Running Rich, black smoke, did lots of searching. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

TTrx7Pete · 08-07-2008, 09:05 PM

Ok, I have a bit of a problem.

First the car:

97 240sx with an S14 SR20DET blacktop VTC.
Modifications:
New spark plugs
255lph Walbro Fuel Pump
GReddy FMIC
Intake
Full 3" exhaust.

Problem:

The car at idle belches black smoke. It smells of fuel and most definitely is because of the black smoke. I'm new to the Nissan scene, but I've been modifying rotaries for over 10 years. The car idles at 800rpm with about 10-11 vacuum. The car will rev past 2500 rpm while at a stop. While driving the car, it will rev freely but feels weak, due to the continued rich state. The engine only boosts about 5-6 psi while floored. I do not have a boost controller and I am only running the wastegate off of the intercooler piping.

If I unplug the MAF, the car revs up for a few seconds then sputters out and dies. The MAF voltages check out. The o2 voltages check out. The igniter chip voltages check out. All of the coil packs have the correct voltage as well. I also check continuity throughout all of the systems.

Next I performed a vacuum/boost leak check. I found a leak at the turbo inlet elbow, fixed it, and it did not solve the problem. I used a homemade pressure testing kit, as can be found on this forum and used a Ford dealership smoke kit, which pressurizes the system with smoke to find vacuum leaks.

All of the electrical connections are done properly with Ford/aero grade electrical connectors, no cheap butt connectors. Everything is shrink wrapped and neat. The MAF and o2 both have the correct shielded wire.

There are no other vacuum leaks, the MAF checks out, the Igniter checks out, o2 checks out, and the coil packs out.

Things I have yet to check:

Timing
Fuel Pressure

----------------------------

As I researched this problem, most Zilvians fail to finish the thread with how the problem was solved. Suggestions litter the threads but no resolution. I wanted some input to see what you guys think. Others have said get an FPR but most other members say you do not need an FPR when using the Walbro. This is really getting annoying and I'd like to enjoy the car.

Any help, suggestions, etc., are appreciated.

If any other information is needed, please let me know.

louisdaboois · 08-07-2008, 09:30 PM

i'd check ohms on the injectors, and make sure that they are sufficient. should read over 10hms for high impedence (which sr's use). my guess is that one or more of the injectors may be stuck open.

MangoDorifto · 08-07-2008, 09:42 PM

Check your connections at the ECU and dashboard connectors. Push down firmly but evenly on the ECU connector and make sure the 10mm bolt is snugged up. Also make sure the lever on the dashboard connector is in the locked position.

Has it always ran like this, or did it just happen? Are you running a wideband?

bmx22 · 08-07-2008, 09:46 PM

vac should be like 19, may be vac leak.

TTrx7Pete · 08-07-2008, 09:48 PM

Quote:

Originally Posted by MangoDorifto

Check your connections at the ECU and dashboard connectors. Push down firmly but evenly on the ECU connector and make sure the 10mm bolt is snugged up. Also make sure the lever on the dashboard connector is in the locked position.

Has it always ran like this, or did it just happen? Are you running a wideband?

The car has always ran like this since I got it first started. I completed the swap and it has been doing this ever since.

The ECU is snugged up and the M63/F4 plug is in the locked position.

I do not have a wideband o2.

I will check the ohms on the injectors.

TTrx7Pete · 08-07-2008, 09:49 PM

Quote:

Originally Posted by bmx22

vac should be like 19 may be vac leak

I've pressurized the system and there isn't a boost leak. I'm pretty sure the low vacuum is due to the car running rich and the car's inability to feed enough air into the chamber to compensate for the fuel.

koukimonster139 · 08-07-2008, 09:52 PM

sounds like timing....
maybe

do you have control over fuel pressure or a way to monitor it?

