J30 Hesitation

[ADiamond75]

Ok guys ... I've read in some of the articles but haven't quite found what I am looking for.

Let me start by explaining that I have 2 j30's that are currently giving me problems ... they are both similar in that it is hesitation, but the symptoms are differnt.

J30-1

This is a 97 J30 with 178,000 miles. It has been maintained through inifinity up too about 6 months ago. Every service has been done and the car just had a new transmission put in it along with new timing belt, front seal and rear seal.

The problem - when the car is warm, and intermitantly, the car will have heavy hesitation between the RPM range of 1000 - 2300. I can practically floor it (just above the spot that forces it to drop into the lowest gear possible) and the car will not accelerate. Sometimes the problem goes away if the car is turned off and then restarted. Sometimes it only shows up if the car is turned off and then restarted within 45 minutes. When the transmission guys pulled the transmission they got a Knock code from the ECU but the check engine light has never come on.

Could this be the crank angle position sensor?the knock sensor ?

Ideas?

J30-2

OK, this is an early model 93 J30 (production year 92) with HICAS and 123,000 miles. The car was not maintained well before I got my hands on it. I haven't had it that long and have put a new transmission in it as well.

The problem - If the car is driven for more than 30 minutes or is driven agressivly (fast accelerations) for a short while it will develope a missfire and has hesitation. Sometimes pulling over and restarting the car causes it to go away, other times it does not. It doesn't gogaway if the car has been driven for an hour or more and will shake violently from the missfire on a load or any attempt to accelerate.

Bad injector? Bad coilpack?

Ideas?

For clarity, if responding please refer to J30-1 or J30-2

[95-J30tt]

for the J30-1, a knock code means a knock sensor, those are a pain to change with the engine in the car, you can relocate the sensor, but i dont personal experiance with that......

by the way, what kind of gas are you using......

for J30-2, ohm the injectors, remove each connector with the engine off and preferably warm, set the multimeter to the lowest ohm setting, place the probes to the injector pins, and mesure the resistance across, it should be 10-14 ohm....

to test the coil packs (symptoms can be either a coil pack or an injector), turn on the engine, and wait untill it warms up a little, remove the coil connectors one at a time, and see if any of them dont effect the idle (when removing a working coil the idle should drop)

i hope this helps, keep us posted

[ADiamond75]

for the J30-1, a knock code means a knock sensor, those are a pain to change with the engine in the car, you can relocate the sensor, but i dont personal experiance with that......

by the way, what kind of gas are you using......

for J30-2, ohm the injectors, remove each connector with the engine off and preferably warm, set the multimeter to the lowest ohm setting, place the probes to the injector pins, and mesure the resistance across, it should be 10-14 ohm....

to test the coil packs (symptoms can be either a coil pack or an injector), turn on the engine, and wait untill it warms up a little, remove the coil connectors one at a time, and see if any of them dont effect the idle (when removing a working coil the idle should drop)

i hope this helps, keep us posted

Thanks for the info. Will try the the tests on J30-2.

Both have run 93 octane or better since in my possesion.

J30-1 The 97 was new when bought so it has always run 93 or better octane. Could something else be causing the hesitation? The knock sensor never causes the check engine light to come on.

[95-J30tt]

i would say it is a knock sensor, they are a common problem with these engine (gives the symptoms that you mensioned) and the TT version of the VG30DE (uses the same knock sensor), i'm not sure if the check engine light would come on when a faulty knock sensor is detected, i know that this sounds strange, but you will be surprised to know how many models dont translate the detonation to a check engine light.....

do you have any strange color smoke exiting the muffler??

[ADiamond75]

i would say it is a knock sensor, they are a common problem with these engine (gives the symptoms that you mensioned) and the TT version of the VG30DE (uses the same knock sensor), i'm not sure if the check engine light would come on when a faulty knock sensor is detected, i know that this sounds strange, but you will be surprised to know how many models dont translate the detonation to a check engine light.....

do you have any strange color smoke exiting the muffler??

Nope, no strange colors at the exhaust

[ADiamond75]

OK .... I'm getting pissed at this car now. I ran the diagnostic for the Crank Sensor and it was fine, I ran the ECM self diagnostic and got Knock and MAF codes.... I swapped for a known good MAF and the problem is still there. I have been told that a bad MAF would also have caused a Knock code ...

Ok, heres what the car is doing as of now. For slow accelrations the car bogs BAD below 3000 rpms. And occasionally will have absolutly NO power for 10-15 seconds even with the accelerator fully depressed.

Here is the strange part. n If I drive the car hard the problem isn't as bad, in otherowords, several fast accelerations over and over again will cause the problem to happen at a minimum. And another thing that is strange is the car almost never has it's fully power, but every once in awhile when I stomp on the gas the car really gets up and goes.

WTF?!?!?!?! Someone point me in the right direction who has been down this road before

[Tribal_Addict]

what you just explained is the exact same thing that is going on with my J it started doing it about 3 day's ago but b4 that it ran great i have done nothing to it besides fill it up with the same gas that it has been running good on. This problem just poped up out of knowhere and i cant find the problem, but im having someone come take a look at it if he fix's it ill post what the problem was and how it was fixed if you still dont have a answer.

