J30 repair nightmare

11-01-2004, 09:22 PM
93 J30 170,000. Bought two months ago, tight, fast, clean and nicer than any much newer car I've ever owned. But....engine progressively began running a little rough - i figured a tune up was due, but eventually stopped to the point that it would start, but skip so badly it would not move. Took it to mechanic, replaced fuel filter (filthy), then fuel pump, then relay, all to no avail. Engine will turn over but is not firing and fuel is not pumping. Mechanic says, take it to someone else he is stumped. One more thing - may help-may not - just prior to this my dash lights blew a fuse. Replaced fuse and blew again a couple days later.... Can't CAN'T CAN'T afford dealership, need tips or things to try CHEAP things, please, I'm a GIRL-a POOR GIRL who needs her ride and is stuck with it since I OWE OWE OWE for it. Am in process of moving and have lost my owner's manual! Please if ever there was a damsel in distress.....I will be ever so grateful for any help.

11-03-2004, 12:37 PM
Well It looks like it a wiring problem in you car what I think base on my opioin is to take the car to check the computer of the car take it to where the do computer digiostis and it might tell you whats problems it has with the wiring of the whole car like also I try to talk to carlos and let me see what he thinks

11-03-2004, 12:46 PM
is there sparks in the spark plugs

11-03-2004, 08:09 PM
Your mechanic was obviously thinking it's a fuel problem. Has your check-engine light come on?

If so, you could take your car to a place like Autozone and have them read the codes off the car. Around here, they do it for free. However, if no check-engine light, there won't be a code to read.

It's possible that you have one of more bad fuel injectors. Bad injectors will make the car run really bad. You can check the injectors by testing the resistance between the injector leads.

Check this document. It talks about how to diagnose bad injectors and furthermore, how to replace yourself.


Good luck.

11-07-2004, 01:23 AM
is there sparks in the spark plugs
The lady said they were firing...

11-07-2004, 09:51 AM
Lisa, you sent me an email and I've replied to it but I wanted to post my reply here for the benefit of others that come across this thread.

You stated: "Thanks for your reply. This is very interesting to me, since I was thinking about having it towed 75 miles to the dealership just to let them run diags. I have no check engine light, ever come on during this whole mess. I just need SOMEONE who can correctly diagnose the problem without just beginning a part replacement extravanganza that will not end before my money does. I don't even know if the guy REALLY replaced the fuel pump. Isn't it necessary to pull the gas tank to do this? I had a full tank and I just don't think he did - he didn't give me a look at the bad pump or any paperwork or anything and yes, I know better! Based on your knowledge, what do you think the most likely culprit is, just guess the best you can based on the info I provided and list it from most likely to least likely.....and maybe another one listing cheapest to most expensive. I'm really not kidding when I say I can't afford this......What about the coil packs? Is there a relay under the driver seat? WHY can't I even ORDER a repair manual for this car? Is it REALLY the same as a 300 zx? If so, couldn't I just obtain a manual for one of those? I used to know a free download site that I got a free extensive manual for my 93 Lebaron convertible somewhere...."

My reply to your email:

First, I see that you're thinking about having your car towed to a dealership. You need to know that it's recommended that a flat-truck tow-truck be used to tow any rear-wheel-drive Infinitis (J30, Q45, etc.).

If the car is towed with the rear wheels on the ground, it makes the transmission components turn as the rear wheels turn. This heats up the tranny fluid but since the car engine is not running, the fluid is NOT cooled. Under normal driving, your transmission fluid is circulated up to through the radiator and back to the tranny to keep the fluid around 140F or so. If towed with the rear wheels on the ground, the fluid gets hot but is not circulated b/c the engine is off. The fluid will basically cook away and cause your tranny to fail. Big $$$$. If towed with the front wheels on the ground, the ignition cannot be in the LOCK position, the ignition has to be in the OFF position and the steering wheel stabilized so it doesn't turn. The easiest thing is to hire a flat-bed tow truck then you don't have to worry about any of it. They just pull the car up to the flat bed and none of the car wheels are turning. Problem solved. Whew... that was long. :-)

