sr20det uses alot of gas...can it be the o2 sensor?

[sr_powered]

when i did my swap, i extended the o2 senosr wires with some electrical wires and wrapped it out with electrical tape. my engine uses alot of gas, and it tends to die every morning i start the car. like, it'll idle for about 5 seconds and then it stalls and dies. but if i start to drive it, the engine wont die anymore. this is weird. i need some help here.

[afracer]

Check your fuel pressure, give it a tune up with new plugs, fuel filter, etc and check the timing. Run some fuel injector cleaner through it. If you still get bad mileage check your injectors individually or swap them out. If still nothing change your coolant temp sensor, and look at replacing your O2 sensor (least likely).

[sr_powered]

ok, i replaced the plugs with the usdm sr20de plugs (ngk) when i did my swap. i haven't gapped them yet, just put it in. i used the original fuel filter that came with the sr20det. there were times when my engine would just crank and wouldn't start. but when it did, i could smell alot of gas coming from my exhaust. i think this is because of the cranking that alot of the gas were being injected into the cylinders. i don't know if this killed my plugs or my o2 sensor. last time i checked the plugs, they were black. i don't know if this is normal. i don't see any corrosion buildup, so i think that maybe it might not be a gas problem, but my gas is getting used up fast.

[Blown240sx]

Black usually is a sign of fouling. Im talking BLACK. Also check to see if the plugs smell of gas you may be running rich cause of timing or something.Car could be dumping fuel then sparking a little to late.

[Neil]

i talk about this so much its retarded.

check your O2 sensor wires. The sense wire is shielded. DO NOT SPLICE THE SHIELDING TO THE INNER WIRES. This will ground out the O2 sensor and make it run open loop, which WILL make your car munch a tank of gas in like 150 miles.

DOUBLE CHECK WHERE YOU SPLICED THE O2 WIRES. Cut back an inch of that (silver wire fibers wrapped around the black jacket) shielding. If even 1 fiber is going up into that splice, it's grounding it out.

p.s. i hope you have a blacktop cuz O2 sensors dont like getting covered in soot and blacktop O2's are cheaper and readiy available at autozone.

P.P.S.

GET RID OF THE ELECTRICAL TAPE. ELECTRICAL TAPE IS NOT MEANT TO HOLD CONNECTIONS TOGETHER. IT'S MEANT TO BUNCH WIRES ALONG ONE ANOTHER, LIKE A HARNESS. FOR THE LOVE OF GOD GET A SPLICING TOOL AND SPLICES AT RADIO SHACK (and some heat shrink tubing). The possibility that the sense wire is not making a good connection to the harness because it's electrical-taped together is VERY REAL. Don't even use electrical tape for your STEREO.

[sr_powered]

i have a red top. there are three wires from the o2 sensor (red, black, and white). i cut the wires and used some electrical black wires (14-16 gauge)for extensions. i also did the same to the other end. yeah, i used electrical tape to cover up the bare wires and to wrapped them all together. so to do this over again, should i just make sure that the o2 wires are cut with no wires exposing and just splice with the some extension wires (or should i just use those wire shrinkers)? what wires are best? im planning on changing my spark plugs and fuel filter since the plugs are fouled and the filter might be too old. thanks for your advices. i appreciated it.

[hazw8st]

when i did my swap, i extended the o2 senosr wires with some electrical wires and wrapped it out with electrical tape. my engine uses alot of gas, and it tends to die every morning i start the car. like, it'll idle for about 5 seconds and then it stalls and dies. but if i start to drive it, the engine wont die anymore. this is weird. i need some help here.

It's more than likely your left foot!

[Neil]

i have a red top. there are three wires from the o2 sensor (red, black, and white). i cut the wires and used some electrical black wires (14-16 gauge)for extensions. i also did the same to the other end. yeah, i used electrical tape to cover up the bare wires and to wrapped them all together. so to do this over again, should i just make sure that the o2 wires are cut with no wires exposing and just splice with the some extension wires (or should i just use those wire shrinkers)? what wires are best? im planning on changing my spark plugs and fuel filter since the plugs are fouled and the filter might be too old. thanks for your advices. i appreciated it.