[95-J30tt]

ohm your injectors.... with the engine off (doesnt matter if it is cold or hot), take out each injector plug one by one, and test the injector terminals with a multimeter, it should read between 10-14 OHM, if not then that specific injector is bad.....

if they all check out, then do a power balance test.... turn on your engine, and while it is running at near operating temperature, take out one coil contact at a time, the RPM should drop slightly every time you remove a coil connector.... if one of the coils dont cause this issue, then that is the cylinder that you should do further tests on......

also refer to the FSM to check the fuel pump.....

i know that this might sound really stupid, and not important, but you will never belive what a vacuum leak does to your idle and acceleration (overall engine performance), it would cause it to sputter and maybe run rich or lean.... check for that also, from the big 2.5" pipes that run into your throttle, to the small hoses that run to the fuel regularot.....

the main thing to check for is spark and fuel....... i hope that this helps, good luck

[ADiamond75]

I would check the plugs or coil pack or the injectors expect it is not a miss ... even a slight miss ... the engine is stable does not shake or anything. It is a complete loss of power overall, not on any one cylinder. I Ohmed out the Knock sensor and it was bad ... so I bypassed it using the method mentioned in several other threads ... the car now doesn't lose complete power but still is super slugish. I will be setting the timing tommorrow and then go drive it to see if this helps any.... My guess is some other sensor is dead as well.

[Tribal_Addict]

waiting on Dale to come check out the car i turned the engine on and found that when i removed the cole paks on the 5th and 6th cylinders nothing happens the engine keeps runing with no sign of change as if it did not have 6 cylinders but they are giving spark i dont have the right tools until Dale comes over to check anything else but was woundering

[ADiamond75]

waiting on Dale to come check out the car i turned the engine on and found that when i removed the cole paks on the 5th and 6th cylinders nothing happens the engine keeps runing with no sign of change as if it did not have 6 cylinders but they are giving spark i dont have the right tools until Dale comes over to check anything else but was woundering

Is it running rough?

[April5112]

Weird that you mention this about your car..... The same week your car started having these problems is the same week my 1998 Maxima started having the same problems as yours. I have my car in the shop today and the mechanic told me that it is for sure the knock sensor. I wonder if you can keep driving the car with that out without any future problems other than gas mileage? I am lost as to what to do now. I was told by another mechanic that because these sensors are known to go out on these models that they have found a way to bypass this sensor instead of fixing it. Is this true?

[pbuddha]

I had this same intermittent problem w. my 93 J30 -- I dunno if it showed a knock code, but def MAF. Turned out to be the Mass Airflow Sensor had gone bad. It also started messing up the oxygen sensors... but not to the point they needed replacement. maybe try another one or check out the o2 sensors...

[DominickJ30]

Ok first thing, DO NOT remove the coil plugs while the car is running, you could really mess some stuff up like that.

Second, I would start with a major tune up on each car before you can diagnose any further problem. You would be amazed at the codes and symptoms a car can show when engine conditions arent optimal.

I would start with a seafoam treatment, change the air filter, clean the maf sensor, change the spark plugs, put dielectric grease on the coil pack boots, clean connecectors on the maf, tps, cas, clean the throttle bodies real good, clean the batt terminals, check the idle control valve and clean if neccessary, check pcv valve, check the egr and clean if neccessary, change the oil.

[J30T_]

I am having the same problem with my j30t ....I just bought it....and when i drive it shakes, idles, and doesnt have as much power as it should, it also sounds like a race car when I hit the gas, what is that????????

[driverdriver]

I am having the same problem with my j30t ....I just bought it....and when i drive it shakes, idles, and doesnt have as much power as it should, it also sounds like a race car when I hit the gas, what is that????????

Sounds like one of two things(its possible it could be both):

(1.) bad ignition coil(2.) fuel injector failure

Both are common due to age of vehicle.

[gotgarth]

hesitation with my m30. after racing across a bridge, the next day i got hesitation problems 1000-1900rpms. egrs ok, pressure ok, throttle sensor ok. it wasnt until i adjusted the distributor until i finally got some relief. i don't know if j30's have distributors, but if you can picture inside the distributor: the cap has metal contacts about 1/4in in length. and the center rotor's metal contact is about 1in in length. it looks to me the car's computer is designed to run at a preset angle. m30 is 15 +/- 2 degrees. so no matter how you turn the distributor (which is designed to change the angle) the car's setting just uses more of that 1inch rotor to contact the 1/4in cap connection. my rotor was burned all along the 1inch length. so when i adjusted the old burned out rotor cap(by turning the distributor) the car was running good again, but i could feel it start to hesitate again. so i put a new cap and rotor and tried a short run. runs ok, slight slight hesitation at 1400 but not sure until tomorrows run to work. another thing, i couldn't find which mark on my crankshaft is 15deg. there's 1 red and 6 others to the right of it. car originally set to the red mark. when first hesitation began i put it to the 3rd mark and ran ok. now with new cap and rotor i put it back to the first red mark because it idles a little more smoothly. i also replaced spark plugs and wires, but these were all things i was trying before i finally got to the distributor which was the only thing that helped. p.s. use a timing light when working with the distributor though. but let us know b/c i never know if this will pop up again.

[gotgarth]

gotgarth: check myself. didn't run well using first timing (red) mark. same hesitation. put to fourth mark and car running good. fourth mark = third mark after the (first) red mark.

[gr8scott72]

gotgarth: check myself. didn't run well using first timing (red) mark. same hesitation. put to fourth mark and car running good. fourth mark = third mark after the (first) red mark.

J's have coil packs not distributors.