Hi All,
I just bought an 87 Maxima SE for $600 which runs so rich it blows black smoke from the exhaust and will eventually foul a set of plugs. I'm trying to pinpoint the problem and so far I've scanned the ECU for codes and found none except for a code 13 "Cylinder Head Temperature Sensor" but the engine was cold so this should be normal. I also pulled the ECU from another good running 87 Maxima and put it in this car to see if the ECU was the problem and it didn't make a difference. Here are the symptoms:

1. Fuel pump makes loud whining sound
3. Raw fuel coming from exhaust pipe
4. Spark plugs fouled up with black deposits

I suspect the fuel pressure regulator or solonoid are the problem but I can't test these since the engine won't idle correctly. I'm thinking of just replacing the fuel pressure regulator, fuel pump, O2 sensor, EGR valve, cap & rotor, spark plug wires, and fuel filter hoping one of these items is the culprit. Is there any way to pinpoint this fuel/emissions system problem without starting the engine? Any help would be appreciated.

thanks,
Jeremy

 

It really sounds like you have leaking fuel injectors. They are not completly closing and shutting off the fuel when they are supposed to. There was a recall on these injectors. Go to any Nissan dealer and they can check the VIN to see if they have been changed.
The noise from the fuel pump is either due to strain (you need a new gas filter), or the pump is getting ready to die.

 

your fuel pump is about to die and youll need to get a new one. Yeah also check to see if your fuel injectors were changed out. If they werent it could lead to a serious flame in the engine compartment. the black smoke, I dunno umm cant help you on that one.

 

Yes, I know there is a recall on the fuel injectors and by the looks of them they've never been replaced. I think the fuel pump is working OK but it's probably going bad. Sounds like I either have leaking injectors or a bad fuel pressure regulator. I'll post an update after I replace some of these things. Thanks for the help.

-Jeremy

 

Definitely call nissan for the fuel injector recall. No matter how many owners of the car and what shape it is in, this will be done free of charge. Normal cost to have this all replaced is somewhere around $1200 so it is definitely worth it. I had this done on a recently bought 87 SE and it has been great.

 

Here are the symptoms:

1. Fuel pump makes loud whining sound
3. Raw fuel coming from exhaust pipe
4. Spark plugs fouled up with black deposits

Ok...I know I'm new here, but let me tell you a bit about myself:

I have an 86 300zx turbo. I have the same engine you do. It is a vg30. There are small differences such as the position in the hood, intake and exhaust manifolds...but it is still a vg30. Mine, I had built to 400hp, but thanks to PepBoys, I'm rebuilding now. I see 500hp in my future

Anyways...to address your problems:
The fuel pump WILL make the noise. It's because it will run continuous. You have the dual fuel rails which accomodate a return to the fuel tank. This helps to keep fuel temps lower.

The ECU is telling you exactly what your problem is. The CHTS (cylinder head temperature sensor). It is a resistor which varies resistence with temperature. The colder it is, the more resistence it will have. For example, if you unhook it, the ECU sees infinite resistence. It then believes that the engine is REALLY cold, and makes a VERY rich mix, similar to what a carbureted engine would when "choked". This is the problem you're having.

I've even used this sensor to my advantage. I made a custom intake plenum which was such a drastic change that the ECU couldn't really adapt well. I put a potentiometer inline with the wiring to the chts. I then ran wires inside the car where I can richen my air fuel mix from in the car.

Often times, the connector to the CHTS will be dirty and cause this, but by the time you get to the thing, you might as well replace it.

 

OK guys, here's an update. I replaced the following components and the problem still exists:

Fuel pump
Fuel pressure regulator
Spark plug wires
Spark plugs
Cylinder head temperature sensor
O2 sensor

After I installed this stuff I started the car up and it seemed to be running pretty well. I was able to drive it around the block and then driveability got progressively worse until the car almost stalled. It started blowing blue/black smoke from the exhaust like I've ever seen. I'm surprised my neighbors didn't call the EPA on me! Either something is making the car run extremely rich or the piston rings or valve guides are shot. I can't tell if it's burning oil, running rich or both? By the smell of the exhaust though, I think it's just running rich.

I called Courtesy Nissan and they have a complete fuel injector replacement kit for $297 which includes injectors, harnesses, o-rings, gaskets etc. I'm most likely going to give that a try but before I order the stuff I'm going to do a compression check on the cylinders. If any of the cylinders have low compression, I'm going to junk the car. Otherwise, I'm going to order the injector kit and continue to try and fix this damn thing. Also, I checked the oil which smells like fuel and is WAY above the full mark. I'm not sure if this is due to the rich running condition or bad piston rings (blow by). I was also told that having too much oil in the crankcase could cause these symptoms. I'm going to change the oil and do a compression check and take it from there. I'll post again once I know more.

