# VG30i dies while driving



## mxer239 (Dec 14, 2017)

I have a truck that has been dying while I'm driving. Sometimes it will die just a few minutes after I get going, other times I will be driving problem-free for 20 minutes before it dies. It will start to "stutter" and the tachometer will spaz out before it dies. It also won't start after and makes a fast clicking noise. I'll try to go into more detail about each time it's happened.

First time - about a month ago after going 4 wheeling - died while idling without any warning as my friend and I were getting ready to go home. I got a tow until we got to the top of a hill where I bump started it and drove home.

Between the first time and the second, about 10 days pass with no problems. However, it showed the warning signs of stuttering and the weird tachometer but did not die.

Second time - It dies as I am slowing down for a stop sign. 2 friendly strangers pushed me to the side of road where one of them looks under the hood and suggests that it could be getting flooded. He takes he cover off the air cleaner and it started right up, then I drove home without the cover on.

Third time - I am driving around to see if it will die again. Does fine for about 20 minutes. Once again dies coming up to a stop sign. I used the slope of the road to coast off to the side. I wait a few minutes before trying to start it.... nothing, just cranks. I give up after about a half hour and walked home, leaving the truck on the side of the road.

After ruling out the fuel pump with a fuel pressure test, I cleaned all the grounds I could find in the engine bay and that _seemed_ to fix it.

Then this last weekend, my friends and I went 4 wheeling and my truck ran OK for about 15 minutes before it died again. I was able to get it started again but had my friend tow me just in case.

Then this morning I was driving to school and the tach bounced a few times but it didn't die. It also hesitated a bit while taking off from a stop sign.

Needless to say it's getting pretty frustrating and I'm tired of wasting time and money on it. Any help is appreciated.


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## rogoman (Dec 16, 2004)

First of all, state the year of the vehicle. One of the first things to do is perform an ECU code readout with a portable scan tool to see if any fault codes are set. The tool can be purchased at most auto parts stores. The condition you're describing can be caused by a marginal crankshaft position sensor or a camshaft position sensor. If you're buying one or both of them, buy only OEM units from a new car dealer. Don't buy aftermarket types; they've been known to fail in a short time; some are even DOA.

How long have you had the old spark plugs? If they are very old, then it's time for a set of new ones.


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## mxer239 (Dec 14, 2017)

Thanks for the reply. Sorry maybe I forgot to say it's a 1986.5 Hardbody. I've checked the ECU for codes and it doesn't give me any. The spark plugs and wires are only about 2 months old.


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## smj999smj (Jan 1, 2006)

It "could" be a bad distributor, which is a very common problem on VG engines as they get older. Often they fail as they get hot and will cause you to lose spark, but as it cools down, it will start working again. So, if you can get it to stall out, check for spark. If there is no spark, there's a pretty good possibility that you need a new distributor.


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## mxer239 (Dec 14, 2017)

smj999smj said:


> It "could" be a bad distributor, which is a very common problem on VG engines as they get older. Often they fail as they get hot and will cause you to lose spark, but as it cools down, it will start working again. So, if you can get it to stall out, check for spark. If there is no spark, there's a pretty good possibility that you need a new distributor.


Bad thing is that I can't get to die when I want it to..


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## mxer239 (Dec 14, 2017)

Ok so I found a complete distributor assembly on Amazon for a pretty good price. (Spectra Premium NS29 Distributor) It's not OEM but I couldn't find any of those anyway. If I installed it then it would replace all the possible culprits mentioned earlier.


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## jp2code (Jun 2, 2011)

I was going to suggest one of the interlock relays, too. @SMJ or @Rogo, either of you know what relays the 1986.5 would have?

I'm guessing this is a 4x4 (he mentioned wheeling) and a manual transmission (he mentioned bump starting). The manual transmission has a clutch interlock relay near the battery. It is sealed, but it can still get corroded inside and not close enough to turn the relay ON.










There are 2 relays in the picture above. I think the clutch interlock relay is circled. Other relays are being pointed to.

