GHS GSX- It's running! Now what?

[gijoe985]

For those of you who have followed some of our posts over the last two years, the Grandview High School 95 GSX turned on today and idled for the first time. And now we continue trying to figure things out.

Backstory- We picked it up from a town over for $1k. Stripped interior (a new parts GST arrives Sunday) with a bunch of mods. Aside from the head porting we did, and the forged rods, upgraded, but NOT forged, pistons, mls headgasket and upgraded lifters, we are using all of the parts that came with the car.

The list- Holset HY35 turbo, 880cc injectors, DSMlink v2, walbro 255, crushed 1g BOV, Tial wastegate on a modified 2g stock manifold, FMIC, a CAI and filter, and 280 camshafts.

So, we just startd it and it sat at 2k and has some backfires. (we can post a video soon). Now I need to come up with a gameplan for how to find out what other problems might be hiding. We noticed that our intake wasn't fully on the turbo. The tranny kinda hits it. We still need to do some other small stuff. Get the accessory belts on, etc. At some point I really need to get in and mess with DSMlink. I've never done it before, but I've used other logging software.

Anyone have suggestions? As I post in other forums, I've got a few engine and car projects going on and it helps when I get some extra brainpower from people online. I've owned a few of these, but never one so highly modified. I think we will boost test it sometime soon.

I'm open to hear peoples' thoughts. And thank you ahead of time.

 

[josh408]

Start ironing out the little things maybe rewire the fuel pump, make sure there's no boost leaks or anything, spark plugs fresh and gapped, and start on the tuning side of things I definitely recommend installing a Wideband to help with the tuning. From there I would take it over to the ecm link wiki for some tuning 101 and setting up a base map.

 

[gijoe985]

So, currently the idle is bouncing a lot up around 1500rpm-1700. I'm trying to get dsmlink installed on my laptop. (School has to approve). The HLAs sound pretty loud to me. I'll have to look into that.

 

[gijoe985]

So, what are your guys thoughts on this-

1) The walbro 255 is creating 65psi of fuel pressure while idling.

2) The pressure bleeds off immediately after turning off the engine.

3) My Lisle fuel tester shows no pressure when I turn the key on. Only once started does it read.

 

[gijoe985]

Ok, well we found a fuel leak. The kids bent/cracked the line coming out from the fuel sendin unit. Thankfully we just got a donor car.

Oh, and the fuel pressure drops back down to 50psi when you turn the battery jumper box off! Didn't think about that when testing.

 

[Vegas Smith]

I'm pretty sure you want your fuel pressure to be 43.5 on a 2g with no tuning. Make sure this is set with the vacuum line removed on the fuel pressure regulator. With an idle that high, you probably have vacuum leaks, need to adjust the throttle cable or need to adjust the biss screw. Probably all 3.

 

[gijoe985]

We've got ECMlink v2, running the V3 software. I may start another thread to see if I can have a few of the experienced guys lend a hand.

So, we have no AFPR for the time being. I measured the pressure so that I'd know what to set ECMlink to. We've got the 880cc injectors. I did turn the BISS in a bunch. It helped some. Obviously our fuel leak is priority 1.

We did find a few vacuum leaks right off the bat. Pretty big ones. I think we're pretty good now, but we can check again tomorrow. We had two loose IC pipe clamps and a hole in a weld on a pipe. I pressurized the system to 40psi.

 

[pauleyman]

So, what are your guys thoughts on this-

1) The walbro 255 is creating 65psi of fuel pressure while idling.

2) The pressure bleeds off immediately after turning off the engine.

3) My Lisle fuel tester shows no pressure when I turn the key on. Only once started does it read.

3. Fuel pressure won't build with key on
You can manually fire the pump in link or there is a factory connection you can apply 12 v

 

[Vegas Smith]

We've got ECMlink v2, running the V3 software. I may start another thread to see if I can have a few of the experienced guys lend a hand.

So, we have no AFPR for the time being. I measured the pressure so that I'd know what to set ECMlink to. We've got the 880cc injectors. I did turn the BISS in a bunch. It helped some. Obviously our fuel leak is priority 1.

We did find a few vacuum leaks right off the bat. Pretty big ones. I think we're pretty good now, but we can check again tomorrow. We had two loose IC pipe clamps and a hole in a weld on a pipe. I pressurized the system to 40psi.

Go through the proper procedure to adjust the biss. If you just adjust it willy nilly then you can burn out the isc as it will be out of operating range for too long.

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[gijoe985]

Proven Member
NewSo it sounds like you can ground the diagnostic port and then adjust the BISS to the desired rpm

OR

Not ground the port and adjust the isc position to 30.

