S10xGN running (too) strong!

[S10xGN]

Hi All,

Well, my little truck is finally roadworthy! I've got all the requisite "legal" stickers in place and all of 20 miles of road time on it. There are several puzzling things ocurring, though:

I can't even come close to matting it, as I'm seeing 18# boost at 1/4 throttle! This is a stock actuator (albeit TIGHT) modified for "fit" on a 45° compressor outlet. I'm *sure* the 'gate hoses are hooked up right...

MAF appears to be pegging around 14# boost, it's hard to tell because you have to feather the throttle to keep from exceeding that value. 238 @ 13#; 253 @ 14#...

I've seen 20# on the boost gauge (again, toeing the pedal) and "0" on the knock gauge. I've suspected the knock circuit is "klabooey", since I've NEVER seen any knock ,and cannot rattle the gauge by hammering on the block or intake. But too, I currently have 10 gals of 93 and 3 gals of Xylene and temps are high 40's...

At a steady road speed of ~40 M/H, my EGT is showing 1140° and these numbers (average of maybe 20 consecutive frames) from my "Lubrant" chip & T-Link:

2225 RPM's (no TCC yet)
42 GPS MAF
4" vacuum (most of the trip, it was around 12", must have been the head wind)
115 LV8
1.28 TPS
124 INT
115 BL
47 xCounts

Please point me in the right direction BEFORE I blow this thing up (again).

 

[1ARUNEM]

Running "tuner" style i assume? If not check your wastegate solenoid. I had one go bad and boost was uncontrollable.. Nearly cost me a motor..
Good luck...

 

[clone311v6]

S10

Sure sounds like retarted timing. Most of your fuel is likely burning in the exhaust. Makes for instant boost and little to no power. I had this problem on my Syclone. Turned out to be a loose distributor hold down bolt. Simple fix. Problem solved.
Good Luck, Mike

 

[S10xGN]

As far as waste-gate plumbing, mine is all stock, right down to the factory "can" that's supposed to let go at 14#. I've checked the hose routing, but NOT the orifice size (remember, there were some that came through too small), so I'll look at it tomorrow.

Err, I don't think there is any to adjust the timing outside of having another chip burned for it. The (Lubrant) chip I'm using at this time has 20° in it. However, my old "mentor" Steve Wood said the same thing (about timing) in a private e-mail, but he's running an extender (I believe) which is adjustable.

Steve also pointed out that my M/H is way off (and of course, he's right), it's likely a result of a misadjusted Dakota Digital "box" that makes the VSS signal(s) for my ECM and speedo. My correct speed at 2225 should be 70, and correct revs for 40 M/H should be 1265. Something else to tinker with...

-> What about the EGT? 1140° cruise... a short 5 second throttle feathering, 20# blast got 'er up to 1400°. I'm running 50#'ers with 44# static fuel pressure.

Thanks!

 

[Steve Wood]

No, I meant your mafs were high like an extender chip and your lv8s did not indicate that much load. Sorry for the confusion.

 

[S10xGN]

Sorry Steve, I'm so stroked up right now, I'm bound to confuse things! After 3 years of head bashing, it's finally up and running!

Did you mean the 42 GPS reading at cruise? I do have a spare MAF I can try after getting the speed/RPM and wastegate issues handled...

 

[Steve Wood]

actually, I think I meant the high numbers when you were feathering the throttle...but...I should not have equated them to the lv8s you had shown for cruise. I mixed the apples and oranges....I ain't stoked..just sloppy.

 

[S10xGN]

Joe told me to start at 44# and adjust from there... I did find one problem today, my boost "tee" orifice was only 0.033" - isn't it supposed to be 0.050" minimum? The orifice is in the (straight section of) line from the compressor scroll to the wastegate solenoid (other side of tee goes to actuator) - is that correct? For a test, I plumbed the boost actuator straight to the compressor scroll, so I should start pulling boost around 14# - correct? Also, I was able to find a "Wells" IAC motor and changed it out today, but the weather and other chores prevented me from running it.

Later,

 

[Steve Wood]

yeah, that is right...most have been .046-.050 as I recall. Depends upon whose wire drill you use to measure it, I think.

If you run the hose from the compressor to the actuator, the boost should reflect the spring tension on the wastegate arm.

 

[S10xGN]

Ahhhh, MUCH better! Now I can mat the throttle and make ~ 12.5# boost. I'll drill out the orifice tomorrow and re-install the hose harness.

Checked the Dakota Digital SGI-5 VSS box and found one DIP switch off that needed to be on - a 33% change in speedo, which made it read correct.

Installed a new IAC motor and adjusted it for ~ 25 counts, which works excellent in closed loop, but when first starting (open loop), it keeps wanting to stall. Idle TPS, after re-adjustment is 0.39, full open is 4.57. What can I get changed in the chip that will cure this?

Driving this thing is a BLAST!

Thanks!

 

[Steve Wood]

Nothing like progress! I am glad it is finally happening.

You might try dropping the iacs to about 15 on a hot engine, in park.

Recheck the tps to make sure it stays under .46.

Might also double check for vacuum leaks that might be messing up the idle...even if the idle vacuum seems okay. check the base of the injectors, the plenum to manifold seam, egr base, hoses, and so on.

 

[S10xGN]

Well, things are looking better today! I found an old "boost tee" in my box that had a larger orifice and installed that, now I can boost to ~ 15.5# or so.

It started right up and didn't give me any idle problems today, but thinking back - it was after shutting down and cooling off then restarting that it kept wanting to stall. I never shut down long enough to cool off today.

I got to make (about a 1/8 mile) full-throttle pass today! BUT - I thought I heard some knock, even though I showed no knock or knock counts. I've GOT to find a way to check this ESC circuit!

15.5# boost
1390° EGT
128 BLM (locked?)
128 INT (locked?)
255 LV8
253 MAF
4.57 TPS
02's went from 824 -> 773

TIA!

 

[GN owner]

ESC Circuit

Please let us know if you find how to check it out. Thanks!

 

[turbosam6]

I noticed you have the caspers knock gauge, which is what I have. When we installed mine, the motor wasn't done yet, but it was in the car. I hooked everything up ecm-wise, and using a long 3/8 extension and a hammer, tapped on the block firmly. Every time I did this, the gauge lit up one more led. This was with the key on, engine off. I've heard that the motor needs to be at 2500 rpm or higher to register knock retard. Try the method I did, and see if the gauge even moves. If not, theres a problem. You've probably got a new sensor torqued to 14 #'s, so maybe the wiring?