I had to replace my cmps the other day, so I thought I put up how I did it. It is a easy job I would say. I got a new sensor from a place that remanufacture distributors for 605ZAR( about 55 USD). I don't know yet if one can fix the sensor itself, it is sealed with a hard glue. Will open it up at later stage.

Ok so here goes:
1. Remove the distributor cap. Held with 3 screws.

2. Mark on the distributor body where the rotor is pointing. Also mark roughly where the bolt is that holds the distributor in place.


3. Remove the rotor.

4. The remove the cover plate that sit under the rotor. held by 2 screws.



5. Remove the top piece of the centre shaft. It is held with a single screw. Mine was hard to get loose so be careful not to hurt the screw.


6. Now carefully remove the slotted disc. NOTE it has a top and bottom. If inserted wrong the slot the indicates cyclinder 1 would be in wrong place.

7. Remove the plate that holds down the cmps. 3 screws.

8. Remove the bolt that holds down the distributor.

9. Unplug the wire connection to the distributor. 1 ground and one plug of 4 wires.

10. Now slightly turn and wigle the distributor as you pull it upwards. It sit a bit tight for a nice seal to the oil.

11. On the bottom is the plug for the cmps. It is held inplace by a small plate and 2 screws.


12. Remove the plug. It sit tight so wigle it a bit.


13. Now the cmps just go out the top.

Ok now it is stripped down.
Also make sure the the slotted plate is good condition.
Now lets put everything back together.

14. First put in the new cmps. Put the plug in at the bottom and screw back the small plate that keep the plug in
15. Insert the plate that holds down the cmps.
16. Insert the slotted plate right way up.
17. Insert alignment washer and top shaft piece and screw it down.
18. Insert cover plate and screw it down.
19. Insert rotor.
20. Place the distributor back in the engine. Note that as the distributor slots back in the rotor will turn a bit,thus you need to rotor the about 20-30 degrees clockwise past the mark you made to have it on the mark once the distributor is back in the engine.
21. Insert the bolt that holds the distributor. Now the marking of the bolt and the marking of the rotor position should be about right. If it is the timing should be the same as before you started.
22. Plug back the wires.
23. Put the distributor cap back on.

Hope i didn't miss something.

 

So big question : did this fix your int "misfire" problem?

 

Thanks for these excellent photos - i'm putting this into my archive.

How on earth does your stuff look so clean? My upper intake is all faded looking. Must be the Canadian winters.

If you could take a snapshot of your engine bay one day.

(Oh god - cape town - that's why....I just noticed. You could have bought a 94 GXE and left it outside in a shed and it probably would stay in mint condition. Now I know where I'm going to pick up my backup 3rd gen. How much do you think shipping would be?)

 

Not totally. After I replace the cmps the car felt more alive. There is still slightly something almost feeling like a missfire but it is light and only under heavy load. The more the load the more I can feel it. and it seems the worst at around 2800-3000rpm

Although it looks clean for you it is not as clean as I would like it to be.

 

^^ RHD and no cruise control.... wild!

so what was wrong with the sensor thing? the pickup was bad? or the disc was bad?

 

and manual
The pickup was bad. Was not getting the 120degree signal at all. Did try to clean the optical but did nothing. Can also not nicely clean it as there is a metal plate that cover them with small slots for the light to go through. I'm planning to try and take the old one apart and see what went wrong, the optical of the wave forming circuit.

 

Excellent pics! U must put this writeup hanging on some site for ppl skiing behind. Here it will be lost for most...

Did u check the signal wave form - is it now healthy square?

Misfire: MAF, CAP, wires, plugs...

 

I tested the old cmps by removing the distributor and turning it by hand slowly and measuring the output. For the 1degree slots i was get the 0v 5v alternation. with the 120degree i was not getting that. The new one gives it with both.

New distributor cap and plugs(ngk copper bkr6-11e). I cleaned the MAF about a month ago, and measured the output as i rev'ed it a bit. The output signal go's up. The spark wires is one of my suspect, but do not have money now to replace them.

Also something weird i ad discovered was when I had the dist cap off with the front cyclinders plug wires still connect and distributor out, I got what sounded like a spark jumping somewhere when I turn the distributor by hand. Now I did not see and sparks jump but it was in the day. Time to do the same at night.

The car has 215000km's and think it might be the original plug wires.

 

I am amazed how sturdy the VGE is!

My original Nissan electron sooth hose - so called wire. See http://www.cardomain.com/ride/748507/12 ... the price for this set is lots of work + 20$. How one can afford NOT to do it?

 

I'm still a student, so no income. Had a few unexpected expenses so need the finances to recover first. maybe next month.
The problem is not big. It is very light. Also my clutch I think is on it's cause it started to shudders not to long ago.

 

This is why its imperative to save. Save by cutting fuel expenses to minimum. Not to suggest that a 4cyl engine would be lots cheaper... I am familiar with that situation: in these straits I just find/lend the money to plug these 'leak$'.

Bad wires easily may consume 1-2 liters extra per 100km - that is not light. Calculate savings...

 

Great post, how did you come to the conclusion that the position sensor was bad in the first place?

 

When I started to look for the problem I check the computer for errors and it had one. I check the service manual and check the components it said.

 

Thanks for posting this and with great photos! I went to try to replace mine but got stuck at the disk between the top shaft piece and the sensor. How did you get that disk piece off, or did you have it? I'm sorry I don't know the actual names of the parts, but I hope you understand what I mean. Let me know if you don't.

Thanks!

 

I was looking for this thread the other day and I couldn't find it. Thanks for bumping it to the top for me.