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hesitation in positive boost

Posted: Thu May 14, 2015 8:05 pm
by zeke
So I swapped my 91ss to a 5 speed earlier this year and ever since it sputters coming into boost and was idling high. I did cut the AT identifier on the ecu but still had a high idle. I ended up screwing in the round plate on the top of the throttle body to get the idle down from 1500 rpms. I have to adjust it all the time though because it constantly unscrews itself. I have replaced the cts, o2 sensor, plugs, bpv, pcv valve, and cleaned the aicv. I have tested my injectors, knock sensor, and tps. The only thing really aftermarket on the 5 speed swap was a lightweight flywheel. My gas mileage has gone down as well freeway in town driving it hard or not results in 17mpg no matter what. It is also hard to start if I have ran it to temp let it sit for a couple hours it just cranks for about 5-10 seconds before it will start and some times I have to give it gas for I to. I had non of these problems with the auto trans not sure what my problem could be. Not sure if I have this in the correct category but my main issue is the stumble upon boost also I only get active codes 51 because I bypassed the neutral safety. Any further help would be much appreciated this car has been driving me nuts.

Re: hesitation in positive boost

Posted: Fri May 15, 2015 12:03 am
by wtdash
Hi,
You shouldn't have any codes. Did you follow Legacy777's 5-speed swap? It explains what to do w/the Neutral Switch.


Per the ECU code page there isn't any 'bad behavior' (Fail-Safe Operation) associated w/the 52 code, but it still might cause your issues.

TD

Re: hesitation in positive boost

Posted: Fri May 15, 2015 5:49 pm
by zeke
Would a jittery Speedo cause any problems?

Re: hesitation in positive boost

Posted: Fri May 15, 2015 5:55 pm
by wtdash
Yes...if you've got a bad cable or connector to the trans (common problem).

Re: hesitation in positive boost

Posted: Fri May 15, 2015 7:45 pm
by zeke
I know its on the transmission side just don't know if the worm gear is messed up its jumpy until around 50-60

Re: hesitation in positive boost

Posted: Sat May 16, 2015 10:56 pm
by Legacy777
Can you please confirm you've followed the same steps in my swap write-up and everything is either hooked up or removed except for the neutral switch in the manual trans?

Did you remove the TCU and key interlock controller?
Did you jumper pins 11 & 12 on the AT B15 connector?

The ECU really doesn't care whether the speed signal is accurate as long as it gets a signal of some kind.


Regarding the needle valve screw on top of the throttle body, put a little lock tite on it and screw it all the way down. Check and adjust if necessary the TPS per the instructions in this scan:

http://main.experiencetherave.com/subar ... sting3.jpg


After doing that I'd recommend resetting the codes and doing an active diagnostic check with the green diagnostic connectors.

The other thing to check is make sure you plugged all the connectors back in that you took apart during the 5spd swap. Lastly, if the wiring was brittle it's possible that disconnecting and moving things around during the swap caused increased resistance in the wiring, which is manifesting as the problems you are experiencing.

Re: hesitation in positive boost

Posted: Fri May 22, 2015 6:53 pm
by zeke
Yeah I did everything in the swap that's on your site except for the reverse lights and clutch inhibitor. It does not make the car undrivable but its just annoying.

Re: hesitation in positive boost

Posted: Fri May 22, 2015 8:19 pm
by Legacy777
When you say clutch inhibitor, are you referring to the starter interlock with the clutch pedal?

Re: hesitation in positive boost

Posted: Thu May 28, 2015 3:52 am
by zeke
i believe so i just jumpered 11 and 12 on the b15 connector

Re: hesitation in positive boost

Posted: Thu May 28, 2015 4:12 am
by zeke
upon further reading i just realized that i did not cut pin 18 on the b36 connector now necessary was that to be cut?

Re: hesitation in positive boost

Posted: Sat May 30, 2015 6:16 pm
by Legacy777
If you didn't hook up the neutral switch it's not necessary, however I would encourage you to hook up the neutral switch. If you decide to, then you should cut that wire.

Does the ECU have a code for the neutral switch?

Re: hesitation in positive boost

Posted: Sat May 30, 2015 10:28 pm
by zeke
Just code 51

Re: hesitation in positive boost

Posted: Sun May 31, 2015 10:06 pm
by Legacy777
I take that back, code 51 is the neutral switch. I spaced on the previous post and that you had posted code 51 came up. I don't think not having the neutral switch hooked up would cause the hesitation, but I can't say for sure. I usually suggest fixing all the codes so the ECU is "happy" to minimize multiple problems.

If you can, as I mentioned above I'd recommend hooking up the neutral switch, reset the ECU, and see if the hesitation is still there.

Re: hesitation in positive boost

Posted: Tue Jun 02, 2015 4:55 am
by zeke
So I noticed some oil in the charge pipe and the resonator box I'm thinking it might be part of my problem there wasn't any oil in it when I had the auto not sure what would have changed. I'm going to be putting on my td05 and top mount my next weekend off but I dont want to get oil in the intercooler how well do catch cans actually work on our cars?

Re: hesitation in positive boost

Posted: Tue Jun 02, 2015 5:58 pm
by Legacy777
There are several threads talking about catch cans, so I'd recommend searching a little bit.

In general if they are plumbed up they work ok. I added some baffling in my catch can which helped the amount of oil it collects.

Re: hesitation in positive boost

Posted: Mon Jun 29, 2015 6:40 am
by zeke
So I finally figured out what was causing the hesitation. I decided to try and relocate the knock sensor when I went to un clip it the wire on the harness side broke off so I put a new wire on it and moved the sensor to the top of the bellhousing I have no more hesitation. I also noticed I still have the gray conector on the sensor so I will be getting a new one soon. Should I get an oem or a parts store part for that?

Re: hesitation in positive boost

Posted: Mon Jul 06, 2015 6:41 pm
by Legacy777
Others have used parts store knock sensors I think with ok success. I prefer getting certain parts from Subaru, but if there's a huge price difference it may make sense to get it from the parts store.

When you get the new sensor, you may want to try mounting it in the stock location to see if that was the issue or the bad wiring.