Fiero 2m8 LT1 NX Roadster conversion (Page 18/46)
Fiero2m8 SEP 11, 12:58 PM
In Canada, or Ontario at least, all emission equipment that came with the vehicle is supposed to be present before a drive clean test. I guess this was a way to appear stock, but they probably would had have to reprogram the ECM so it didn't throw a DTC code relating to the EGR system.

I'm going to continue to post every fix for the benefit of the search feature on the forum.
Hey, I'm learning by fire here too

Thanks again GoKart...

[This message has been edited by Fiero2m8 (edited 09-18-2006).]

Fiero2m8 SEP 11, 02:49 PM


The results of my GM Tech I are available and I will post them if anyone is interested.
Even though I didn't have any DTC codes, I checked all output tests and misc tests.

I have come to the conclusion that my rich conditon is caused by oversized Accel injectors.
Acutally they are the right size for my horsepower based on this calculation for my nitrous setup 9.5:1 compression with wet kit that doesn't relay on injectors for added fuel delivery when on the spray.

Injector flow (lbs/hr) = Engine HP (Normally aspirated for wet NO kit) * 0.07 (Nitrous compression)

26.25 = 375 * 0.07

I have 26 lb/hr injectors in which should be good for my setup but the PCM thinks the stock 22lb/hr injectors are still installed! I know that the computer can compensate up to 15% but I am over that, so I conclude that I need someone to burn me a new 1993 F-body ODBI chip based on the info below. I've also added the cam specs that I mentioned earlier in the thread that I would post.

Info for chip programmer:

This is a custom application I will tell you everything about my fresh rebuild and installed setup.
Details of my finished project in desperate need of a proper tune:

Chassis:
1986 Fiero sport coupe FORMER drivetrain - 2.5L 4 cyl THI25C Auto trans w/ODBI

LT1 Computer:
Street and Performance chipped 1992/1993 computer for stock LT1 engine 260HP (4 square plug style), 3 speed stock Fiero auto TH125c trans, 26" diameter tires, emissions on, VATS removed etc.
Piggybacked to Fiero harness as per V8Archie method.

Engine:
1995/1996 iron head 2 bolt main LT1 from Impala SS or Caprice 9C1? - not sure of exact year (had MAF but I removed, has vented optispark, water pump without bottom right front port)

Fresh performance rebuild - approx 375HP:

Bored 65 over approx 364 cu in or 6.0 L
Balanced stock crank
Wiseco Pro Tru Forged pistons 4.0600 bore, comp height 1.5605
Ported / Polished stock heads - do not have flow numbers or valve sizes yet but should be able to get specs from engine builder Stroker Performance
Stock spec rockers, lifters, new valves
Crane Cam Intake 228 / Exhaust 232 at 50 thou. Lift - Lobe separation 114 - Straight up
Shorty hugger headers with dual 2" exhaust approx 30" length each with twin cats and muffler tips.
Accel 26 lb/hr fuel injectors
Stock 48mm TB with TB coolant bypass
3"x30" CAI in stainless with IAT installed and K&N cone filter
Stock 1996 LT1 intake reversed on block
EGR hooked up, MAF removed
TPS, IAC, IAT, CTS, Oil pressure sensor, knock sensors, all new except MAP sensor
Optispark and MSD blaster coil new with Taylor 8mm wires
NGK TR6 plugs
Nitrous Express 100-300HP LT1 Pro (direct port wet kit) installed with 150 HP jets installed (#24 NO #20 fuel) as per Nitrous Express jetting chart.
Holley 255lph (Walbro) in tank fuel pump with stock regulator (41-47psi)
Performance High flow Oil Pump

Transmission Rebuild:

1990 Cadillac STS (Northstar) 4T60 - (non elec.) 4-speed overdrive transaxle
Rebuilt with hardened parts where available
333 Final Drive installed
1675rpm 10" Torque converter (new) - theory is that it will act like 600rpm higher approx 2300 stall when mated to torque of LT1 (also want to minimize broken axles)
37/32 sprockets / chain (3.73 Overall ratio)
2 wire trans plug
TV cable
Fixed Vacuum Modulator - hose from intake manifold


Misc. info:

