My max has developed an intermittent miss. When it happens the exhaust makes a sputtering sound it doesn't normally, and the engine shakes. I need your guys help fixing this. This is an '89 GXE Auto with a 200k mile VG motor. When it's firing on all 6 cylinders, the engine runs very well and has good strong power.

When it starts missing, it keeps doing it no matter what the RPMs and throttle position. It can take anywhere between a few seconds to a few hours before it stops missing and goes back to firing on all cylinders. I can't put my finger on the conditions that make it start or stop missing. Often it will start or stop missing while I wait with the engine switched off. So after waiting, I start it and it either has started or stopped missing. Other times it starts or stops missing while driving. I've had it go 2 days without missing, and then it starts again. If I just shut it down and immediately restart it without letting it sit, it doesn't seem to change.

Once when it was idling while missing, I pulled sparkplugs to see which cylinder it was. Looking into the engine compartment, it was the cylinder closest on the far right. When I pulled that plug, the idle RPMs did not drop like it did with all the others. When I pulled the plug I heard an arcing noise, which seems to me that it indicates that there is spark getting through. For good measure I pulled and inspected the plug (looked good), and the cap and inspected it and the rotor (looked good) and checked for a good spark plug wire ends and installation.

The check engine light has not come on, and I verified that it does work during the gauge check.

I used a mechanic's s***hoscope, putting it on each injector while the engine had the miss happening, and I found they all were clicking (although some had more sharp and pronounced clicks than others.)

I tried running some SeaFoam through the throttle body to try and clean things up inside, in case a valve might have been stuck open, or something.. It didn't seem to make any difference.

What on earth could this missing problem be? Should I try a leakdown test on the missing cylinder? Or what else to try? I need help from you gurus!!

 

If its always the same cyl missing, then possibilities are:
- plug (swap)
- wire (renew)
- cap (lacquer)
- injector ...hmm try cleaner before swap.
- the mentioned valve (I've never seen such, do compression tst, 10$gauge)

If its NOT always the same cyl missing, then possibilities are:
- TPS (cold)
- groundings, especially distr tacho
- sensors
- cap, coil, transistor, ECU ctrl
- voltage low (bad connectors)


My bet is on clogged injector or its screen. (ask internetautomato, he'll verify this one

... see http://www.cardomain.com/ride/748507/1

 

How old are the plugs -n-wires/cap/rotor??? You may just need a tune up...Even if they look good....

 

Thanks for the info. And, GREAT web site, I'm going to read that whole thing... thanks!

Are the screens you mentioned built into the injectors? To access my injectors, I'd need to remove my upper air intake plenum, yes?

I think I'll try and verify that it's the same cylinder missing. Then I will try swapping spark plugs and see if it fixes it or make the missing cylinder change. At the same time, I will fill the fuel filter with some sea-foam to try and clean the injectors.

Question: by "laquering" the distributor cap, do you mean spraying clear laquer spray paint onto it or painting it with a little brush? Does it go onto the inside or the outside?

PS - I also recently found a coolant leak near the engine temp sensors. It was caused by a broken coolant spring clamp (I have no idea how it got that way...) It leaked some coolant around that whole rear side of the engine compartment, (near the power steering pressure line). I replaced the broken clamp and fixed the coolantleak, but should I do be concerned about the coolant residue? I noticed you mentioned it could cause electric connection problems. Also, I noticed many of my electrical connectors dust boots have cracks in them. Including I think every individual injector connector. Is that a problem and is there any easy fix?

I guess I will try and re-verify that it's always the same cylinder that is misfiring, or if it can vary. Thanks again!

 

MyGreenMax94: I replaced all the Plugs, cap, rotor and I think maybe even the wires about 2 years and 12k miles ago. Is it time for new plugs again already?

 

Try testing that one cylinder that you said was missing...Take the plug out and put it back on the plug wire,then lay it on the intake,start the car and see if it is firing.....

 

Personally I think that it might be your Plug Wires. My 89 Se was doing the same thing and I changed out the wires with new Bosh ones and it works great. At the same time I changed out my Plugs too so it may have been them. But I would check firing issues before fuel.

And If you do change out your plugs, I suggest NGK Irridium plugs. I love them, they're my first set of them but I've noticed way smoother firing and running conditions

 

As shown on the web page: spray both sides. Tape electrodes. These plastic caps are terriblese, I am tired in swapping. Last time I used engine lacquer (electronics (TV) hi voltage lacquer would be better). Even new caps may have cracks; visible only with magnifier, super bright light...

Make real wires as suggested on the site; even new so called wires =soot hose resistance may be over specs about 10kOhms. I find best run with 1k resistance, and also radio interference is ok with that...

Std plugs last 3k, then they start sputtering. Now I've got platinum plugs, GREAT! They promise 60k, with that, its worth the price.

