Sr20 Running Rough

[SRSmith]

After fixing the MAF problem, my sr20 was running great.

Some time later, I noticed that the car "hiccupped" when it hit around 4000 rpm when accelerating. I thought it was probably my restrictive china filter, or that the car still needed the timing dialed in with a test light.

I bought a K&N and installed it. To do so I had to disconect the hot side of the intercooler piping for some modifications. I didn't start it that night.

Unfortunately it rained and I didnt have a hood on, but i didnt find any water in the intake. When I went to start it, it ran just fine for 4 minutes, and then it started running real rough. The ECU said it was a knock sensor.

I bought a new knock sensor, and it no longer threw the code. It still ran rough.

So I checked the timing with a light and its fine. I also intalled a wideband. The reading is good for the first 4 minutes after starting, but then it runs rough and the afr reads lean.

I swaped back in the old filter: still no change.

Here is a video:
https://drive.google.com/open?id=11R...JCQje7W0HD0LWf
Thanks in advance

[brndck]

FAST
Fuel
Air
Spark
Timing

you need to check those 4 things before coming to us for solutions.
without knowing the condition of your engine, we're just shooting in the dark

we can tell you shit like "check compression" or "get new spark plugs" but they're just vague guesses

[duballstar37]

Did you replace the MAF with a OEM or OE unit?

Also, I would try to identify if the problem is within a single cylinder or across the board. Once the engine is running rough, try pulling off each injector clip (one at a time). If the engine starts running even worse (or dies) then onto the next cylinder/injector clip. If pulling the injector clip does not effect the engine at all, that cylinder is your problem.

Best of luck! Test for compression, spark, and the above should help with fuel.

[SRSmith]

Thats a great tip Duball.

I was out of town and didn't get to the car till this evening. I ended up isolating cylinder 2 using Duball's advice. I pulled the coil pack and the spark plug well was full of water. I hadn't had the hood on during the torential downpour we got, and the water must have gotten under the cover and past that coil's seal.

I removed all the coils and checked for water. I reasembled everything and it now runs like a top.

Until....I took it for a test drive. Once I hit boost the engine bogs down. I messed with the boost controller as a last result when the engine was running rough. I tried bypassing the boost controller, but that didn't help. The engine revs all the way up fine when its not under load.

I never ended up checking overall fuel pressure. I'll do that tommorow.
Should I be worried that my turbo is bad?

[duballstar37]

Shooting in the dark, but I'm hitting targets!

Usually a bad turbo will smoke its ass off. Before I understood the importance of a trailer, I blew a SR turbo at the track and had to drive 2hr home. Let me tell you about rolling coal. You can always remove the piping and check for shaft play or oil in the intercooler piping. I usually associate load related issues with fuel, but it could be anything.

Do you have a tuning device to accommodate the boost controller changes? If not, remove the boost control (wastegate actuator straight to hot pipe) and put it back to stock to minimize variables.

What does the wideband say when you are breaking up under load?

[SRSmith]

Yep, I bypassed the boost controller and went strait to the hotpipe, but it didn't change anything.

I forgot to mention I was getting a little smoke from around the turbo.

I'll check the turbo as soon as I get a minute. I hope its not blown. I wasn't planning on going the t28 route just yet.

[duballstar37]

What does the wideband say when you are breaking up under load?

This will help us identify the issue. If the turbo is going bad... can you verify if its building boost?

Is the car running rich because there isn't enough air to accommodate the extra fuel under load?

Or is the car running lean due to a fuel issue (not sure if you have an updated fuel pump, but the SR will kill your +25 year old OEM pump after a while)?

Also, I should've mentioned this earlier, but you should probably change your oil considering water made its way all the way down into the spark plug cavity.

[S14rebuild]

Check for boost leaks!

[SRSmith]

I spent a couple hours on it this evening. I'll try to make this as concise as possible.