About your fuel pump. In the J30, it's suggested that the tank stay in the car when replacing the fuel pump. This is because in the J30, the gas tank sits upright between the back seat and the trunk liner. It's not under the trunk as in most cars. The pump itself sits on top of the tank so the gas doesn't have to be drained. It's possible that the fuel pump issue was not with the fuel pump alone but with the fuel pump controller (a circuit card that connects to the fuel pump) as well. A malfunctioning fuel pump can cause the controller to overheat and eventually fail. The controller is what tells the fuel pump when to turn on, how much fuel to pump, etc. If it dies, the pump will not work at all. I don't recall how much the controller costs. I'm thinking they're around $200 but don't quote me on that price.

Real car nuts suggest that you not let the fuel get lower that 1/4 tank. The fuel pump is cooled by the gas around it. The thought here is that if you let the fuel get lower than 1/4 tank, the pump is not fully submerged in gas to it's not as cool as it can be so it's life is shortened. I have no way to prove or dispute it but I've read it many times in other forums.

Your issue is so vague that I can't rank my guesses (and they're just guesses!) in order of likelihood or importance. Engines are simple in nature. They require fuel, oxygen, and spark in order to turn over. Also, your issue progressed from running rough to now not running at all.

Running rough can be caused by any of the following (not in any order): Vacuum leaks, Mass Air Flow (MAF) sensor (usually triggers check-engine light), Oxygen sensor (also triggers check-engine light), fouled plugs, fouled fuel filter, malfunctioning injector coil or fuel injector, dirty throttle body, perhaps something else I can't think of this second.

From your email, I see that after this mechanic replaced the fuel pump, the engine doesn't even run. I'd check the fuel pump fuse in the engine compartment (I'm sure he's done that already). The other suspect thing would be the fuel pump controller itself. Especially since the current mechanic is seeing NO fuel flow whatsoever. There was fuel flow before he worked on the car. I guess it's also possible that he didn't install the pump correctly so it's not working but again, I'm just trying to guess what could be happening.

My recommendation would be to flat-tow the car to an Infiniti dealer and let them diagnose. They are not cheap but they are experts on these cars. If money is tight, you could pay to have the diagnostic - anywhere from $65 to $100 depending on where you live. But the dealer has the Consult machine (nissan-specific diag. computer) and that alone can point to EXACTLY what may be going on.

About obtaining a manual. You can get them off Ebay (avoid the CD ROM version). Don't get a 300zx manual as the cars only shared the engine and I believe transmission. Although for the J30, the transmission is geared differently due to the J30s weight. All the electronics and diagnostics, etc. are different between the two cars. If you can't find one on Ebay, you can download EVERY manual and TSB (technical service bulletin) for most nissan-infiniti cars by paying $20 on the nissan website.

The link is: http://www.nissan-techinfo.com/infiniti/
Or you can call 1-800-247-5321.

If you use their web site's publication locator you'll see that they have the J30 service manual for years 94-97. Get the 94. I actually use a 93 manual for my 95 J30. I got my manual from Ebay. The car only had minor changes during it's production run (HICAS changed, Bose unit changed, etc.). 99% of the components are the same - any model year manual will do fine as long as it's a J30 manual, not 300zx.

Good luck.

11-08-2004, 02:03 AM
whoa awesome post! i hope she got it fixed.. any news on her?

11-08-2004, 06:34 PM
I haven't heard anything. Hopefully she can get it resolved easily.

11-17-2004, 11:38 AM
Yo carlos Should I get so points after all I told her to ask you man

11-24-2004, 04:22 PM
Lisa, I am unsure if you have resolved your problem by now or not, but I can help you with some of the basic troubleshooting steps, some you will be able to do yourself. Last resort I would take it to the dealer, especially if your short on money. A car needs 3 basic things to run:fuel, spark and compression and there are some basic tests to run to direct you down the right path. Feel free to email me if you are still having problems. ashswat24@aol.com

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