-Jeremy

 

hi,
I've done many of the same things with my 84 max. It will smoke bad, plugs foul. Replaced injectors, air flow meter, had it to Nissin and spent $250 for nothing. Ran worse. I've checked the gas line. But just recently checked the Carbon canister. If I remove the line from there it idles and starts fine. No fouled plugs. But to drive it I need it connected. The amount of air is being restricted either in the tank. The line from the gas tank.
Just a thought.

Mark

Question if anyone looks... Is the gas tank always supposed to be under pressure? I open the cap and it's always drawing air in. My other cars do this rarely. Is there no where for it to draw in air for the gas used? I have replaced the cap and it does the exact same thing as the other one.

 

OK, I have an update. I did a compression check on each cylinder and they're all between 150 to 160 psi which is really good for an engine with 195K miles on it. The new plugs I installed when I first got the car were completely fouled with black carbon deposits when I took them out which confirms that this is a fuel system problem, not a bad engine. Needless to say, I'm very happy about this.

I'm going to order the fuel injector kit and new harnesses from Courtesy Nissan but I don't think the injectors are the problem considering the amount of fuel this engine is blowing from the exhaust. I'm going to test the charcoal canister, check valve, and make sure the fuel return line is working OK. Other than that there is nothing left in the fuel system that I can replace so hopefully this will fix the problem. I also noticed some of the electrical connectors like the cylinder head temperature sensor and mass air meter had corrosion so I cleaned them and reattached them. I'm going to pull the mass air meter from my other 87 Maxima and swap it with this car to rule out that component. More to come.

-Jeremy

 

man dude i boght a 2nd gen2 maxima for 500 and it runs alot better then that lemme tell you what was wrong wid my 2nd one, tire unblanced, rear right brake caliper sticking, air filter dirty, um leaky sunroof, starter make that F$@$@ed up noise instead of working some times, ands the exhaust gasket infront of cat was leeking, and one fire wall side manifold bolt is not tight, rack and piniont needed to be remounted basically, but actualy it runs smooth, not fast like my other one though. thats basically it same head lights not bright enuff and the digital gauges go out some times well just thew digital speedoomter and the auto matic **** selector cable is out of adjustment...

 

Don't replace the injectors!!! You don't even know what the problem is. This is why people complain about having their Z worked on...the shops just replace items one at a time and figure eventually you will either give up or they'll get it fixed...either way they make money while it lasts. The bad side is that you spend money that is just wasted.

have you checked the FPR control solenoid, the harness to the CHTS or the FPR? the fuel temp sensor? Checked the ECU codes?

If you replace the injectors, you will just be wasting money...but if you do, let me know and I may buy your old ones. Never hurts to have spares...

 

It's not wasted money since the existing injectors and harnesses are old and I want this car to run perfectly once I get it running. Yes, I tested the FPR control solonoid, replaced the fuel pressure regulator, temp sensor, and CHTS. The ECU only had a code 13 (CHTS) sensor code stored but my other 87 Maxima has the same code in memory and it runs perfectly so that's not the problem. I'll post more next week after I have the new injectors installed.

 

Old injectors do not mean bad injectors...but if you feel this way, it's your right...no reason to argue the point...

Anyway, I may be telling you something you already know here:

Codes are STORED in the ECU until they are erased. Your other maxima could have no problem with the chts at this time. Say your car is free of all codes...none show but the normal ones...and you disconnect the CHTS harness for a second and hook it back up. During this brief time it was unhooked, the ECU saw infinite resistence at the CHTS. It then thinks there's a problem. Although you hooked it back up, the code will be there till it is erased. Now, say you just have a loose connection at the CHTS or the harness....and it wiggles loose, but them makes connection again...this enters the code also.

You need to (if you havn't) clear all codes from both your cars...and then if the CHTS code reappears after going through the test sequence, then fix the problem..be it the harness or the chts.

It sounds to me that your other maxima just has the code stored. But on the one you're having problems with, reread my original post on how the chts works...because your symptoms are EXACTLY the same as having chts or connection problems with it.

 

You are correct - old injectors do not necessarily mean bad injectors. I was going to take the car to my local Nissan dealer to have all of the injectors and harnesses replaced under the recall but they told me my car is not affected. If you want to buy the used injectors for VERY cheap, I will sell them to you. I can event do a resistance check on them first if you'd like.

Yes, both cars have the 44 and 13 codes stored. I've looked through several Maxima forums for info and it seems that quite a few other 87 Maxima owners have the code 13 stored in their ECU's so I think this must be a common occurrence. The FSM says the CHTS will throw a code if the "resistance is out of range" or something to that effect. I should be able to rule out the CHTS by disconnecting the harness to it on my good running 87 and seeing what happens. I'll try this today and post the results.

