91 SS surges under boost and stumbles off-idle. Still broke

[shtbxr22]

holy crap, this sounds all too familiar. take 10 minutes to remove your crank pulley, please. look at your sprocket.

[Boostedballs]

holy crap, this sounds all too familiar. take 10 minutes to remove your crank pulley, please. look at your sprocket.

I'll bet you are right. That was my biggest fear, and I have a bit of a wobble on the crank pully.

I just built my own water injection system. I'm gunna hook it up and if I still have this issue- I'll be looking at crank issues or knock sensor wiring. In fact, I'll check out the wiring right now. I'm at work with nothing going on and it's NICE out today!

I'll post some photos of the water injection system in the Intercooling area when I get it all installed.

[Boostedballs]

I just replaced the wastegate solenoid because I had one sitting around from my old ea82 project and they were the same part.

of course, no difference in performance.

[Boostedballs]

1. I got my home-built water/meth kit working and tested. It dops the intake temps 20-25F under WOT. It still surges under boost.

2. While testing the water/meth kit, I held the engine at 3000rpm or so. I noticed some metallic sounds coming from the engine. Could be the alternator, could be the bottom end. I'll bet this is affecting the knock sensor.

Any ideas what could be rattling in there? It ain't rod knock. Sounds like it comes from the center. hmm

[Boostedballs]

Well, I pulled the timing belt covers and found the belt to be one tooth off. I could only get to the cam sprockets because I didn't have time to get the balancer off before going on a trip out of the country. I moved the belt one notch so that both cam sprockets match, but I have no idea if the crank sprocket is right. I either fixed it or made it twice as bad. Either way, the car runs the same!

I'll be replacing the belt tensioner in hopes that it's the source of the 3000rpm rattle that may be setting off my knock sensor...

[shtbxr22]

Yes indeed, could be a failed tensioner that allowed it to skip around. when they fail, it kind of sounds like piston slap.

[Boostedballs]

I'll be replacing the tensioner just as soon as I get back from Israel in 3 weeks. I'll be able to check the timing gear keyway while i'm in there too.

[Boostedballs]

I replaced the timing belt and tensioner today. The pullys were not lined up because the TENSIONER WAS SHOT!

Now this sucker runs! No more surging under boost. I'm gunna hit the 1/4 mile with it today to get a stock baseline (except for 3" downpipe and H2O/Meth injection). Then I'll slap on the NOS. Just a 30shot to see if I can feel the difference before I go crazy with it. I have a water-to-air intercooler in the mail.

I'm stoked. I'm guessing it'll run high 16's tonight.

[Boostedballs]

Well, I thought it was all good but it ain't!

Having new timing belts lessened the problem but the problem is still there.

Here's a recap: When the engine is cold, it pulls harder at 1/2 throttle than it does at WOT. It pulls, then falls on it's face, then pulls again.
When I have been driving for a hour or so, the engine runs awesome, no problem at all. It's worse on a cold day, on a hot day (like the day I changed the timing belt and tensioner) it runs great.

I get codes:
13-Cam position sensor or circuit (TDC sensor on Justy)
22-Knock sensor or circuit (right side on SVX)
24-Air control valve or circuit (exc. Justy); Idle speed control solenoid valve (Justy)
32-Oxygen sensor or circuit (my fault, ran w/o sensor for test)
35-Canister purge solenoid or circuit
42-Idle switch or circuit
44-Wastegate duty solenoid (turbo)

I've replaced:
O2 sensor, wastegate solenoid, removed front cat, timing belt tensioner, the knock sensor was replaced right before I bought the car, fuel pump upgraded to Walbro 255, fuel filter, plugs, wires, air filter

-I installed H2O/meth injection to see if there is actual detonation that could be causing the timing to retard.
-Ran a BUNCH of lucas oil and sea foam through the engine.
-Checked crank timing gear keyway.

I drove the car with the oxygen sensor disconnected and again with the knock sensor disconnected. I have pulled the negative batter lead fter this but I doubt the codes cleared. I'll clear them the right way tomorrow and see what codes are left.
I'm thinking about replacing the purge solenoid next; I know that thing can cause some real issues.

[legacy92ej22t]

Have you done a D-check?

[Boostedballs]

Have you done a D-check?

Are you refering to pulling the codes? OR is this the green connectors while driving thing(which I don't know how to do)

[Legacy777]

Green connectors are the d-check.

Instructions for d-check are on my site.

[Boostedballs]

Green connectors are the d-check.

Instructions for d-check are on my site.

777, you da MAN! nice write-up!

your procedure worked and after 9 miles of hard driving, no codes returned!
I hope this was all due to the knock sensor replacement that was done before I bought the car. maybe the mechanic didn't clear the codes and the car has been running in default mode ever since? hmm...

I hope it continues to run this good, here comes the N2O!

ps: A gas station near me just started carrying e85! yeeha!

[Boostedballs]

Well, I have done about 10 1/4 mile passes and about 200 miles of driving with no codes stored. I still have the surging. Time to shotgun the knock sensor...

[Boostedballs]

Well, the car still has the surging when the engine is relatively cold. Now that it's summer, the problem only last a few miles before going away.

My CEL came on the other day for the first time. It had only one code, code 35, purge solenoid. I'm wondering if this can actually cause the lack of power???

[Boostedballs]

I replaced the ecm coolant temp sensor today and I removed and inspected the knock sensor. Still bucks under load.

Also- I can hear a weird psht psht psht sound when I get on it, like the wastegate or BOV is cycling really fast when the problem occurs. When the engine is runniing strong, all I hear is that boxer growl, no psht psht psht.


The noise is very rapid, like 2 or 3 cycles per second and I only hear it when the windows are down. It has a somewhat metalic and pneumatic sound to it. I don't like it.

Anyone want to loan me an ecm?

[Boostedballs]

The issue is fixed.

I relocated the knock sensor to a cleaner spot on the block and cleaned the sensor with a wire brush and applied electrical compound. I don't know if this fixed the issue or if moving the wires around gave me a temporary fix. Either way, I'm happy now!

[US-RX]

The issue is fixed.

I relocated the knock sensor to a cleaner spot on the block and cleaned the sensor with a wire brush and applied electrical compound. I don't know if this fixed the issue or if moving the wires around gave me a temporary fix. Either way, I'm happy now!

so, it's been a month or so, are you still happy? Is it still fixed?

been lurking here for years, this issue has moved me to register just to get updated on the Bucking Subaru...
(I'm getting the same codes after rebuilding my rolled BC67 into a BC63 shell.[/quote]

[biggreen96]

Is your fix still working?

[Boostedballs]

It's been a while and the thing runs awesome!. No I have a lot more goodies added to it and I'm really enjoying it.

[biggreen96]

That's good news. If you don't mind, where did you relocated the knock sensor to?

[Boostedballs]

That's good news. If you don't mind, where did you relocated the knock sensor to?

I moved it up near the bellhousing. Only a couple inches from original location. I think the block down under the intake is too nasty and heard to get to in order to clean it up and make a good connection.

[biggreen96]

Ok I think I moved mine to the same place the other day. Seems to run smoother.