SR20DET - Running Rich - Need Additional Suggestions

[voiddweller]

Hi,

I recently finished a SR Blacktop swap with my S13. The engine running extremely rich (less than 10:1 for most of the power band) and a 1200 to 1500RPM idle.

After doing some searching, a few things came up, so I checked the coolant temp sensor, MAF, TPS, 02, the harness (for continuity) and all the vacuum lines.
I cleaned the MAF and readjusted the TPS. From what I read in the S14FSM, they all seem within spec. The ECU is an E5 and does not appear to be modified.

The only mods on the car are an 11lb flywheel, FMIC and turbo back exhaust with test pipe.

Any suggestions would be greatly appreciated.

Thanks!

Dyno run results:

[GRIPPY]

Check for boost leaks first and foremost. Then if not that, pull of your fuel rail and make sure none of the injector o-rings are leaking.

[grnappletree14]

how did u clean ur maf. lmk please

[voiddweller]

Originally Posted by grnappletree14

how did u clean ur maf. lmk please

I removed it from the housing (2 screws) and sprayed brake cleaner on the sensors and in the channel that directs the air to the sensor.

After they were all completely dry, I took off the O-Ring and put a tiny dab of oil on it with a Q-tip and then wiped the oil off. When it all looked clean, I resealed the system.

[slider2828]

Would never spray mafs with brake cleaner. It really messes it up. Use mafs cleaner from CRC available at Kragens. Swap about the stock FPR or get an aftermarket FPR and see what it is. That will tell the whole story. Megan is about 90 bux or something which is what I am using.

[mRclARK1]

How well do you boost? I'm guessing you have a boost leak somewhere. Also, I'm told a test pipe will cause a slight running rich situation.

[voiddweller]

Originally Posted by slider2828

Would never spray mafs with brake cleaner. It really messes it up. Use mafs cleaner from CRC available at Kragens. Swap about the stock FPR or get an aftermarket FPR and see what it is. That will tell the whole story. Megan is about 90 bux or something which is what I am using.

The rich condition was before I cleaned it, but you are right, I should have used something a little more gentle, like electronics cleaner.

Originally Posted by mRclARK1

How well do you boost? I'm guessing you have a boost leak somewhere. Also, I'm told a test pipe will cause a slight running rich situation.

I get a solid 10psi of boost and vacuum is around 20. That's interesting about the test pipe...

[nakedave]

Sorry to bring this thread back from the dead, but did you ever figure out what was causing your problems and making it run rich. I'm having the same issues.

[Triperformance]

Are you guys getting it fully warm? my car runs rich as shit till its warmed up, even when my temp gauge is where it should be. My cooling system keeps her cool till I do some boosting.

[voiddweller]

Originally Posted by nakedave

Sorry to bring this thread back from the dead, but did you ever figure out what was causing your problems and making it run rich. I'm having the same issues.

Wow! Yeah, this was dead!

I was cleaning out my email and noticed the thread notification on Zilvia.

To answer your question, I lost my job soon after posting this and couldn't put any money into the car. I put it up on jacks in my garage 3 years ago and haven't touched it. The Harbor Freight jacks are still holding

The suggestions I received for finding the culprit were good: FPR, Injectors and Boost Leak, so I still think it's one of those areas.

After picking up an S14 recently and being fairly stable in a new job, I'm starting to get interested in Nissan's again, so I'll be on the forums more often.

What did you do to fix your issue?

Originally Posted by Triperformance

Are you guys getting it fully warm? my car runs rich as shit till its warmed up, even when my temp gauge is where it should be. My cooling system keeps her cool till I do some boosting.

A car is supposed to run rich when cold, so I always made sure it was fully up to normal operating temperature before attempting take measurments on the dyno. Trust me, it was running way too rich...

Here's the dyno result from 3 runs. The last was unmetered air...

[nakedave]

What did you do to fix your issue?

wow just stumbled back upon this thread. Car ran like crap for a while unti I completely stopped driving it altogether. I haven't had time to work on it for almost a year.

Started her up two weeks ago for the first time in months and still running pig rich. I've tried the TPS, cts, and checked repeatedly for boost leaks. I think part of my problem might be my harness and how it's reading the maf, I've got a brand new one on the way from wiring specialists. I'm really hoping this helps. I really miss driving this car.

[cbcm2435]

check your ignition, mine was doing that, and i found two of my ignition coils were bad and my ignition harness was hacked in 8 different spots, put in a splitfire dis, and i had to get it tuned because it was running lean. so it just wasnt burning all of the fuel in the cylinder so it was reading it was running rich

[ttyner1212]

hey did the new harness fix your problem? mine is doing the same thing but it will run for like a minute or two then it just goes to 10.0 airfuel and isnt reading the maf anymore. I know the maf is good i have changed all the ignition coils and the coil harness done the coolent temp sensor and knock sensor. I have no idea other than maybe bad ecu or engine harness.

[nakedave]

Forgot about this tread! Actually, my sr had been running so rich that I burned up my rings so I pulled the mother apart and replaced the rings. While it was out I also installed some S3 cams from JW. Got it all back together a couple weeks ago, with the new harness an I'm still running rich! I've replaced my harness, my cts (twice), z32 maf, o2, spark plugs (gapped to .027), this is the second ignition harness I've tried and it's still running rich! I guess next move is to check my grounds??