Z U L8R · 08-07-2008, 09:54 PM

put in a new coolant temp sensor (for the ecu aka 2 wire) out of a 92 sentra se-r (they came with sr20de and they're the same part) it's all of a $20 part

after you put that in with a very deep 19mm socket and teflon GOO (not teflon tape)
get a timing light and set the base timing to 15 degrees before top dead center (15 degrees advanced)

and that should take care of that

post back with the results once you're done with that.

MangoDorifto · 08-07-2008, 09:57 PM

Did you change the fuel pump out at the same time of the swap? Have you tried putting the stocker back in to see if it still runs rich?

TTrx7Pete · 08-07-2008, 09:57 PM

Quote:

Originally Posted by Z U L8R

put in a new coolant temp sensor (for the ecu aka 2 wire) out of a 92 sentra se-r (they came with sr20de and they're the same part) it's all of a $20 part

after you put that in with a very deep 19mm socket and teflon GOO (not teflon tape)
get a timing light and set the base timing to 15 degrees before top dead center (15 degrees advanced)

and that should take care of that

post back with the results once you're done with that.

Is it common for these temp sensors to fail because the engine has sat? Just curious because most of these imported engines purportedly have 30-50k miles on them. But I shall try that and see what happens.

Any other advice is greatly appreciated.

Z U L8R · 08-07-2008, 10:00 PM

yes, it is very common

in fact just about every swap we do that is one of the thing's replaced as well as the thermostat etc etc etc

when a coolant temp sensor fails it typically tells the ecu it's -20 to -40 degrees outside, so the ecu responds (like a choke on a cold lawn mower engine) by dumping fuel

Dave

Z U L8R · 08-07-2008, 10:07 PM

these motors are 20 years old.....i don't believe the 30-50k talk like it were written in stone any longer, and honestly how many importers drain the block?

sr's are luckier since they're an aluminum block but 90% of all rb's coolant passages have a ton of rust in em.

on sr swaps i leave it up to the customer but i always recommend it. on rb swaps you don't have a choice, you're getting a new thermostat and a new coolant temp sensor, and it'd be in your best interest to do the timing belt water pump as well. heh

gl man, keep me posted
Dave

TTrx7Pete · 08-08-2008, 08:03 AM

Quote:

Originally Posted by Z U L8R

put in a new coolant temp sensor (for the ecu aka 2 wire) out of a 92 sentra se-r (they came with sr20de and they're the same part) it's all of a $20 part

after you put that in with a very deep 19mm socket and teflon GOO (not teflon tape)
get a timing light and set the base timing to 15 degrees before top dead center (15 degrees advanced)

and that should take care of that

post back with the results once you're done with that.

Dave @ Lethal Injection Motorsports
770-343-9969

Do you know the Nissan part #? The dealership told me that there are 2 engine temp sensors and were wanting my VIN#. I figured they would be interchangeable but I just need to make sure before I special order the part.

Z U L8R · 08-08-2008, 11:12 AM

i don't know the nissan part number but you can google it. the wells part number is SU4115 (a brand that most part stores will have in stock)

if you want to get it from the dealership tell the guy it's the one on the left, the one with the 2 wires that's for the ecu, not the one with 1 blade on the right that's for your coolant guage, you want the one for your ecu.

Dave

TTrx7Pete · 08-08-2008, 11:51 AM

Quote:

Originally Posted by Z U L8R

i don't know the nissan part number but you can google it. the wells part number is SU4115 (a brand that most part stores will have in stock)

if you want to get it from the dealership tell the guy it's the one on the left, the one with the 2 wires that's for the ecu, not the one with 1 blade on the right that's for your coolant guage, you want the one for your ecu.

Dave

Yeah the dealership was saying that there are 2 different 2 wire coolant temp sensors. I'll basically have to look at mine and see which one of theirs I need. Until then I'm going to check out the timing next week.

0wn3r · 08-08-2008, 12:11 PM

Quote:

Originally Posted by TTrx7Pete

Until then I'm going to check out the timing next week.

