A vacuum leak will very likely cause the P0507 code. To set that code the PCM must see "The actual idle speed is 200 RPM greater than the desired idle speed for more than 5 seconds". Could be related to the speed problem too. The PCM only looks for the condition to set this code when the vehicle is below 1 MPH (which yours always thinks it is).

 

am having all kinds of problems, I got Pictures for you techs. I know it is not safe to put phone numbers on here but if anyone can help I will be glad to call you. Thankx

Mike

 

p0507 is tripped due to the fact that the pcm determines its fuel trim stft and ltft off of the vehicle speed. it will also determine dashpot setting and base/curb idle off the vss sensor.

jack up the rear of your car and unplug the vss. get a volt meter and put it on the AC setting-install the leads on you vss and rotate the wheels-you should be seeing a slight voltage on/off from the sensor. it produces its own ac current when the reluctor passes by it through what is called the "hall effect"...it will produce a sine wave on an oscilloscope! if you do not have current-check your continuity on the sensor-if you have none, then the sensor is bad. if you do, you could have a broken reluctor or bad wiring to the sensor.

p0500 and p0507 are related in this case!!! good luck send me a pm if you need anymore help!

 

He replaced the VSS and got the same results. I'm suspecting the PCM plugs or wiring right under the battery. He was working in that area on a vacuum issue when this problem started. I PM'ed him PCM pinouts and a photo of the vacuum tank so he can fix that problem too.

 

that sounds like fun!!!

 

HAving problems getting to the pin assignment/layout page. Oh, Where does the vacuum line go when it leaves that switch? I found that I am battling a problem that someone else had with this car. That vacuum can wasn't even plugged up but all the plastic hoses are attached. I need another vacuum can as when i was unbolting it it fell due to a broken plastic boss and snapped the vacuum line port off. Anyone have one for sale? If so do u take paypal? I'll probably just get a new one. Does anyone have the proper name for this reservoir>

Mike

 

I am going to check the vss wiring up to the red PCM plug 2morrow.

Thanks for everything. I will post results, hopefully in my favor, hehehehehe

 

I have a signal coming from the VSS and I also have an output signal going to the instrument panel. Ok Wizards, Hud Works but no speed, Tach works but analog Speedo doesn't work, Cruise Control does not work, Reverse lockout doesn't work, Traction Control issues, may not be related, Car Dies sometimes as I slow to a stoplight. There has to be some kind of answer. has anyone else had this problem?

Mike

 

Does anyone have any idea where i should bring this car? Should it go to the dealer?

 

You have a strange one here! With the cruise and reverse lockout not working it really seems the PCM "thinks" the car is not moving. Try to find (beg, borrow, or steal) an ODBII scanner so you can see what the PCM thinks is going on. Since you have VSS single to the PCM connector the PCM should know the car is moving. An ODBII scanner will show this in seconds. If the scanners show no speed then look at the PCM and towards the VSS (which at this point looks good). If the PCM shows speed then look at the PCM and towards the IPC.

Way back in the 80's a Datsun dealer hired me to come look at a 280ZX that they had been working on for a long time without success. They had replace nearly everything on the car but the car would still just die and not restart for several minutes to hours. Obviously it was not getting fuel when it died. Everything pointed to the fact that the fuel computer was loosing signal from the distributer but when checked the Hz using a hand held multimeter it had a signal. The mechanics laughed at me when I brought my old antique 5MHz oscilloscope to the shop. They said "whats that? A fish finder???". But quickly I found, using my fish finder , when the car died the 0-5VDC pulse from the distributer to the fuel computer was now only 0-2VDC. As soon as the car cooled off the pulse went back to 0-5VDC and the car started again. After pulling the brand newly rebuilt distributer (which just happened to have the exact same problem as the original one ) we found a hairline crack in the solder joint for that output. A quick touch with a solder iron fixed the problem which had eluded several dealers for months. Morel of the story? Even if you have a signal, if it is not the correct amplitude it will often cause problem or not work at all. Could possibly be what is happen here. We see the signal on a voltmeter but the PCM does not.

 

Where the hell is my distributor? HEHEHEHEHEHEHE Just Kidding.

Mike

I very much appreciate all the help that you and others have provided.

I am started to maybe thing a grounding issue, we will see next week.

Mike