Ok, I've installed a Vararam 2 system without the Powerduct. And now the cars rpm's are surging at low speeds. And dying at when I come to a stop. It a PCM learning issue? It's not thrown a code one. But oh, how it doesn't run as it did prior.
Any suggestions?

 

Have you done the required relearn driving loop?

 

You need to do the idle relearn....

 

Idle relearn is a procedure that allows the PCM to recalibrate air/fuel ratios. This procedure may be requried after changing an air intake, MAF, porting a throttle body etc.
It should norrmally not be required if no changes have been made One exception.. . ( there may be others) If you have recently changed from an alcohol free to an alcohol containing gasoline, you will have leaned out your air/fule mixture.

Idle Learn Procedure

Automatic Transmission
Perform the following procedure in order to return the learned idle to the correct position:

1] Turn OFF the ignition.
2] Restore the PCM battery feed (if disconnected).
3] Turn OFF the A/C controls.
4] Set the parking brake, and block the drive wheels.
5] Start the engine.
6] Ensure that the engine coolant temperature is more than 80°C (176°F).
7] Shift the transmission into Drive.
8] Allow the engine to idle for 5 minutes.
9] Shift the transmission into Park.
10] Allow the engine to idle for 5 minutes.
11] Turn OFF the engine for 30 seconds.

Manual Transmission
Perform the following procedure in order to return the learned idle to the correct position:

1] Turn OFF the ignition.
2] Restore the PCM battery feed.
3] Turn OFF the A/C controls.
4] Set the parking brake, and block the drive wheels.
5] Place the transmission in Neutral.
6] Start the engine.
7] Ensure that the engine coolant temperature is more than 80°C (176°F).
8] Allow the engine to idle for 5 minutes.
9] Turn OFF the engine for 30 seconds.

The A/C compressor kicking in and out at idle speeds puts a high load on the engine at those rpms and will affect idle speeds on most Vettes... Some with modified cams have a very rough idle and may stall with the A/C on at idle...

To complete the PCM relearn...

Restart the engine and check for DIC error codes (there should be none).
10 Drive car for a minimum of 30 miles at varying rpm settings and speeds. PCM will now re-learn and adjust for the new air flow and temperature at the intake.
a) If error codes persist, repeat steps 1-7. Make sure fuses are properly inserted before repeating steps.
b) Do not deviate from the sequence outlined above. If you do, restart the sequence from scratch.
c) Steps 1-4 are also necessary if you ever disconnect your battery or lose power for any reason.

 

Normal is a must to drive at least 50-75 miles to let the fuel trims learn out--However also normal for Varrarams to cause some surging/dying with the changed airflow signal--The ECM has the ability to learn out only up to a certain point--generally between plus or minus around a 20% change---On some applications the varraram will require a change beyond the 20% and issues or codes will pop up--Also some "false codes " will appear which require codes to be permanently omitted

 

I also installed the air bridge with mine. This allowed me to relocate the MAF. I had no problems after the install.

 

Nor did I.You may wish to check closely for vacuum leaks at all the duct/maf connections.

 

Well I've checked recheck the tightness of the connections. I've completed the relearn procedure. I've taken it apart and cleaned it. And it's much better. But still at 1000rpm and lower, it still searches.
It's not thrown one code, but the surge is getting annoying.
But here is something I noticed, the screen mesh, has been smashed from some previous installation. it's on the outer edge. Is it possible with the extra air flow from the Vararam system, that it's effecting the flow across the metering wires? Possibly?

 

Not much more air at low rpm's with that intake-you messed up something. The relearn for a CAI seems silly, you should be able to completely remove the air filter, start the car and have no issues, especially at idle.

 

Sorry, I didn't explain myself clearly. It will idle all day, smooth as a babies butt.. But when driving, and slowing down, ex: coming to a stop sign.. it searches (rpms). Dunno.. it's got me baffled

 

How far have you actually driven the car? Surging issues went away with my car in under 100 miles, sometimes aggressive!

 

OH, I've put on around 30 or so.. maybe not even that much..

 

The VR people recommend 100 miles + at highway speeds or three to five 1/4 mile passes at WOT to get the computer lined out.


Some here will say that you need a tune,,,I know a lot of LS1 owners running the VRB2 that did not and none that did!

 

oh, another question and or thought. When installing the VR2, is the MAF to be moved closer to the intake or remain near the air filter assembly.
I ask this, because I didn't install it. And I just thought of this, not an excuse but truth..

 

Are you saying you didn't reinstall the MAF unit? I can't see anyone not reinstalling the MAF. If you used the VR Power Duct, that installation calls for relocating the MAF forward. Many have reported problems with the Power Duct install. I would not use the PD. My MAF is in stock position with my VRB2,,,,no problems.

 

You didn't install your MAF, or you didn't install the Vararam Power duct?

 

Yes, I installed the MAF in the stock position. The power duct is apparently the wrong one. It wont fit, so at this time, I'm stock on the PD.
I'm forgetful, but not silly. LOL I might for get a bolt or two, but not a major part of eq like a MAF. LMAO

 

I have installed both Vararam and power duct with relocated maf with no problems of any sort. I just ran my best time of 12.77 last week.Basically stock coupe with 3.15 gears and A4.

 

LOL, excellent. I'm not so lucky. And thanks for rubbing it in!! LOL I guess I'm just to old for this stuff.. Buddy!! Good run!

 

LOL I will be 61 in January!