-Jeremy

 

OK, I've got another update. I pulled the harness to the CHTS on my good running 87 Maxima and the car ran as if nothing had changed. In other words, I know the CHTS isn't the cause of the rich running condition on the problem Maxima. I also switched MAF meters between the two cars and the MAF from the problem car is good. Next, I pulled the fuel canister and tested it with compressed air per my shop manual; again, it too tested good. Finally, I pulled the fuel check valve near the gas tank and it tested good.

Now I know the rich running problem MUST be caused by one of the following:

1. Leaking injectors and/or bad harnesses.
2. Fuel return line plugged.
3. Saturated carbon canister
4. Defective gas cap

The crankcase is definitely contaminated with fuel which leans towards the injectors. I'm going to pull the fuel rail tomorrow and turn on the ignition to see if the injectors drip. More to come...

-Jeremy

 

Did you unhook the chts with the car started? Did you leave it unhooked for days? Did you start it cold? Did it even slightly change the idle, immediately when unhooking and hooking it back up? (It should)

My point is that by unhooking the chts on the good car, you didn't duplicate conditions on the bad car.

Also, in doing what you said, you will also want to crank the car and be sure it sprays them all at once. When starting, the injectors spray togeather.

I don't think the gas cap will be your problem at all.

You said your crankcase is contaminated with fuel...meaning that there is a gas smell in the oil? if so, it could be the fuel pressure regulator. If you unhook the vacuum line going to the top of it and gas comes out (while running), it is bad.

If the return line was clogged, you might burn up the fuel pump (just a thought), so maybe that's not it...


I don't see how the carbon canister could be the problem...tell me if you don't mind.

WHere are you? If you're close to me, maybe we can get together and look at it..I'm in Tennessee.

 

OK, the mystery has been solved; the injectors are toast. I unbolted the fuel rail and lifted it off the engine. When I turn on the ignition and leave it in the on position, the injectors squirt fuel every few seconds and in no particular order. Sometimes they all squirt at once and sometimes only one or two leak. My understanding is that the injectors are not supposed to release ANY fuel until the engine is cranked over. It feels good to finally know what's wrong with this fixer-upper Maxima I bought.

I should have it running in about 2 weeks once I have $350 for the new injectors and harnesses. After that I need to replace the master cylinder, valve cover gaskets, front exhaust manifold, motor/tranny mounts, CV joints/boots, various leaks and some other miscellaneous stuff. When it's all said and done, I will have invested about $2000 into it.

I'm not sure about the carbon canister thing but given the amount of fuel this thing is dumping from the exhaust it had to be either bad injectors or bad pressure regulator. BTW, I'm located in Santa Clara, CA which is about an hour south of San Francisco. Thanks for the advice.

-Jeremy

 

Although I see all your points on diagnosing this problem....let me suggest something else.

you are right in that the injectors should not spray anything until the engine is cranked. However, if there's a clog, do you think it would affect ALL the injectors as you said they spray? I don't. The reason is that the injectors only open when they get electric current (12 volts is normal). So, your injecrors are sticking open, and then closing intermittently on their own with no current to them? I dont' think so.

Have you thought that maybe your ecu has a problem and is sending the current to them in all these odd sequences you speak of them spraying? Now bear with me...I talk to MANY people about car problems...if you've already told me that you swapped ecu's with your other Maxima, I've forgotten it...
If you wanna email me on this, I'm at Engloid@aol.com

I don't frequent this board, but when I get replies, I check out the link...so unless you just want it up for others' input, email is easier for me....either way is not a problem, though.

 

Yes, I did swap ECU's with my other 87 Maxima and it didn't help at all. I'll post more once I get the new injectors installed. Thanks again for the advice.

-Jeremy

 

IT LIVES!!! I installed the new injectors, fuel rails, valve cover gaskets, and put it all back together last night and it runs great. The only problem is the idle is too high; it's supposed to idle at 700RPM but it's currently at 1200RPM. I tried to manually adjust it with the idle screw and that didn't work. Also checked the timing and it's correct. There are no obvious vacuum leaks so I'm not sure where to go from here but I need to get the idle down. Any ideas?

Thanks,
Jeremy

 

Jeremy,

Congrats with your rebuilding. Now with the solution to
your problems. First, check to make sure your throttle
cable doesn't have any tension on it when in idle.
Secondly, if your idle screw is all the way down check
your air fuel mixture screw. Third, check all the vacuum
lines and make sure they are correctly connected. Finally,
adjust the booster control (BCDD), fuel pressure regulator, and pressure regulator control solenoid valve. Good luck!!!

