New injectors

S

spindrift

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Jul 23, 2009
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Just completed my stud job. While I was at it, I also went with 155 injectors and added a Stage I fuel system. The truck now pulls great when I've got a load behind it. Need to watch EGTs, which I never had to worry about before. Also seem to be getting better fuel mileage.

What has me a little baffled is my new lope at idle. It's somewhat irregular, but definately a lope and not a miss. Almost sounds as though the ECM is cutting out a downstream cylinder. I've heard that larger injectors can do this, but I'm not sure I understand the "why". Has anyone experienced the lope? Just to be sure, I'm not talking about a tuner induced lope.
 
you have more fuel then you used to at idle. Your tuner can pull more fuel back at idle to smooth it out. 155s and a stock turbo is a good combo
 
What injectors did you use for the swap? Sounds like a great combo when you get the tuning set.
 
I went with RCDs 155s and the Trusted Stage I. The first batch of injectors had a few QC issues but that got worked out with a very fast turnaround.
 
The funny idle is the computer trying to bring the RPMs down to the desired idle speed... Similar to a rev limiter on a gasser dropping spark to cylinders to keep it from winding up higher.
 
Try raising your idle speed a little with your SCT.....
A Tuner could also do it for you.
 
After driving the truck for a few weeks now, including a couple of good tows, I'm a little confused by what I'm seeing. Truck starts good whether cold or hot. Still pulls real good with no misses. However, once the truck gets up to 185* coolant temperature and I come off the throttle, I'm hearing what I think is a cylinder or two cutting out. Do you think this is still a tuning issue?
 
Are you hearing what sounds like the idle noise, but just a lot quieter? If so, it's normal (if the noise is what I think it is) and my truck with stock sticks and just a race tune does the same thing. Being that it runs fine any other time, I'm betting it's normal. There is a name for it, but it escapes me at the moment.
 
Abrannan19 said:
if it just gets really quite, its normal, mine does the same thing.
Click to expand...

It doesn't get really quiet. The other odd thing is that the lope/dead cylinder/etc. appears to be dependent upon road speed. If I've been into the throttle, then let off (say I was coming up to a red light), I'll hear the lopiness (the lopiness has a fairly rapid frequency to it) as the truck is decelerating. Just as I come to a stop, the lopey sound will dissappear and the engine will return to a normal idle. When I pull into the driveway, as long as I'm in gear I'll have a normal idle. Once I shift into PARK, a more erratic lope or miss will take over. Again, this is only when the ECT reaches 185*. :confused:
 
mine does this with the casserly 190's i have. seems normal to me with larger injectors.
 
strokin6L said:
mine does this with the casserly 190's i have. seems normal to me with larger injectors.
Click to expand...

I was gonna say something along the same lines. I've ridden in/driven Dalpilot's 03 with Casserly 190s, and it does the same thing. Just one of those things that comes with larger injectors!
 
Welcome to the big injector driving world. You get used to it, but its definitely different. Also you are suffering from Zilch's law. Now your afraid at every second that you have, or are going to hurt something. Just out of curiosity, what EGT's are you considering high? If your not seeing 1600, your not trying hard enough. LOL I've seen 1600 every time I drive it for the last 2 years. Stop looking at it.
 
LOL This truck tows almost exclusively so I don't get on it that much. As soon as I start to see 1200* I pull out of the throttle. I must be a :homo:
 
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