Motor currently runs very rich/hot. I believe this is due to the stock 22lb injectors replaced with 26lb Accel injectors and performance rebuild with only stock LT1 tune
Running 94 Octane all the time
Nitrous activated by MSD Digital window switch and WOT switch. Window was suggested to me on at 2500-3000 rpm and off at 5500-6000 rpm.
Approx 9.5:1 compression
180 degree thermostat - 4 core rad with trans cooler and fan in operated manually currently - motor stays at 190 F after idling 5-10 minutes.
I currently have a GM Tech 1 and downloaded Data Master version 3.5 that I can use to gain more data
No codes flash other than 12 when pins a/b jumped
New O2 sensors are 93 Z28 spec - 2 both before cats one wire sensors (non-heated)
VSS is Fiero elect gear driven - Speedo not working
Tach wire on LT1 does not successfully operate Fiero tach - tach mod from 4 to 8 cyl completed
2 Knock sensors - no knock detected at idle - spark advance is 20-21 degrees.
Future plan to add MSD digital 6 box to retard timing on larger sprays i.e.. 200
Idle currently hunts from 700 to 1000 rpm.
Hard start when engine hot
Misses develop quickly with rich condition and fouls plugs quickly.
Left drivers 1,3,5,7 bank currently 100 degrees hotter than right as per laser handheld temp gauge - burnt paper collector gasket - replaced both with aluminium ones - problem also existed before rebuild.


If anyone knows a good programmer in Canada let me know - here are a couple links I found on some U.S. guys - let me know if they're good....

http://www.madtuner.com/index.php
http://www.pcmforless.com

Fiero2m8
Fiero2m8 SEP 18, 10:25 PM
What's going on - I haven't posted in a week due to laptop issues.
The new one is up and running so I've got some updates for you.

Tuning update:

After speaking with Mark at Street and Performance, I chose to keep dealing with them for the following reasons:

1) They required the most data in order to program and burn the chip
2) I agreed with his assessment of the data that the rich / hot exhaust problem is mainly at idle.
3) The ECM is going to fuel enrichment mode due to a lack of vacuum / map reading at idle.
4) That the low vacuum at idle is mainly due to the performance cam I am using.
5) The original chip was his best guess to get me close for a stock LT1/TH125c but now it's anything but stock! He still offered to do the chip at no charge since I couldn't provide an original data sheet when I ordered the ECM (motor not installed etc)

Since I didn't want to wait longer and would be without the car - he is going to burn a new chip and I will send him the old one back after I swap the new one in. (He has my CC# in case I don't return the old one)

Here is the data sheet I filled out using the GM Tech 1 scan tool and a vacuum gauge:



Some interesting stuff the Scanner told me:

A) Even with the low gearing, I am only revving 2100rpm at 100km (62mph) in overdrive using 25.6 diameter tires.
B) The speedo was only off 3% using his guess based on my tires and the stock TH125 - 62mph was actually 59mph on my GPS.
C) Spark advance was 21 degrees at idle with no Knock Retard
D) Running temp maintained at 190 degrees after it went into closed loop mode
E) Idle long term fuel trim dropped down to minimum 108 quickly after resetting trim to 128 on both banks.
F) O2 sensors functioning within specs when tested
G) TPS 0.64 V at idle
H) System voltage at 12.1 - 12.6V until I added a 4 gauge ground wire from the negative battery to the engine block - now 13.5 - 14.1 volts.

They are burning the new chip tomorrow in Arizona they think I will have it Thursday or Friday up here in Canada.

Here is a great link of theirs for the LT1/LT4 - great TECH info for anyone else is considering the LT1 swap including harness instructions for the ECM.

http://www.hotrodlane.cc/New%20LT%20Tech%20Page/LT%20links%20page.html

P.S.

ECM - Engine Control Module (ODBI)
PCM - Powertrain Control Module (ODBII)

I learn something new everyday

Fiero2m8
Fiero2m8 SEP 19, 06:02 PM
Saturday was the first day ALL the guages on my Fiero worked at the same time since the swap.

First I got the fuel guage working, then the temp gauge using the new LT1 sensor in the rear head.
The oil pressure guage worked once I connected the correct white wire from the new ECM to the white Fiero oil gauge wire.

That left the speedo and tach (the big gauges in the dash).

Here what I did to get them up and running....

Speedo - downloaded a diagram of the VSS system shown here:



I don't have cruise, so I needed to find the yellow and purple wires running to the instrument cluster.
I ended up running new wires from the C203 connector below the Fiero ECM location in the console to the governor.
The new wires were spliced into the new purple and yellow wires that go to the LT1 ECM matched yellow/yellow and purple/purple at the governor. At the C203 connector, again purple/purple and yellow/yellow were spliced. Now gauge works well and no VSS trouble codes shows up!