Make sure you have the right MAF. The Zenki one plugs in but it will run very rich. (240sxmotoring.com has the part numbers listed in their SR Swap FAQ)

You should have already checked your timing too. Mine wasn't billowing smoke after I got the right MAF on, but my CAS was dirty as hell. Reset the timing, then my idle got weird and turns out the IACV needed to be cleaned.

Does it idle smoothly?

Also, like mentioned, the 19inHG is about where you should be (i'm typically around 18-22 when sitting at idle...depends if brake is pressed or not) It only goes to about 16 if I'm repeatedly pumping the brakes.

Z U L8R · 08-08-2008, 01:50 PM

just go to autozone or advanced auto parts and pick one up

Dave

TTrx7Pete · 08-08-2008, 06:55 PM

Quote:

Originally Posted by 0wn3r

Make sure you have the right MAF. The Zenki one plugs in but it will run very rich. (240sxmotoring.com has the part numbers listed in their SR Swap FAQ)

You should have already checked your timing too. Mine wasn't billowing smoke after I got the right MAF on, but my CAS was dirty as hell. Reset the timing, then my idle got weird and turns out the IACV needed to be cleaned.

Does it idle smoothly?

Also, like mentioned, the 19inHG is about where you should be (i'm typically around 18-22 when sitting at idle...depends if brake is pressed or not) It only goes to about 16 if I'm repeatedly pumping the brakes.

I don't understand what you are saying about the maf. I have a wc ecu with an oval plug hitachi nissan maf. This should mean I have a chuki harness and maf.

0wn3r · 08-11-2008, 08:21 AM

Quote:

Originally Posted by TTrx7Pete

I don't understand what you are saying about the maf. I have a wc ecu with an oval plug hitachi nissan maf. This should mean I have a chuki harness and maf.

Well I have an NA ecu and the zenki MAF was able to be plugged in to the kouki harness but it ran too rich. Turns out they gave me a Zenki MAF instead of a kouki MAF. I can't say off the top of my head whether or not it's a Hitachi though, sorry. (According to what is written below, it would seem as if they gave me a "Chuki" MAF....but unfortunately I think everyone's definition of zenki/chuki/kouki vary slightly)

Quote:

WC*= S14 (notchtop) MT5 - 94-96 Zenki Silvia or Chuki Silvia*

* = Red connector was used on Zenki Silvias, Black connector was used on Chuki Silvias. The only difference is in the MAF connector. Zenki's used a rectangle plug while Chukis used the same oval plug as the NA/NB ECU kouki motors.

Look to see whether the motor has fins on the head too.

Then check this page out: Part Numbers!

TTrx7Pete · 08-11-2008, 09:26 AM

Right, but Zenki's have a rectangular plug. Chuki and Kouki both had oval MAF plugs. The crossover year, Chuki, ran a WC Ecu with a "kouki-style" MAF.

The Kouki SR20 uses an NA ecu with an oval MAF plug...

How were you able to plug up an Oval connector to the Rectangular MAF? Or is this just some confusion on my part?

shmiddy · 08-11-2008, 10:00 AM

Quote:

Originally Posted by bmx22

vac should be like 19, may be vac leak.

+1 for you

vac seems kinda low....

check that out

TTrx7Pete · 08-11-2008, 10:20 AM

Quote:

Originally Posted by shmiddy

+1 for you

vac seems kinda low....

check that out

Read OP...

Already checked that. Pressurized and smoked the entire system. I will be doing my timing tonight after I get in from out of town.

blackej7 · 08-11-2008, 10:33 AM

Any codes?

0wn3r · 08-11-2008, 11:35 AM

Quote:

Originally Posted by TTrx7Pete

How were you able to plug up an Oval connector to the Rectangular MAF? Or is this just some confusion on my part?

I think just some confusion, I made a post elsewhere to try and clear up the chuki and zenki part numbers.

One thing I do know, they handed us a MAF with a rectangle plug when were were there, and it didn't line up. They shipped another one later that fit, but it was 22680-69F00, when I really needed the 22680-69F01. It fit and was still giving a signal but it wasn't right...different part number for a reason I guess.

