1 more time, code 31, map ecu2, and vpc...wtf? Please HELP

[empera]

ok i figured i will post this once more maybe someone will have a clue or maybe my car is just possessed. the story goes...
a few months ago i decided to do a bunch of things to the car all at once (bad idea) which included a new t4 exhaust manifold, a new crank seal and timing belt, and the installation of a map ecu 2. After a few weekends of working on these things and having the engine half out because i needed to tap the oil pan for the new manifold we put everything back together. Before the map ecu 2 i was using the good ol' vpc and safc 2 combo but i wanted something more powerful and in fact discreet. Soooo....after wiring it up we got nothing...idled for a second and died...ran the codes got #31 AFM signal code. Ok the wiring is messed up, checked it...nothing, double checked...checked again...wiggled the wire...nothing. Replaced the ECU...nothing, tried my ecu on another car...nothing. Ok maybe its the map ecu 2 box, got a vpc....4 wires easy installation...nothing. Tried the vpc on a diff. car this time a 89+ and that worked, well it idled and i got no CEL, so atleast i knew that worked. Sent the map ecu 2 out to get checked...its fine.
WHAT THE HELL IS WRONG WITH MY CAR!? we replaced the ENTIRE KS (green/red strip) and nothing. Is there a ground that could be causing a code 31? could my timing be 180 off but how would that explain the code? I need serious help...my last resort is to either swap the wiring harness or try to convert to 89+ wiring/ecu and try to get a pnp harness....

PLEASE HELP!!! :1zhelp: :1zhelp: this has been going on forever.

 

[empera]

anyone?

 

[lagged]

sorry i cant help but if youre considering selling the map ecu2 please let me know!

otherwise good luck with your problem.

 

[empera]

lol, ok i am considering it...but we'll see

 

[lagged]

ive read your other thread where drj was trying to help and the only advice i could give would be to double and triple check your wiring.

even if you have to put the car back to stock, get it running with the stock ecu, THEN try and install the map ecu2.

 

[Piratetip]

Sounds like you need to start from the basics.
Get your manuals diagrams and other important documentation. Sit down for some time and study what has become f'ed up. You have electronics or wiring issues.

 

[F_T_F]

too wierd i have a Map-Ecu and im having the same problem. i can tell you that when i adjust my TPS it seems to help a little but im still in the process of diagnosing the issue. i can tell you that i have replaced ISV, TPS, air filter, checked for anysort of boost leak/vac leak, and rechecked timing, not to mention the hours upon hours i spent going over the engine bay with a multimeter with no luck. deffinitely subscribing to this thread
EDIT: i did notice that my idle issure started rite after i rebuilt the engine and befor i had the map ecu in so this is making me thing that its in the wiring harness somewhere

 

[empera]

im gonna try the map ecu2 on a 89+, if it works...im swapping over to 89+ wiring or maybe just the harness itself.

 

[Bondango]

Emp have you hardwired the VPC using the 3 resistors as per pre 89 hardwiring?

http://oldschool.supracentral.com/htm/hardwire.htm

I think the MAP ECU2 requires the same resistor placement because of the HAC

 

[empera]

Emp have you hardwired the VPC using the 3 resistors as per pre 89 hardwiring?

http://oldschool.supracentral.com/htm/hardwire.htm

I think the MAP ECU2 requires the same resistor placement because of the HAC

nope i used that diagram posted by someone using the 1 resistor on the afm clip, pins 1 and 2... im also having a hard time understanding that wiring diagram on that site.

also should i be using the Baro. output wire on the map ecu 2?

 

[Bondango]

nope i used that diagram posted by someone using the 1 resistor on the afm clip, pins 1 and 2... im also having a hard time understanding that wiring diagram on that site.

also should i be using the Baro. output wire on the map ecu 2?

Think thats your Problem, the VPC/safc hardwiring diagram i done was for 89+, never got round to doing one for the pre 89. Pre 89 needs to be done with the 3 resistors

No need to use the baro wire IIRC.

 

[empera]

ah, well if its that then i might have a fighting chance...hehe thanks bro! i'll see if i can do it this weekend if i can get my hands on those resistors.

 

[empera]

and so i came up with this....

hopefully i can find a 5.1k ohm resistor.

 

[empera]

couldnt find a 5.1k ohms resistor only a 5.6k u guys think that should be fine? its either that or a 4.7k.

 

[lagged]

couldnt find a 5.1k ohms resistor only a 5.6k u guys think that should be fine? its either that or a 4.7k.

you can make your own. i dont know anything about the preferred values of resistors but do they have 10.2k? you could use two of those in parallel. or run a few lesser values in series to get 5.1k ohms.

theres lots of ways to do it, you can get your 5.1k.

 

[dbsupra90]

use a 5k ohm and 100 ohm in series (ie wire them like christmas lights).

ever think maybe your map sensor is bad?

 

[empera]

cant be bad. tried the vpc on another car (89+) and it idled fine...

5.6k too much?

 

[dbsupra90]

i didnt know you moved the map sensor and all over to the other car. just thought it might be a possibility.

5.6k would probably be ok. if you already have it, you could try it. if not, 5k and 100 are easy to find.

 

[empera]

yea i thought that too, but both vpc and map ecu 2 cant be bad ...well they could but chances are slim...i also sent out the map ecu 2 to PHR to get tested, they say its fine.

 

[dbsupra90]

cant really help w/ the map ecu, dont know much about it. sounds like its fine anyway. but when you had the vpc/afc combo, it did the same thing? did you have the afc wired after the vpc?

also, what map sensor are you running?