Ok, now that it idles at least consistently, I started pulling plugs to see when it stumbled. 4 gives me no change. I pulled the plug and the piston looks bone dry as well. Injector ohms at 13, I juiced it with 12v and it clicks. Sounds like most of the others when it's running with stethescope on it.
Maybe it's just do for a new set...??

 

perhaps its clogged up? clicking but not spraying? if the plug is white it could mean that the injector kept getting more and more clogged until it just stopped spraying (running leaner the more clogged it got, thus, white plug)

ALSO, get hook your multimeter into the injector harness and watch voltage as you mess with the throttle, to see if the injector is even being told to fire by the ECU. DO NOT use a test light for that.... the resistance is wrong, and can cause damage to the ECU.

 

If the injectors are ohm'ing out ok, then don't bother swapping in new ones, they are just too expensive to troubleshoot with. If you haven't already, start with a simple full ignition system tune up. (plugs{ngk only}/ wire set/ dizzy cap/ rotor button)

 

I'll check the harnes and see what that gets me.

I did do a tune up, all except the wires as they weren't in stock. But the wires on it look to have recently been changed.

Several plugs were white when I changed them, but I don't remember which cylinders now.
I pulled the injector plug and fired it up, then slid it on/off a few times. It does make a difference, but not much. Unhooking that injector does not change the idle as much as pulling a plug from another cylinder.

 

Ok, on this particular cylinder, swap the plug wire from this one with another plug wire, then see if the partial miss follows the swapped wire.

 

timing ???

 

no....

Siggy a little large there dude?

 

Nope. Pulling 4 still causes no drop with different wire.

I pulled all the plugs to get a look;
1 is black at the insulator but white at the tip. 3 is close to the same. 5 is black at the insulator, tanish at the tip, it's the closest to "normal".
2 is wet with fuel, well blackened, 4 looks like it's only been my engine for about 15 minutes, very little black color at all, 6 was black and sooty, but not real bad.

And the timing is slightly more CW than when I got it, it was fully CCW. I moved it about 1/8th inch. I've no timing light here so that's the best I can do..

 

How are your injector terminals?(harness side and injector side) Do they have any corrosion(green looking crap) on them? How do they fit on the injectors? loose fitting or tight?

 

I would say they are not tight, they slip on and off pretty easily when the keeper is out.

The did have green goo inside, but I cleaned them up pretty well. I sprayed them all out with elec. parts cleaner, then filled the female terminals with die-electric grease.

There was no corrosion at the main harness connection, they looked new inside.
Using a hose as a stethiscope, I get good sound from all injectors.

 

Try to "smash" the little female connectors a bit(not too much), a small nail or eyeglass screwdriver works well for this.

 

Great idea, actually what I did was to slightly twist the male tabs on the injectors, then plug/unplug several times and reclean..

It seems quit drivable now, just went around the block. It still stumbles a bit at part throttle but it's 200% better than it was..

 

Now clean/smash the rest of the same type connectors on the tps/cts/etc.


I wouldn't recommend twisting the male ends, you might break them off, or damage the internal connections inside the part. but it's your ride and your decision in the end.

 

Yes that sounds like a plan.. Should be the mantra, "When you think you've cleaned ALL your connections good enough, CLEAN THEM AGAIN." LOL

Your probably right on the twisting, but it was just a slight bit. I'll spend the rest the weeks evenings squishing them tight instead.

Thanks for all the help. I'm sure more issues will come up.

 

All depends on the materiel, tools and how u do it. I do it routinely, no problem for me.

- get new NGK plugs (If bosch = all your problems)
- even new soot hoses (some call em wires) can be dead. You cannot measure soot resistance, can you? With wires, the resistance is 1 to 5kOhms.
- the cap can also be dead straight from the shop
- turn engine to 15BTDC. Install a spare plug on wire no1. ... Loosen, then rotate distributor. Ground the plug and watch for spark. Tighten.
- GET that 30$ timing lamp.

 

Back again...

I received my FSM, been browsing it trying a few different things.. The oxygen sensor tests ok up until I do the ECU mode 1 test.
I get no green light. Run up to 2000rpm for about 29 seconds, sometimes it takes longer, then the green light will light and the engine immediatly runs smoother and the rpms go up to about 2500 (at same pedal position).
After 10-15 seconds light goes out and engine goes back to running like crap.

