Injectors Bad???? JK, dmaxalli Tech

[chuntag95]

She started running a bit rough when cold. I pulled out the Predator and looked at the injectors. I was running the 100 Hp program, but backed down to the 85 to see if it made a difference. Answer to that is no. SO, I think I might have a problem. When cold, the number 7 and 8 injectors are:
7=-5 to -7
8=+6 to +7 and the pulse width is running 2 ms higher than all of the other injectors on #8.
Once it warms up, both injectors are 3 to 4 (same sign) and #8 is still 2 ms more than the others.
Now, I think the balancing is adjustments to the size of the hole and the pulse with is how long it stays open. I looks like #8 might have something in it, if I understand what's going on. #7 has not really caused any problems and has shown over 5 a couple of times, but when I rechecked it was back below.
What do you guys think?
:confused:

[Kennedy]

The engine should be at normal operating temp and no load (idle in P or N) in order to gain any useful information.

It is best if they balance less than 3mm, but I believe Eric said GM uses 4mm as a dividing line. From what I've seen, the ones that are balancing on the + side are returning excessive amounts and need to have a longer pulse in order to get adequate delivery.

[ 05-22-2003: Message edited by: kennedy ]</p>

[chuntag95]

So would the #8 be the one on the way out?
The last time I had this rough stuff, they replaced 2 injectors.

[ndamico]

checked mine today, and my #4 is ~+4.5 when the engine is in P and warmed up. seems worse when cold but i suppose that makes sense. most of my others are between -1 and +2...

if it was starting to go south due to dirty fuel, will it continue on its way now that i've installed my 2 micron filter or will it just hang there? hmm?

any thoughts from the experts?

Nick

[dmaxalliTech]

Yes, like JK said, must be warmed up (above 140 degrees ECT) and in park. Op temp is ideal for accurate diagnosis. I have a cold idle problem with my truck when I have Predator loaded to 100hp tune. backed it out and problem went away?

Usually an injector will not cure itself, damage is done. 2 micron filter will slow further damage and possible damage to others but...

Gm says 4 to-4 is ok, but I like to see them in the 3 range instead. 5 to 14 mm can cause a drivability concern with no dtc, over 15 mm will set a dtc.

Since you have ability to monitor it, I would keep and eye on it and see the dealer when its get worse. Dont tell them you know what you know, let them figure it out ;)

[chuntag95]

Well, I have the extra filter, and I was planning on waiting till it got worse, i.e. closer to 36K before I took it in. I also want to finish my fuel system work before.