Fiero 2m8 LT1 NX Roadster conversion (Page 38/46)
Fiero2m8 JUL 08, 05:50 PM
Big plus for the ogre!
Found my problem without spending any money.
It was the ECM in my trunk getting heat stroke from engine bay heat.
Just needed to seal up and insulate the large hole and I will make a vented computer cover to replace the solid one in the trunk.
I guess it took a couple really hot days to show the problem as it hadn't been an issue in the past.
To confirm my diagnosis, I drove out to Niagara on the Lake with the computer just resting on the trunk carpeting (no cover) and the hole sealed.
It restarted everytime hot with no quick start needed.

As promised, here is the scan data after letting it idle 15-20 minutes in 90plus degree weather:

Idle - 950
CTS - 210F
INJ 1 Fault NO
INJ 2 Fault - NO
Knock - OK
IC - OK
System Volts - 13.6
Learned IAC - 33
INJ Pulse Width Bank 1 - 3.5msec
INJ Pulse Width Bank 2 - 3.5msec
Lo Res Signal - 15 msec
Hi Res signal - 1-250
Knock Retard - 0 degrees
Knock Signal - NO
Spark Advance - 20 degrees
Fuel Trim Cell - 16
Fuel Trim Enable - YES
Short Term Fuel Trim Bank 2 - 122
Short Term Fuel Trim Bank 1 - 124
Long Term Fuel Trim Bank 2 - 148
Long Term Fuel Trim Bank 1 - 152
TPS - 0.46V
Throttle Angle - 0%
MAP - 60 KPa (2.66V)
Baro - 103 KPa (4.98V)
Engine coolant temp 223 degrees
Intake Air Temp 163 degrees

The only real engine annoyance I've never been able to solve is the loping idle 800-1100 rpm.
It did it before and after the engine rebuild with cam change.
IAC was replaced but I've been told the problem is due to relatively low vacuum at idle (12-15 in Hg) so that was why I had the new chip burned.
Although did it before and after chip reprogram - the ECM seems to keep hunting as it moves the IAC in and out trying to make corrections.
If anyone can tip me in the right direction, you'd be my hero as it even has the GM mechanics stumped - I know that's not saying much

Fiero2m8
Fiero2m8 JUL 11, 12:35 AM
Picked up a Corvette master cylinder for the Roadster:






Couldn't find clear marker lens from a 2000 VW so I went with small surface mount amber lens from a Nissan 240:
Here's a similar one on a 95 Altima:




Made new holes with the drill bit and angle grinder, spliced the wire and here's the new look:



Molding will be filled and flare smoothed out and fender painted black - whatcha think?
doublec4 JUL 11, 12:48 AM
hmmm I think the stock locations look pretty good to me to be honest, maybe a little lower than stock.. that looks a little too low in my opinion...
DeLorean00 JUL 11, 01:31 AM

quote
Originally posted by doublec4:

hmmm I think the stock locations look pretty good to me to be honest, maybe a little lower than stock.. that looks a little too low in my opinion...



Agreed... I little low. But just IMO
Fiero2m8 JUL 11, 11:01 AM

quote
Originally posted by DeLorean00:


Agreed... I little low. But just IMO



Well I'm glad I didn't go even lower then as that was my other idea.
They are very low on the Nissans as pic above.
I wanted it near a body line, away from the curve of the fender flare, and below the original location.
Next time I might ask for opinions before cutting the holes
DeLorean00 JUL 11, 07:17 PM

quote
Originally posted by Fiero2m8:


Well I'm glad I didn't go even lower then as that was my other idea.
They are very low on the Nissans as pic above.
I wanted it near a body line, away from the curve of the fender flare, and below the original location.
Next time I might ask for opinions before cutting the holes



Its your car!! Do what you think looks the best!! After all your the only person that it really matters too.

I'm sure it look better when its all one color.
Fiero2m8 JUL 12, 07:36 PM
Thanks - back to the powertrain in the meantime.
I decided to replace the ECM with a reman unit and just transferred the custom PROM:



The lower trunk got a coat of high heat paint and the Nitrous bottle was refilled.
A new 6 foot feed line installed to replace the 20 footer since I'm not using a purge:




The carpeting was redone to surround the new stainless grill.
Once the engine was up to operating temp, the bottle pressure guage reads 1050psi.
NX recommends 1000-1050psi for best results from their jetting charts.
I am currently using the 150HP setup but am planning to change to 100HP jets so I can reduce the timing retard on the MSD box and have the juice last longer:




I also did some work under the car, changing the plugs to new colder NGK TR6's.
I ordered some copper header/collector gaskets as the old ones are starting to burn out.
A minor oil drip turned out to be coming from the oil pan filler bolt, so a new copper washer was installed.
Also added was another chassis to engine ground to serve as a backup.
Lastly, a new 15390 fan belt was installed as the old one developed a cut when I was having issues with the alternator bracket.
After a test drive, the ECM will need a little time to learn the fuel trim blocks but the idle and hot starting has improved.




Keeping an eye out for reasonably priced 16" rims to use with my set of Toyo 225/60/16 tires:
Fiero2m8 JUL 22, 10:42 AM
Just a few updates:

Brought the Roadster to the muffler shop Zoro that built the exhaust.
I kept burning exhaust gaskets out, so they welded a new collector flange on and installed some copper gaskets for me at no charge.

While under the car, I noticed the Inboard passenger axle boot developed a split and started leaking, so I picked up a new one yesterday.

I also installed the LT4 Prom in the ECM to see if I can improve the idle a little - time will tell.
It's been raining here a lot lately and I've been too busy to get more bodywork done.
If I can get the newest project street legal in time, I will be bringing it - if that falls through, the Roadster is in the on-deck circle

Ryan

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1984 Indy Northstar-Porsche~1986 LT1-4T60 NitrousRoadster

fieroguru JUL 22, 12:01 PM

quote
Originally posted by Fiero2m8:
I kept burning exhaust gaskets out, so they welded a new collector flange on and installed some copper gaskets for me at no charge.




I burned through 2 set of the blow proof aluminum ones before going to copper. It has been about a year now and the copper ones are holding just fine. I have tightened them up 2 times since they have been installed.

I am looking forward to seeing either one of your cars at the 25th!
Fiero2m8 JUL 22, 10:22 PM
Thanks Guru - sounds promising with the new locknuts I'm using.

Well I got a lot of apparel birthday gifts from the Fiero Store (hat, T-shirts, golf shirt and fleece) which is great since I didn't have any yet
The big surprise was the FIERO2M8 personalized plates - they were ordered online 5-1/2 weeks ago, so I'm hoping they arrive soon, but unfortunately probably not in time for the 25th.

Ryan