I have no trouble codes. I've clamped off both crankcase pressure feeds to the manifold and the idle doesn't rise, so I think I've solved all the vacuum leaks. It does idle without dying, just rough and crappy. Runs good when I punch the throttle, but any mid throttle is just as before, rough, surging.. Almost like its flooding. When driving it around it will straighten up once in a while, this must corelate with the green light on the ECU but I can't see it when I' driving. When it does, it runs drives perfectly.
I just put a new TPS on it today, with no change, as I broke the other one.

FSM simply says I should see green light flashing 5 or more times in 10 seconds on mode 1 diag, else replace the o2 sensor...? But it checks out otherwise.... Should I ebay a used one?

 

Glad you're making progress though, this thread has been a cool read so far.

Are you still not firing on #4 though?

I've found bad o2 sensors by removing and then physically shaking that even 02+ ecu's didn't pick up on, just by seeing fuel trim problems and then taking it out on a whim, you can forget about seeing the fuel trims, but you can do that diag mode 1 and watch the light, which is what you did and to answer your question no it shouldn't do that, it should do as the fsm says. Most o2 sensors only have a 4yr/60k lifetime on them anyways, and I'm sure you will see benefits of a new one, if not the problem solved.

In the meantime try disconnecting that thing, it's not used until it reaches temp anyways, which IIRC goes along with your symptoms right? With it unplugged the car will go into open loop and ignore the o2 sensor and focus just on rpm, tps, cts, MAF, etc.

This is all barring you checking 4 again anyways, and if it still has issues you can always pull the sparkplugs and run it briefly while you see the ACTUAL spark on that cylinder with that Plug, wire, etc. I actually do the same thing with injectors as well, I've had a few fits trying to find problems on VQ's where I've physically removed the rail + all injectors, turned it all upside down, disabled ignition, and while cranking watched them physically spray. After doing the conventional test first this is the MOVE as it lets you see the spray pattern very well. But I'ts been awhile since I owned or wrenched on a VG, not sure but I don't see why you guys couldn't do that with your cars, maybe someone will confirm, because that really is the best way to rule out an injector problem.

 

Wideglide:

have you replaced the coolant temp sensor yet?

 

It seems to be hitting on #4. Pulling the plug drops rmp, as well as pulling the injector wire..

I tested the old one, seems to be the same readings as the new, but I swapped it anyway. First restart it seemed better. The light in mode 1 was blinking, it was running smoother. I shut it off, restarted, and it's back to the same ole- same ole... Even with the o2 sensor unplugged I get the same sequence as described above. I've video it after dinner.

 

What do you mean when you say it checks out otherwise? What is the voltage reading at idle?

Physically shaking it is one of the best ways I've found, allthough I've also seen them fail without breaking internally just as many times, it's just that alot of times (with the newer ecu's) when they break the car just runs pig rich in closed loop and the ecu doesn't pick up on it

Anyways, I still think you should follow the procedure for setting the timing, that's crucial. Also, I'm a little confused, but it could be because I'm using a '94 FSM, at least on the '94 TPS output voltage between terminals 4 & 5 should be 0v @ 0% throttle and 4.5v @ 100%, but you said it is between 1 & 7? That right there would explain the bucking driveability issues, as well as not being able to adjust the iacv, and I wouldn't be suprised if it skews the diag 1 mode but don't quote me on that.

 

I didn't get a voltage at idle, I had forgotten about that one. I'll do that in the AM. I meant by checking the ohms and cleaning the ground and checking the volts at the plug with the key on. So I guess I've not completely tested it out, but I'll hit that tomorrow. I found one online for $50 so I'm ordering it anyway.
It is running rich as it's sucking down fuel.
The TPS measurement I was talking about was also the ohm reading, not the voltage. The old TPS was 1 ohm/zero throttle and 7ohm/full throttle, this was a resistance test based on pohjola's web site.
The new TPS ohms out at 1/zero throttle, and 13/full throttle. Either way, it's brand new. I"ll see about the output voltage in the FSM and test that if need be.

After swapping the coolant temp sensor, it didn't seem to run much different, so I unhooked it and it totally changed. I had unhooked the old one and there was not much difference... Unhooking the new one takes the idle up to around 1200 till I rev it a bit then it drops down to 900ish. Takes away almost all of the part-throttle stumbling while driving, and takes away all the rough running at idle. I don't get it..

 

Everytime I say something makes it run different, it goes back... lol

Just drove it to pick up kids from movies, and it's all the same with the coolant temp sensor unhooked as it was. Poor idle, part-throttle almost kills it, I have to stab it to get going. But it ran great going around the block a couple times right after I unhooked it..

 

Well I went through the Diag procedure #31 for the o2 sensor, and everything checks out with the ecu and the harness. I pulled the o2 sensor and shook it, sounds like a bad light bulb. Hopefully the new one will cure this..