I installed a Fuel pressure gauge. When idling (900 rpm), the pressure remained at 38 PSI (46 with FPR disconnected). Upon shutting off the engine, it immediately dropped to 32. Over the next 5 minutes, the pressure dropped by 10 PSI.

AFR started at 14 but moved up to 17 when the engine warmed up. The reading jumped around a lot, so the most precise number I could get was a whole number.

I took it for a drive. First acceleration was ok, but the rest of the time it lagged when I hit boost. When giving it throttle AFR went up to and Fuel PSI went up to 50.
https://drive.google.com/open?id=147...qUad81MeN7A9vD

When I got back , I got the CAS code from the ECU. I retimed it and the code went away.

At idle: AFR 15-16 PSI 38
I took it for another drive. It was a little better.
https://drive.google.com/open?id=13h...M1UG9liFK8jK0w

I got home and pulled the plugs. As expected, they're dry.
https://drive.google.com/open?id=13g...csVMwHYPM6GpSo

I replaced the iridium BKR6's with some new BCPR7's.
I took it for another drive. It ran even better. Now and then it was able to build full boost, especially after letting off the throttle for a while.

When it's working: AFR 12-13
https://drive.google.com/open?id=13R...rujT2t6pnKmopY

When it's not: Throttle is to the floor.
https://drive.google.com/open?id=13B...Z0O9gHoJQMw9Tc

Pulled off the fuel pressure gauge. It looks pretty restrictive (Harbor Freight).
https://drive.google.com/open?id=13B...M1wveXrt6Mm1MH
I ran it again and it seemed about the same.

I'm thinking I have a fuel problem. Or maybe a boost leak? Should I start with a smoke test? I still have the boost controller bypassed, so I should be at stock boost.

What do you guys think? I don't really want to drive the car any more when its lean.

And thanks so much for the input.

PS: Anyone want a Greddy Exhaust? I'd like something a bit quieter.

Edit. Had some of the videos mismatched. Fixed that.

[duballstar37]

I'm at work and can't watch the videos, but I've got some thoughts...

If you have a smoke test, great! If not, an old trick that I've used for finding boost leaks and/or vacuum leaks is to (with the car running) spray some Brake Cleaner around all the intercooler couplings and points of connection (anywhere it might be able to leak from). If the engine responds (due to the flammable aerosol being introduced into the air mixture) then you've found your leak. Quick and easy test to help narrow down your issue.

Do you have a boost gauge? What does the boost gauge read under full load when breaking up/lagging? Your engine should boost around 7-10 psi stock (depending on the quality of your gauge, mechanical vs. electric, etc).

Regarding fuel, I've been through quite a few fuel pumps in my day. They will usually whine really loud when they are on the way out. Do you have a walbro 255lph in there already? If not and you have another brand, some of the cheaper alternatives come with plastic gears that fail.

I'll watch the videos when I get home and let you know what I think.

[brndck]

Originally Posted by duballstar37

If you have a smoke test, great.

not gonna lie, a vape works pretty well as a smoke tester

[SRSmith]

I'll be assembling one of these once I get a moment.
https://www.youtube.com/watch?v=EhNQiIRsCCk

My boost gauge has broken plastic floating around in it. It was reading 5 PSI when the engine was running rough. I don't know the reading when the car was working better. I'll have a new one soon.

I honestly don't know what fuel pump I have. What fuel pressure should I be getting at WOT?

[S14rebuild]

Boost leak test it, make sure ur bov isnt bleeding pressure off. Fuel pueessure should stay steady apecually on stock setup. Make sure ur maf is reading correctly too. Thats ur main input sensor for adding fuel. Try cleaning it out or swap with a known good unit

[SRSmith]

I checked for vacuum leaks and dont have any.

Wouldn't a bleeding bov show in a vac test?

I'm pretty sure its not the maf. All the wires are good and Im not getting the code fore it.

