SOLVED! Dead Cylinders/ Lean Condition

[McShanks]

Ok, I have a 1990 NA 2+2. Cylinders 3 and 5 are dead (used the pull individual coil plug method.) The others are live. Compressions are all between 150 and 170 (not great but above minimum and close to within 10%). I have swapped the coil and then the spark plug in #3 with the good one from #1 with no change in #3 or #1. I pulled the injector connector on #3 and there was ALOT of verdigris (green corrosion) that I cleaned very well with vinegar and a toothbrush and plastic paint brush and coated with dielectric grease. Re-installed. No change. I am thinking injector needs replacement but I am also suspecting wires? So I checked ECU codes using http://www.ttzd.com/tech/diagnostictech.html and got a code 33 which is apparently the "left" O2 sensor. Is that the passenger side or driver side? It is not clear if that is left from looking at the front or left while in the car. Since both of these cylinders are on the same side, could the code be a cause or effect of the dead cylinders? I have not tested #5 yet as I am trying to get each one done one at a time. I know to test injector ohms (I need to borrow a multimeter) but is there a way to test if wires are sending the electrical signal properly? Please help. Any other ideas are greatly appreciated. I will update once I troubleshoot #5 while waiting for your help with O2 sensor and #3. To summarize my questions:

1: Is the left O2 sensor on passenger or driver side?
2: Does the O2 sensor code tie in with the dead cylinders?
3: Is there a way to test if wires producing proper signal?
4: Is there something that can cause both #3 and #5 cylinders to stop working simultaneously?
5: Is there a way to tell if my ECU has more than 1 code? (I am only getting 33, but I suspect I should be getting a 21 or 51 with two dead cylinders...)

Thanks in advance!

-McShanks

*EDIT* ok weird thing... don't know if good or bad... just shut down all ecu testing. Retried and got a 55 - no malfunctions. WTF? So I guess that means no code 21 or 51 for ignition or injector cirtuits. Getting very frustrated...

*EDIT AGAIN* Ok, so I am going to go finish that diagnostic thing for the left and right O2 sensors just for the heck of it. Will update that. Meanwhile, any help on dead cylinders greatly appreciated. Thanks!

*EDIT 3RD TIME* Ok, Update: Did the left O2 test: Normal. The right one: Lean the whole time. I NEVER saw the light come on, so I know the "right" side is the one with #3 and #5. I also know that the cause of my missing is lack of fuel. So now... Questions 1,2, and 5 are answered by myself, lolz. But I am still stumped on questions 3 and 4. If I am not getting an injector circuit code, does that mean the injectors are working right electrically? Perhaps they are clogged? Argh... I dunno! But I am gonna troubleshoot #5 the same way and see if I can get that one to work.

*EDIT...* #5 plug and coil work fine in known good cylinder. I am guessing the only way to find out if it is the injector or the wires is to pull the plenum and play musical injectors... Before I spend all that time doing that, PLEASE someone tell me if I am at least on the right track. I need all the info and advice I can get!!!

[McShanks]

bump

[McShanks]

Double bump

[McShanks]

Triple bump. Done with the O2 diagnostics, still working on #5 but it is so hot outside. Weekends are only time I have to work on this...

[McShanks]

Super bump, sorry for being impatient but I need the car to drive to Indy next week. Help!

[nissanfreak12]

Check the PTU, make sure all the connection is good, that will cause havoc if its corroded or not plugged in tight. Another thing you can do is pull off the CAS, and you can turn by hand with the ignition on and you should be able to hear the injectors click if they are working.

How do the spark plugs look? Are they wet, black, anything odd with them?

[TTkickedin]

Some of the most complicated problems can be the easiest fixes, make sure you've checked your fuses, other than that, at the moment

Idk if I missed this or not, but are you missing a spark at those cylinders? If so, check to see if you're electrical system has a draw.

Check the Ohm readings for the injectors in the faulty cylinders and compare it to your other good cylinders. If that checks out, take a test light and plug it into the injector harness and make sure you are getting a current pulse. If you are getting pulse and the injector ohms correctly it could just be the injector is clogged.

I don't know if the 300zx's have a resistor pack for the injectors, or if you're running one because of an upgrade. but if they do or you are running one, this may be the issue.

[McShanks]

Thanks to both of you. I picked up a DMM to test resistance, current and voltage. I have a few questions for you. Where is the PTU and what connections am I checking? Is that the thing next to the ECU? The spark plugs... Well, I recently ordered a whole set of the PFR6G-11's because when I checked compression... The ones in there looked ok, but they were NOT the right plugs. They are all NGK's, but some are different types than the others, and none are the PFR's. But I swapped plugs and coils around to verify they work in the known good cylinders. The #5 one I think looked a little wet-sludgy. Very slightly. The others were fine. If I recall correctly. I haven't checked for spark yet as I am not sure how to do this without an extra spark plug on hand. I obviously don't wanna pull the plug and RUN the engine. And I think the fuel pump fuse says EGI INJ on it. I tried to check for spark with the fuse out and I couldn't see one in ANY plug. (It was bright outside, so idk.) My new plugs will be here mon. or tues. so I can definitely do it then.

