The never ending open loop idle problem!

[GeforceXtreme]

This problem for me has been going on for months. Everyone that has looked at the car has not been able to figure out wtf is going on with my car? I have no leaks, everything on the car is pretty new, no misfires, and I just can't figure out why my car will not idle correctly in open loop mode? As SOON as the car enters closed loop (when the maf sensor takes over) the idle is perfect. The car drives perfectly fine and my LTFT are pretty darn close to 0. I still have a feeling its my VE table but before this issue the car seemed to start perfectly fine? I have tired multiple VE tables in the car and some I can't even get the car to fire over and others it idles like its running on 1 cylinder. If i even attempt to do a VE tune the more tuning I do on the worse it gets. It gets to the point where it will idle up and down so drastically the car will stall. The starting idle problem will never be the same every time I start the car. Sometimes its able to save itself by revving up pretty high then its ok. Other times it will rev down so low it stalls out. I have some videos of what the car does.

In this video you will see my car idling without the MAF sensor plugged in (open loop) then I plug it back in a (closed loop) then unplug it again. You can see that in open loop the idle is not smooth.

Engine Start Open loop- Closed Loop

This is how my car starts most of the time. It almost stalls then saves itself. In all of my videos I NEVER touch the gas petal. It rev's like that by its self.

Normally Starts

This is what my car does almost every day.

Bad Starts

This is the worst I have seen my car start. It does this once every other week. Sounds like its missing cylinders...

Worst Starts

Its just so embarrassing when I have guests or clients in my car and it does this stuff. Its getting to the point where I may need to get another car just because of this.. I am going to need some major suggestions on this guys. Does anyone have a VE table I can try with similar mods like mine? I have an HP tuner which I can import the VE table.

[coachcrow56]

I have had the same problem ever since I installed the N*. Car will start and rev up and down, then smooth out. Other times I have to blip the throttle to get it to start. Very annoying, but car runs great after that. Hopefully someone knows how to fix this.

[dchale]

I had similar issues and a VE tune seemed to help for a while but then the problems returned (details below). When I did the VE tune I used the smoothing options so that the low end of the VE table would get modified as well.
I began to have warm start issues shortly after the VE tune. Do you ever have starting issues after filling up with gas? I had a couple of occurrences where I would fill up with gas and the car would start/surge/stall and repeat. It got to the point where I was afraid to stop for gas. Once I had to sit there for 10 minutes before it would start. Then the next time I filled up I had to get towed home. To make matter worse my wife was with me both of these times. After the last incident I checked the FP regulator which tested fine and then I replaced the fuel pump (about 1 1/2 weeks ago). I have not had any start up issues since. The surging is gone and the warm start issues are gone as well. I'm wondering if a weak fuel pump was the main culprit although my fuel pressure was good other than the time I had to get towed ( I have a FP gauge installed).

If you'd like I can post my VE table but given the differences in our setups I'm not sure it would be of any benefit.

[GeforceXtreme]

I had similar issues and a VE tune seemed to help for a while but then the problems returned (details below). When I did the VE tune I used the smoothing options so that the low end of the VE table would get modified as well.
I began to have warm start issues shortly after the VE tune. Do you ever have starting issues after filling up with gas? I had a couple of occurrences where I would fill up with gas and the car would start/surge/stall and repeat. It got to the point where I was afraid to stop for gas. Once I had to sit there for 10 minutes before it would start. Then the next time I filled up I had to get towed home. To make matter worse my wife was with me both of these times. After the last incident I checked the FP regulator which tested fine and then I replaced the fuel pump (about 1 1/2 weeks ago). I have not had any start up issues since. The surging is gone and the warm start issues are gone as well. I'm wondering if a weak fuel pump was the main culprit although my fuel pressure was good other than the time I had to get towed ( I have a FP gauge installed).

If you'd like I can post my VE table but given the differences in our setups I'm not sure it would be of any benefit.

I don't have any issues after filling my gas up at the gas station. It just seems to have this open loop idle/starting problem every time I go to start it. I wish I could better tune the VE table however every time I go to do it the car seems to run worse.

[dchale]

This might be of interest:

http://www.regalgs.org/forum/viewtop...er=asc&start=0

I don't have any first hand experience with the product though but it seemed to help with this persons surging, etc.

[bilemke]

Let me get this straight... You are describing open loop as simply being the state of having the MAF unplugged?

If so, and your idle is bad, you need to tune the ve table. Simple as that.. But, it can get tricky.. This idle issue, without the MAF plugged in, is quite common for Grand Prix guys tuning VE.

[japslpr]

Open loop is not when you have your MAF sensor unplugged; Open loop is when the computer does not receive its information from the oxygen sensor and uses tables in the PCM for fueling. Generally this is done at first start up until the engine reaches a certain ECT and the o2 sensor has been warmed. you will go into open loop if you unplug the oxygen sensor, not the MAF sensor.

[GeforceXtreme]

That is my mistake. Well whatever the car does when the MAF is not hooked up is the cause of why my idle is crap when I first start the car. I been told it could be my map sensor which I am going to get a spare one to test next Saturday. If i try to do a VE tune on the car.. it just seems to get MUCH worse....

[bilemke]

That is my mistake. Well whatever the car does when the MAF is not hooked up is the cause of why my idle is crap when I first start the car. I been told it could be my map sensor which I am going to get a spare one to test next Saturday. If i try to do a VE tune on the car.. it just seems to get MUCH worse....

Exactly what I thought.. If it is when the MAF is unplugged, it is a most likely a VE problem (not an Open Loop problem).

Caution, tuning the idle area of the VE table can be tricky. Do not let the engine (coolant and IAT temps) heat soak (resulting in data that will not neccissarily represent the average number you need for chaning the VE values).

Anyway, good luck with the VE tuning.

[Perforator]

Have you checked for any codes ?

[02bluegt]

When I had a Failed MAF it did this plugged in and not plugged in

[bilemke]

When I had a Failed MAF it did this plugged in and not plugged in

Yes, the key is.. MAF is failed if is plugged in or not in you example.