Major Gremlins in tune/PCM. Please help.

[carneb]

I have been tuning for about a week using the Roadrunner PCM and have been getting the hang of it, with the tune improving each day. I have had a problem that when the cooling fan kicks in while idling, the engine dies. I have tried heaps of things including B4301, Desired air, richening up idle, but it still stalls. I turn the a/c on and there is no problem.

Yesterday while driving home the car started surging badly and the check engine light came on. I pulled over and the engine died. I restarted and all seemed OK. I checked the DTC's and found Cam position sensor circut high, cam position sensor circuit low, and Theft deterrent learn mode. I hoped it was just a gremlin.

Today while driving home as I pulled away from a traffic light the car started surging again, but no check engine light. It was so bad I had to stop. The car would idle OK but as soon as any load was applied it would buck like crazy. I turned it off and tried again but same thing. I flashed back in my last tune and it bucked a bit for a second but then was OK and I got going and got home.

I checked the logs and the injectors where being shut off, like a rev limiter! Attached is a screen grab of the log.



Also attached is a pic of the log where the fan starts and the car stalls. When I restart some strange things happen.




My car is a VY Commodore with 222/224 112lsa cam. The tune is based on a 2004 VY GTS with custom os1.

Can someone tell me what is going on?

[Delco]

Are you using a laptop with a 12v invertor or the battery ?

Disconnect the pcm from the car for 5-10 mins , reconnect and then do a full flash then disconnect the RR USB cable and see if the issue is still there.

I have seen this sort of issue before when the data gets corrupted when using a laptop with a invertor supply.

[carneb]

The laptop was running off its internal battery but it was connected to the Roadrunner (physically and software) at the time.

Before doing the reflash after the problem occured I had to reboot the laptop to get it to communicate with either the Roadrunner or V1.2 cable. BUT I had turned off the ignition without disconnecting either in software.

I'll try your suggestion thanks Delco.

[ringram]

You might want to try the stock pcm again to eliminate the RR from the source of possible issues too.
See if you get any dtc's with that etc.
Might be dodgy ram in the RR etc. PM Craig at Moates he might have some suggestions once you have eliminated other possible sources.

[ringram]

I just noticed your air is 0.21g/cyl mine is 0.14 at idle. When I first got my cam it stalled with too much air. Have you done your RAF tune? Did you change your effective area table as Tordne sugguested, with say the R8 285KW one? If you want I can send you my current 220/224-114 cam tune. PM me your email addy if you do.

Dont worry you will get there, there are a lot of things that can mess with stuff.
If thats the comp cams cam with around 27x adv duration then it should idle with better map than that too. I get 40kpa with 282 duration (but slightly less duration than you at 0.050) Im thinking its getting a little too much air now.

[SSpdDmon]

There's some major swing in spark in that first log. That might be another source for where the surging is coming from.

[carneb]

I just noticed your air is 0.21g/cyl mine is 0.14 at idle. When I first got my cam it stalled with too much air. Have you done your RAF tune? Did you change your effective area table as Tordne sugguested, with say the R8 285KW one? If you want I can send you my current 220/224-114 cam tune. PM me your email addy if you do.

Dont worry you will get there, there are a lot of things that can mess with stuff.
If thats the comp cams cam with around 27x adv duration then it should idle with better map than that too. I get 40kpa with 282 duration (but slightly less duration than you at 0.050) Im thinking its getting a little too much air now.

The second log I posted is when I had increased some cells in the VE table around idle as they looked lower than surrounding cells. As you can see that gave me a 12.8:1 AFR at idle, maybe thats why the DYNCYLAIR is high. Looking at a previous log it is usually 16g/cyl and 47kPa MAP at idle. I've done my RAF tune and the car idles quite nicely, except when the fan starts

There's some major swing in spark in that first log. That might be another source for where the surging is coming from.

I think the big issue in the first log is the injectors. (green trace bottom chart). They are flowing then off, flowing then off etc. Very strange

I've put the old PCM and program back in the car for now to make sure that runs OK. On the weekend I'll follow Delco's suggestion with the Roadrunner and have another go.

[Doc]

There's some major swing in spark in that first log. That might be another source for where the surging is coming from.

As a fellow Moates owner, I'll second this idea.

[carneb]

As a fellow Moates owner, I'll second this idea.

Do you mean you have had problems with spark with your Roadrunner, or that it's a problem with the spark and nothing to do with the Roadrunner?

Will the fluctuating spark cause the fuel to be turned on and off?

[Doc]

Unfortuneatly I have not been able to use my RR on my 98Z, yet!-Soon What I meant was with my H/C/I combo I had surging issues that ended up being cured with spark table adjustments. Everybody elses' cars have had the Moates Controller put to use on it with great results-nice piece of equipment.