- This topic has 11 replies, 6 voices, and was last updated 10 years, 3 months ago by
.
-
Topic
-
Ok guys first off ETCG is awesome! I am not a complete noob to auto repair. I can install a timing belt with the best of em. I however have never mustered up the courage to take on something as in depth as say rebuilding an engine. I also am not the worlds best diagnostician. (Did I just make that word up?)
Anyway, I seem to have taken up this hobby of resurrecting completely worthless classic cars that I find that are in good condition. I am currently tinkering with a 1987 Maxima SE auto with a VG30E. The car, when I got it, ran so so. It lacked power, but seemed to have a good solid engine and trans, and the interior and body are almost perfect. I loved these cars back in the day and would like to get this one going good again.
It seemed to me at the time that it had a one cylinder miss. No CEL, no smoke, no bad engine noises, etc. Just down on power. I was thinking vacuum leak. And it did turn out to have a couple. Also I found that the timing on the left (rear) cam was one tooth off I think. I checked it because the guy said that he had just put a new timing belt on it. (So I figured that he had done it wrong, given up on it, and dumped it on me.) the pulley marks still dont line up perfectly with the reference marks on the rear timing cover and oil pump. But I think they are correct now according to what I’ve read online and in the book.
I also found that the electrical connectors to the injectors were broken when taken off at some point( all of them) and that they were horribly corroded. I cleaned those up. Helped a little. But somewhere around that point the car started doing WAY worse. Then it would run great for a minute or two, then barely go or quit, then back to ok. Randomly, hot or cold, I couldn’t find any method to the madness. So I gave up for a week or two and now I’m back at it.
It will throw different codes, first was a fuel system code, but I put a fuel pressure gauge on it and its around 40 psi, which is a little high according to the book I have, and goes up to about 60 when I pinch the return line. And now I don’t get that code.I’ve been cleaning connections and looking at wiring lately since that seems to be the biggest issue I’ve seen with it. And at some point after I cleared codes it threw a ignition system code, a 21 “ignition signal” this is currently the only code showing up. Last night I was “spraying?” propane around checking for vacuum leaks again and bumped the TPS (they call it something different) and it cleared up and ran like a champ. For a while. I ohmed it, got NOTHING, took it off, cleaned it inside (took the cover off) got it working, and put it back on. When I first got it I noticed that the connector to the Air Flow Meter was off. I just put it back, well today I was cleaning it and when I put it back on it helped. A lot. Its back to where it was when I got it now. Running good at lower RPM’s, but lacking power across the board. I did a power balance test and each cylinder seems to be the same. It will drive ok until you try to “get on it” at all then it goes crazy. But if I go back to babying it it will clear up fairly quickly and do OK again. uhm… lets see, also, with no load, in park it will generally rev up just fine. Although not always. I know this post was long, and a bit random, but I wanted to give all the info I have on it. (Compression was around 140-145 across the board as well) 155k miles. ANY IDEAS WHERE I GO FROM HERE!?!? Thanks to any that so much as out in the time to read this. Much less offer advice.
-
Replies
-
That is a wall of words… but very descriptive…
If it runs decent one minute, bad the next, I suspect electroncs/wiring issues…
You mentioned the fuel injector electrical connections… That can be suspect (did you do a power balance test by disconnecting these one by one?, or test with a noid light?)
The timing may have been fixed or made better, but here is something about timing belts and the marks on them…. They sometimes do not line up correctly… Also, they are designed so that the same places on the belts do not consistently hit the same cogs, so it really is no surprise they are not lined up after the engine has been run for even a short period of time…
Vehicles this old can be challenging to find the solutions….
The other end of the electrical problems are the grounds… Bad grounds can give you fits… What looks like an ordinary bolt into a metal piece can be a bad or highly resistant ground issue…. These should be checked…
Other things can factor in… Spark plugs, rotor, cap, etc…. so in a vehicle this old, they should be eliminated as a possible cause (not saying this is the issue though)…
I would look at the ignition system for wiring/ground issues… OBD II makes it so much easier nowadays and these old ones can present a real challenge… I would look at an electrical schematic for the ignition system for grounds and check the wires…. Not fun… You may get lucky and run the car and “shake” wiring harnesses till the vehicle runs well and locate an issue…
Best of luck…
-Karl
Well, by “it goes crazy” it generally acts like its running out of gas more or less. It starts missing really bad. It will keep running most of the time, but only at idle. Will not take fuel. And I have the hood off with a FPGauge connected inline and it doesn’t change. So it is getting fuel. If I turn it off and start it back up 90% off the time it will clear up and run better for a minute or two. ( literally) Then sometimes I can drive it for miles without a problem. The other night it ran like it should for quite a while. That was a first. Had plenty of power, no misses. Yes, it needs a complete tune up. But I’ve done the balance test by pulling the injectors one at a time and they each caused about the same RPM drop. I sprayed pretty much everything with water at night and didn’t see a spark one. I’ve never had a sensor go bad on a car, so I hate to blame one,(other than an oxygen sensor or two) especially by the condition a few of these connectors are in, but messing with the air flow sensor seems to cause improvement sometimes. Are these symptoms something it could do? Thanks for your relies guys.
and I was scared to hit enter for fear that it would submit my rant a little prematurely.
