PD74

Hi, could someone significantly smarter than me please take a look at my attached log file? The car is an 89 IROC with the L98. It has ZZ4 heads, MSD 6-BTM, supercoil, and shorty headers. It also has a Vortech supercharger, which is not currently installed (getting rebuilt). I do not know if the PO did anything to the internals, but I know it does not sound like it has an aggressive cam and maintains the stock stamped rockers. I finally got the car to idle, but my BLM is still high and the idle is rough. The car does not want to idle when cold. I have 43lbs of fuel pressure on the rail. It has a new IAC valve. I am not a ECM programming type of guy and was hoping someone could see something in the attached data log. I am not throwing any codes. I initially thought it was the MAF sensor, but not so much anymore. Thanks for any help you may provide.

Phil

Tuned Performance

iTrader: (92)

Any idea what has been done to the tune ?
Have you pulled the memcal to see if it’s a stock delco.
I don’t recognize the prom Id in your datalog.
It looks like to correct the 140 blm you will need to tune it.
what injectors are you using ?

ULTM8Z

MAF cars with high blms and rough idle, I'd start thinking about vacuum leaks.

How much manifold vacuum do you have?

PD74

I just replaced all the gaskets on the top end. I did the smoke test, carb cleaner test, and the sea foam test. Not seeing or hearing anything. At idle, when it warms up and idles, I get 12 to 13 psi of vacuum.

PD74

Unfortunately I have no idea what the PO did regarding the tune. The memcal is an APYN 3496. I believe the injectors are stick, at least I cant find any aftermarket markings on them. I am attaching pictures of the injectors and the memcal.

Tuned Performance

iTrader: (92)

Those are stock multecs, junk as far as injectors go.
There coils short out. The APYN is for a 89 350 automatic.
You might consider changing injectors and start to do diy prom burning or buy a dynamic efi ebl.
If you have the zz4 heads and a mild camshadt starting with arap would be a decent spark table.

http://www.gearhead-efi.com/gearhead...%206E%2094/6E/

Tuned Performance

iTrader: (92)

psi of vacuum lmao
If it’s stable I think the camshaft is causing the lower reading

PD74

Umm yeah, sorry force of habit with the psi...
I just bought a set of dart pro 1 230cc heads for the car. They are at the shop getting some work done right now. They are the pre 86 bolt pattern. I was going to wait a little while before I put them on. Now I think I am just going to rip this computer and harness out and get the Edelbrock Pro-Flo 4 XT and make my life simpler.