injector leak (code 45). knock sensor(code 34)

[mike7401]

Still waiting on parts from Scotdale Infiniti. The Q no longer shuts off.

[silver2k2]

Did you end up fixing your problem?

I ohmed my injectors and they all came back the same 15-16 ohm

I need to ohm the knock sensors when I get home

[Q45tech]

OEM injector are all exactly the same [which of course varies with temperature of the internal copper coil].

15-16 ohms tells me you have an inaccurate ohmeter which probably need a new internal battery............to read the correct 12-13 ohms at 77F.

I get upset if there is a variance of 0.2 ohms from 12.4 ohms.

Everything here must be presented with a decimal point [or two] if we are to resolve problems!!!!!!!!!!!!!!!!!!!!!!!!

[silver2k2]

I ohmed my knock sensors and got 550 for each. Now I am really confused. I will replace the battery and re ohm. This was on a hot engine

[Q45tech]

550,000 ohms is in the range of correct KS value [also depending on temperature and ohm meter battery].

In my first electronics course [1963] we spent an entire week learning how to use a volt-ohm meter. Measuring milliohms, ohms, kiloohms, megaohms.

Often the decimal points and multipliers are confused by the novice.

[Q451990]

Many multimeters have "auto range" features. Yours is probably showing a KOhms on the screen somewhere. The good news is that your knock sensors are probably OK.

Being able to see the ECU history with Consult or a laptop with the correct interface is even better, since you're able to see if they passed the ECU's check for a long history of startups. The ECU will actually tell you if they failed the test 18 cranks ago...so you can get an idea if you're developing an intermittant problem.

Heath

[silver2k2]

I ohmed my knock sensors and got 550 for each. Now I am really confused. I will replace the battery and re ohm. This was on a hot engine

[silver2k2]

Many multimeters have "auto range" features. Yours is probably showing a KOhms on the screen somewhere. The good news is that your knock sensors are probably OK.

Being able to see the ECU history with Consult or a laptop with the correct interface is even better, since you're able to see if they passed the ECU's check for a long history of startups. The ECU will actually tell you if they failed the test 18 cranks ago...so you can get an idea if you're developing an intermittant problem.

Heath

I have the laptop consult, It does seem intermittant.

[silkysmoothyjud]

The longer your one way trip, the more likely the CEL will come on from bad KS; at least in my case. Acceleration is random at best, but the Q will almost always fall flat on its face (both of my ks were totally cracked, but I could not tell until I took em out) during WOT and it will occasionally tease you with it's true acceleration with bad KS....

[silver2k2]

It hasnt came back on I drive 25 miles to work each way. It is probably the the KS. I am going to check them with the engine hot after the drive home today

[Q45denver]

So, is there any way to disable the KS's? I do have the upgraded NICO ecu in both my Q's but I don't know how that effects these bad boys?

[Infinitiguy19]

So, is there any way to disable the KS's?

Why on Earth would you want to do that?

The Knock Sensors are like a saftey net incase you get bad gasoline. They prevent the engine from knocking and destroying its self.

Are you wondering how to disable them because you don't want to replace them?

[Q45denver]

I'm getting some intermittent hesitation at WOT on the '95. The engine did overheat a little due to low coolant (leaky water pump) awhile back. Disabling the KS's would take another factor out of the equation. Not sure I would run it w/o the the KS's very long or with bad gas but an on/off switch would be nice for testing purposes. I seem to recall that one of the JWT or NICO programs disabled the KS's? Personally I have never noted any engine knocking but I may just be insensitive to the noise.

[mtzgr777]

Disabling the KS's would take another factor out of the equation. Not sure I would run it w/o the the KS's very long or with bad gas but an on/off switch would be nice for testing purposes. I seem to recall that one of the JWT or NICO programs disabled the KS's? Personally I have never noted any engine knocking but I may just be insensitive to the noise.

Same boat as you man. If there really is some sort of program to disable the KS I would definitely be interested.

[mtzgr777]

On the 95Q you may have to turn the ignition to the ON position to get a reading. If you clear the codes does the KS code come back right away?

If both KS were dead it would affect your acceleration. If only one is dead you won't notice it. If for some reason you can't get a reading from the KS harness clear the ECU codes and if the KS code doesn't come back immediately they're fine.

If only one KS is defective you won't notice it? Can anyone verify this? I ask because my acceleration seems to be very slow and I only have 1 bad knock sensor. If that's the case, then it may be my fuel pump and or MAF sensor. And for the record, the KS code came after I filled it up with a tank full of gas (when I bought it, after it was sitting for a couple months) then I got it turned off and it hasn't come back since, even after 1300 miles.....any ideas?

[silkysmoothyjud]

I have a NICO ECU and I have been running in stage III (I didnt know it) for about 6 months (stage III turns off ks and o2 sensors). I did have some spark plug fouling over the winter months that I now attribute to the stage III. I use QT gas ONLY, as per Q45 tech.I had pulled my NICO ECU while trying to diagnose an injector failure and checked it for codes. I ran OEM for about three months but that is a different story. Bottom line, outside of the fouled plugs in the winter; I have no damage whatsoever running w/o ks. I drove my Q like I stole it for a minute until I got caught doing 110 in a 55.....

If one is bad, replace them both and dont forget to do the harness, not a hard job, just tedious. If you have any questions, just ask, but REPLACE THOSE PLENUM GASKETS unless you wanna play find the smell.....

The fuel pump will have a noticeable hum (swarm of angry bees) comming from the trunk when its bad. Bad MAF will cause idle fluctuation: It may cause the car to die at random.

I just recently had a "misfire" like vibration in Niqole at idle and during light acceleration when cold, then she wouldn't start. I cleaned the battery terminals, and all fixed, silky perfect smooth again. Those gremlins come out when the battery has a bad connection....

Modified by silkysmoothyjud at 7:50 PM 9/22/2009
Modified by silkysmoothyjud at 7:55 PM 9/22/2009

[mtzgr777]

The reason I want to disable ks if because my Q is DEAD SLOW up a hill once warmed up. Sometimes I don't think I'm going to make it. Besides that, she runs like a dream. Is it difficult to install a new ECU? I know there are posts on this, but is it quicker to do than actually replacing the ks themselves?

[silkysmoothyjud]

Its the easiest upgrade there is, but you have a 96, I doubt Wes can help you with that, but shoot him an email.

It might be your cats if it is dying going up a hill...

[Infinitiguy19]

1994-1995 ECU's are hard to do

1996+ ECU's are near impossible/not worth doing.

Better off dropping a 1990 VH in there with a 5 speed.

[silkysmoothyjud]

I was talking about the install of the ECU itself. That program is bad a**, well worth the money....

[mtzgr777]

I was going through the list of things I've replaced and things I have yet to replace, and I forgot to replace one simple thing......the fuel filter. Do you think this could possible be causing my problems going up a hill once the engine has warmed up? Also, do auto parts stores such as NAPA, Advanced Auto Parts, Auto Zone etc.. usually have these in stock.....or are they special ordered because this isn't a very common car? I'd like to replace it as early as tomorrow.

[silkysmoothyjud]

Its a good start, you already did the air filter, but that symptom sounds like cats. My fuel filter was bad when I first got mine. It would die sometimes, black smoke sometimes.You can get a filter at napa or wherever, I dont think non oem would matter there...would it? Mine is about due again in about 5k please advise...

[mtzgr777]

It's not really the fact that just hills are affecting it....It's more of a problem that once the engine warms up, its slow off the start. In other words, if I were going 45 MPH and then go up a hill, I'd be fine. If I were to be stuck at a light at the bottom of a hill and try to work my way up from a dead stop....it goes about 15-20MPH with the pedal to the floor! (It's even worse with the AC on.) In a similar situation; If the engine had just started up and was still "cold" it would climb like a bat outta' hell up that hill......strange.

[silkysmoothyjud]

you have a different q than I do, performance change with temp change is eather ks, the injectors, the injectors or the injectors. Those dam injectors on this car are its downfall.... Almost every prob I had was injector related. A bad injector will cause knock and the ks will protect your motor, retard your timing and cause crappy performance, but if you know your ks is bad, there ya go...

Modified by silkysmoothyjud at 5:14 PM 9/27/2009
Modified by silkysmoothyjud at 5:15 PM 9/27/2009

[mike7401]

Sorry been away for a while I did not due the knock sensors yet, have the whole kit from scotdale. The Q doesnt turn off anymore but does not feel quick as it should. Will try to due soon I know the #1 injector is omhing at 15.24 others are fine . Maybe its the injector but no check engine light, only code that still comes up is knock sensor. And abs trac light comes on sometimes.

[Q45tech]

Important to research how the ecu detects a fault and then sets a code.

For example KS STATUS is measured [via a convoluted resistance measurement] by applying a voltage and sensing drop as the engine is cranked.............not while driving. It may take a few minutes to set code flag depending on how busy ecu is doing engine management.

The 94 and later have faster and more powerful microprocessors so they can do things faster and simultaneously.

The KS circuitry can advance the base + preprogrammed advance vs rpm by +3 or any increment DOWN to -10.

The real way to see what's happening is to data log advance under WOT from 3,000> 6900 in first gear.

The worst case knock condition occurs around torque peak rpm or as the ecu advance up to 6 degrees from there up to redline.

Sudden high load [in high year] rattle [2000 rpm] is from ecu not reducing cruise advance [40 degrees] to 20 degrees [for acceleration] FAST ENOUGH.Once knock starts it is very hard to stop and you must grossly over exceed the amount of reduction in advance.

The quality of gasoline determines how much you have to back off EXTRA to extinguish it.

A course in algorithms and software is very useful if you hope to deal with ecu.

[silver2k2]

Codes are back. Make me wonder if it is gas I only get shell or chevron from busy stations. I need to track down the part numbers. IOS only has a hose kit on for the 90-93 on the site. I emailed but did not get a response. Hoses were done by PO at about 115k, I am at 164 now

Thinking I may just do the gaskets and save the hoses as they should be fine after 50k.

[silkysmoothyjud]

I agree. It dont get cold there does it? If it does, do the gas lines on the FPR and the rail. If it don't get cold, don't worry, those 15 year old gas lines wont stink like gas in warm weather. Members standards may vary...

[mike7401]

It turns out I have a bad connector for mass sensor car was running rough and shutting off, wiggle connector,started, ran fine when connector is wiggled turns off. Secured with some wire ties for now, so I guess I have to do ks jod along with mass sensor wire, called IOS said they sell in pices and has to be soldered( mass sensor wire and connector)

[3Q Jay]

Jared- hoses should be fine as long as you (PO) has not had an overheat. one exception might be the right angle hose on back of spider to power brake booster.I would however suggest using (replacing what you have with) genuine nissan fuel hose HOSE, FUEL NISS#A6440-N7686. I have found that this stuff does not require the progressive retightening plan that so many of us have suffered from when using 'generic' SAE R9 hose.