All I'm saying is it might be worth checking. Who knows, it could be an injector or o-ring.

*njd07* · 08-11-2008, 11:57 AM

10 to 11 vac is very low...you must have a leak somewhere.

TTrx7Pete · 08-11-2008, 06:06 PM

Quote:

Originally Posted by 0wn3r

I think just some confusion, I made a post elsewhere to try and clear up the chuki and zenki part numbers.

One thing I do know, they handed us a MAF with a rectangle plug when were were there, and it didn't line up. They shipped another one later that fit, but it was 22680-69F00, when I really needed the 22680-69F01. It fit and was still giving a signal but it wasn't right...different part number for a reason I guess.

All I'm saying is it might be worth checking. Who knows, it could be an injector or o-ring.

Interesting... I actually have a 22680-69F01.

I checked the timing today and it was perfect. So that leads me to believe it is either the MAF if you are correct that the part numbers really make a difference, or an injector, o-ring, engine temp sensor, or somehow a magic vacuum leak.

To all posters suggesting a vacuum leak. It's been suggested. I have already smoked my system and pressurized it in an effort to find one. Thank you all for your help, but if you have any other suggestions besides Vacuum leak, please post.

0wn3r · 08-11-2008, 08:48 PM

Quote:

Originally Posted by TTrx7Pete

Interesting... I actually have a 22680-69F01.

I checked the timing today and it was perfect. So that leads me to believe it is either the MAF if you are correct that the part numbers really make a difference, or an injector, o-ring, engine temp sensor, or somehow a magic vacuum leak.

To all posters suggesting a vacuum leak. It's been suggested. I have already smoked my system and pressurized it in an effort to find one. Thank you all for your help, but if you have any other suggestions besides Vacuum leak, please post.

maybe borrow someone's F00 and test it out.

TTrx7Pete · 08-12-2008, 10:53 AM

Quote:

Originally Posted by 0wn3r

maybe borrow someone's F00 and test it out.

That will be easier said than done. I'm going to replace the ECU's coolant temp sensor and recheck for any vacuum leaks.

Erjay1 · 08-12-2008, 12:24 PM

Quick question since we are on this topic. Could a faulty CTS cause my idle to be ridiculously high in the mornings?? Or even if the car sits for maybe two or three hours my idle will shoot up pretty high until it warms up.

0wn3r · 08-13-2008, 09:29 AM

Quote:

That will be easier said than done. I'm going to replace the ECU's coolant temp sensor and recheck for any vacuum leaks.

I'm sure there's alot of XAT-swapped cars down there...shouldn't be too difficult, but def easier said than done haha.

Quote:

Originally Posted by Erjay1

Quick question since we are on this topic. Could a faulty CTS cause my idle to be ridiculously high in the mornings?? Or even if the car sits for maybe two or three hours my idle will shoot up pretty high until it warms up.

define ridiculously high (with a #).

