.cruzinperformance.com/fuelinj.html The info that he provided was very professionally done, and showed the injectors' performance before and after cleaning.

 

[kwkshift]

Stock injectors. The car only has an intake and exhaust.

Here is a video of the drivers side valve train with the valve cover off. There is definately some bad noises happening here.

http://members.cox.net/kwkshift/CIMG1588.AVI

The car ran perfectly fine Thursday night when I came home. Then, ever since I swapped those injectors around, it's been a disaster. I don't know if there are 2 different problems here that coincidentally started at the same time or what. The valve springs all look fine, the pushrods aren't bent. I was thinking about using a screwdriver as a stethiscope against the rocker arm bolts to see which one is making the most noise. This is, if it's a valve train problem....

Talk about being stressed out!

Thanks for the help!!