Need Help diagnosing - Infamous Nissan

Kevin Lewis · 11-04-2020, 12:56 PM

I have my 1993 Nissan Hardbody 2.4l and i am concerned with some popping noises coming from my exhaust. It only happens when i decelerate. I hear a popping noise that wasn't there before. If im cruising steady it doesn't do it so Im not sure if its a fuel issue or something else. im sort of new with this kind of stuff. Any help id appreciate it!

YEPEE · 11-04-2020, 03:16 PM

backfire? might see if there are any codes

LugNut1990 · 11-04-2020, 09:44 PM

Classic sign of a sticky exhaust valve. Or running too rich.

street_rulerr · 11-05-2020, 06:57 PM

how is this a "sticky exhaust valve" ive literally never heard that.

sometimes in the transition from accel to decl all the fuel doesnt get burned in the cylinder and it gets sent out the exhaust. little bit of "running rich" for a second and you get this feature.

you might be suddenly hearing it because your muffler is worn out or theres a small hole in the exhaust you just recently acquired etc. my point is, it might have been happening before but you just now noticed it.

89'HBV6 · 11-10-2020, 03:50 AM

Yea, check your exhaust. Do you have any leaks/holes? Is it loud(er than normal)? Improper back pressure, or............

Running rich. Search the forum for carb cleaning for your 2.4.

A few questions:
FI or carb'd?
How long have you owned?

nunya · 11-10-2020, 10:23 PM

testing, testing....

Kevin Lewis · 11-12-2020, 05:47 PM

89'HBV6
This one is FI, I bought the truck from one of my dad's friends and they had everything replaced. I bought it with no problems ive had it for about 6 months now.

89'HBV6 · 11-12-2020, 07:38 PM

OK, thanks for this.

Well, per your other thread you said the exhaust was replaced/worked on recently and that it's not stock. I would still wonder if there's too much, or not enuf, back pressure...... and being FI, I don't know about rejetting for a "non-stock" situation. (ol'school carb guy here and know a bit about tuning/jetting)

I would still suggest doing a basic carb cleaning. I'm still feeling it's a fuel/air issue.

update: OH, please stick with one thread on this issue, K? ......thanks man!

LugNut1990 · 11-12-2020, 11:01 PM

Air filter new/clean? I've had a new Chinese cheapo air filter have too much air pressure drop vs. OEM for one of my yard tool's engines.

(Upstream) O2 sensor functioning and newish?

street_rulerr · 11-13-2020, 12:05 AM

you know every car ive ever had gurgled and popped a little on decel. it was more a matter of could you hear it before or not.

and to 89'hb, there is no such thing as "rejetting" with a fuel injected motor. you need some kinda piggy back ecu if youre willing to only take fuel out (leaner) or a full on standalone if you want to add fuel back in. thres a few piggy backs that can add fuel in but, meh.

11-04-2020, 12:56 PM	#1
Kevin Lewis Kevin Lewis Join Date: Sep 2020 Location: Tennessee Posts: 6 Vehicle: Nissan D21 1993 Thanks: 12 Thanked 1 Time in 1 Post	Need Help diagnosing I have my 1993 Nissan Hardbody 2.4l and i am concerned with some popping noises coming from my exhaust. It only happens when i decelerate. I hear a popping noise that wasn't there before. If im cruising steady it doesn't do it so Im not sure if its a fuel issue or something else. im sort of new with this kind of stuff. Any help id appreciate it! Last edited by Kevin Lewis; 11-04-2020 at 06:42 PM.

11-04-2020, 09:44 PM	#3
LugNut1990 Join Date: Jul 2015 Location: N.E. Kansas Posts: 681 Vehicle: 1990 Nissan Hardbody Thanks: 0 Thanked 88 Times in 77 Posts	Classic sign of a sticky exhaust valve. Or running too rich. __________________ Original owner 1990 Nissan Hardbody, Aztec Red Standard cab, 4x4, KA24E, 5-speed Intentionally near-stock Mods: Second OEM horn, stereo/speakers/sub, mud and snow tires, HD trailer hitch (cat 3+), liquid bed liner, G1W dashcam Definitely not for sale!