1: fix the connections. get the splices and crimp tool from radio shack and hook the wires together better. To 'clean up' the look of the job, use electrical tape AFTERWARD to bunch the splices together.

2: Make sure you dont have a wire going from the white wire harness side to the red wire on the plug, or any combination of mishaps herein... make sure youre extending like wires and not accidentally mating them to their incorrect counterparts on the plug.

3: The larger wire on the harness side (solid black i think) has the shielding i mentioned. make sure the shielding is NOT touching the inner-core wires that you are lengthening. The shielding is to help dissipate electromagnetic interference so the ECU sees a clean signal from this prominant A/F tuning device. It is not meant to carry a current.

To splice wires together, you do have to have the inner core exposed. I usually shoot for about 3/4 of an inch. Radioshack also sells a nice wire stripping tool that cuts the jacket cleanly off for you specifically for the purpose of helping to ease soldering/splicing jobs. Once the braids are exposed, you twist them so theyre wound tight and you slide that up into the splice. The crimping tool will chomp down on the splice and crush itself onto those bare wires, making a solid, un-pull-apart-able (if you do it right) connection.

4: Really any gauge wire is fine... 14awg i think is a little overkill but it will work 100%. even speaker wire would work. As stated above, if youre using 1 long length of a single color wire, just be sure to not get confused and that youre hooking them up to their proper counterparts.

5: you dont have to change your spark plugs. The excess carbon will burn off very quickly after the motor begins to run properly.

If you sort out the O2 wiring with solid proper connections and it's still acting up, Contact my boy Jeff at 240sxmotoring.com and order yourself a new skinny O2 sensor.

Or, buy an aftermarket turbo outlet pipe (like a Trust ) and get a blacktop sensor for it at autozone. Its just a physical size issue, the blacktop/redtop o2 sensors read the same.

As for your fuel filter, new ones are always a good idea. I personally went and bought a 300zx turbo fuel filter. Its a squeeze getting it into the bracket but its a much bigger/better/higher flowing filter.
Modified by Neil at 6:51 AM 2/9/2006

[hazw8st]

Nice write up.

[Neil]

thx. good luck!

[sr_powered]

thanks for the info bro. if all that is done, and my gas mileage is still horrible, i'll give give your boy a call. thanks again. just one more question: running without the thermostat would also be bad for my gas mileage too, don't you think? i don't know, just asking.

[Neil]

mmmmaaaaybe. If the motor gets up to temp, if the needle comes up half way and stays there, its not affecting anything. If it stays cold, the temp sensor on the inlet plenum on the motor will be reading cold all the time which tells the motor to richen the mixture.

[sr_powered]

ok, what about the coolant temp sensor? wheres that located on the sr20det? cus on my old ka24e, there this sensor thing located in the middle of the radiator hose (the bottom hose). i kept wondering what that was for? and autozone sells sr0det o2 sensors? WOW! one more thing: what if the shielding on the o2 sensor wires has been cut? can i buy some from an electronic store?

[Neil]

ok, what about the coolant temp sensor? wheres that located on the sr20det? cus on my old ka24e, there this sensor thing located in the middle of the radiator hose (the bottom hose). i kept wondering what that was for? and autozone sells sr0det o2 sensors? WOW! one more thing: what if the shielding on the o2 sensor wires has been cut? can i buy some from an electronic store?

in order:

There's 2 sensors on the SR that detect coolant temperature. They are both located to the right of the throttle body, in line with the radiator hose coming off the bottom of your radiator. The 2 wire plug with the red connector is the one that tells the ECU what temperature the motor is at. The smaller single wire one to the right only feeds the gauge cluster needle. Ive never seen a KA-E so I dont know what was in the middle of the radiator hose... possibly a temperature sender for some thermostatic switch. possibly for the stock electric fan? i seem to recall some didnt-pay-close-attention-to tech talk about KA-E's and thermostatically controlled stock electric fans.

