*HELP*DSM afc related

[ZMN BY U]

hey peeps how is the car running now that you have disconnected the 02 sensor wire. And i cant remember which wire its is can you tell me i want to try it this weekend. John will this hurt the afc or the car?

 

[tallrd]

hey peeps how is the car running now that you have disconnected the 02 sensor wire. And i cant remember which wire its is can you tell me i want to try it this weekend. John will this hurt the afc or the car?

I spoke with John today, and I haven't disconnected any wires yet. My problem MAY have been that DSM's instructions state to use a "vacuum source off the intake," but it wasn't specific on which one. So, I assumed that I needed the "vacuum source" *only* (as opposed to a combi vac/boost source). After speaking with John today, I found that my hunch was correct; it requires the use of a vac/boost source. So, that was 80 miles ago, and in the meantime I'm waiting for the car to run it's ~150 mile re-learning curve after resetting my ecu. I'll keep everyone posted if my idle problem comes back.

 

[31R]

would using my Brake booster line be considered a vac/boost source?

 

[peepsalot]

hey peeps how is the car running now that you have disconnected the 02 sensor wire. And i cant remember which wire its is can you tell me i want to try it this weekend. John will this hurt the afc or the car?

I wired the my O2 to bypass the AFC and my idle became much better. I only had it like this for a few miles, then I removed the AFC entirely.

I had some other strange problem of bucking during part throttle acceleration(about 0 vac/boost), that I wasn't sure if it was due to the AFC. I still have this problem even without the AFC, so I'm going to figure this one out before reattaching it. I'm thinking it is a boost leak in an IC pipe.

The wire is Pink/blue on the ecu, and it goes to the pink AFC wire input then outputs through the pink/blue afc wire. It's all in the instructions.

 

[Ryoga28]

I wired the my O2 to bypass the AFC and my idle became much better. I only had it like this for a few miles, then I removed the AFC entirely.

I had some other strange problem of bucking during part throttle acceleration(about 0 vac/boost), that I wasn't sure if it was due to the AFC. I still have this problem even without the AFC, so I'm going to figure this one out before reattaching it. I'm thinking it is a boost leak in an IC pipe.

The wire is Pink/blue on the ecu, and it goes to the pink AFC wire input then outputs through the pink/blue afc wire. It's all in the instructions.

I don't have the AFC at this time, but I encountered the buckling a couple of times already. Try going about 40 mph on 2nd gear (or 3rd not sure which one). The rpm should be around 4000 with parial throttle. I thought it was the motor mounts that caused the buckling.

 

[peepsalot]

I don't have the AFC at this time, but I encountered the buckling a couple of times already. Try going about 40 mph on 2nd gear (or 3rd not sure which one). The rpm should be around 4000 with parial throttle. I thought it was the motor mounts that caused the buckling.

Dude, exactly! 2nd gear 4000rpm not sure what speed that is, but my car goes ******* crazy. Feels like it cuts power off all the sudden. If I floor it, it doesn't seem to happen, but if I keep my boost gauge around 0, it flips out. Does this happen on everyone's car? (boom01)

 

[Ryoga28]

Dude, exactly! 2nd gear 4000rpm not sure what speed that is, but my car goes ******* crazy. Feels like it cuts power off all the sudden. If I floor it, it doesn't seem to happen, but if I keep my boost gauge around 0, it flips out. Does this happen on everyone's car? (boom01)

Did you upgrade your motor mounts yet? I will have inserts installed on monday and see if my car will do the same thing. It's rather easy to reproduce this problem. It feels like the car is hitting a wall a couple of times.

Personally I don't this think this is caused by DSM's afc. Hopefully, John will be able to fix the idle problem by the next shipment.

 

[peepsalot]

Oh I'm definitely not saying this problem has anything to do with the AFC, that was just my first hunch, but with it removed now I know for sure that is not the cause. I have front, rear, and driver's side motor mounts, I don't think that has anything to do with it really.

 

[Ryoga28]

Peeps maybe we're experiencing fuel cut

http://www.msprotege.com/forum/showthread.php?t=88139&highlight=fuel+cut

But my car is running at 6.5 psi at 90 degree weather.

 

[peepsalot]

Peeps maybe we're experiencing fuel cut

http://www.msprotege.com/forum/showthread.php?t=88139&highlight=fuel+cut

But my car is running at 6.5 psi at 90 degree weather.

Yeah I had a feeling that it might be, I mean it fits the description of fuel cut, that I have read, but why the hell would it only happen at part throttle? Seems like you'd be more likely to draw too much air at full throttle. Isn't fuel cut when the ECU sees too much voltage from the MAF? This would imply that part throttle actually intakes more air than full throttle, which doesn't make any sense to me. Crap, I don't know man. Same psi and weather for me too...

 

[peepsalot]

Sorry, I'm not trying to clog up this thread with OT, maybe we should start our own thread.

