Same 'Ol Weirdness

[Funmart6]

It has been a while since it happened, but my problem has returned, that weird shift problem going into second gear where the engine revs up and sounds like it is on the limiter, and is not in gear. I can shift manually and it does fine. I was told it was RF interference. This problem is so intermittent that I cannot seem to figure out what is causing this, how does one track down a problem like this? No SES light or anything.

 

[SHOZ123]

Data logging the EPC pressure would tell you what the pressure is. It would also tell you what gear is being commanded.

 

[SHO#7]

On a manual shift, you command the transmission to go into second gear. If you select second from a start, the car will start out in second. Meaning, you manully overide the process.

I would think along the lines of a 1-2 accumulator. Try some red **** guard. In case of a stuck or sticking valve, it may help.

Mike

 

[SHO Dude]

Data Logging EPC will only tell you what the computer is commanding, not what the tranny is doing. EPC is not a closed system with feedback.

You can however measure slip times. You can also get the slip across the converter. Lots of information spread over a short amount of time.

 

[Funmart6]

Update,
I discovered that my hood ground strap was broken again. I stuck the broken end down in between the hinge so that it made a good contact and would not move. I drove the car all day today, really getting on it several times and had no shift problems at all. So.... could that have been the problem all along? RF interference caused by the broken strap?
This car is so weird.

 

[SHOZ123]

I don't have a strap on my CF hood and have no problems.

There have been reports of a bad coil causing problems with the MAF because of RF but through the wire harness.

 

[Funmart6]

I think that is also adding to my problem. I have noticed my misfire has returned but it also is very intermittent. When I changed out my plugs last fall the misfire disappeared. Now if the A/C is running, I will get that little skip now and then when waiting at a stop light. When the radiator cooling fans kick on, my radar detector will chirp, if the lights are on, you can see a instant dimness and return to normal (flicker). So.. there is definetly an electrical issue going on somewhere in this car.
I know absolutely nothing about electrical stuff, I guess to start I should look at replacing the coils and check out that rear wiring harness again.

I must really love this car because I haven't beat it with a sledgehammer yet!

 

[SHOZ123]

So when was the alternator last replaced?

 

[Funmart6]

So when was the alternator last replaced?

I bought this car back in 2003, I have never changed the alternator. As far as I know, it could be the original one.

 

[Funmart6]

So..... ya think this could be part of the problem?

 

[SHOZ123]

It's pretty easy to tell if the alternator is any good by attaching a voltmeter to the car and watching it while you drive. Generally the alternator will slowly lose voltage over time as the brushes wear down. If the car is running at 1500 rpm and the voltage is less than 13.5 it's doomed.

I have heard that coil misfires can cause RF problems with the PCM though.

 

[Funmart6]

Thanks. Great, so I should first check the alternator, then have the coils checked out to see if any (or which ones) are misfiring.
The RF interference could be affecting the computer? Wonder if that would cause the dimming of the lights, chirping of the radar detector and also when the a/c is on, sometimes it will be blowing ice cold air and then when the engine may studder (misfire) and all of the mentioned happens pretty much at the same time, then the a/c stops blowing cold air.
Hmmm this is really puzzling. ....and all of this could be caused by a misfiring coil?

Guess it is time to work some OT and buy some new coils.

 

[SHOZ123]

Many of your symptoms point to low voltage.

If you have bad coils they need to get changed. After all they won't get better with time.

 

[Funmart6]

Thank you, the first thing I will check is the alternator and go from there.