Cylinder 3 & 5 misfire but no one knows why
02-15-2017, 09:56 PM
#1
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Join Date: Feb 2017
Posts: 10
Cylinder 3 & 5 misfire but no one knows why
I have a 1991 Nissan Maxima and it has a pretty nasty misfire. Cylinders 3 & 5 either never fire or fire at random times. I have taken it to many shops and they don't really know what the problem is. The coils and spark plugs are good. The one thing I don't understand is that the mechanics automatically decided it couldn't be injectors because its intermittent. Some said the ECU is bad and some said the cylinders were flooded.
The crazy thing is that when it is cold out (-10 degrees F) the car seems to run perfectly, but when the car warms up it starts to run like crap again.
It idles around 400-500 RPM when its in drive with my foot on the break. When in park it idles at 1100 RPM but never keeps a steady rpm. Also, when accelerating through first and second gear it feels like there is absolutely no low end power but as soon as it hits 3k it just takes off. Me and my buddies have been calling it hidden V-Tec lol.
I need help with this because I love my car and want to start building it but I can't work on it if I don't know how to fix the current problem.
The crazy thing is that when it is cold out (-10 degrees F) the car seems to run perfectly, but when the car warms up it starts to run like crap again.
It idles around 400-500 RPM when its in drive with my foot on the break. When in park it idles at 1100 RPM but never keeps a steady rpm. Also, when accelerating through first and second gear it feels like there is absolutely no low end power but as soon as it hits 3k it just takes off. Me and my buddies have been calling it hidden V-Tec lol.
I need help with this because I love my car and want to start building it but I can't work on it if I don't know how to fix the current problem.
02-16-2017, 10:41 AM
#2
If it's a 91 then it's a vg engine and just has one ignition coil and distributor and wires. It could very well be injectors. If you have a multi meter you could test them and should be between 10-14ohm. Might be a good idea to check them if the shop didnt. Also a good tune up ie cap and rotor plugs and wires and filters and check over your vacuumed lines for cracking or dry rot might not be a bad idea either.
02-16-2017, 11:46 AM
#3
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If it's a 91 then it's a vg engine and just has one ignition coil and distributor and wires. It could very well be injectors. If you have a multi meter you could test them and should be between 10-14ohm. Might be a good idea to check them if the shop didnt. Also a good tune up ie cap and rotor plugs and wires and filters and check over your vacuumed lines for cracking or dry rot might not be a bad idea either.
02-16-2017, 02:11 PM
#4
he means your VG30E has a distrubutor and 6 spark plug wires vs the 92-94 se which has the VE30DE engine with direct coil pack x 6 and no distributor,its like the modern version of your VG30E
testing injectors look very diff BUT you can test them at the harness connection under the s bent plastic air intake tube
(its in the factory service manual but mines gone from my moving sale)
and a few you can access and test at the injector
pulling the big metal air intake and looking/replacing vacum hoses and then having direct test access to the injector itselfs prongs and ohm test them and hope they are all under 14ohms if i remember right,then go harvest some good testing used ones or buy new
id rather get used factory parts than cheap imported junk parts anymore
you mention cold stumble,so also test your O2 sensor since it starts feedback whether correct or broken AFTER the engine is up to operating temp
like alot of sensors on the max,unplug it and test drive(ecu will use its same preset value it uses until engines up to temp,it if it dont have stumble when warmed up when the suspect sensors unplugged try a new or good known used sensor
why not just leave o2 unplugged altogether?bad mpg(same reason they say short trips are the worst mpg)(o2 sensors on open loop)
When the engine is running in closed loop, it is using the A/F signal from the 02 sensor to regulate the mixture. There is a feedback "loop" between the sensor and ECU so the ECU continuously makes adjustments based on the 02 data.
In open loop(ALL COLD ENGINE SHORT TRIPS) the 02 sensor isn't used and the ECU sets mixture based on stored maps and other sensors (coolant temp etc).
Usually open loop is used on initial start and during warmup, until the 02 sensor reaches its operating temperature and produces a signal and the engine also reaches its operating temp, at which point the switch to closed loop takes place.
Under heavy acceleration(FULL THROTTLE) the system will generally go open loop
(FUELS FLOWING HIGHEST RATE) (some MAKES/MODELS vehicles may remain in closed loop).
testing injectors look very diff BUT you can test them at the harness connection under the s bent plastic air intake tube
(its in the factory service manual but mines gone from my moving sale)
and a few you can access and test at the injector
pulling the big metal air intake and looking/replacing vacum hoses and then having direct test access to the injector itselfs prongs and ohm test them and hope they are all under 14ohms if i remember right,then go harvest some good testing used ones or buy new
id rather get used factory parts than cheap imported junk parts anymore
you mention cold stumble,so also test your O2 sensor since it starts feedback whether correct or broken AFTER the engine is up to operating temp
like alot of sensors on the max,unplug it and test drive(ecu will use its same preset value it uses until engines up to temp,it if it dont have stumble when warmed up when the suspect sensors unplugged try a new or good known used sensor
why not just leave o2 unplugged altogether?bad mpg(same reason they say short trips are the worst mpg)(o2 sensors on open loop)
When the engine is running in closed loop, it is using the A/F signal from the 02 sensor to regulate the mixture. There is a feedback "loop" between the sensor and ECU so the ECU continuously makes adjustments based on the 02 data.
In open loop(ALL COLD ENGINE SHORT TRIPS) the 02 sensor isn't used and the ECU sets mixture based on stored maps and other sensors (coolant temp etc).