Ppl here know better the injector issue: never dived after Nissan injectors as mine have been always w/o problems. Check the Favorite Links on my page, left side to get 'all' info. Yes, to replace injector, intake has to be taken off.

 

OK, I did some further diagnosis. I bought a new fuel filter and replaced my old one with it. I pre-filled it with Sea-Foam to try and clean the injectors. I dumped the rest in the fuel tank. So far it doesn't seem to be doing anything... car still misses.

I pinpointed the missing cylinder again by removing spark plug wire with engine running to find to RPM drop, and removed its plug and another plug. Although they both looked OK, I cleaned them up with wire brush, filed the tips, and swapped them. Engine still missing and it's still coming from the same cylinder. So it's not the plugs. I checked again for cracks. The cap (Bosch) looks really great - couldn't find any cracks or carbon trails or anything.

I will check the resistance of the plug wire on the faulty cylinder, and I might as well try removing the plug and putting it on cylinder head to verify it's arcing as well. Thanks for the suggestions.

It turns out that to remove the fuel injectors requires removing both the upper and lower intake plenum. If I were to do this, should I take them to a fuel injector shop to have them cleaned and checked? Or should I buy a set of new ones to install in there? I've got a feeling it could get pricey. Any other ideas folks? Can the injector screens be cleaned or removed? Thanks!

 

Do u have the service history? 200k is a long leg for injectors...

Prices from one reman start 35$ (nobody recommends) to anythin above hundRed....

Do the cheapest first: compr tst.

 

Test the resistance on the injector of the cylinder that is missing. It should be 10-14 ohms. You dont need to remove the intake plenum to do this, just remove the harness that plugs into the injector, and check resistance between two electrode thingys.

 

it probably is the injector, I have as of yet to see anyplace clean the injector and "make all better". All a rebuilt injector is, is an injector that has been untrasonically cleaned in solvent, and electrically tested. sometimes they'll replace the plastic ends.
Just get new, but remember when one goes, the others aren't far behind.

I sell the injectors new http://www.internetautomart.com/maxima/3rdgen/FI.html

 

Plug wire of the missing cylinder is 12k ohm, well within specs. I also removed the plug and managed to observe the spark while the plug was grounded on the intake manifold with the engine running. The engine sure didn't like running without compression in one cylinder, but the spark was definitely visible. I think it's pretty certain now this problem isn't the spark.

Thanks for your guys suggestions. Any more info about the injector screen?

 

That depends who gives the specs... nogood, such resistor will kill half the spark: when u plug is under pressure, your spark is about dead. Btw, who says the carbon dust in u hose stays constant 12k ?

Dont waste time writing, but NOW first thing DIY real conductors or buy semiconductors (also called "wires" in the 20bn$ sparkwire industry) from NGK. Its the only known about workin solution (lol: some of the wires in their set caps are even terminated properly)

Nissan stealership installs these electron agilitytrack / killer hoses:



Which way will the electrons jump in this hole aka wire???

For details, click http://www.cardomain.com/ride/748507/12

.

 

Is there any way to easily test your injectors? My car doesn't misfire but it sure is running really badly in terms of low range torque at the moment. I have SO MANY QUESTIONS and good points but I still can't post my own threads!

 

Yada yada yada. Blah blah blah

 

Sooooo many questions, tips and stoies I have to ask and tell. Just 2 more posts away!

 

U have to grow to mid teen (postings) to become informative...

Knock Sensor? HowTo: click http://www.cardomain.com/ride/748507/9

 

I found my problem... bad injector. I pulled off the upper and lower intake plenums and pulled the entire injector rail out of the motor. Four of the injectors measure 13 ohms. One measures about 130 ohms! And the one that had the missing cylinder measured infinite ohms. So shoot, since its coil is shot, it's not even rebuildable...

I am pleased I found the problem finally!

 

IMHO: You've got a short in that injector's coil that measures 130 Ohms. It either does not work or is extremely inefficient (opens up 10% of the spec).

 

I agree - both injectors need to be replaced before I'm buttoning this motor back up.

Getting the injector out of the fuel rail was a big pain. I cracked the plastic thing on the tips on three of them, including one that wasn't bad. I want to fix this up without spending a whole lot of $...

 

Are Python remanufactured injectors any good? I am consider ordering up a complete set because I found them at a half-way reasonable price and that way they're all restored and last maybe another 200k miles (hehe... OK probably not quite that long .)

 

I recommend that you steer clear of remanufactured injectors...They will not last long.....

 

For some strange reason, it turns out that Python new injectors were cheaper than their remanufactured ones. Needless to say, I am giving the python new injectors a try. They should be here in a couple days! Can't wait to put my car back together.