Autozone sells a '93 300ZX Turbo O2 sensor which is the same part number they began using on SR's when they went to black valve covers. I heve never heard of someone being able to buy a redtop O2 sensor from autozone, i believe they are a nissan-japan special order item only. Thats why I mentioned my boy Jeff, cuz he usually likes to have at least 1 in stock. See the link in my signature.

If the shielding has been cut, that's *FINE*. Youre not going to be able to get it to run up across the back of the motor up to the plug. there's plenty buried down in the main engine harness (where all the e.m.i comes from anyway) to be effective. I just cant emphasize enough, don't splice the shielding in with the core wire!

Modified by Neil at 7:26 AM 2/9/2006
Modified by Neil at 7:35 AM 2/9/2006

[Neil]

any more q's i'll answer them to the best of my knowledge. My personal swap troubleshooting issues are still fresh in my mind

P.S. Jeff also sells SR Thermostats. theyre cheap.
Modified by Neil at 8:42 AM 2/9/2006

[sr_powered]

ok, i just checked my ecu diagnostic codes; it gave me a 55 which means "other malfunction, CONSULT terminal something something". at first, it gave me a 21, which is the ignition signal code. nows its just gaving me the 55 code. but im still gonna redo the wirings for the o2 sensor.

[PhopsonNY]

The redtop (skinny) sensor is a Titanium (resistance based)sensor - rare while The Blacktop (fat) sensor is a Zirconium (voltage based) sensor - more common

They are not interchangable

read the following links;

http://www.sr20forum.com/showthread.php?t=124479

[Neil]

I see... a lot of contradicting information online, I've been reading that E5 and 62 ecu's are directly interchangable unless its a post-'96 e5, which indicated to me they operate based on the same O2 sensor information.

[mallbor240SR]

i used to have the same problem with my swap, you should check your fuel pressure, i got a nismo FPR and it solved the problem.

[Blown240sx]

I heve never heard of someone being able to buy a redtop O2 sensor from autozone

I have a Redtop and I picked my O2 up for AutoZone. Its a later year 300zx Skinny O2 plug only difference is the wires have to be spliced into the SR O2 plug that leads to the ECU.

Also while reading the info on the Blacktop and Redtop motors. I noticed it said the E5/E6 ECU was in the early Blacktops. I have a SR Redtop with a E5 ECU.... Would this hurt me or help me? Or niether?

[hazw8st]

What color are the plugs?

[Neil]

I have a Redtop and I picked my O2 up for AutoZone. Its a later year 300zx Skinny O2 plug only difference is the wires have to be spliced into the SR O2 plug that leads to the ECU.

Also while reading the info on the Blacktop and Redtop motors. I noticed it said the E5/E6 ECU was in the early Blacktops. I have a SR Redtop with a E5 ECU.... Would this hurt me or help me? Or niether?

Does your car run fine?

cuz

The redtop (skinny) sensor is a Titanium (resistance based)sensor - rare while The Blacktop (fat) sensor is a Zirconium (voltage based) sensor - more common

They are not interchangable

If thats true, wouldnt a 62 be looking for ohms instead of volts that an E5 is looking for? or does the ecu know to interprit both? If it doesnt, wouldnt an E5 on a redtop not work properly?

[Neil]

ok, i just checked my ecu diagnostic codes; it gave me a 55 which means "other malfunction, CONSULT terminal something something"

I wouldnt bug out about that... to install an sr you basically concede to not being able to use Nissan's consult diagnostic tool anyway.

