need help with nissan pick up

1988 nissan pick up, 4 cylinder standard 2.4 motor. engine knocks when taking off from stop, seems to get better when higher rpm's. rough idle also.
any ideas as what to look for.
I changed wires, found one that was arching. cleaned plugs as they were not too old ?

 

The effects will be felt more under load (like when taking off as opposed to highway cruising). Is this knock a result of the misfire?, or independent of it? or can't you tell?

And when cleaning plugs have an eagle eye to look for any hairline crack in the cone part of the insulator (the part that is inside the cyklinder head). These cracks can be extremely fine and clear looking.

Arcing can be a result of insufficient grounding of the high power electrical coming through the wires when it can't find a good ground - like if there is something wrong with the plug or break in plug wire at boot area. What then it does it tries taking another easier path to ground.

 

That is when it is noticable, upon acceleration. I guess it could be misfire, but not really sure. It would idle smooth before and now it chugs.
Suggest changed plugs ??

 

Plugs are chep enough. But I always took pride in my diagnostic abilities and hated to change plugs after careful inspection revealed nothing wrong, including no insulator crack or carbon-fouling. I pick plugs clean with knives and dental picks, down in the cone area (VERY important area to prevent spark jumping across to thread area without having to spark at electrode tip!), and also brighten up both tips of the electrode, and blast clean with starting fluid and reinstall. It never hurts to re-remove plugs to see if something telling is going on in some particular cylinder including a wet plug or plug going carbony or oily looking, or even TOO clean looking compared to the others.

 

I agree it is usually noticable to find something with a plug.
But I did buy new plugs, lol, it actually seems worse.
Will the distributor only move a little bit on these unlike a chevy SB.?
I am going to check timing next ?

 

what brand of plugs did you buy? My wife's V6 Nissan runs like crap with Bosch plugs. You may want to try another brand, I don't know why, but there is a difference.

If you haven't done one in a while, you may also want to do a full tune up, cap, rotor, fuel and air filters. Look closely at the wires, if over 100k miles, you may want to replace them.

Hope this helps!

 

Bosch is what I bought, thats what was in there before and it was fine.
I didnt the rotor, filter was only a couple months ago.
Wire are new, just replaced when this started as plugs the same.
still looking ??

 

You may want to do a compression check. When compression is bad, the vehicle runs the worse at idle or just getting going, more so then, than when cruising. The reason for this is when cruising, the pistons are traveling faster preventing any suspect cylinder from leaking down as fast.

 

late reply on this one timing chain was loose. thanks for help

 

Thanks for the (late) information. It's always nice to hear back from people. Did you find/fix it yourself, or take it to a garage? And it was absolutely the loose chain and not something else that also was fixed while someone was at it?

 

I finally pulled the cover off to see if I could see anything like valve sticking etc, right away you could see the chain sloppy. which sort of makes sense now, wouldnt loose power or anything, just make noise.


next item I have posted is do you know how much fuel preseure I should have on a 94 nissan pick up. 6 cylinder FI.

 

Don't quote me, but about 40 psi I think.

 

thx, thats what I get if I have the coil wire off cranking it over.
If I have it running I get 32psi, and like 37psi when I rev it.