For the Tach, I first did the tach mod using the easy capacitor method of soldering in 64 micro farads using 2 - 22's and 2 - 1's in parallel to make 64. I used a cordless low heat/instant heat handheld that did a very nice job.
I finally convinced myself that I had the wrong white wire from the Fiero harness and downloaded a pinout diagram for the C500 connector (engine harness connector on passenger shock tower area in bay). Even though all the diagrams on the net and in my Haynes manual were white, mine was BLACK! I had predispositioned in my mind it had to be white, which drove me crazy until I decided to start from scratch. Turns out this black wire probably went to the Fiero Tach Filter which low and behold had black wire connected to it
Since I had sold the iron duke and didn't have another car to look at, I didn't remember this key information.

Below is a scan of my worksheet and pictures of the C203 and C500 connectors - I didn't agree with 100% of the info on it, so I made notes and labelled all my wires while going through the connector rows/columns. Perhaps different years, engines, or options have slightly different pinouts?



C203 connector


C500 connector



I can hardly believe that I may be ready to finally wrap the harness wiring!
A few wires I will keep handy for future wiring projects include decklid solenoid, fan control, hot engine idiot light and an Ign-on 12V+ wire I could mount an engine compartment light to on a switch for night viewing.



Fiero2m8
Fiero2m8 SEP 20, 12:58 AM
A must have link for the LT1 swap!

http://shbox.com/1/4th_gen_tech1.html

I used it to verify all my vacuum connections tonight.
I had to make a couple variations due to:

1) intake is reversed
2) Vacuum for 4T60 was required
3) My ECM and the Fiero didn't use a solenoid for the EVAP system

On the left side of the intake (now rear) I used the OptiSpark vacuum port for the 4T60:


One the right side of the intake (now front) I used the HVAC port for the Optispark:


All others remained as per the diagrams.

Fiero2m8

------------------

1986 Fiero2m8 (LT1 NX / 4T60 Roadster Build)
http://www.fiero.nl/forum/Forum2/HTML/071642.html

Fiero2m8 SEP 20, 01:07 AM

quote
Originally posted by MotorTV:

btw... you are going to find that the line you pluged on the water pump.. (the line that goes nowhere in Wiston's pic) is REALY needed....




quote
Originally posted by Fiero2m8:

Thanks Chuck - I think that explains it.
I pulled the old pump out of the box that came with my iron head LT1 and as mentioned nothing at that port location on the housing - not even a plug.
However when I ordered the replacement pump I got one for an F-body that did have the aluminum heads...

Ryan



Hey Chuck,

I stumbled across this picture tonight confirming my hunch that the pumps are different on the Vette and Imapala versus F-bodies - I'll sleep better now



Fiero2m8 SEP 20, 03:58 PM
Well now I've got a sheered off bolt in this end of the head to match the one at the other end

Any ideas of how to support this torque monster from trying to jump out the back of the car?



Fiero2m8
Jake_Dragon SEP 20, 04:26 PM
Yep, solid mount the front of the motor and the tranny.
Fiero2m8 SEP 21, 08:34 AM

quote
Originally posted by Jake_Dragon:

Yep, solid mount the front of the motor and the tranny.



I do have Archie's front solid mount and the trans braced with a solid strut bar.
The top front of the motor still tries to twist rearward.
I'll post what I try next.
tvelarde SEP 24, 09:26 AM
Wow!

Still totally amazed at the work you have put into this swap. Not being quite as ambitious as you are, I am in the midst of my own LT1 with 4T60 install but with a carbed motor. You indicated that you had issues with the rear header as far as clearance and had installed a 3/4 inch spacer to help move the exhaust outlet far enough away from the speedometer housing to clear. In your pictures I can see just how close it is.
I can't seem to locate any shorty headers that will allow this side to work, even with 3/4 and 1.5 inch spacers. I have tried some stock Corvette tubular headers, quite short but still too close, regular block huggers, Sanderson C90, and a couple of others with no idea of origin.

How did you modify the header to allow the clearance? I have gone through all my spare headers and many cast exhaust manifolds trying to gain sufficient clearance to get by my sppedometer housing, which looks identical to yours. Thanks for all the work you have done and for the boost to those of us not quite as intuitive as you are.