[sr_powered]

yo neil. i think i fixed my fuel problem. i installed the thermostat and the gas mileage got pretty good. i did some calculations and got about 20-25 mpg. but after the installation of the thermostat, my idle's really rough. it will stall, dropped to almost zero and rised back up to about 900 rpm. it keeps doing that, and on cold starts, the engine will died instantly right after i started it up. i'll have to step on the gas pedal and set the rpm at about 2500 for like a minute in order for it the idle below 1000 rpm. and just last night, i installed the stock intake arm ( the one connected to the turbo and maf), my engine was really choking, like its not getting enough air. it keeps dying, doing the same thing as described above, only worse. it was really rough idle. any help would be great!

[Blown240sx]

When I checked the Voltage coming off the Sensor wire of my O2 I was reading really high like 15 volts with the car off and the engine just turned on but not running. The car had already been warmed up.

I havnt had any running problems out of the motor though...

[Neil]

after the installation of the thermostat, my idle's really rough. it will stall, dropped to almost zero and rised back up to about 900 rpm. it keeps doing that, and on cold starts, the engine will died instantly right after i started it up.

could be throttle position sensor, but I don't think the ECU looks at its values until its warmed up. My TPS was filled with water and was reading all over the place in any single position, so at idle it would rise/fall/rise/fall but it would always cold start and run at 1200rpm like normal. once it got half way to running temperature is when my problem would start.

Check the stock rubber intake tube for any cracks and generally poke around, check out couplers, clamp tightness, make sure any of the 3 tb vaccuum ports are either being used or are capped off airtight, etc... If it's letting unmetered air in anywhere past the MAF, that'll lean it out a bunch and would definitely account for a rough idle. Do you have an aftermarket BOV? My Greddy RS was set up way too loose out of the box and was letting air in at idle. heh.. the reason i got an RS is because the ancient original "pressure bypass valve" on the Sidemount IC was bad and leaking pressurized air back into the intake.

if you haven't done so yet, make sure your O2 wiring is sound.

Take a couple minutes and pull out a spark plug, see what it looks like after installing the t-stat. If the ceramic part around the cathode (or anode? w/ever) is still black it's still too rich. If the ceramic part looks white and the rest is chalky tan, its too lean. On a happily running motor, that ceramic part should be golden brown-ish.

If it's indicating rich, the fuel pressure regulator on the outlet of the fuel rail may be bad, letting fuel pressure build up in the rail so whenever the injectors open too much gas squirts through. Check to make sure the the vaccuum line connecting the FPR to the throttle body isn't dry rotted. Like previously suggested the O2 sensor may just be dead as well. to be sure of that though, you should check the reading at the O2 sense line's pin on the ECU with a multimeter.

also, check your timing! you can rent a light gun from autozone, or just buy one, i think theyre like $30. To use it though you have to cut an ~8" length out of a KA's wire, put the KA wire boot down on the No.1 cyl plug and stuff the cut off end up into the coilpack. this gives you a good place to put the light gun's spark-fire sensor. With the throttle position sensor unhooked, the ECU goes into "set ignition timing" mode. Idle should be at 700rpm when the motor's warmed up with the TPS unhooked. If it isnt, adjust the idle via the IACV adjustmet screw down in between the 1st and 2nd intake runners. Once the idle is at 700rpm, point the light gun down at the crank pulley, the 2nd timing mark from the right (15° before top dead center) should line up with the needle sticking off the oil pump cover. If theyre misaligned, just un-snug the 2 bolts holding down the cam angle sensor and rotate it while still checkin with the gun on the pulley till they line up. then snug the CAS back down, reconnect the throttle position sensor, put the coilpack directly onto the spark plug again and see if anything's better feeling.

If the timing marks are way off, don't worry about setting the idle first cuz it just might want to stall on you worse. get the timing marks ball-park and then adjust the idle and proceed from there.

Every little thing you can do helps you at least figure out what's NOT your problem.