Kickedin, what fuses should I be checking? And what kind of test light do I need? Can I use my DMM for this on the injectors?

I will do all these things tomorrow, and if still no definitive results, I will pull the plenum and swap around injectors to see what I can see.

Thanks! Any more help is awesome!

[TTkickedin]

For the test light, the NOID light would be the one you want. as for the fuses, check the EGI and possibly ENG CONT.

IF none of the above steps work, this could also be an ecu issue...

Future reference, don't solely rely on a test light to test everything electrical. a good multimeter is your best friend.

PTU LOCATION:

[TTkickedin]

Just did some more research: If you are getting spark, and you are getting proper flow with the injectors, next step is to check for a vacuum leak. Any hissing sounds at all? Too much fresh air = no combustion.

[McShanks]

Ok thx, Kickedin, I am gonna check the PTU connections and all my fuses before I pull the plenum and swap around injectors. And I will test resistances with my DMM on the injectors, too.

[McShanks]

Ok, so I tested resistance of #3... Open. So, it's dead. Now I am gonna test #5. Gotta take the vacuum line off for that one, but at least I might not have to play musical injectors. Is ebay the cheapest place I can find reman injectors? The sooner I fix this the better...

[McShanks]

Well I just ordered 2 reman fuel injectors. Both were open resistance on #3 and #5. They will be here by Thursday. I will pu them in when they get here and update then. Meanwhile, any other input or tips would be appreciated. Thanks!

[TTkickedin]

I think now its a waiting game to see if the new injectors will fix the problem unfortunately. Did u use the DIMM or NOID to check the injector harness?

[McShanks]

I used the DMM to test resistance in the harness to see if I got a short. No short in either one, so that's good. But I am not sure what voltage/amperage the fuel injectors run off of so I did not test it under power. Any tips on that? Thx.

-Z

[TTkickedin]

10-14 ohms is the correct resistance.

this should help you http://s95014253.onlinehome.us/63104/159859.html

maybe this is the same problem?

infamous-fuel-injector-problem-t420995.html

[McShanks]

Thanks again kickedin. My others tested at about 12.5-13.3 ohms, so that's good. The two bad ones were infinite, so that's not, lol. But I got 6 PFR6G-11 plugs and 2 injectors on the way to replace this week. First plenum pull for me! Yay... Should I do the EGR delete while it's off? I have heard I should, but is that legal? Any post links to more info and detail on that from anyone is appreciated. Thanks!

-Z McShanks

[es.biggs]

Most of the time, left vs right side of the engine is from the driver seat point of view. So in most cases, left is going to be drivers side...I don't see why this car would be any different, but there is always that possibility and I don't want to mis-inform you

EGR delete is illegal (but 99% of the time you would never get into any trouble), and it's very difficult with just the plenum off. I'd do the throttle body coolant hoses bypass while you're down there, but as long as the EGR isn't giving problems, I'd leave it alone. Especially since you are working with something that you need back running asap.

http://s95014253.onlinehome.us/63104/16304.html -- TB coolant hose bypass. The write up isn't crystal clear and it's hard to understand on paper sometimes (personally it was for me) but when you get in there and look at it, it will make sense.

[McShanks]

Great, Thanks biggs! I will leave that EGR alone then, especially since it is "sub"-legal, lol. Actually, since everything else seems to be working, I am hesitant to pull the whole plenum just for 2 injectors. I am going to use the filing method, since that seems to be what the dealers use, lol. And much less time consuming. And I won't have to replace dozens of hoses and fuel lines. Couple more days til the new injectors get here. Hope this goes well.

[McShanks]

So, I am a little pissed at FedEx. My fuel injectors were supposed to come in today. But, well, I will let the tracker speak for itself:

Shipment Dates
Ship date-Aug 1, 2011
Estimated delivery-Aug 4, 2011
Destination-WEST LAFAYETTE, IN

Shipment Travel History
Aug 3, 2011 4:53 AM-Departed FedEx location-KEASBEY, NJ
Aug 2, 2011 5:30 AM-Departed FedEx location-KEASBEY, NJ
Aug 2, 2011 2:21 AM-Arrived at FedEx location-KEASBEY, NJ
Aug 2, 2011 2:19 AM-Shipment exception-KEASBEY, NJ-Barcode label unreadable and replaced
Aug 1, 2011 8:14 PM-Left FedEx origin facility-BETHPAGE, NY
Aug 1, 2011 6:01 PM-Arrived at FedEx location-BETHPAGE, NY
Aug 1, 2011 3:31 PM-Shipment information sent to FedEx
Aug 1, 2011 3:18 PM-Picked up-BETHPAGE, NY

So, WTF, why did it depart from Keasbey, NJ TWICE!? Yesterday, my Estimated delivery was Aug 3. Now it's the 4th. I hope this is some stupid system error and the parts will actually get here today. I need the car Friday, and I wanted an extra day to work out the kinks. I was gonna put new ones in today, and tomorrow would have been my buffer to make sure everything worked properly before driving down to Indy then back to Chicago, then back to Lafayette this weekend. Kinda wanna make sure my car will run properly for the 300+ miles of driving I need to do. Thanks FedEx for raising my stress level...

