Help--RoadRunner Causing Surging

[finishline]

2000 Supercharged Vette

I've only had my roadrunner a few months. This is the second time I've used it. First time I was using factory operating system, this time COS3 for my supercharger.

I had the main ve table finished and was working on the boosted VE tables. My son was driving and I was datalogging. The car started surging a little on the way to our test and tune area. I wasn't datalogging at the time. It cleared up above1700 rpm and I paid it no more attention.

We did our first run into boost everything looked good until we got back down to idle, the car stumbled, caught itself, sputter a little and then ran fine. We did another run and when we stopped again the same thing happened only a little worse. We did 5 or 6 runs in all and the car got to where it would barely idle. The car was going EXTREMELY lean then back to 14.7 and then EXTREMELY lean again. We called it a night.

Today I installed new plugs. Fired the car up and the surging started all over again. Real bad at 1200 rpm. Same as yesterday. Fuel pressure was dead on at 60 psi. Pulled out the oscilloscope and checked the plugs for firing, all were good. I know we all like to blame little black boxes for our problems but I really think the roadrunner is messed up. I did the "hard reset" procedure a couple times with no success. Up loaded, down loaded it all went on and on. I didn't reinstall my original tune because of the 2 bar map sensor being a bear to get to on the vettes. I don't think the tune is the problem.

Any ideas?

I'm lost and hoping someone else has experienced this.

Randy

[ScarabEpic22]

Is there any way you can swap PCMs (dont know how hard it is) and put the latest tune from your RR into it?

[finishline]

It's a real pain on the vette. That is my backup plan for tomorrow because I've gotta finish this tune.

Still hoping someone has an easier answer.

[Highlander]

Would you mind sending me your tune? desaintpreux at gmail.com

[finishline]

Sure I can send you my tune.

I was getting error codes from the RR for my injector control circuit.

I talked with Craig Moates yesterday and we came up with a game plan for this problem. We flashed the tune I've been running on for the past year into the RR to see what would happen. While I didn't drive the car it acted just like it did before the COS3 was put into the RR. (Ran Perfect). So that tells me there is nothing wrong with the RR. Craig seems to think the COS3 file I'm running on is corrupted. I only had the 01 Vette file so I tried to build off it again thinking maybe I corrupted it during a download to the RR or something. I still had the problem so now I'm looking for another "Stock 01 Vette with Automatic Trans File". My car is a 2000 Vette and I want to stay as close to that year as possible so the tables will be closer to the same format.

If I can't get an 01 file then I'll start the upgrade to an 02 file and then move to the COS3 with that file.

BIG QUESTION!!! What do I do with the "Knock" tables? I would guess leave them alone. The 2000 and 2002 Vette use the same sensors. I'm stock except for a supercharger that I've been running for a little over a year now. I definitely want to make sure my knock sensors are working correctly!

As I find out more I'll post my findings right down to the end for anyone else that has this problem.

[JezzaB]

Ive never had surging but ive had a couple "lose" timing after a Custom OS upgrade. I tend to find this happens if I upgrade it on the RR. Just drops 4deg or so timing from the commanded and there is no single modifier touching it. Continues to happen even when its been flashed into a standard PCM.

Also I have found sometimes I can read the tune out of the RR and it wont start. I can tell because the fuel prime will be very short and I know i need to write the cals back in (even the ones I just read out) and it will be fine.

Just little glitches but not too bad.

Hope you fix your problem

Jez

[finishline]

Thanks for the heads up on that one. You've helped me make some decisions off of your experiences.

I got another 01 file, went through the whole process of moving up to the COS3 again with the same results. Did the same with an 02 file. Same results. However I used the road runner instead of my pcm to get me up to those files.

I've had enough of these games. The factory pcm is going back in. I'll upgrade to the COS3 system and tune the old fashioned way. After a few weeks I'll put the RR back in and just play with it to see what happens.

I would still like to hear from others who have had similar problems and what you did to resolve them.

Randy

[Highlander]

A few questions... aside from the supercharger.. what other mods do you have???

Why are you using PE instead of the B3647 to command fueling?

[finishline]

Just the typical mods for a supercharger. No headers. I run without a hood liner and I have a lot of expensive paint work under the hood and I worry about to much heat.

On the 3647,,,,, I want to be able to run in full closed loop LT and ST Trims fully operational.

I really only upgraded to COS3 for the timing tables.

I had a great tune before I converted over to COS3. The only thing I didn't like was I had to fully retard my timing before I got past 105kpa. Now I can run a lot more timing all the way up to 105 kpa and then start slowly pulling out what I need only where I need to. It was a bummer only running 14 degrees of timing at 105. Now I run 28 and you can really feel the difference.

[Highlander]

So you are using MAF?