Mike

 

Thanks Mike, it sure feels good to finally be able to drive a car that was such a basket case when I bought it. I've basically replaced the entire fuel system now so it should run well for a long time now. I still have to replace the motor mounts, CV's and the broken exhaust studs. The really nice thing is that the AC works which I was not expecting with such an old car. This thing runs like a champ for having 197K miles on it; Maxima's just seem to run forever.

OK, I already backed the idle screw almost all the way out and I know the throttle plate will not close any further. There is no tension on the throttle cable either. I also checked the BCDD with a vacuum gauge today per factory manual and it's working correctly (max vacuum when I chop the throttle after revving the engine). I also tested the PCV and EGR valves and those too are working correctly. I sprayed carb cleaner all around the intake and vacuum lines to see if I could find a leak - no luck. As well, timing is at 20 degrees BTDC. So that leaves me with these choices:

-adjust fuel pressure regulator
-adjust fuel pressure regulator solonoid valve
-check vacuum lines

The fuel pressure regulator is BRAND new and I'm not aware of any adjustments that can be made. Could you elaborate on this procedure? I'm going to use my other 87 Maxima as a reference and double-check all of the vacuum lines tonight. It's got to be something simple.

Thanks,
Jeremy

 

OK, I checked all of the vacuum lines and they are routed correctly and no leaks. Must be something else. I just thought of something. I swapped the mass airflow meter from my 87 5-speed Maxima into my auto to make sure the air meter wasn't bad. Could this be the problem? The one from the auto works fine in my 5-speed but maybe the auto doesn't like the MAF from the 5-speed? Also, I thought the mixture screws weren't adjustable on these cars. HELP! This fast idle is wasting gas and driving me nuts :-O

-Jeremy

 

Jeremy,

You sure making me think hard on this aren't you..
O.K. Here we go, look like you've checked everything.
The fuel pressure regulator has a fuel temp sensors
If that's not working your idle may climb, next thing
is the throttle valve switch. You may have to take this
thing apart to see if it's working. It informs the control
unit when the accelerator is at idle, and on AT tyranny
it informs the control unit when the throttle is open. If
this is malfunctioning, your control unit might be getting
mixed signals. Your ECU might have a problem as well. Check
the fast idle screw you may have to turn this one down. It
works in conjunction with your idle screw. The fast idle
is well hidden behind the "N" on the nissan plate on your
intake collector. It might have a rubber plug I believe I
haven't looked at my car yet so you'll have to look and see.
You'll need multimeter on some of the procedures I just
mention. Lastly, while checking Fast Idle Control Device
(FICD), check the solenoid valve you may have to replace
this valve. OK I think that's everything.. If you done all
of this and it's still given you problems, than take a
sledge hammer to it and show your car who's the boss!!!
Good luck

Mike

 

Yep, that did the trick. That device right behind the "N" at the rear of the plenum has two screws that you can turn to adjust the idle speed. I turned the large screw inward and was able to get the idle down to 700RPM per factory specs. Thanks a million for your help man. BTW, the car passed CA emissions today with flying colors. I'm stoked!

-Jeremy

 

Jeremy,

I ran out of ideas so if one of those suggestions didn't
work you would of been stuck.. What part in Cali do you
live. My parents live in Mojave, CA. About 20 minutes from
Lancaster/Palmdale. I'll be going home from Ohio within the
month to visit.

mike

 

That's why this forum is so great; we can save each other time and money. I guess I owe you one huh? I know quite a bit about Maximas now since I'm on my third one. I changed broken exhaust studs, motor mounts, transmission, rear main, front main, and a bunch of other stuff on my 87 5-speed so I'm pretty comfortable wrenching on these 2nd gens now. I sold my 93 SE 5-speed Maxima a while back because it was using oil and the VTCs were going out for the second time. I'm located in Santa Clara, CA which is right by San Jose. Mojave is way down south by Palm Springs so I don't think we can hook up and talk shop. I'll be lurking in the forum though so I'll keep an eye out for your handle.

Later,
Jeremy

 

Jeremy,

Thanks and no you don't owe me at all. You would of
figured it out sooner or later. I was just looking at
your problem with a fresh eye. Enjoy your max... :P

Mike

 

I have the same codes 13 & 44, Swapped out chts ran fine for a while then the same stuff - wet plugs - die in the street when at idle. Not sure of my daughters driving habits. It took maybe four days of short in town runs. I'll look at the fuel return and the carbon can. Thanks ALL

 

So I read the second page when I got home fron work, played with the Max and came to the conclusion that I need to slow down. Ckeck each componet and use the f^%$#$g SEARCH FUNCHION.

My 53' Chevy pickup was so easy