[di-devol]

Did you check your injectors? Boost leak test? Try a different maf?

[nakedave]

Originally Posted by di-devol

Did you check your injectors? Boost leak test? Try a different maf?

Yes, I actually replaced the injectors and resistors, and have tried 3 different mafs.
While I may have a small vacuum leak somewhere, I've searched to no avail, it would lean it out at idle, not cause it to run rich, like (10:1-11:5) at idle once it's warmed up. I'm going to test my grounds tonight and see what I get.

[nakedave]

UPDATE* Well since I've ha it back together, I've had a problem with the car running massively rich, like 10:1 ratio at idle, after it was warm. I replaced and tested a couple sensors like my coolant temperature sensor and throttle positioning sensor and haven't been able to figure it out. Well, I was reading through Dominski last night and got a couple ideas to try today.
1) check my ecu for codes
2) check my grounds
3) again, check for vacuum leaks

Well my ecu wasn't showing any codes so that didn't really help.
I checked for vacuum leaks and found a small one, that I repaired on site, helped a little.
I went to check my grounds and found one conning off my lower harness that I had missed, that was disconnected. Once I reconnected it, my afr leaned out. I took down the street for some gas and it's running just a bit lean now, lol. It's drivable though. I'm not going to boost on it, until I figure it out, but at least it's not dumping fuel anymore!

[Matt191]

Where was the un hooked ground that you found?

[nakedave]

Originally Posted by Matt191

Where was the un hooked ground that you found?

On the lower harness, bolts to the strut tower. Not out of the woods yet though. Noticed my fuel pressure was little low (40psi) so I adjusted it up to about 43-44 and now it's running a little rich again!

[Matt191]

See I have the same problem that you have going on my SR is running really rich and I just cannot figure out why for the life of me it is really frustrating. I have that ground wired up and grounded but I just can't seem to figure it out. Maybe I'll take it off while the car is running to make sure I have a good ground there cause I did paint my engine bay so that could be upsetting my car. I am throwing code 55 which makes me happy though(: so I'll go tinker some more and let you know what I find

[voiddweller]

I hate bumping old threads, but I wanted to post back and close the loop since I was a SR20DET greenhorn when this was written.

Turns out the Walbro 255lph fuel pump was pushing way more gas than the stock ECU and FPR could handle. It was my first high capacity fuel pump and it didn't even dawn on me...I probably had a boost leak somewhere and couldn't find it, but this engine is in the S14 now and running great!

I installed a Wiring Specialties harness, z32 MAF and Martin at R.S. Enthalpy did a ROM tune. It's running really smooth and the MPG jumped from 17 to 25.

[KYZAAC]

So you need a tune with a walbro pump Is what your saying fixed the issue? I'm running really rich and tried everything mentioned in this thread. Can't figure it out

[voiddweller]

It's the same engine in a different chassis with a different harness, so it's hard to be 100% sure. All I can say is after talking to several Tuners and describing the symptoms, they independently agreed that it was probably the fuel pump. After the Enthalpy tune, it runs like a top.

[KYZAAC]

I have a whole new turbo setup to put on so i need a tune anyways. But I was told to get it running right b4 installing the turbo. If I knew thst was the problem for sure I'd just go ahead and throw the turbo in

[Fre3_World313]

Bringing back an old thread, so I’m running rich, brand new plugs halfway fouled in 4 miles..

Stock everything except t28 and Bosch 550cc injectors

Do have a dirty ass A’PEXi air filter, have not boost leak tested it.

Don’t know how to work air flow controller

And boost gauge reads 25 lbs of boost.

Does have a manual boost controller.

Is 25 lbs too much?

[voiddweller]

I can't speak to the T28 but maximum efficiency on a T25 is 14lbs.

Your A/F ratio is probably way off. I invested in an AEM UEGO and it helped with the tuning.

[jedi03]

what tune are you using? also would check your boost reading with a known working gauge...

[Fre3_World313]

Not running a tune

All is stock

Guy I bought it from didn’t want to spend a lot of money swapping everything from his rusted s13 to this s14

I talked to him yesterday he said only thing he changed was he zeroed the afc.

Other than that he drove it for like 4 years daily driving.

My 1 afr reads rich at idle all the time, then right in middle during boost,

Reads 11.5 under boost, at the 25lbs( very concerning) haven’t had a chance to blow it up lol. Means I live several miles from black top

And 11.5 under boost is right where previous owner said it should be.

He also said ngk bre6 plugs are shit ass copper

And he said to get iridium. Which he had better luck with.

You guys think the dirty ass air filter? And copper plugs. Are reason it’s running rich? Thanks fellas!!!

[Fre3_World313]

And btw, previous owner drove for many years with the setup I have now, 550ccs and t28 and all.

Never had it tuned or anything, just drove it, without plug fouling issues.

I have a 87 $ A’PEXi filter here today. I’m going to put it on. Put brand new plugs in again.. and see if the filter is the issue. Only way to eliminate it.

Where’s Alberto big boost when you NEED him lol

[brndck]

wtf 25psi on a t28 is WAY outside its efficient range. you need to stop what you're doing, and go give your keys to a REPUTABLE tuner.

get a power FC or at LEAST JWT or enthalpy reflashed ecu, and invest in a real wideband gauge.

air filter is NOT going to solve your problems.