*king of editing posts*
Modified by Neil at 2:59 AM 2/13/2006

[sr_powered]

"If the timing marks are way off, don't worry about setting the idle first cuz it just might want to stall on you worse. get the timing marks ball-park and then adjust the idle and proceed from there."

ok. i dont quite get this part. just how do i do this^ and thanks for the info. ill do them step by step. and how do you check for leaks in the stock BOV thats what i have. im began to think that maybe my BOV is leaking, causing the engine to die when i installed that stock intake. and where can i find the pin # for the o2 sensor on the ecu. can i just measure the the o2 sensor at the end of the connector? thanks alot man. youre great help!

[Neil]

"If the timing marks are way off, don't worry about setting the idle first cuz it just might want to stall on you worse. get the timing marks ball-park and then adjust the idle and proceed from there."

ok. i dont quite get this part. just how do i do this^

by using the light to check the crank pulley for timing marks. if its WAY OFF, rotate the cas in the appropriate direction to get it at least near the 2nd mark from the right. THEN adjust the idle. then rotate the CAS some more to get the timing mark lined up perfectly.

If no amount of CAS adjustment allows you to line up the 15° mark, the CAS is most likely off by a tooth (not uncommon when buying warehouse stored motors)... which means to be sure its installed properly you have to take off the valve cover, make sure that No1 Cyl is at top dead center (full up with its cam lobes pointing away from each other), and reinstall the CAS, making sure its own markings line up properly.

You can find ECU pinout diagrams for SR20DET's with wire colors and descriptions of each online. Check out some of the stickies near the top of this forum. For example the S14SR20DET user manual found somewhere in there has generally all the same torque specs and troubleshooting procedures as the S13, its just got its own version of vtak. check it out to see what i mean about checking the timing and installing the cam angle sensor and whatnot.

You COULD pull a reading off the O2 sensor itself, but that wouldnt tell you about any potential bad connections you'd have to figure out that are preventing the ECU from seeing a good reading.

how do you check for leaks in the stock BOV

with my sidemount off, i got my lips dirty and blew thru the inlet pipe while capping the exit with my hand. plenty of air was leaking past the bypass valve and out the ~1" black recirculation tube. I wonder now... When the car is in boost it helps keep the valve closed cuz air is pushing on it. I wonder if it would have worked okay. actually probably not, cuz most of the time, namely cruising, im in vaccuum... which is what pulls the valve open... and me blowin on it with no pull to encourage it to open air was able to leak past. so yea it probably would have leaked at idle and while cruising.


Modified by Neil at 8:28 PM 2/13/2006

[PhopsonNY]

Does your car run fine?

cuz

If thats true, wouldnt a 62 be looking for ohms instead of volts that an E5 is looking for? or does the ecu know to interprit both? If it doesnt, wouldnt an E5 on a redtop not work properly?

Both O2 sensors actually give out a voltage reading for the ECU, but they are derived in different ways;

Zirconium voltage will vary directly as a result of the amount of O2 present. This I believe ranges from 0-1v, and is read by the E5 ECU.

Titamium feeds the 12v accross a resistance that varies with the amount of O2 present. For a constant current, the voltage will change and is senced by the E62 ECU. I am not sure of this, but I think the votage output range is 0- 0.5v
Modified by PhopsonNY at 9:01 PM 2/13/2006

[sr_powered]

alrite..i fixed my timing, but the idle still sits at about 1100 rpm. it'll go down to about 750 rpm, but rises back up again. it does this every 10-15 seconds or so after i have been driving and come to a stop. (i adjust the idle controller to the lowest point already) and the engine still dies every cold start. it'll start and dies right away if i don't step on the gas and keep it at about 1500-2000 rpm. but it won't do this when the engine is warmed up. what could be the problem? oh yeah, about the idle, here's what happened: when i was doing the timing, i adjust the idle controller to the lowest point, but when i advanced the CAS, the idle rised up, and when i retarted it, the idle goes down and this is with the idle controller all the way to the lowest point. please don't tell me i need a new CAS! i also figured out that my "ancient pressure bypass valve" was leaking. i didn't even need to take out the IC to figure it out. i just pull on the throttle cable and felt the cold air coming out of the BOV pipe. thanks for your time and help!