If I did the latter, what if you get 30, but your idle is still off?


I haven't done a vacuum test yet. I should do that.

Also, I have a boost gauge on this thing, but it hasnt shown anything yet. Even when I rev. Maybe just not enough rpms. Unlike a previous gauge I've had, it only shows boost, no vacuum.

 

[pauleyman]

Proven Member
NewSo it sounds like you can ground the diagnostic port and then adjust the BISS to the desired rpm

OR

Not ground the port and adjust the isc position to 30.

If I did the latter, what if you get 30, but your idle is still off?


I haven't done a vacuum test yet. I should do that.

Also, I have a boost gauge on this thing, but it hasnt shown anything yet. Even when I rev. Maybe just not enough rpms. Unlike a previous gauge I've had, it only shows boost, no vacuum.

Engine needs to be under load to build boost. Rev it hard enough and it will show very briefly. Or just drive it.

 

[Vegas Smith]

Proven Member
NewSo it sounds like you can ground the diagnostic port and then adjust the BISS to the desired rpm

OR

Not ground the port and adjust the isc position to 30.

If I did the latter, what if you get 30, but your idle is still off?


I haven't done a vacuum test yet. I should do that.

Also, I have a boost gauge on this thing, but it hasnt shown anything yet. Even when I rev. Maybe just not enough rpms. Unlike a previous gauge I've had, it only shows boost, no vacuum.

There are multiple ways to set the biss screw both of which you mentioned. If you get the isc to 30 and the idle is still off then there is still some type of vacuum leak (boost leak test the car at the throttle body elbow) or blow cigar smoke into a vacuum line leading to the intake manifold to see if it escapes somewhere. Also, make sure your mechanical timing is on point. Bad idle is usually an air leak or an improper biss/isc adjustment.

 

[1990TSIAWDTALON]

Probably needs to make sure the idle stop is doing its job too while making sure the throttle cable has a bit of slack. Simple stuff.

 

[streetraceboi]

There are multiple ways to set the biss screw both of which you mentioned. If you get the isc to 30 and the idle is still off then there is still some type of vacuum leak (boost leak test the car at the throttle body elbow) or blow cigar smoke into a vacuum line leading to the intake manifold to see if it escapes somewhere. Also, make sure your mechanical timing is on point. Bad idle is usually an air leak or an improper biss/isc adjustment.

Bro, they're in high school. You shouldn't be advising them to smoke cigars

 

[Vegas Smith]

Bro, they're in high school. You shouldn't be advising them to smoke cigars

Ok....smoke a joint? I'm not sure what your point is

 

[gijoe985]

We actually have a smoke machine for diagnosis. It is older though and doesn't make as much smoke as it used to. We did that already and got a few leaks fixed.

 

[1990TSIAWDTALON]

If your kids haven't constructed a boost leak tester, now would be a good time to build one and put it to use. It is a tool that you will need sometime on a boosted car.

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or
https://www.evolutionm.net/forums/evo-how-tos-installations/339529-how-boost-leak-tester-5-02-a.html from the Evo forum
or
http://www.dsmtuners.com/threads/making-a-boost-leak-tester.476861/

 

[gijoe985]

Thanks, yes, we made one yesterday and used it to test. I think we got 3 big leaks, but there may be some smaller ones hiding.

 

[1990TSIAWDTALON]

Soapy water with about 15-20 lbs of air should find most of them. Make sure that when you use the boost leak tester to tell the kids to wear safety goggles/glasses and have most stand clear of the area. I have had a tester come off before at 40 lbs and when that happens, you DO NOT WANT TO BE ANYWHERE CLOSE, it can hurt someone pretty seriously, so make sure that thing is clamped on super tight and I watch mine as I introduce compressed air to see if it looks like it is slipping off and if it moves at all, I get the heck away. It dented one of my charge pipes it came off so explosively.
Just don't want anyone hurt!
Keep up the good work!!!
Marty

 

[Vegas Smith]

He's the type of guy that stops at a red light ^^

 

[1990TSIAWDTALON]

Now now, thats what we are supposed to do. Then, when the opposing light turns "yellow", you practice your reaction time!

 

[gijoe985]

So, our parts car had a different style fuel sending unit, so we are using this as an opportunity to modify ours for a larger pickup tube. We're getting some 3/8" brake line, we drilled out the old pickup and plan to solder in the new one. We also found another hole in our IC pipes. So we welded that back up.

Little by little...

Oh yeah, had an egr vacuum line unplugged as well.

 

[buddahboost]

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I like this one since it's for a 4 inch inlet .