Weird idle and lean on wideband??!

[98gsspy]

Ok I just got my car back from getting the tps adjusted. I am working out all the problems for putting on the turbo.

PROBLEM:
The rpms are bouncing from 1250-1900 constantly. My wideband says it is so lean that is it not on the chart. When I am on the throttle the wideband works fine, it is new so no bad sensor. Even with the safc at +30 it barely gets on the chart. When I am on the road the car feels like it is hesitating but the o2 are fine.

HELP and thanks

 

[KazooGS-T]

Is it only lean while you are at idle? You should expect high AFR's while in idle.

 

[98gsspy]

I know but you should at least see it on the wideband. I had the wideband in my car before with the turbo on and I was seeing lean AFRs which I understand should be low at idle.

 

[GVR4592]

Sounds like a big vacuum leak. Have you done a boost leak test lately?

 

[98gsspy]

The boost gauge shows no vaccuum. I think I dont have the lines right on the tb.

 

[KazooGS-T]

Ok, what all is your car equipped with? Cruise, evap, ac, etc. I can help you source that out. You should have a three prong splitter on the back of your intake manifold. Are the ones that are not being used blocked off? Also, the one that connects to the a.c. and powersteering seem to get close to the cams. Make sure that they are not ripped or torn. I don't see why that would cause a problem though, because I just have electrical tape covering the two ports on the back of my intake manifold and my WB02 still reads at idle. Do you have your boost gauge and wastegate actuator hooked up properly? No leaks?

 

[98gsspy]

I just hooked up the 1g tb lines wrong. i think that is what the problem is.

 

[98gsspy]

I fixed the vacuum problem, the line to the gauge was twisted.

-The idle still bouces
-No AFR at idle--why when I turn my safc to +50 is does not change the APR

 

[ChunkyLover53]

If you are running lean and the idle is high, do a boost leak test to make sure you do not have air coming into the intake from unwanted places.

 

[oldman]

1. Boost leak test.

2. Check for exhaust leaks before the 02 sensor.

 

[98gsspy]

After a day of bad idle I just through the code the wants me to get a new ISC. Is it throwing that code because of the boost leak or do I really need I new ISC. That is quite possible the tb is off of a 92, but why wasnt the code thrown when I first had the car running?

 

[ChunkyLover53]

Someone correct me if I am wrong.

I believe that you will not get a CEL for having a faulty ISC. The reason is because there is just a voltage sent to it and the motor is expected to do it's job. The ECU does not know if the ISC is doing its job or not.

 

[98gsspy]

so what else could be causing the rpms to constantly go up and down and run very lean?

 

[oldman]

So what else could be causing the rpms to constantly go up and down and run very lean?

What were the results of your boost and exhaust leak tests?

 

[1g_tsi_awd]

How much vacuum do you have at idle? You should have 12-15psi. [for reference]

 

[oldman]

How much vacuum do you have at idle? You should have 12-15psi. [for reference]

Unless OP has CAMs, he should be pulling -18 to -20 in HG, vacuum is not measured in psi.

 

[98gsspy]

My vacuum bounces from 15-18 with the bounce of the idle.

 

[oldman]

I will get to the point. First, you need to perform a thorough boost leak test, boost leaks (vacuum leaks) will make you run lean under idle and part throttle, it will also cause idle surge. Secondly, you need to check for exhaust leaks before the location of your sensor, pre-sensor exhaust leaks will cause your wideband O2 to read lean. Now quit looking for easy answers and start testing.

 

[1g_tsi_awd]

Unless OP has CAMs, he should be pulling -18 to -20 in HG, vacuum is not measured in psi.

Oops, my bad. Sorry about that, I was at work... His mods didn't say cams so I was assuming he didn't have them.