11-12-2020, 11:01 PM	#9
LugNut1990 Join Date: Jul 2015 Location: N.E. Kansas Posts: 681 Vehicle: 1990 Nissan Hardbody Thanks: 0 Thanked 88 Times in 77 Posts	Air filter new/clean? I've had a new Chinese cheapo air filter have too much air pressure drop vs. OEM for one of my yard tool's engines. (Upstream) O2 sensor functioning and newish? __________________ Original owner 1990 Nissan Hardbody, Aztec Red Standard cab, 4x4, KA24E, 5-speed Intentionally near-stock Mods: Second OEM horn, stereo/speakers/sub, mud and snow tires, HD trailer hitch (cat 3+), liquid bed liner, G1W dashcam Definitely not for sale!

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11-04-2020, 03:16 PM	#2
YEPEE Join Date: Mar 2013 Location: Phoenix Posts: 1,831 Vehicle: 86.5 HB,95 HB, 02 Sentra Spec-V Thanks: 264 Thanked 309 Times in 266 Posts	backfire? might see if there are any codes

11-05-2020, 06:57 PM	#4
street_rulerr Join Date: Nov 2015 Location: West Coast Posts: 2,267 Vehicle: 1996 4x4 5spd Thanks: 0 Thanked 201 Times in 190 Posts	how is this a "sticky exhaust valve" ive literally never heard that. sometimes in the transition from accel to decl all the fuel doesnt get burned in the cylinder and it gets sent out the exhaust. little bit of "running rich" for a second and you get this feature. you might be suddenly hearing it because your muffler is worn out or theres a small hole in the exhaust you just recently acquired etc. my point is, it might have been happening before but you just now noticed it.

11-10-2020, 03:50 AM	#5
89'HBV6 Ol'school Geek Join Date: Mar 2020 Location: Washington State Posts: 208 Vehicle: 89' D21 KingCab SE V6 5spd 2WD - 87' D21 KingCab SE V6 5spd 2WD Thanks: 237 Thanked 59 Times in 50 Posts	Yea, check your exhaust. Do you have any leaks/holes? Is it loud(er than normal)? Improper back pressure, or............ Running rich. Search the forum for carb cleaning for your 2.4. A few questions: FI or carb'd? How long have you owned?

11-10-2020, 10:23 PM	#6
nunya Join Date: Apr 2019 Location: Southeast Posts: 973 Vehicle: nissan d21 93 kingcab 2wd Thanks: 287 Thanked 217 Times in 180 Posts	testing, testing....

11-12-2020, 05:47 PM	#7
Kevin Lewis Kevin Lewis Join Date: Sep 2020 Location: Tennessee Posts: 6 Vehicle: Nissan D21 1993 Thanks: 12 Thanked 1 Time in 1 Post	89'HBV6 This one is FI, I bought the truck from one of my dad's friends and they had everything replaced. I bought it with no problems ive had it for about 6 months now.

11-12-2020, 07:38 PM	#8
89'HBV6 Ol'school Geek Join Date: Mar 2020 Location: Washington State Posts: 208 Vehicle: 89' D21 KingCab SE V6 5spd 2WD - 87' D21 KingCab SE V6 5spd 2WD Thanks: 237 Thanked 59 Times in 50 Posts	OK, thanks for this. Well, per your other thread you said the exhaust was replaced/worked on recently and that it's not stock. I would still wonder if there's too much, or not enuf, back pressure...... and being FI, I don't know about rejetting for a "non-stock" situation. (ol'school carb guy here and know a bit about tuning/jetting) I would still suggest doing a basic carb cleaning. I'm still feeling it's a fuel/air issue. update: OH, please stick with one thread on this issue, K? ......thanks man!

11-13-2020, 12:05 AM	#10
street_rulerr Join Date: Nov 2015 Location: West Coast Posts: 2,267 Vehicle: 1996 4x4 5spd Thanks: 0 Thanked 201 Times in 190 Posts	you know every car ive ever had gurgled and popped a little on decel. it was more a matter of could you hear it before or not. and to 89'hb, there is no such thing as "rejetting" with a fuel injected motor. you need some kinda piggy back ecu if youre willing to only take fuel out (leaner) or a full on standalone if you want to add fuel back in. thres a few piggy backs that can add fuel in but, meh.