Jump to content

Trouble starting Cold Engine, Differential Jerks, and Rpm's slowly go down.


db280z

Recommended Posts

I have a 1977 Nissan 280z and i have about three major problems. The first is that the car jerks really bad when im going really slow in all my gears especially when i try to accelerate slowly. i feel like its coming from the differential. I still have to replace he mustache bar bushings and the differential mount. i am currently replacing the u-joints as well. i just want to make sure what to do before i start spending money left to right.

the second problem i have is starting up the car in the mornings or at any time when the engine is cold it takes me about 3 to 4 minutes just to get it to turn on. The car turns over and over but sometimes it doesn't want to catch on until i keep trying over and over. i checked my fuel pressure regulator and that seems to be pushing out 40 psi, and the fuel pump has been replaced as well. the car does not tend to have this problem when the engine is warm. My third problem is that when I'm accelerating sometimes my rpm's stay up really high and i have to wait for it to slowly come back down in order for me to put it into gear so i don't get a bad shift. thanks for your help guys.

 

Link to comment
  • Replies 6
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Yes the motor is timed a buddy of mine had done the timing for me like about a week ago. We had to retard the timing because it was too far up. But now when its idling at warm temperature it runs pretty smooth @ about 800rpms

 

is the motor timmed?
you have a timming light?
intake is tight for the starting proplem

Link to comment

thats the far as I can go. I assume this is Fuel injected

yea it is fuel injected. i did a full tune up on it and still continues to do the same. 

 

Confirm that the air regulator/choke is functioning properly

How would i go on about testing the air regulator? would i just have to check to see if it has continuity in order to see if its still good?

Link to comment

The next time you try to start it pull the coil wire off the distributor cap, stick a spark plug in it, lay it on a grounded surface, and have someone turn the engine over. Is there spark??????

 

NO............... find out why and fix. A loose wire on the coil would also explain the jerking. The ignition would be randomly interrupted just like turning it off and on.

YES............. connect the wire back up and pull a spark plug wire off and try the same thing. Is there spark?????

 

NO................ something is wrong between the coil wire and the spark plugs. Inspect the rotor, cap and plug wires.

YES............... timing....

 

 

 

You said the timing was wrong and you retarded it. Maybe your buddy means well but doesn't know what he's doing and it's now severely retarded? Getting the idle correct by adjusting the timing is wrong. The timing should be 7-10 BTDC with the vacuum advance hose off. (I don't have the exact amount but you can safely advance it bit by bit until it pings and then retard slightly until it stops)  

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.