08-07-2008, 09:05 PM	#1
TTrx7Pete Zilvia Member Join Date: Apr 2008 Location: Florida Age: 39 Posts: 179 Trader Rating: (0) Feedback Score: 0 reviews	Running Rich, black smoke, did lots of searching. Ok, I have a bit of a problem. First the car: 97 240sx with an S14 SR20DET blacktop VTC. Modifications: New spark plugs 255lph Walbro Fuel Pump GReddy FMIC Intake Full 3" exhaust. Problem: The car at idle belches black smoke. It smells of fuel and most definitely is because of the black smoke. I'm new to the Nissan scene, but I've been modifying rotaries for over 10 years. The car idles at 800rpm with about 10-11 vacuum. The car will rev past 2500 rpm while at a stop. While driving the car, it will rev freely but feels weak, due to the continued rich state. The engine only boosts about 5-6 psi while floored. I do not have a boost controller and I am only running the wastegate off of the intercooler piping. If I unplug the MAF, the car revs up for a few seconds then sputters out and dies. The MAF voltages check out. The o2 voltages check out. The igniter chip voltages check out. All of the coil packs have the correct voltage as well. I also check continuity throughout all of the systems. Next I performed a vacuum/boost leak check. I found a leak at the turbo inlet elbow, fixed it, and it did not solve the problem. I used a homemade pressure testing kit, as can be found on this forum and used a Ford dealership smoke kit, which pressurizes the system with smoke to find vacuum leaks. All of the electrical connections are done properly with Ford/aero grade electrical connectors, no cheap butt connectors. Everything is shrink wrapped and neat. The MAF and o2 both have the correct shielded wire. There are no other vacuum leaks, the MAF checks out, the Igniter checks out, o2 checks out, and the coil packs out. Things I have yet to check: Timing Fuel Pressure ---------------------------- As I researched this problem, most Zilvians fail to finish the thread with how the problem was solved. Suggestions litter the threads but no resolution. I wanted some input to see what you guys think. Others have said get an FPR but most other members say you do not need an FPR when using the Walbro. This is really getting annoying and I'd like to enjoy the car. Any help, suggestions, etc., are appreciated. If any other information is needed, please let me know. __________________ 1993 AW Mazda RX-7 1997 Nissan Silvia Last edited by TTrx7Pete; 08-07-2008 at 09:07 PM.. Reason: Edited while driving

08-07-2008, 09:46 PM	#4
bmx22 Leaky Injector Join Date: Feb 2005 Location: hawaii, Posts: 108 Trader Rating: (0) Feedback Score: 0 reviews	vac should be like 19, may be vac leak. Last edited by bmx22; 08-07-2008 at 10:21 PM..

08-07-2008, 09:52 PM	#7
koukimonster139 Zilvia FREAK! Join Date: Jan 2006 Location: Birmingham, AL Age: 34 Posts: 1,379 Trader Rating: (0) Feedback Score: 0 reviews	sounds like timing.... maybe do you have control over fuel pressure or a way to monitor it? __________________ ho ha ho chi chi

08-07-2008, 09:54 PM	#8
Z U L8R Zilvia FREAK! Join Date: Jan 2007 Location: Georgia Age: 39 Posts: 1,194 Trader Rating: (0) Feedback Score: 0 reviews	put in a new coolant temp sensor (for the ecu aka 2 wire) out of a 92 sentra se-r (they came with sr20de and they're the same part) it's all of a $20 part after you put that in with a very deep 19mm socket and teflon GOO (not teflon tape) get a timing light and set the base timing to 15 degrees before top dead center (15 degrees advanced) and that should take care of that post back with the results once you're done with that. __________________ RB25 280z GT30/76R 441hp/381tq [email protected]

08-07-2008, 10:00 PM	#11
Z U L8R Zilvia FREAK! Join Date: Jan 2007 Location: Georgia Age: 39 Posts: 1,194 Trader Rating: (0) Feedback Score: 0 reviews	yes, it is very common in fact just about every swap we do that is one of the thing's replaced as well as the thermostat etc etc etc when a coolant temp sensor fails it typically tells the ecu it's -20 to -40 degrees outside, so the ecu responds (like a choke on a cold lawn mower engine) by dumping fuel Dave __________________ RB25 280z GT30/76R 441hp/381tq [email protected]

08-07-2008, 09:30 PM	#2
louisdaboois Zilvia Addict Join Date: Dec 2006 Location: LA, CA Age: 32 Posts: 851 Trader Rating: (28) Feedback Score: 28 reviews	i'd check ohms on the injectors, and make sure that they are sufficient. should read over 10hms for high impedence (which sr's use). my guess is that one or more of the injectors may be stuck open.

08-07-2008, 09:42 PM	#3
MangoDorifto Leaky Injector Join Date: Oct 2005 Location: Oregon Posts: 113 Trader Rating: (8) Feedback Score: 8 reviews	Check your connections at the ECU and dashboard connectors. Push down firmly but evenly on the ECU connector and make sure the 10mm bolt is snugged up. Also make sure the lever on the dashboard connector is in the locked position. Has it always ran like this, or did it just happen? Are you running a wideband?