 

Have you checked the connector on your AFM? A bad connector or AFM can also cause similar problems. As far as I know the TPS isn't used by the ECU at all, only for the TCU, I think the 5 speed version doesn't actually have the potentiometer section of the TPS.

 

What's the AFM???

 

Air Flow Meter. mounted in the intake piping, directly after the air filter.

 

More commonly known in the states as the MAF.(mass air flow)

 

Thanks, I shall keep that in mind!!

 

Firstly, Happy Thanksgiving everyone!!!!

Ok so I finaly got the o2 sensor yesterday, popped it in this AM, and there are changes, some good, some bad...

Starting cold was rough, wouldn't idle on it's own till warm. Once warm I started the mode 2 diag. I get nothing. Holding the car at 2k for 10-15 seconds I finally get some lights. Gren and red both on, and engine smoothes out considerably and pedal becomes responsive. Idles good, little high, for about 15-20 seconds, then starts sputtering slowly (when lights go out) and runs rough, low pedal sputters and coughs. I rev it up to redline, lights back on, smooth again for another cycle.

I took it for a drive like this and it's repeatable everytime I did it. Run great for a few and I could see the check engine light on (red light shadow). Then it would go off, start sputtering, low pedal makes it worse. Hit neutral, rap to 6k, back in drive, the light back on and good again...

No codes in mode 3.... I did change the position of the butterflies in TB, but I think I have them now back where they were. It sure sounds like it's loading up, stuck injector maybe????

 

Acting injector is one possibility (as is MAF). Depending actin inj location, the cyl may get some juice from other cylinders, and unplucking spark wires (or injectors) may not give any perceivable results. Anyways, in this case O2 erroneous feedback may cause ECU to choke all injection. Disconnecting O2 will help here as system goes open loop -and- 'rests' only on ECU table, TPS and MAF.

 

I've done this.. That's how I got to where I am. Following the O2 sensor tests.. This actually didn't change the running of the car, I simply "discovered" if I floor'd it, it would show the mixture lights again briefly.

I'm starting to think it's leaking fuel past the seals. Any way to test for this with them all in the engine?

 

Pullin my hair out here...

I blasted TB cleaner in the intake behind the MAF while idling and it seemed to do some good. I could hear the IAC altering air flow while doing this. Sprayed the MAF directly and it dies. I sprayed small bursts all around the engine (hoses, connections, etc) and there is no "apparent" vacuum leak.

When I put it in mode 1, nothing happens like it's supposed too.. Then I rev it up to 6k and both lights come on, idles better. Then if I stab it a few times I see the green light goes out for a split sec when I hit the gas, then right back on. Red light never goes out as far as I can tell.

If I let it idle very long (15-20 sec) then the lights go out and everything is rough again. Whole time, no codes...
Finally it will get to surging so bad and so low it dies.

Could this be a sign of a bad ECU???

 

Well it's not running rich... Here's a link to my photobucket album with plug picks..

http://s271.photobucket.com/albums/j...eglide/Maxima/

 

I bet on bad MAF.

Have u ?
- tested MAF disconnected? (get/show a new video)
- checked MAF output voltage
- checked supply voltage at ECU
- checked all signal levels at ECU
- cleaned ECU connectors


What plugs u have?

Platinum NGK looks like this

 

Yes, I'll video in a few. Unhooked I can't run above 2k rpm.
Yes, again I'll get it on the video.
On todays agenda....
I've only had the connector pulled once when checking the O2 circuit continuity, and it's the cleanest part of the car. No corosion, no not even any dust in there. It's clean.
NGK Platinums, very similar to those.

 

... = drops into safe mode, just as designed. If MAF is the problem, idle should become more steady.

 

I would check the MAF wiring first the way it's secured to the harness and left to wiggle between the sensor and the harness, it normally fatigues the wiring and alters the operation of the entire vehicle....

 

Ok.. based on that statement, MAF is the problem them.. Idles quite nicely unhooked.. Hit the link above again and play MAF 1.

http://s271.photobucket.com/albums/j...eglide/Maxima/

 

I just went out and tried that, no go.. The wiring seems pretty well intact in the car for the age. Nothing I've found has been brittle or cracked.

Also went through ALL of the signal checks, everything is good on that end.

Also the MAF passes the manual tests.. Only checks voltage in and out tho...

 

True, points at least to MAF. Try cleaning it with some cleaner spray (wont help I suspect). Get another MAF (ask for warranty in case it fails too).

Dont delete but leave the link for other ppl skiing behind .. very informative video!