You can jury-rig a couple of jumper wires to completely bypass these safety relays. I tested a bypass with this setup below, and used it a couple of years before I went in an clipped those connectors off and soldered the wires together forever.












rogoman said:


> One of the first things to do is perform an ECU code readout with a portable scan tool to see if any fault codes are set. The tool can be purchased at most auto parts stores.


Unless I am misunderstanding you, that only works on OBD2 and up models, which didn't start until 1996 - after Nissan stopped putting V6 engines in these. The VG30i ran until 1990 or so, I believe.


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## rogoman (Dec 16, 2004)

Yes, the scanning tool only works on OBD-II systems starting in 1996 on these trucks. The poster never specified the year of his vehicle so it's like the blind-leading-the-blind. With something like this, you can only suggest diagnostic procedures. Well he finally stated the year. The 1986.5s should have a clutch interlock relay mounted on the passenger's side inner fender well.


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## mxer239 (Dec 14, 2017)

Sorry about the confusion about the year and such. I'm used to another site that lets you put information about your rig under your name. Just to be clear its a 1986.5 Hardbody SE V6 King Cab 4x4, manual trans.


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## smj999smj (Jan 1, 2006)

mxer239 said:


> Bad thing is that I can't get to die when I want it to..


Get the engine hot and while idling, heat the base of the distributor with a hair dryer or, better, a heat gun, to see if it stalls. If it does, then it's likely the distributor, but you can check for lack of spark at this time, as well.


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## smj999smj (Jan 1, 2006)

_"Unless I am misunderstanding you, that only works on OBD2 and up models, which didn't start until 1996 - after Nissan stopped putting V6 engines in these. The VG30i ran until 1990 or so, I believe."_

There was actually a code reader tool for the Nissan OBD I style connector (picture linked below):

http://nissannut.com/maintenance/obd/connector.JPG

It was called the "Checker Box" and made by Kent-Moore. You would plug it into the connector and it had a toggle switch, a numerical display and it "beeped." It essentially was a remote tool to access the ECM so you could see the green and red LED flashes without have to pull the passenger seat or kickpanel cover, depending on the vehicle used. You could read the codes and switch between the five diagnostic modes on five mode systems. They are like finding a needle in a haystack, these days! I have one and you might find them in older Nissan dealers, but I'm pretty sure Kent-Moore stopped offering them decades ago.


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## smj999smj (Jan 1, 2006)

mxer239 said:


> Ok so I found a complete distributor assembly on Amazon for a pretty good price. (Spectra Premium NS29 Distributor) It's not OEM but I couldn't find any of those anyway. If I installed it then it would replace all the possible culprits mentioned earlier.


I hate using anything other than genuine Nissan reman distributors, but, those have been discontinued for those VG30i engines. Spectra Premium is a pretty good brand, reputation-wise, but I can't guarantee that replacing the distributor will fix any of your problems until you can isolate the cause of the problem to the distributor. 

It also sounds like there may be two problems to figure out. One is the stuttering and stalling while driving and the other is the starting issue. If a distributor fails, it can cause hesitation or "stuttering," misfiring, stalling and/or cranking but no start/no spark conditions. It won't cause the battery to make a "clicking noise" nor will it cause a "no crank" condition. Those are more typical of a battery/charging system issue. I would check the charging system voltage to make sure it's within specs (13.2-15.5 volts, @ idle and @ 3000 RPM, with and without loads "on" (headlights, rear def, etc.). Also, have the battery tested and make sure the terminal connections at the battery posts are clean and tight. Make sure the battery cables are good, as well. If the interlock relay is bad, you will get a no crank/no start condition and you also will usually not hear any noise, unless it's coming from the relay, itself (and, yes, it's the relay with the two harness connectors going to it).


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## mxer239 (Dec 14, 2017)

Well smj999 the truck ran fine while I pointed a hairdryer at the base of the distributor, so it's probably fine. I'll have to look into the charging system and get the battery tested before work tomorrow.

I also checked the interlock relays and they looked clean and corrosion-free.


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