Questions and Answers

Nissan D-21 Intermittent No Start Q. Vincent, I really appreciate the info on the About Pages, however, I would like additional information concerning whether or not I need to drop my fuel tank in order to change the electric fuel pump on my 1987 Nissan, 4WD, model D-21 pickup with a VG30 engine. VIN is: JN6HD16Y5HW000981.

I have had a problem which is quite intermittent with starting the vehicle, much of the time it kicks right over and starts just fine, there are times that I crank engine and nothing happens, if I keep cranking it will eventually catch and start. There is black smoke when it does initially start when the latter happens and once engine smooths out it disappears.

It doesn't pick a particular time to do this, sometimes the engine is cold, other times it occurs when engine is hot. It is very random and unpredictable. I have throttle body injection and have recently changed the injectors as the original ones were still installed and have had no maintenance since truck was new.

I may be looking at the wrong thing and perhaps this is an ignition problem, I don't know. I tried to take it to a local repair place to have them diagnose this and was told that the problem would have to appear at the time or they couldn't diagnose it. Of course, the problem never appears when you want it to.

Could an electric fuel pump cause this? Perhaps I am hasty in that I suspect a fuel pump, it may not even cause the problem I described. I have also changed the fuel filter. Truck has had exceptional care and has received routine maintenance faithfully. I have only used genuine, new Nissan parts when needed.

I am quite frustrated trying to figure out what would cause this problem. Yesterday it acted up while driving which is the first time this has happened, engine lost power and started running roughly. I pulled over, stepped on the accelerator pedal and got it running smoothly and came home.

Again, when I was able to get some RPM's I noted the black smoke as in a rich fuel mixture. This has been a tremendously reliable truck and it has run great with absolutely no problems since new, until recently.

Can you provide me with any enlightenment as to what I should look for and perhaps what may be causing my problem? I thank you sincerely for your attention to this inquiry. Appreciate reading your articles.

Gerald
California City, CA

A. We have to confirm it is a fuel problem first. The next time it won't start, spray some carburetor cleaner down the throat of the throttle body while someone cranks it over. If it starts and runs as long as you are spraying, you do have a fuel problem.

If not, pull a plug wire, stick a spark plug into it and lay it on something metal so it has a good ground. Crank the engine and observe the spark. If there is none, then we are looking at an ignition problem.

This particular engine had problems with distributor caps cracking so that would be a good thing to check and replace. They also had problems with the Crank Angle Sensor in the distributors.

A fuel pressure tester will tell you if there is good fuel pressure or not. It should hold pressure over night to make starting easier.

If push comes to shove, the fuel tank does have to come out to replace the fuel pump.