08-07-2008, 09:57 PM	#9
MangoDorifto Leaky Injector Join Date: Oct 2005 Location: Oregon Posts: 113 Trader Rating: (8) Feedback Score: 8 reviews	Did you change the fuel pump out at the same time of the swap? Have you tried putting the stocker back in to see if it still runs rich?

08-07-2008, 10:07 PM	#12
Z U L8R Zilvia FREAK! Join Date: Jan 2007 Location: Georgia Age: 39 Posts: 1,194 Trader Rating: (0) Feedback Score: 0 reviews	these motors are 20 years old.....i don't believe the 30-50k talk like it were written in stone any longer, and honestly how many importers drain the block? sr's are luckier since they're an aluminum block but 90% of all rb's coolant passages have a ton of rust in em. on sr swaps i leave it up to the customer but i always recommend it. on rb swaps you don't have a choice, you're getting a new thermostat and a new coolant temp sensor, and it'd be in your best interest to do the timing belt water pump as well. heh gl man, keep me posted Dave __________________ RB25 280z GT30/76R 441hp/381tq [email protected]

08-08-2008, 11:12 AM	#14
Z U L8R Zilvia FREAK! Join Date: Jan 2007 Location: Georgia Age: 39 Posts: 1,194 Trader Rating: (0) Feedback Score: 0 reviews	i don't know the nissan part number but you can google it. the wells part number is SU4115 (a brand that most part stores will have in stock) if you want to get it from the dealership tell the guy it's the one on the left, the one with the 2 wires that's for the ecu, not the one with 1 blade on the right that's for your coolant guage, you want the one for your ecu. Dave __________________ RB25 280z GT30/76R 441hp/381tq [email protected]

08-08-2008, 01:50 PM	#17
Z U L8R Zilvia FREAK! Join Date: Jan 2007 Location: Georgia Age: 39 Posts: 1,194 Trader Rating: (0) Feedback Score: 0 reviews	just go to autozone or advanced auto parts and pick one up Dave __________________ RB25 280z GT30/76R 441hp/381tq [email protected]

08-11-2008, 09:26 AM	#20
TTrx7Pete Zilvia Member Join Date: Apr 2008 Location: Florida Age: 39 Posts: 179 Trader Rating: (0) Feedback Score: 0 reviews	Right, but Zenki's have a rectangular plug. Chuki and Kouki both had oval MAF plugs. The crossover year, Chuki, ran a WC Ecu with a "kouki-style" MAF. The Kouki SR20 uses an NA ecu with an oval MAF plug... How were you able to plug up an Oval connector to the Rectangular MAF? Or is this just some confusion on my part? __________________ 1993 AW Mazda RX-7 1997 Nissan Silvia

08-11-2008, 10:33 AM	#23
blackej7 Zilvia Junkie Join Date: Jul 2006 Location: Midwest Posts: 324 Trader Rating: (9) Feedback Score: 9 reviews	Any codes? __________________

08-11-2008, 11:57 AM	#25
njd07 Premium Member Join Date: Jan 2004 Location: canada Age: 35 Posts: 644 Trader Rating: (14) Feedback Score: 14 reviews	10 to 11 vac is very low...you must have a leak somewhere. __________________ s13 parts fs:#/f/showthread.php?t=193416 sr parts fs: #/f/showthread.php?t=193399 s14 parts fs:#/f/showthread.php?t=193420 180sx part out #/f/showthread.php?t=203711

08-12-2008, 12:24 PM	#29
Erjay1 Zilvia Junkie Join Date: Apr 2008 Location: Los Angeles Age: 35 Posts: 479 Trader Rating: (2) Feedback Score: 2 reviews	Quick question since we are on this topic. Could a faulty CTS cause my idle to be ridiculously high in the mornings?? Or even if the car sits for maybe two or three hours my idle will shoot up pretty high until it warms up.

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