Hi everyone. Nice forum! I have a 94 mpv v6. It is running rough during acceleration and missing when ilding, so I checked to see if any codes came up. I got a code for the engine, and a code for the tranny by jumping the computer port. For the tranny I get a seven. (seven quick flashes of the hold light) For the engine I get 25. (two slow flashes followed by five qick flashes) I can't seem tofind the codes online.Does anyone have a code list for that year? Thanks!
Mike

 

The 7 code from the Transmission is for Speedometer sensor. If your speedometer does not work then Trans module would set this type of code.
Code 25 from engine computer is for open or short circuit of the Fuel pressure regulator solenoid valve.

 

Thank you! Could this pressure regualtor solenoid make the engine miss and run rough under acceleration.? I just changed the fuel filter today and it did not help.....with the tranny speedo code, does that effect tranny performance? It seems to shift weird in overdrive. Thanks for your help. This is great!

 

No, I would not expect a fuel pressure regulator solenoid fault to cause a missfire on accelleration. Ignition missfire is a much more common problem with missfire under accel or climbing a hill as this is creating a heavier load on ignition system. Check for spark plug wires sparking to ground on the cylinder head near the plug. Boot ends tend to get brittle and crack being that close to exhaust manifold. Distributor cap center buttons that transfer spark from rotor to cap are a somwhat common problem to as they get burnt and cause miselaneous problems.
Yes the speed sensor code would affect transmission operation. The transmission in the V6 is electronically controlled and any missing or eroneous signals will often put the transmission in a failsafe mode. Trans needs to know how fast you are going in order to make intelligent shift decisions.

 

Hmmmm....Maybe I'll just give it a full tune-up.The cap and wires look new, but I guess looks can be decieving. How hard do you think that speed sensor would be to change? Does the fuel pressure solinoid need to be relaced soon? I'll keep you guys updated and post what I do.

 

Speed sensor repair depends upon what is wrong with it. This particular speed signal is output by the speedometer in the instrument cluster. The speedometer is cable drivenbut the speed signal to the transmission module is generated electronicaly.Should be four pulses output per 1 rotatation of the speedo cable If the speedometer is not working then would need to determine why it is not, get it working and problem will probably be solved. If it working normally then would suspect the speedometer itself or a loose/poor electrical connection between the speedo and transmission control module.
As for the fuel pressure solenoid. As far as I can remember the only time it really doesanything is tocut vacuum to thefuel pressure regulator for approx 3 minutes after a hot restart. This raises fuelpressure to help in purging any air bubbles that may have formed in the fuel rail during the heat soak.Commonly known as vapor lock.

 

The speedometer works fine. Maybe I should pull the dash apart and check the connections, to start with.

 

Well....I reset the computer and the tranny code is gone. I took the van to my local backyard mechanic and had him do a tune up on it. bad news...the #2 cylinder plug was so fouled that it wasn't fireing at all. This explains whyI am going through oil. I guess it's a piston ring problem. I guess it's time for a new engine. Where do you guys get your re-buit engines?

 

Best prices I found for my 2000 mpvengine was at www.precisionengine.com. Before rebuilding the engine I suggest dumping some Seafoam inand letting it soakovernight. What cha got to lose.

 

I went with a JDM engine that I found on E-bay for $450. I'm getting it swapped this weekend. It has (supposedly) 45000 mi. on it. As far as the other one, I got a month out of it by swapping out the plug every 400 mi. and smoke be gone with stop leak. It's still running, but smoking bad.