Usually open loop is used on initial start and during warmup, until the 02 sensor reaches its operating temperature and produces a signal and the engine also reaches its operating temp, at which point the switch to closed loop takes place.
Under heavy acceleration(FULL THROTTLE) the system will generally go open loop
(FUELS FLOWING HIGHEST RATE) (some MAKES/MODELS vehicles may remain in closed loop).
02-17-2017, 12:03 AM
#6
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Thread Starter
Join Date: Feb 2017
Posts: 10
he means your VG30E has a distrubutor and 6 spark plug wires vs the 92-94 se which has the VE30DE engine with direct coil pack x 6 and no distributor,its like the modern version of your VG30E
testing injectors look very diff BUT you can test them at the harness connection under the s bent plastic air intake tube
(its in the factory service manual but mines gone from my moving sale)
and a few you can access and test at the injector
pulling the big metal air intake and looking/replacing vacum hoses and then having direct test access to the injector itselfs prongs and ohm test them and hope they are all under 14ohms if i remember right,then go harvest some good testing used ones or buy new
id rather get used factory parts than cheap imported junk parts anymore
you mention cold stumble,so also test your O2 sensor since it starts feedback whether correct or broken AFTER the engine is up to operating temp
like alot of sensors on the max,unplug it and test drive(ecu will use its same preset value it uses until engines up to temp,it if it dont have stumble when warmed up when the suspect sensors unplugged try a new or good known used sensor
why not just leave o2 unplugged altogether?bad mpg(same reason they say short trips are the worst mpg)(o2 sensors on open loop)
When the engine is running in closed loop, it is using the A/F signal from the 02 sensor to regulate the mixture. There is a feedback "loop" between the sensor and ECU so the ECU continuously makes adjustments based on the 02 data.
In open loop(ALL COLD ENGINE SHORT TRIPS) the 02 sensor isn't used and the ECU sets mixture based on stored maps and other sensors (coolant temp etc).
Usually open loop is used on initial start and during warmup, until the 02 sensor reaches its operating temperature and produces a signal and the engine also reaches its operating temp, at which point the switch to closed loop takes place.
Under heavy acceleration(FULL THROTTLE) the system will generally go open loop
(FUELS FLOWING HIGHEST RATE) (some MAKES/MODELS vehicles may remain in closed loop).
testing injectors look very diff BUT you can test them at the harness connection under the s bent plastic air intake tube
(its in the factory service manual but mines gone from my moving sale)
and a few you can access and test at the injector
pulling the big metal air intake and looking/replacing vacum hoses and then having direct test access to the injector itselfs prongs and ohm test them and hope they are all under 14ohms if i remember right,then go harvest some good testing used ones or buy new
id rather get used factory parts than cheap imported junk parts anymore
you mention cold stumble,so also test your O2 sensor since it starts feedback whether correct or broken AFTER the engine is up to operating temp
like alot of sensors on the max,unplug it and test drive(ecu will use its same preset value it uses until engines up to temp,it if it dont have stumble when warmed up when the suspect sensors unplugged try a new or good known used sensor
why not just leave o2 unplugged altogether?bad mpg(same reason they say short trips are the worst mpg)(o2 sensors on open loop)
When the engine is running in closed loop, it is using the A/F signal from the 02 sensor to regulate the mixture. There is a feedback "loop" between the sensor and ECU so the ECU continuously makes adjustments based on the 02 data.
In open loop(ALL COLD ENGINE SHORT TRIPS) the 02 sensor isn't used and the ECU sets mixture based on stored maps and other sensors (coolant temp etc).
Usually open loop is used on initial start and during warmup, until the 02 sensor reaches its operating temperature and produces a signal and the engine also reaches its operating temp, at which point the switch to closed loop takes place.
Under heavy acceleration(FULL THROTTLE) the system will generally go open loop
(FUELS FLOWING HIGHEST RATE) (some MAKES/MODELS vehicles may remain in closed loop).
02-17-2017, 06:53 AM
#7
Thanks maximagician for the clarification. These old cars don't throw codes too easily. Only if there's a short or open circuit.. if the shop said the plugs and wires were good then it wouldn't hurt to ohm test the injectors. A bad maf ( mass air flow) sensor could be an issue aswell if it's intermittent. You may want to try unplugging it and plugging it back in to make sure there's a good connection and not too much corrosion on the harness.
02-18-2017, 05:14 AM
#8
with the car being so old with unknown history it could be any number of things. until you figure out how to tell if a part is bad or not you/we are all guessing at what's wrong with the car.
if you're relying on a code then you're better off with an OBDII car.
also most shops won't know how to handle these old cars unless you have someone who's very knowledgeable with older nissans.
if you're relying on a code then you're better off with an OBDII car.
also most shops won't know how to handle these old cars unless you have someone who's very knowledgeable with older nissans.
02-19-2017, 09:51 PM
#9
Senior Member
Join Date: May 2004
Location: los Angeles, Ca.
Posts: 315
I had the same issue I'm my 90 max. Random missfire at the same cylinders 5 and 3 .. the injectors fired fine when tested and would work fine for a while then starts acting up . I'm one of the missfire events I pulled over and started pulling injector plugs and wouldn't you know it . When pulling 5 there was no change. So I replaced #5 and problem solved till 3 started to act up more often and that's when I replaced all of them and problem solved . The injectors might tiger when testing with external voltage but won't work all the time when triggered by the ECU as resistance builds up over time (corrosion). Rockauto was my friend that day . Got each injector for 55 $