gregs86

[ATTACH]47882606 hello and thanks for any help in advance.
I recently got a moates cable and downloaded datamaster but am novice at reading information I have a 86 with zz4 shortblock 180 afr heads a tpis bigmouth intake . zz9 cam long tube headers a 52 mm bbk throttle body 1.6 roller rockers and a tune from pcmforless sorry if I leave out any important info but my car seems to run rich to me and every so often dies at idle but will start right back up. f someone could please look at my datamaster file and gie some insight I would greatly appreciate it

gregs86

Oh I have 24lb injectors and the car dies in attached file towards the end

Thanks Greg

FrankieD

Can you verify, in this datalog at the end when the car died do you turn off the ignition. I noticed that it was idling ok then all of a sudden it died and I noticed your battery voltage go to 1Volt. The datalog indicates that you have about 5 degrees of spark retard from 2800 to 4000 rpm when in full throttle. Also, when you were cruising at 28Mph and 2000 Rpm you also had 5.3 degrees of spark retard.

gregs86

Yes at the very end I turned it of. At the rec#9521 it dies by itself Also checked fuel pressure yesterday its at 38 lbs with vacuum unhooked but dropped really fast when I turn the engine off

gregs86

At the very end I do turn off the ignition But at rec # 9521 it dies by its self then I restart it
I also check the fuel pressure yesterday with just the key on its 37 pounds Engine running 38 pounds when I turn the engine off it drops to 10 pounds within a minute

gregs86

Any indication why it dies ?

FrankieD

There is no indication of anything abnormal prior to it dieing...it was idling fine then just died. Maybe it could be fuel related such as your fuel pump ??. II keep reviewing the datalog but nothing sticks out. This one has me stumped.

gregs86

Sometimes when driving it will give a quick stumble and check engine light will flash on then off really quick. But no codes

FrankieD

can you provide another datalog. Perhaps we could capture the stumble.

gregs86

Okay I replaced my ECM about a month ago because sometimes when I turn the key on the fan would be on now it still does it every now and then let the computer hooked up in the floorboard and I found sometimes I wiggled some wires the fan would stop with just ignition on today on the way home it was running very rough and wanting to dieso I gave the ECM a little smack and it made my card now while I'm idling I can give it a little smack on the side and it makes the light come on and causes it to stumble and the check engine light to come on and go off real quick I have a custom chip from PCM for lists don't know it maybe it's making a bad connection

FrankieD

Hmmmm good place to start troubleshooting.

gregs86

So I remove the ECM checked all the connections remove the factory prom and the custom prom from PCmforless could not find anything wrong plug it all back in and hook it back up and have the same problem so the ECM is under warranty I'll have a new one tomorrow hopefully a good one

gregs86

86 vette.zipso I guess prom wasn't seated properly. I cleaned all connections with contacted cleaner and made sure was seated good seems to have fixed the smacking and dying issue. I then changed the o2 sensor and spark plugs. seems to be running very good it is however retarding timing at certain rpms attached is another datalog if anyone wants to take a look and give me any input would be appreciated Thanks Greg

gregs86

86 vette.zip

FrankieD

I'll look it over tonight and provide you an update.

gregs86

thanks a lot

FrankieD

Starting at Rec 5484 there is 5 degrees of spark retard (from 3500rpm to 4300 rpm) and it looks like you were full throttle at the time.

Then once again starting at Rec 11799 there is 4 degrees spark retard ( from 3600rpm to 4300rpm) and it looks like you were full throttle at the time.

The following BLM Cells indicate rich and should be leaned out by reprogramming the Prom.
BLM CELL O - LTerm BLM average is 116 (rich AFR)
BLM CELL 1 - LTerm BLM average is 118 (rich AFR)
BLM CELL 2 - LTerm BLM average is 111 ( rich AFR)
BLM CELL 6 - LTerm BLM average is 112 (rich AFR)
BLM CELL 10 - LTerm BLM average is 116 ( rich AFR)
BLM CELL 11 - LTerm BLM average is 113 (rich AFR)

It would be recommended to get the above BLM CELLS closer to a LTERM BLM of about 124. This will have to be done through reprogramming the Prom.

gregs86

Thanks for the recommendation

Cliff Harris

I don't agree that all those cells need to be leaned out. If you look at the BLM boundary parameters you will find that the only way to get into cells 1 and 2 is while coasting with the throttle closed.

The important cells are 0 (idle), 5, 10 and 15. Those will be the cells that you will spend the most time in, especially 15.

This article I wrote on BLMs will show how to arrange your results into something meaningful:

https://www.corvetteforum.com/forums...with-blms.html

gregs86

So would you also recommend a retune. Just not all cells?