*EDIT* Nope, not gonna get them today. They did make an error, something about an improper label, and it got scanned yesterday, but it didn't actually leave until this morning. I really don't wanna have to drive the wife's Malibu on this trip... At least I can get the old ones out and have everything ready to put new ones in... I hear getting the old ones out is the hardest part.

[McShanks]

Ok, so Wednesday night when I got home from work, I Dremelled out the grooves for the injector screws using multiple sources/tutorials. PB Blasted the crap out of the screws and injectors themselves. All in all took about an hour. Not much more to do but wait for the injectors.

They came in yesterday (Thursday, a day late!), so on my way home I pick up the couple things I forgot. Petroleum jelly and I grabbed (5) hex cap screws in jace I dropped one. Injectors looked good, resistance good. I took the advice of many and borrowed an impact screwdriver. This made the task of screw removal EXTREMELY easy. Put the tip in, pound it, and it comes. Talkin about screws here, stay with me. One of the screws was stripped, probably from the PO trying to replace this same injector. The impact drive even got that one out. So I get the screws out all the way. More PB Blaster on the injectors. Used vice grips and twisted and pulled and after a few minutes, the #3 injector came free!

Lubed up the new injector with petroleum jelly and popped it in. Got it most of the way in with twisting and pushing at the same time. Then used my nice new 5mm hex cap screws to push it in the rest of the way. Done! On to #5....

This one sucked. Screws came out easy enough, got the injector cap/clamp thingy off and the metal spacer. After 15 minutes of twisting and pulling... The whole plastic piece came out. Broke right off. Crap. So I got my Vice Grips and grabbed the injector by the metal core around that little pintle thing and pulled and twisted and pulled and twisted... Finally came free! Yay! Home free, right? No...

So I get the new injector, put it in. Twist and push... doesn't wanna go all the way in. So I grab the cap/clamp thing and spacer, put them in place. Grab one of my hex cap screws, start to put it in... and it falls. Dang. So I grab my extra one. And guess what? Wrong size! It is almost 8 at this point, so I try to get the other screw I dropped out using 2 screwdrivers like chopsticks. Fail. And not only fail... I knock the cap/clamp off and the spacer vanishes. Double fail. Friggin great.

I book it to Ace in my wife's car and they are closed. So I knock on the door and beg to come in to replace the screw. They let me in, and I got the screw and a suitable SS washer as a replacement for the spacer. Ok, cool. Get home, it's 8:30... Finally got the injector in after some finagling. Took another hour and a half to get everything put back together in the dark and put in the new spark plugs.

Then... I start her up... coughs and sputters, then roars to life! Then the car makes some noises like it's trying to clear its throat, and I can smell the carbon burning off the valves. Runs very smooth for a few minutes with a couple coughs in there, so I let it run while I put my tools up. Then I take it for a run to the gas station to get some gatorade and fuel the the trip to Indy/Chicago today...

Now let me start off by saying I got this car for about $2500 under KBB value knowing it had an issue, and have been working to find the issue while driving it. I got used to driving it in its reduced power state, not knowing how much the power was reduced (2 cylinders so about 80-90 HP!). I shift it into first like normal, and accelerate like I normally would, and I burn out! HOLY CRAP!

I did not realize how much power this car has when the engine is running perfectly. I was yelling for joy the whole way to the gas station. So excited. I am in Indy right now, and everything went perfectly fine the whole way down here. One thing is that the car used to idle around 800RPM, but now idles at about 1100 RPM. What is the proper idle so I can set it? I have a feeling the PO adjusted the idle so the car wouldn't stall while showing it to potential buyers.

Thanks to all of you for your help, and I hope I can be of help as well!

-Z

[NolimitZ32]

Glad you got all figured out, nice when the car roars to life isn't it?

[TTkickedin]

Good work!! I knew you'd figure it out sometime or other. It's a nice feeling when you fix your own car.

[GerryO]

What is the proper idle so I can set it? I have a feeling the PO adjusted the idle so the car wouldn't stall while showing it to potential buyers.

Thanks to all of you for your help, and I hope I can be of help as well!

-Z

Setting the idle involves a number of steps and most of them are described here:

http://www.mdsmarthome.com/z/Z%20Tech/Z ... 20Idle.pdf

[McShanks]

Thanks, GerryO for the link!