Indigent Posted December 23, 2007 Share Posted December 23, 2007 (edited) Hey everyone. It has been a very long time since I have posted. I was in the Air Force stationed in Japan, but I am back in the States now. I had to get rid of my TD Terrano as I couldn't bring it back with me, but now I have a 91XE. I know very little about the VG30E's. I picked this pathy up for $1000 bucks. Body is in great shape, but the engine runs like crap. Most of the time it takes 8plus cranks to get it to start, and when it does, it just dies right away. When it is finally going at idle, it lopes really bad and dies sometimes. There is really bad fuel smelling smoke coming out of the exhaust, and when I stick a piece of paper in front of the tailpipe, it sucks it in every once and a while. There isn't any real rhythm to it, so I don't understand that. I put seafoam in the gas and in the oil and it started spitting out black liquid from the tailpipe. It runs slightly better on higher octane gas, but not much. Also sometimes there is a severe lack of power from stop, but it goes away when i reach about 25 mph. The previous owner said he just had the timing belt done a few months ago and that was when it started. I know it seems like a no-brainer to check it, but is there anything else it could be? I would like to figure out everything I could try before I go tearing into this thing as it is my daily driver. I have done all the tests, mode3 kicks out a 55. As a last resort, I increased the idle speed so it would quit dying. Any and all suggestions will be greatly appreciated. I did search quite a bit, but all I found that was similar was this: http://npora.ipbhost.com//index.php?showto...l=valve+problem but there was no sollution. Indigent. Edited December 23, 2007 by Indigent Link to comment Share on other sites More sharing options...
94extreme Posted December 23, 2007 Share Posted December 23, 2007 i'd bet on the timing as that was just messed with. put the light on and see what you get. Link to comment Share on other sites More sharing options...
Slick Posted December 23, 2007 Share Posted December 23, 2007 start with the timing... how is the exhaust system? look old? bad o2? bad cat or muffler? Link to comment Share on other sites More sharing options...
Indigent Posted December 24, 2007 Author Share Posted December 24, 2007 I have checked the timing, but I can't see a definite timing mark. The shop that did the timing put an ambiguous white mark on the pulley, and i have no real idea if it is at 15btdc like it is supposed to be. Also, I can't get that white mark to line up with the 0deg mark post. How would I check the O2 sensor. I have a chilton's but it is one I bought in Japan, and it doesn't really say how to check the sensor. A buddy of mine said that on his pickup, he had to check for voltage there, but he doesn't seem to remember how much. The exhaust looks fine physically, but the last section of the pipe is moveable. I can literally shake it. It is the section just aft of the muffler. It actually looks like it is not really secured to the muffler itself. Would that cause my problems? The main thing I am concerned about is the exhaust pipe sucking. I am hoping it isn't a head. But the thing I don't get is that there isn't a real pattern to it. It is off beat, which suggests that it isn't just one valve, or that it isn't sticking all of the time. Thanks for the fast replies btw. indigent. Link to comment Share on other sites More sharing options...
94extreme Posted December 24, 2007 Share Posted December 24, 2007 is the mark at 0 at TDC? does the rotor point to wire #1 at TDC? Link to comment Share on other sites More sharing options...
88pathoffroad Posted December 24, 2007 Share Posted December 24, 2007 I would check your cap and rotor first. Besides timing belt issues, a MAF sensor issue could contribute to your problem...wiggle the MAF sensor wiring while it's running and see if it changes the idle or anything. The VG30E MAF sensor wiring is notorious for possibly hitting the underside of the hood and damaging itself. Connectors also corrode over time. You can also pull and clean the MAF sensor... There's a thread covering that topic in the Garage: How-To section. Link to comment Share on other sites More sharing options...
jj big shoe Posted December 25, 2007 Share Posted December 25, 2007 Could be that the belt was put on wrong which could explain the lack of power off idle and the sucking at the tailpipe. If your cam gears are off time with the crank, you're valves won't be opening at the right time which will allow the compressed air/fuel to escape before detonation and a lack of power. It may also explain the tailpipe sucking in if one head's exhaust valves are still open during the piston's intake stroke. Link to comment Share on other sites More sharing options...