But that doesn’t seem to be the case 😀
[quote=”boostedbox” post=107567]Well, by “it goes crazy” it generally acts like its running out of gas more or less. It starts missing really bad. It will keep running most of the time, but only at idle. Will not take fuel. And I have the hood off with a FPGauge connected inline and it doesn’t change. So it is getting fuel. If I turn it off and start it back up 90% off the time it will clear up and run better for a minute or two. ( literally) Then sometimes I can drive it for miles without a problem. The other night it ran like it should for quite a while. That was a first. Had plenty of power, no misses. Yes, it needs a complete tune up. But I’ve done the balance test by pulling the injectors one at a time and they each caused about the same RPM drop. I sprayed pretty much everything with water at night and didn’t see a spark one. I’ve never had a sensor go bad on a car, so I hate to blame one,(other than an oxygen sensor or two) especially by the condition a few of these connectors are in, but messing with the air flow sensor seems to cause improvement sometimes. Are these symptoms something it could do? Thanks for your relies guys.[/quote] take out the ignition coils and inspect the spark plug wells for oil…I had that happen once because of a bad gasket.
Well, you say it ran nice the other night. This is kinda off the wall but it is possible that your fueling station is selling winter gas. Winter gas has additives in it to make it more volatile. Running on that on a hot summer day might cause vapor lock. It would be a simple solution if it works and its not costing you anything so try some different gas.
[quote=”Monkey wrench” post=107583][quote=”boostedbox” post=107567]Well, by “it goes crazy” it generally acts like its running out of gas more or less. It starts missing really bad. It will keep running most of the time, but only at idle. Will not take fuel. And I have the hood off with a FPGauge connected inline and it doesn’t change. So it is getting fuel. If I turn it off and start it back up 90% off the time it will clear up and run better for a minute or two. ( literally) Then sometimes I can drive it for miles without a problem. The other night it ran like it should for quite a while. That was a first. Had plenty of power, no misses. Yes, it needs a complete tune up. But I’ve done the balance test by pulling the injectors one at a time and they each caused about the same RPM drop. I sprayed pretty much everything with water at night and didn’t see a spark one. I’ve never had a sensor go bad on a car, so I hate to blame one,(other than an oxygen sensor or two) especially by the condition a few of these connectors are in, but messing with the air flow sensor seems to cause improvement sometimes. Are these symptoms something it could do? Thanks for your relies guys.[/quote] take out the ignition coils and inspect the spark plug wells for oil…I had that happen once because of a bad gasket.[/quote] whoa! nm just seen that your Nissan is an 87 lol….sorry bout that
I had a 93′ Maxima that acted very similarly when the Mass Air Flow sensor was taking a dump (something that happened pretty regularly with that car). I had very limited success cleaning them, and generally wound up just hunting down used ones cheap on Ebay. As a matter of fact, I used to try to keep one on hand so I could swap it in quickly when needed.
Thanks for the replies guys. For some reason I’m thinking it is a bad mass air flow sensor. Especially if they can just kinda work. I’ve had bad connections and while this car certainly acts like it could be one… at the same time it doesn’t. It acts more like a computer going nuts or at least SOMETHING important going nuts.
Do any of you guys know if the other cars with this engine from the same general era use the same maflow sensors will interchange? Specifically the pathfinder ones. My local pick a part has several of those.OK, with any performance problem, start with the basics. You say you have yet to start with a basic tune up, I would recommend you start there. Many performance problems have simple causes. I agree with ToyotaKarl in that it sounds electrical but if you need the tune up items anyway, why not replace them to eliminate them from the list of possible causes. As for testing MAF sensors, I often tap on them with the butt of a screwdriver while the engine is running. If the engine acts up, I can be reasonably sure there may be something going on with the sensor.
BTW Nissans of that vintage had issues with coils and also fuel injectors. Although that should have showed up during a power balance test.
I also cover a lot about performance problem diagnosis here.
http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
Good luck and keep us posted on what you find.
- You must be logged in to reply to this topic.