Injector Detector....-=Jeff=- ?

[69MyWay]

Okay,

I just dropped the 36# injectors in the 90. For those of you that don't know my specs....

350 .030 over
Edelbrock RPM heads
Crane hydraulic roller 20/50 cam
1.5 full rollers
Headman long tube headers
flow master
9.6:1 compression
TPIS mini ram
52 mm tb
ZF 6 speed
single mas flywheel (quick revs, lots of noise)
3.75 richmond gears.

It use to have a mild dead spot off idle. I spoke with TPIS and they informed (much like Jeff has) that the stock PROM is so busy trying to take fuel out at idle, that as you transition to WOT, it gets "confused" and delays the fuel transfer. (due to vacuum changes from the bigger tb, miniram, cam, etc.)

Well, for giggles and grins, I just dropped Ken's old/new 36" injectors in. WHOA MOMMA! the car idles just fine, drives slow just fine, has TONS of instant throttle snap...but...(there is always a but)....It drops off after 4,300 RPM. I am not able to read my scanner and drive, so I don't know if I am actually flooding out at that spot, or getting lean. The pump is stock. I don't know if it is struggling to feed the different injector...or what In fact, the car is hitting so strong off idle, that attempting to set my scanner to "movie" mode causes it to trip out as the G force is knocking it out of the power socket.

Ideas?

Oh, I changed the fuel pressure up and down by "ear", and it seemed to make some difference. The steets are wayyyyy tooo busy right now to really rip up and down and flog it out.

I will say that twice, it KICKED, while I was holding the throttle to the floor at the 4,200 mark, and nearly spun the car around with an explosion of power, then dropped back.

 

[Ken]

I'm sure you'll work it out.

_ken

 

[69MyWay]

I am wondering if I got moisture in the distributor........

I rinsed the engine off to get the fuel off the manifold, and those of you with Minirams know how water puddles on the intake. That was steaming a bit.

If that steam was going up in the cap, that would cause it to break up and foul out....right?

That would also explain how it tried to go, but wouldn't?

Still checking.

 

[69MyWay]

I put some more seat time in it.

It runs fine all the way past red line...if you don't tilt the TPS over 3 volts--or at least over 3 volts quickly.

When you hit that magic zone, it drops off hard like you lost four cylinders, and will not build an ounce more of power. If just mashing it in lower gears, this is right at 4,000 RPM that it breaks off.

So....is the 36# injector opening up and dumping too much too fast when the TPS is going to WOT, or......something else?

It sure runs nice up until then. In fact, if you are not hot rodding, you would never even notice.

I did get a "rich" O2 code pop in while I was in low gear holding the throttle down watching, listening, feeling. So, that makes me think I am not getting a good spark and running rich, or...too much fuel. However, the more I add fuel pressure, the better it seems.

 

[Ken]

Jeff, we're waiting for a response from you.

(I can't help you there Chris. Sorry.)

_ken

 

[-=Jeff=-]

Hi Guys.. sorry it has been a busy Saturday..

Okay, First off, as TPiS explained, the ECM is trimming the fuel like crazy. You should at least change the injector constant int he PROM, it will give the ECM a breather.

What scanning software are you using Chris?? is it a Laptop or is it Auto Xray? Assuming you have a laptop and hoping you have datalogging capabilities, to get it dialed in a bit better you want the BLM to be at or near 128 ( I tune to +/-4 from 128)

I would say if you change the injector constant and tune it a bit you will see a big improvement.

As for going over that 3volt threshold, sounds like too much fuel. in WOT it uses preset values for many to the pieces, so if the ECM is adjusting it in non-WOT, it may not keep those values in WOT.

Also on fuel pressure, you need the pressure to get a nice spray in the chamber, but again, going from a 22# to 36# injector is A LOT of Added Fuel being dumped in the chamber, while it may help I am guessing you are really rich as well.

Shoot me an email about the PROM I have a suggestion..

 

[69MyWay]

Jeff,

For reasons unknown to me, my in car ACTRON scanner won't display BLOCK LEARN under the 1990 Vette setting. It will do it with my truck, and other cars....but not that one...????? Is there any other name for the Block Learn mode.....? I have some numbers on a setting (but can't remember what the scanner calls it) that stay close to the 128 zone.

Anyway,

I am thinking 30# would be the ticket. I am so amazed at how smooth and strong the car is with these 36# in all driving zones except WOT.

I think you are right, the computer can control these larger ones very well under 3.0 and with higher vacuum readings. When the vacuum dumps, and the tps tips over 3 volt, they just open up.

The car might be sold today. Due to my sudden angry rant with scoring a nice little speeding ticket with it yesterday, somebody is coming to look at it today.

So, Ken....we will talk about the injectors as soon as I know what is up with the ride. They need to come out, but it runs sooooooo nice otherwise right now. It is leading me to believe that one or two of my stock injectors may have been failing.

Let's see what happens.....ie, if I am ordering new, smaller injectors and a JEFF chip soon, or if the new owner is doing it himself.

 

[-=Jeff=-]

Let us know what happens

Also there is the intergrator that should be at 128.. it is the short term fuel, the BLM is long term

 

[69MyWay]

Ken,

I am probably wearing out my welcome on scavaging your old parts.....but what would it take for me to talk you into sending me your old Stage VI chip? My thinking is, it was programed for your motor which is very much like mine, only more cubes and more radical cam....However, you were running the 36# injectors. It would be an easy swap to slap it in and see where it brings me to do the final dial in....in other words, cut some guess work out of it.

????????

 

[69MyWay]

This should be fun.

I just picked up a set of 94 (batch fire) LT1 injectors.

I am going to pop them in and see.

 

[-=Jeff=-]

This should be fun.

I just picked up a set of 94 (batch fire) LT1 injectors.

I am going to pop them in and see.

94 LT1's were sequential fire with 24# injectors..

I think I may have a PROM file that would work well for you


Also Ken, if you are going to send Chris your PROM, could you send it VIA me? I would like to check out the parameters of it..

 

[69MyWay]

Happy Man!

She's back!

WOW! What a difference! I think I found 25-35 more hp!

More details to come.

 

[Ken]

Well, what do y'all want me to do next?

 

[69MyWay]

Well, what do y'all want me to do next?

I am going to try to give you call today. The fellow that bought my old 383 stroker 85 Vette was over last night. He said he might be interested in the injectors, and possibly the harness and chip. He asked me to get a price from you for him to consider.

He just bought a 2003 GSX R freak mode race motorcycle....and has yet to put the Vette motor back together from 2 years ago when he burned a hole in a piston....RUNNING LEAN.

 

[Ken]

You know as well as I what I paid for all that stuff you mentioned.