Indigent Posted January 6, 2008 Author Share Posted January 6, 2008 First of all, Sorry about the delay in updates. I really appreciate everyone's suggestions. I put a timing light on it, and there is an arbitrary white mark on the crankshaft pulley. It is about 85deg after the 0tdc mark. I pulled the radiator and the fan out, and turned the crankshaft to 0tdc. Then I pulled the dizzy cap off and the rotor is at the #2 cyl position. Turns out I don't have a big enough socket to pull the crankshaft pulley off, so alas it will have to wait until Shuck's opens in the morning. I am so relieved to have found something. My main question now is how many teeth off would the belt have to be for it to advance almost a whole cylinder? I tried advancing all of the plug wires to compensate for it, but the engine wont even turn over. More updates tomorrow (and probably more questions) after I get the timing covers off. Indigent. Link to comment Share on other sites More sharing options...
adamzan Posted January 6, 2008 Share Posted January 6, 2008 IIRC if the belt is off three or more teeth, pistons start hitting valves. Link to comment Share on other sites More sharing options...
95shakinPF Posted January 6, 2008 Share Posted January 6, 2008 Just pull the belt back off and start over!! Line it all up put the belt back on and go with that!! If you loosen it up to try to move it a couple teeth, you may end up bending valves. Be safe and correct!! Good Luck!! Link to comment Share on other sites More sharing options...
88pathoffroad Posted January 6, 2008 Share Posted January 6, 2008 IIRC the crank pulley can be reinstalled in 6 different positions, someone may simply have put it on the wrong way after doing the t-belt. The balancer is keyed for one position so it only goes on one way, but the six bolts on the pulleys mean it can be put on any which way. I'd check into that first. Link to comment Share on other sites More sharing options...
Indigent Posted January 10, 2008 Author Share Posted January 10, 2008 Well I think I have it all fixed up. I made sure the teeth are 43 and 40 on the belt and it is now running much much better. There is still a bit of a problem though. I think it was a combination of a few things including the timing belt. I definitely found the timing belt off 2 teeth, but now it sounds like it is backfiring. When I give it some gas and let go, while the RPMs are coming down, it backfires a few times. Thanks all for the help on this. I know it has been covered a thousand times, but thanks. Hey 88, if you are ever in the mood, and are up in yakima, give me a holler. Link to comment Share on other sites More sharing options...
Indigent Posted January 11, 2008 Author Share Posted January 11, 2008 (edited) One really awesome update! I was browsing other topics that might be similar to mine and heard people talking about the vacuum line by #6 Cyl. so I decided to check it out. I went to pull off the vacuum line to inspect it and when I did, BAM, the engine perked right up! The hose is perfectly fine. I just want to confirm that that vacuum line is for the fuel pressure regulator. Would it be the fuel pressure regulator, or maybe the fuel pump? I hope that is all that is wrong. I am super glad to have found something dramatically wrong! indigent Edited January 11, 2008 by Indigent Link to comment Share on other sites More sharing options...
Kittamaru Posted January 11, 2008 Share Posted January 11, 2008 That is def. a good find! The vacuum line and the system attached to it can cause some... interesting... results when it starts reading incorrectly. I got to watch my mechanic work on a 2001 pathfinder that was running very weak... guy couldn't even put it in reverse or it would stall, same when stopping completely at red lights and stop signs. My mech took something in a spray can (not sure what it was) and sprayed it around the top of the engine (at the time I had no idea what he was doing). As the engine idled, it suddenly perked up. Apparently that was what he was spraying (some form of evaporiate compound) being pulled INTO the bad seal and temporarily forming a secure bond. A few seconds after he stopped spraying it, the engine started to choke again... he repeated this till he located the problem area. Was, of all things, a leak around the vacuum sensor that was giving a bad reading on the sensor itself. At this point I had to leave as my truck was finished by his younger brother (was just getting an oil change) so I'm not sure how he fixed it... I assume he'd replace the tubing and/or the gaskets? Link to comment Share on other sites More sharing options...
tbone Posted January 11, 2008 Share Posted January 11, 2008 (edited) I've seen mechanics use propane out of a small tank to find vaccum leaks. It pulls the propane in and revs up . I think wd-40 does the same thing Edited January 11, 2008 by tbone Link to comment Share on other sites More sharing options...
Indigent Posted January 12, 2008 Author Share Posted January 12, 2008 I don't think it is a leak. When I pull the hose, the engine runs great. I can duplicate the problem with the hose disconnected by blocking the port on the injector manifold with my thumb. It is like the fuel pressure regulator is stuck or something. I am going to pull the regulator out and try to test it manually somehow, maybe even take it apart. The hose is fine and there isn't anything in it. Could this be caused by the fuel lines being installed wrong somewhere upstream? Link to comment Share on other sites More sharing options...
88pathoffroad Posted January 12, 2008 Share Posted January 12, 2008 I'd check prices on the FPR, if it's cheaper than buying a fuel pressure guage, get a new FPR and see if that fixes it. If not, put the guage inline after the regulator and check fuel pressure, you should have 43 psi IIRC. Or was it 46? I forget. Somewhere in there. Link to comment Share on other sites More sharing options...
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