dubcaps

Today I went to pick my car up after having new turbos installed. I started the car, idle was normal, and everything seemed to be working perfectly. As I went to drive off, the car bogged really bad and died. I then pulled over, reset the ECU, and the car ran and boosted perfectly. (10-8-10)

I came home, turned off the car, ate some lunch and decided to make a quick run to the gas station. As I went to drive off, same story, the car bogged really bad, but ran fine until it got to 0 psi on the boost gauge. So i pulled over again, reset the ECU, and the car ran and boosted perfectly again.

So i get to the gas station, cut off the car, fill it up, and restart it. Same thing, car runs fine until you get to 0 on the boost gauge, then it just bogs and feels like it wants to die. So i grannied it down the road to where I could pull over and reset the ECU yet again. Once again the problem was fixed, i could boost, and the car fine.

I drove home, turned off the car, and decided to go ahead and pull the negative battery cable off again, just in case I needed to go somewhere. Well about an hour goes by and I decide to go for a little drive. I reconnect the negative battery cable start the car up, and it does the whole no boost thing again. Frustrated, I tried to reset the ECU again, but the problem remained.

I came back inside and did a quick search of the forum to see if i could find a solution.....

I learned that what I had been experienced was called "limp mode"

Per someone's advice in another post I checked to see if the car would rev past 4500 rpm, and it did as long as i revved it slowly not letting the engine get out of vacuum.

I checked the MAP sensor's vacuum hose and electrical connection, and nothing was loose or broken.

I hadn't seen any check engine lights, but i figured id see if i was throwing any codes anyway. I connected the GND and TEN terminals with a paperclip, and It flashed one code, 45 "solenoid valve - charge control".

Also, I am using a PFS PMS piggyback ECU.

Could my MAP sensor have crapped out?




Anyway, I have no idea what could be wrong, and came up empty handed in terms of my forum search. Does anyone have any ideas?

Thank you very much!
-stephen

rajeevx7

iTrader: (11)

The Map sensor has a different code then 45 I believe. If 45 is your charge control solenoid, you know where to look, right?

I have the PFS PMS as well and mine went into limp 3 weeks ago w/ the 27 code; MOP/OMP. I set the computer to full stand alone mode, and it didn't help. I am now waiting on my new OMP to arrive.

I suggest you replace the solenoid, or at least test the wires and solenoid ohm's to see if they are in spec.

Limp mode always throws a code, CEL, so start with what it is telling you. I originally hoped it was just a bug in my stock computer so I swapped it and got the same code. Search my name for my post on this, it has a link to all the codes.


Raj

dubcaps

isnt the charge control solenoid under the UIM? If so I can't wait to start the "fun."

4Fun

iTrader: (8)

your correct on the location, you might get luckie. Check the vaccum lines and the electrical lines first/

dubcaps

Which vacuum and electrical lines? All of them? I think its going to be something electrical b/c on the few times i got it off limp mode, the turbos were spooling faster than they ever had before, and the boost pattern was absolutely perfect. Anyway, here is a good place to start troubleshooting??

rajeevx7

iTrader: (11)

Removing the UIM isn't terrible, just intensive. You have to disconnect so many things, but they are all visable. Don't disconnect the TB, just leave it attaced and pull the whole thing. Every FD owner should do it at least once. I did mine inorder to paint it.
Order a new or used solenoid. Mazda sells them for around $?? and used they are around $10.

The whole process of straight removing, switching and installing is easy to do with in a few hours. But, once you take it off you will want to stay in there and look around/clean/inspect stuff.

Good luck.
Raj

4Fun

iTrader: (8)

If your car is wires are anything like mine the sheilding around the wires are brittle. So I would look at around to make sure the insulation isnt gone and the wires are not touching.

dubcaps

I've removed the UIM twice before, I just hate doing it b/c its a PITA.

I'm about to go check the wiring right now to see if anything looks out of order.

Also, I forgot to mention this, but the one way check valve going to the map sensor had gone bad, and it was allowing air to be blown both ways. I got a universal one from pep boys, but it still won't get out of lmp mode.

dubcaps

everything electrical looked fine, so did the vacuum hoses. I took out the PFS ECU on the off chance that it might fix it, but no luck.

I'm still throwing the same code so im going to assume the solenoid is the problem. I just posted a WTB in the parts for sale section, but if anyone has any suggestions in the mean time, let me know.

What does the charge control solenoid do anyway? I'm just not understanding why the car won't come out of limp mode. When it did 3 times before.

thanks,
-stephen

dubcaps

Well I borrowed a friend's MAP sensor just b/c it would be the last easy possible fix, and the problem remained. So right now i'm trying to track down another charge control solenoid.

But i read somewhere that the charge control solenoid wouldnt cause the car to go into limp mode.

Also, if there are any other suggestions, please let me know

thanks for the help,
-stephen

jetmech77

Hey mine did that today for the first time ever today.....I was washing my engine with steam at the car wash and it happend.......I hate the limp mode....But after it dried.....my HORSEPOWER was back.......I would love to have a switch to put this in for valet use.....does anyone know??

dubcaps

Just a quick question for anyone that knows, but would the charge control solenoid cause the car to go into limp mode? I had read earlier that it shouldnt.

4Fun

iTrader: (8)

No it wouldn't. It would how ever cause you to have low boost.

4Fun

iTrader: (8)

No it wouldn't unless its unhooked or the wire going to it might be shorting out. Error codes are shown when sesors are not within factory specs. It would how ever cause you to have low boost.

dubcaps

but when the car was out of limp mode, it boosted perfectly 10-8-10 so that doesnt make any sense. There must be something else causing the car to be in limp mode, but the ECU isnt throwing any other codes.

I just pulled the UIM, so i guess i'll look for leaks and test the solenoid. I'll be back in an hour or so, if you have any other suggestions just send them my way.

by any chance do you think my ECU crapped out?

thanks
-stephen

4Fun

iTrader: (8)

Look at the car manual and see what the ohm reading sould be on your charge control solinoid and see if thats off or not.

dubcaps

everything was connected, so i'm just going to go ahead and replace the solenoid and see what happens. i might have found a local guy who has a good spare, so hopefully i can have a new one on tomorrow.

thank you for all the replies so far, as always, if anyone has any other suggestions feel free to send them my way.

-stephen

dubcaps

Alright, i have one more question. When the car is cranking the little LEDs on the air:fuel gauge move around, but once the car starts they disappear. Prior to having this problem the gauge always worked. Could this problem be related to the car staying in limp mode?