 

where did you find NEW Python injectors for a VG

 

Well they arrived and indeed they are new python injectors. (They are clearly labeled "New" right on the box. They also sure do look new.)

Anyway, I'm very pleased with them so far, except that after I installed them in the fuel rail, I pressurized it by powering up the fuel pump, and found one of the injectors had a slow fuel drip. Not good! There was clearly something wrong with that injector visually, as its pintle tip stuck out further than the rest. Not to mention it had sort of messed up looking electrical terminals. It kind of sucks I wasn't able to bolt it up already, it looks like I'll have to send it back.

When I had the plenum bottom off, I gasket-matched the intake manifold to the bottom plenum with my new fast-cut carbide burr used with my air-powered die grinder. It worked great and now it's all smooth! Was surprised how mismatched that joint is out of the nissan factory. I ran a vacuum cleaner nozzle right next to the area I was porting, so it sucked up almost all of the aluminum shavings while doing the gasket matching on the fly. After that I also thoroughly vacuumed out all of the aluminum shavings that happened to make their way inside the ports. I think I got them all. I can't wait to get it put back together and see how well it runs!

Oh yeah, I forgot to mention that I found that with vacuum cleaner nozzle set to suck into the intake port, a 45 degree chamfer drill bit just rotated into the injector bore by hand worked wonders to break up the nasty hard carbon deposits and they shot right up the port into the shop vac. This cleaned up the injector holes very nicely!

 

That is like a mountain range, cannot understand nissan quality specs here.

kcidmil suggested takin off flange in airbox top part: I did, MAF is actually larger than the top cover hole. Cover can be grinded 1-2mm bigger dia (=5% more)

Also grind the stock plastic tube engine side end - if its crimped to 66mm like mine was.

 

Doesn't sound like a trully new injector to me. Also Python doesn't show a new stock replacement injector for your max.
The Venom line lists some universal "performance" injectors for nissans
What part # were they?
and I'd wonder about the quality when you've already had 1 leaker straight out of the box.

 

I agree they don't come up in the on-line python internet catalog, but they are definitely new injectors. Their Python part number is 630-121N. There plastic parts are new plastic molded, there are no nicks in the metal parts (just fresh-turned marks left over from the lathe machining process), no sign whatsoever of any reused components from an external inspection. They must be a new product offering from Python.

The installation instructions included with the injectors apply to various Nissan, Infiniti, and Subaru part numbers and it lists some reman and some new. There are far fewer applications available in the new category. Out of 10 reman Python part numbers for Nissans, only 3 are listed under new on this instruction sheet: 630-119N, 630-121N, and 630-251N.

 

My used injectors are now up on e-bay:
http://cgi.ebay.com/ebaymotors/ws/eB...tem=8006253489

 

OK, lesse if these pics work...

port matched lower plenum to intake manifold:


new injectors installed in rails, passed leak test, and everything ready to go back together:


Result: new injectors are working, missing is fixed and car is running smoothly. Car seems to have more mid-top end power! (probably because of the port matching.) But, car doesn't start up quite as quickly as it used to (I hope it's just some air in the fuel rail that will burp out or something.)

 

Update: I have been living with crappy idling and has smells that may be a cause of these injectors, or perhaps crappy o-rings. I used grease when I installed them but maybe used the wrong kind (the instructions didn't clarify what kind to use.) Probably petroleum jelly/vasoline would have been best, I used a general purpose/chassis type grease.

I am really sick of dealing with injector problems... Argh! I am goign to take the manifold off and do another leak test and maybe injector spray test. Maybe I'll just put back in a good used set of stockers that haven't been disturbed from their rails.

 

besides the o'rings there are insulators at the tip that I've heard of going bad before (only 1 time though)

 

The latest in the injector ordeal is... I'm back running on good used stocker's (I got the set undisturbed in original VG rails from a forum member up here, Justin... thanks!) These new ones are "blue dots", I don't think it makes any difference.

And, now all the bad behavior of those crappy "new" injectors has been fixed. There are no leaks and thank god no more awful gas smell coming through the vents whenever the car speed slows down. The car idles so much better (maybe still not perfectly) but very nearly as good as I can remember, and the auto now upshifts with beautiful Revv-matches. Full, smooth engine braking (with the characterisitc droning noise out the exhaust) is back! No more sputtering during engine braking. And after a new air filter, the car now has better power than I can ever remember. Yay!

I found that scraping the old injectors terminals to fresh, shiney, clean copper was exposed turned from from total non-conductors (infinite ohms) into very low ohm, as good as can be expected "perfect" conductors. I did this with two of them that changed them from missing to reliably working. It's on my list to scrape all the other terminals I can get to, to try and make it more reliable and improve the idle and performance even further.

 

were they actually new or rebuilt?

 

I belive they were new. But please dont misintepret this to read that they are any good!