I fixed my boost guage and I was boosting to 15 PSI! Im tuned for 7.

I had the boost controller bypassed. I ended up hooking it back up and putting it on the lowest boost setting. Still boosts way high.

Could It be that I'm overboosting because Im set too low? It sounds weird to me but I read an article that implied that.

As always, thanks for the input. I apologize if the questions seem nooby. This is my first turbo car, so Im sure they are.

[S14rebuild]

At idle spray some brake cleaner at the bov port, see if its leaking.

U need to find the culprit to the over boosting

[jedi03]

you can check flow of pump by running pressure line into a bucket...255s usually do about a gallon a minute...if more you have larger pump, less of course closer to OE

[SRSmith]

I sprayed some brake cleaner in the BOV, but I didn't notice any difference between it when it was idling or off.

I haven't tested for leaks with brake cleaner before. What should I be looking for?

[S14rebuild]

If there is a vacuum leak, the engine will suck the brake cleaner in and cause the rpm to rise...since it is flammable.

I use it to check around intake manifolld gaskets, vacuum hose etc

[S14rebuild]

This issue only happens after a few minutes of running? Is that when the engine is cold and then first starts up. Runs good for 3-5 mins then goes rough?

What happens if you shut the car off, and then start it again in 5mins? Does it run rough immediately?

[SRSmith]

Well, in that case the bov in not leaking at idle.

I guess I should change the listing description. The car is now running smoothly, it just lags one I hit boost. Its also overboosting up to 15psi. Its set at 7. It happened even with the boost controller bypassed. And the boost controler cannot limit boost, it only makes it higher, right?

[S14rebuild]

Sounds like wastegate issuse. Make sure you have a good boost soucre running to the wastegate. Also remove the arm from the wastegate actuator and see if it can swing freely.

[SRSmith]

Well I don't know what is going on.

I finally got a minute to work on the car. I connected the boost controller back and unscrewed the knob to just shy of the lowest boost setting. I also changed the fuel filter.

I took the car for I drive, and the first 3 pulls went great with the car boosting to 8 psi. Then it went back to bogging once I hit boost.

If I accelerate at a normal speed or if I peg it, the car bogs at boost. If I accelerate super slowly, it will build boost all the way to redline.

At wide open throttle, my afr is 13.5. I should be at 11.8, right? Am I in danger of blowing up my engine if I run it this lean?

I didn't disconnect the arm from the wastegate, but it did open and close when I moved it back and forth.

[brndck]

Originally Posted by SRSmith

I didn't disconnect the arm from the wastegate, but it did open and close when I moved it back and forth.

you shouldn't be able to just open and close it by hand, with the wastegate arm attached.

[Kingtal0n]

make sure wide open throttle a/f ratio (anything over say 6psi of boost and below 15psi) is in the mid 11's or at most 12.0:1

or yes, it runs the risk of engine damage, broken piston first is likely. followed by QQ and big $$ to replace

[S14rebuild]

Originally Posted by brndck

you shouldn't be able to just open and close it by hand, with the wastegate arm attached.

Yea gonna say the samething

Wastegate probly fukd

[SRSmith]

I took off the wastegate actuator. Compressed air causes the arm to push out, and if I pull the arm out and put my thumb over the inlet, the diaphragm holds pressure.

Do you think I should take the whole turbo off and look at the actual wastgate? The door seems to swing freely, so I don't think anything coukd really be wrong in there.

[brndck]

Originally Posted by SRSmith

I took off the wastegate actuator. Compressed air causes the arm to push out, and if I pull the arm out and put my thumb over the inlet, the diaphragm holds pressure.

Do you think I should take the whole turbo off and look at the actual wastgate? The door seems to swing freely, so I don't think anything coukd really be wrong in there.

just get an inspection mirror and a flashlight
check the exhaust wheel for damage and play.

[ultimateirving]

Boost leak sounds most viable. But With water in the coil packs have you tried known good ones ?