Hesitation, limp mode, running like crap.

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Davins94ss
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Hesitation, limp mode, running like crap.

Post by Davins94ss »

My 94 SS has been having Issues running right for a while, at first I thought it was a misfire, I changed spark plugs and Wires and no change. The car sputters and sometimes pops quietly on its own on deceleration, it shakes the whole car. (It feels like someone’s tapping on the throttle really fast while I’m decelerating down a hill for reference). The Tachometer is all over the place (Dropping to 0 and bouncing all over) when I am accelerating, sometimes in boost, sometimes at WOT, and sometimes but rarely with normal driving. It seems to lose power and almost cut when the tachometer starts doing weird things. Also, the temp gauge is spiking or moving up and then back down rapidly when the tach is moving all over. I’m throwing codes:

Current
22:Knock sensor
41:A/F learning function
32: 02 sensor

Stored codes
49: Maf
24: Air control valve
I swapped the Maf out first. Reset ecu. (I think) No change there, then i swapped the 02 sensor, reset Ecu. (I think, don’t know if I’m doing it right) it ran pretty good for 2 days. Still not perfect on decel but better overall, no limp mode. Hit about 9-9.5 pounds consistently at WOT and pulled like it should. Then it went right back to where it was before. Back into limp mode we go. Then I swapped the knock sensor. No change. Almost worse but that could just be my mind messing with me. I don’t know why swapping the o2 sensor would make it run good for just a couple days then go back to where it was before. I’m lost. This is all so intermittent and it doesn’t always run like this. Runs great and drives great for the most part until I get it into boost or get higher into the rpm’s after the car has been sitting overnight or for a longer period of time during the day. But as soon as I give it a little it doesn’t like it. Thanks, Davin

Legacy777
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Re: Hesitation, limp mode, running like crap.

Post by Legacy777 »

Hi Davin,

Your stalling and loss of power sound like a MAF issue I had years ago. However the temp gauge moving all over the place is new. It almost sounds like a ground issue. The ECU grounds go to a spot on the back side of the driver's side intake manifold. That is where everything grounds. I would suggest double and triple checking all your grounds. Use a multi meter and check the resistance between the ECU grounds and the ground point on the back of intake manifold. Also check to the negative terminal of the battery, chassis, etc.

Once you've checked all that, let us know what you find. If you don't have close to 0 ohms on all the checks then you have grounding issues that need to be addressed.

Once you've confirmed the grounding You may also want to check the voltage to the ECU to ensure it's not too low. It should be battery voltage at the battery terminal.

I would also suggest running the D-check mode or (active) code check. You connect the green connectors only. The instructions to running the active check is on my site.

https://www.surrealmirage.com/subaru/en ... #enginetip
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm

Davins94ss
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Re: Hesitation, limp mode, running like crap.

Post by Davins94ss »

Thanks Josh, I will do some testing and diagnosis, and get back to you sometime soon.

Legacy777
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Re: Hesitation, limp mode, running like crap.

Post by Legacy777 »

You're welcome.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm

wtdash
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Re: Hesitation, limp mode, running like crap.

Post by wtdash »

HI,
+1 to what JC recommends.
The KS was my issue when I had a limp mode. The KS are known to crack AND their wiring gets brittle after so many years. I saw you replaced it, but I'd double-check it and the wiring.

Also, Battery condition? Make 100% sure that there is no corrosion/build-up on the terminals. I've had a few issues w/Subies and other cars related to the terminals.

GL,
Td
Turbo Subies:
'87 GL-10 Turbo 4WD Wagon (pre-Loyale) - SOLD
'90 BJ, EJ22T/DOHC and 5-speed swap - SOLD
'04 FXT, Forged internals, VF39, STI TMIC, Cobb AP- SOLD
'93 Legacy SS - 5-speed, SOLD :-(
'02 WRX GG-SOLD
'96 BD - turbo'd-SOLD

Davins94ss
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Re: Hesitation, limp mode, running like crap.

Post by Davins94ss »

Well Josh, You are the master, it was the ground on the back of the intake manifold. I just relocated it to the block in the same area with that 12mm bolt hole. Cars running amazingly now. Will update and whatnot if any other problems arise, but as of right now it runs exactly how it should be from the factory.
And thank you Wtdash for the suggestion. Battery terminals are cleaner then they were now haha.

Legacy777
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Re: Hesitation, limp mode, running like crap.

Post by Legacy777 »

You're welcome! I'm glad that solved the issue :)
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm

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