97 Nissan PU - Need help bad

Mar 17th, 2003, 01:12 PM

I have a 97 PU. I have been running on 3 cylinders for 30000 miles, 3 people (mechanics) have looked at it - NO ONE knows why - I have compression, fuel, spark, etc.... but a terrible running engine. Has anyone heard of this ? I am a huge Nissan fan, I have had Nissans for 15 years now but this is really turning me off.......

Please help anyone..........

Thanks
Tom

jadcock · Mar 17th, 2003, 02:16 PM

Somebody is mis-diagnosing the problem somewhere. There are only a few things an engine needs to run. Fuel, spark, compression, and timing. If it has fuel and it has spark...and you're SURE it has proper spark on all four cylinders, the problem has got to be in the spark/valve timing or the compression.

Assuming it has solid compression on all four cylinders, I'd suspect bad spark on one of them. It may come down to putting the thing on an oscilloscope or something to watch the spark on each plug wire. If you take the valve cover off, are all the valves operating as they should?

1997XETruck · Mar 17th, 2003, 11:39 PM

How did they verify that you have fuel? Sounds like it could be a bad injector to me...

Is the check engine light on? How does the spark plug look on that cylinder compared to the others (black, same, etc.)?

Heath

Mr.Mike! · Mar 18th, 2003, 03:29 AM

Take it in to a professional shop. I'm talking the dealer or some place where they can run an oscilliscope and/or whatever other tests they feel necessary.
Let us know what numbers they came up with. This may cost you between 50-100 or so, but they can find this problem for you.

JoanJetta · Mar 18th, 2003, 06:44 AM

check timing, codes, fuel pump pressure. if you have spark the primary and secondary electrical system is working. you obviously have strong enough fuel pressure to run it but maybe not properly at full throttle. My guess is the timing is off or there is a problem with a sensor, computer, etc.

super22ll · Mar 24th, 2003, 12:05 AM

The first thing I would check is the firing order. It's possible someone go the spark plug wires crossed and it's firing out of sequence. This is a common mistake. It may be as simple as that.

aaronford · Mar 24th, 2003, 09:36 PM

Pull plug wires one at a time to find which cylinder is not firing. (With truck off, pull No. 1 start truck see if the truck runs worse. If so reconnect No. 1 and proceed to No. 2 Do this until the truck runs the same with the plug wire on or off. This is the problem cylinder.) Let's say it's No. 3. Swap spark plugs from 1 & 3 and see if the problem moves, then try the same stunt with the plug wires (if they reach). The try moving the injector. I figure you have a bad part somewhere and a some mechanics who are unwilliing to spend the time to diagnose it properly. Write back and share what you have found. Good Luck Aaron

1997XETruck · Mar 25th, 2003, 10:55 PM

Quote:

Originally posted by aaronford
then try the same stunt with the plug wires (if they reach). The try moving the injector.

Just a quick addition to this... make sure you change the plug wire on both ends! (e.g. Plug end and Distributor!) - you don't want to change the firing order, just eliminate good parts.

Heath