I am struggling with my 99 Integra LS and this darn evap. system code.

I have followed pootbag's instructions from another thread and I have found the following.

1. With the cns and bypass valves shut, I can pull vac. and hold it at the purge and there is no change in ftps voltage.

2. When I open the bypass valve, the ftps voltage drops and holds to within a couple hundredths of a volt for at least minute. (no leaks in system)

3. When I close the bypass valve and open the cns valve, the ftps voltage drops a couple hundredths initially, but then holds steady for at least a minute. (no internal leaks at the 2 way valve)

I have been driving with a DMM hooked to the ftps wire on the back of my ECM and I have not noticed any sudden drop in the reading (I don't think the purge is pulling vacuum). If I start the car, after removing the fuel cap I have about 2.5-2.6v. When driving, the voltage slowly increases until it levels around 3.1.

I have done all my testing by grounding different wires on the ecm to actuate the different solenoid valves. Does this method ensure that the ECM drivers are working, or is this likely to be my problem?

I sure would appreciate some help with this. It's driving me NUTS!

 

Here's where I'm at:

I reset my ecm this morning before driving to work. I released the gas cap at that time as well. When I started out, I had 2.6v on the FTPS. By the time I got to work I had about 3v. When I left work (the car had been sitting 9 hours) I had 2.2v. The voltage dropped a few hundreths within a minute of starting the car and then held steady around 2.2 until the temperature gauge started getting to the normal range. By the time I got home, the FTPS was almost 3v and it seemed to be still going up.

As a result of not ever seeing the numbers suddenly fall during my trip, I suspected that the bypass valve might not be opening. I grounded the bypass pin on the ECM and then took off up the road. Almost immediately, the FTPS numbers started falling. They did not hold steady though. If I let off the gas for a while or stopped, the voltage would go back up to 2.5 - 2.6. I guess the CNS valve was open? So I grounded the CNS valve, then it pulled and held vacuum.

I am pretty sure I have completed two drives as far as the ECM is concerned, and I don't have a CEL yet, but it sure doesn't seem like the system is working correctly according to the numbers and my understanding of how it is supposed to operate.

Thoughts anyone?

 

I think you are in the wrong forum

 

I posted here because this forum already contains the most knowledge base I have found so far on the 1456 and 1457 codes. I have not located a single post regarding this topic in the Integra Forum, so I posted here with the assumption that these systems basically operate in the same way. If there is a better source for information on this, please point me in that direction.

 

My check engine light came on this morning once I hit the highway. When I started the car, I had a FTP reading of 2.02v. The lowest it went was 1.98 and the highest was 2.10.

What would cause my bypass solenoid not to open???