 

[tallrd]

would using my Brake booster line be considered a vac/boost source?

good question; don't know. But my periodically-flawed logic tells me it would be vac only; b/c how does a spooling turbo cause pressure (i.e. "boost") in a brake line??...but...um...then again....it's a called a "brake booster" line so i dunno

 

[31R]

Currently i have my Boost science BPV and HKS BOV running of my brake booster line. Then i have my AFC T'd of my the line going to my BPV. You think i sould have my AFC line going somewhere else?

 

[peepsalot]

good question; don't know. But my periodically-flawed logic tells me it would be vac only; b/c how does a spooling turbo cause pressure (i.e. "boost") in a brake line??...but...um...then again....it's a called a "brake booster" line so i dunno

The brake booster line is a very good vacuum/boost source. The only thing you have to watch for is the inline check valve. You must tap the brake booster line on the intake manifold side of this check valve. It is a hard lump in the line a little less than a foot(i think) from the brake booster. The check valve is what allows the brake booster to hold vacuum even when you have just boosted.

 

[tallrd]

Currently i have my Boost science BPV and HKS BOV running of my brake booster line. Then i have my AFC T'd of my the line going to my BPV. You think i sould have my AFC line going somewhere else?

I'll try to pass along facts and not "what I think;" cool? First, it's a big photo on purpose for easier viewing; hope you don't have a 56K dial up.

This is the setup which John @ Air Flow Logistics recommended to me. The red arrow is pointing to the tap for the DSM unit. To make sure I don't create a misunderstanding, as you look at the engine from the front, your intake mani is at the backside, right?. You can plainly distinguish the corresponding paths for air to each cylinder (forgive my "ball-park" terminology). If you we number them 1-4 from left to right, the tap you want to use is towards the backside of #4. One end of that short line should be a solonoid of some type and the other goes into the intake mani. *THAT'S* the spot John told me to tap.

The green arrow is the "t" for my boost gauge so I can monitor my "oh s***!" levels from the MBC.

I am also using the brake booster line for by greddy blow off valve so we agree there.

Is this too much info, or does this help you?

 

[31R]

Thats does help. I just ordered a new Brake booster line because when i tap'd into it i accidently almost cut my check valve in half. I did a quick fix, but once i get my new Brake booster line i want to get one of those fancy vacuum manifolds from MAM that way my set up is nice and pretty. I still want to try that setup John recommended to you.

 

[tallrd]

Thats does help. I just ordered a new Brake booster line because when i tap'd into it i accidently almost cut my check valve in half. I did a quick fix, but once i get my new Brake booster line i want to get one of those fancy vacuum manifolds from MAM that way my set up is nice and pretty. I still want to try that setup John recommended to you.

Glad it helps *subliminal man says: "don't forget to give rep points to anyone who helps you" (and not just me)

There's a saying that goes something like "often we learn not by doing things right, but by doing them wrong" (bang) The downside to being incorrect with a car is it costs you money.

*head's towards light at end of tunnel from thread start*

 

[CasopoliS]

tallrd looks like everything is lookin good in the pic. Other than that crappy stiff hose you used for the gauge! j/k

 

[tallrd]

tallrd looks like everything is lookin good in the pic. Other than that crappy stiff hose you used for the gauge! j/k

lol. yeah, I got lazy on that part. I didn't realize they'd ship such a bad line with the guage, and I'd already cut the hoses to tap them by the time I realized it. So... on went the bad line

 

[Wingman21]

I know its an old thread, but I have an idle issue with my AFC. So I was wondering, if you plug back the O2 wire like it was stock (still keeping the input to the AFC I presume, but removing the output), the AFC is only affecting the MAF signal? Is that how its supposed to work or the AFC also has to change the O2 signal in order to affect the A/F ratio?

Thanks

OK everyone, I got some info you guys might want to hear. I got my zeitronix wideband hooked up, and was datalogging some signals.

I found out that the AFC alters your O2 signal even during vacuum. It sends out a sine wave to trick the car into thinking it is at 14.7. This basically puts the car into open loop all the time. It is no wonder the car could not idle properly like this.

I think there are a couple solutions to this.
1. Disconnect the O2 wire from the AFC, and reconnect the two ends normally. If my theory is correct, then this will still allow the AFC to do it's thing when the car is in open loop (WOT for example), and let the car do it's thing during idle and light throttle.
2. There is a setting under the "Output Settings" menu, called Output B. On my unit it came set to "Over Pressure", and below that, the pressure value was set to -18.12. I think if you were to set this to something like 0, then the AFC would not do any O2 sensor trickery until you are actually in boost. Alternatively it looks like you can set this to also switch by rpm if you wanted.
*Note: I couldn't tell how you are supposed to load this setting onto the AFC, if writing the fuel map to it does it, or if the Reset ECU button is necessary. If you reset it, you should have to write the fuel map again.

For now I have disconnected my AFC. I'm not sure when or if I'll reinstall it. But you guys can give this a try and see if this helps. I did try #1 briefly, and my idle worked well like this. I'm not completely sure if this disables the AFC too much, but I think it should still work only when the car is in open loop(which seems like the ideal situation anyways).
As for option #2 I did not try this, but here is a correspondence I had with a Spit Second rep which was a little vague to me, but I think this confirms my thoughts: