1994 Infiniti Q45 injector ohms

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94Q45Beast
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I replaced my knock sensors and #8 injector recently but now im getting the same codes again with the same symptoms (code 34 and 51), I have 3 brand new oem injectors in hand ( got them for 70 bucks for all 3 + 1 "refurbished"), so I ohmed the injectors and im getting a reading of 7.54 ohms on all injectors. iv pulled off the plenum already, without throwing a fit. as of now i'm trying to take out #1 injector (its hard without stripping the screws holding it) and seeing if that would make any difference. and im getting 17 ohms for knock sensors. (the multimeter was set at 200k and 20k for injectors) what is going on?


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94Q45Beast
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anyone?

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I would try changing the battery in your meter or using a different meter. None of those readings sound right... failing injectors usually build resistance (especially when hot) before they eventually fail open. I'm assuming your new injectors test the same way... in the 7 ohm range?

Heath

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yes they tested 7 ohms, and I thought the multimeter got power from placing the positive red wire to the battery (if testing injectors), and the meter is brand new from home depot. I'll try my analog multimeter.

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ok, my analog multimeter didnt work, but i check again with the digital multimeter. exact readings =

Knock Sensors = 136.4 ohm and 162.8 ohm
injector #1 = 7.98 ohm
injector #2 = 8 ohm
injector #3 = 7.92 ohm
injector #4 = 7.92 ohm
injector #5 = 7.95 ohm
injector #6 = 7.95 ohm
injector #7 = 7.93 ohm
injector #8 = 7.92 ohm

I thought the analog should work also but I got no reading at all, here is the multimeter im using http://www.homedepot.com/p/Commercial-E ... er_reviews

Im gonna buy another one and not cheap out on it.

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94Q45Beast
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sorry, the order for the injector reading is not 1234..., its 1 7 6 4 8 3 5 2

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goody90q45
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94Q45Beast wrote:ok, my analog multimeter didnt work, but i check again with the digital multimeter. exact readings =

Knock Sensors = 136.4 ohm and 162.8 ohm
injector #1 = 7.98 ohm
injector #2 = 8 ohm
injector #3 = 7.92 ohm
injector #4 = 7.92 ohm
injector #5 = 7.95 ohm
injector #6 = 7.95 ohm
injector #7 = 7.93 ohm
injector #8 = 7.92 ohm
Something is wrong with either the multimeter settings or the way you're getting the readings. It sounds like you know where to put the probes for taking the readings.....

for fuel injectors- positive probe to the pos. post of the battery, neg. probe to each of the 8 pins on the connector.
for knock sensors- neg. probe on the neg battery post, pos. probe to pins shown in pic

Image

KS ohms should read in the 500k to 550k ohm range (thats 555,000 ohms) and the FI should be 12-15 ohms. I've got to think that your multimeter is on the wrong setting or defective from the factory since it's new.

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goody90q45
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94Q45Beast wrote:.......here is the multimeter im using http://www.homedepot.com/p/Commercial-E ... er_reviews....
After looking at the picture I think you should use the settings in the 6-9 oclock positions. Yes? 3QJay will know.

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its 8pm here, I don't get back to my car till 9pm, probably gonna pull a all nighter. I messaged Dr.Jay (thats what I call him) let see if he gives his input.

that's the setting im using between 6 and 9 positions.

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my genuine knock sensors are cracked, dam, I installed them few weeks ago. I already picked up new knock sensors from a shop and will send the cracked knock sensors back with the copy of the invoice of the new ones from the shop, they agreed to to pay the price of the knock sensors I bought from the shop.

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Unplug the connector from #1 or #2 FI and get a reading directly off the injector pins. You won't need to use a probe to the battery for these two.

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I did and I got 0 ohms, and I tested the 4 injectors facing the towards the grill

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goody90q45 wrote:Unplug the connector from #1 or #2 FI and get a reading directly off the injector pins. You won't need to use a probe to the battery for these two.
Good thought Mike.
With the harness off he can probe the injector pins directly.
I looked at the home depot meter.
Black test lead plugs into the COM port, red one Plugs into the right most port with the V and omega symbol.
Yes, the selector to the 8 o'clock scale 2 megohms for the knocks,
200 ohm scale for the injectors.

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I tested right off of the injector pins and i got 0 ohms

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goody90q45
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94Q45Beast wrote:I did and I got 0 ohms, and I tested the 4 injectors facing the towards the grill
Impossible that you would have four dead injectors. The engine would be shaking worse than an L.A. Earthquake and smoking like a forest fire. Get another ohmmeter.

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roads are heavily iced in my area, will go to Sears and pick up a craftsman multimeter. I'm a die hard fan of Craftsman, its either craftsman or go home.

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ok I got the new multimeter and I tested each injector idividually and found #1 and #5 injector to read O.L multiple times and #7 injector gave 14.3 ohms the rest of the injectors produced anywhere from 10.3 ohms to 10.6 ohms. wow did I get lucky or what, I only have 3 brand new injectors on me. + 1 refurbished. :mike

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has anyone tried using metal braided hoses to replace the regular annoying hoses?

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ok, im stuck again, the screws holding the fuel injector won't come off, iv already stripped the screws holding #1 injector iv used pb blaster and wd 40

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94Q45Beast wrote:ok, im stuck again, the screws holding the fuel injector won't come off, iv already stripped the screws holding #1 injector iv used pb blaster and wd 40
The phillips head bolts securing the injectors caps are a poor design and do strip out. You'll need to drill a small hole in the head and use an easy-out to remove it. Replace the phillips bolts with a standard bolt with a six sided head or a hex head bolt. You can find replacements of the same size at any hardware store. I got mine at Ace Hardware.

Before you bolt the plenum back on do a pressure check of the fuel rail to make sure that all the lower orings have seated properly. There's nothing worse than hydrolock to destroy an engine.

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yeah I figured it out, I used a hammer and a small tip screw driver, and kept hitting the side in the direction I wanted it to turn, 1 screw down, 5 more to go. as for the knock sensors I had a regular socket that I cut in half to fit the tight space but now I cant find it. how is it normally done?

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I've found that tapping a screwdriver in to the Phillips head screws with a hammer before trying to twist them sometimes helps seat the screw driver. Ditto on replacing them with hex head bolts - or if you want the car to feel all "German" you can use allen screws.

For the knock sensors, I've always removed the hoses and metal collars that bolt in to the heads to access the knock sensors - but your way sounds like a winner if you can do it that way. Reinstalling those things is a real PITA.

Heath

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where can I find under plenum hoses for my Q, I'm gonna have to cut that big hose thats only like 3 inches long to remove the "pipes" on top of the knock sensors.

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Q451990
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I'm not sure if they're still available through Infiniti dealerships, or if they're non-stock. I've never heard of or purchased them anywhere else.

Heath

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I'll just use aftermarket hoses, dam fuel injectors are hard to pull out. :bang

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94Q45Beast wrote:I'll just use aftermarket hoses, dam fuel injectors are hard to pull out. :bang
The two large-ish hoses in the bottom of the valley are
14055-60u60 (the big one that runs front to back)
and
14055-F6511 (the one that runs from the middle to driver side).
the f6511 should be pretty easy to find, since it was also used on the Z32 chassis.
you can also use generic, but make sure the rubber is epdm spec.
nissan used extremely high quality rubber on the cooling system hoses.
to 'pop' out the injectors, put a small screwdriver into the side holes on each side and use the rail as a fulcrum to lever them out. careful though, the plastic can be brittle and snap.

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yeah I cut the big hose thats right before the "T", I was thinking maybey I can buy a upper radiator hose from advace auto parts or something and cut that piece to fit. I think they should be the same size. and meet the specification. as for the FI, haha I tired using pliers to grab onto it and pull, and it broke the plastic, also for the plenum, I washed it with really hot water and Dish soap, then blasted engine cleaner inside, then another rinse in hot water, same with the "pipes" that the plenum bolts onto. it looked more dirtier than the dirtiest engine oil with gunk on the sides. I'm probably gonna blast it with a can or 2 of Aircraft Paint Remover, then clear coat the outside.


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