Ignition system recommends

[PNW 720 97499]

I've seen in here before for setups with the twin plug z24 motor, but can't find the thread anymore. Anyhow, I'm looking at my ignition and timing as an issue with low power (foot to the floor to hit and stay at 70mph). Pretty sure datzenmike said keep it mostly stock. I'm looking only at replacing my coils and re-timing the distributor. I don't want anything crazy on this truck. It mostly runs fine, just seems weak. The most outrageous thing I'm doing is installing an electric fan tomorrow. Recommendations are always welcome. Also, now looking for a new tailgate skin as a jackass over-the-road maggot backed his trailer into my truck (I drive a log truck, this should never happen unless you're not looking in your mirrors). Hoping for a light blue?

[datzenmike]

DO NOT replace the coils unless proven one is bad or not. Replacing good equipment with new unknown quality parts is expensive and potentially a waste of time. It can add unknown problems. It's hard enough to diagnose problems without adding random other ones.

 

 

Have to ask... is this something that suddenly happened?

 

Many easy to fix/cheap or out of adjustment things can cause loss of power. So check these off first...

 

Definitely set the valve lash (0.012) on all.

Definitely set the timing.

Definitely replace the fuel filter.

 

 

1/ Loss of one side of the ignition system will leave you with an engine that acts like the timing was suddenly retarded and a serious loss of power.

 

Check that both sides, intake and exhaust, are firing a spark. Put an old plug, even a lawnmower plug,  in each of the two high tension leads to the distributor cap, lay it on a grounded surface and turn the engine over with the starter. Got sparks???

 

YES ... go down to a/  below

NO..... one of them (exhaust) not firing. Check or replace the first fuse on the left hand side of the fuse box. Got spark now???

 

YES... Problem solved,q go down to a/  below

NO.... swap the non working high tension lead over to the coil that is working and check for spark now...

 

No spark... the wire is bad.

Yes spark... on one coil still nothing on the other... swap coils

 

Did the missing side start working but the other side now stopped sparking???.... The coil is bad, needs replacing.

Did nothing change???... the EI module in the distributor under the rotor is bad.

 

.........................................................................................................................................................

 

a/ pull  all plug wires of one at a time and check for spark. Got spark on all 8??'

 

Yes.... ignition is working fine

No... one or more are not firing. Problem is the distributor cap, rotor or plug wires. Replace    

 

 

 

 

2/ The Z24 is known for blowing head gaskets every 100k or so. Blowing the gasket between two cylinders will hamper both their operations and their power output. So...

 

Is there an unusual amount of steam out the exhaust?

Does exhaust have a sweet smell of hot coolant?

Is your rad level always needing to be topped up.

Does the overflow or coolant recovery container over flow?

 

3/ Take you spark plug wrench and go for a drive at 70+ for 10 min or so, longer is ok. Pull over safely and remove an intake plug. What color is it???

 

Light creamy, slight brown..................... normal

White, extremely clean no deposits...... Running very lean.

 

If foot really 'to the floor' I would say the secondary jet is partly plugged and not enough gas getting through. Lean is more than bad for power it's hard on the interior of the combustion chamber which includes the valves which rely on a proper amount of gas to cool them. Carburetor should come off and jets (both primary and secondary) examined.

[PNW 720 97499]

Hasn't just popped up, been ongoing since purchase last month. My guess would be secondary jet; however, I will be doing valve lash, timing, and fuel filter. I'll check the jets before going on to other steps outlined. The truck wasn't driven much before me, so I'd imagine gummed up jets and fuel system issues. Like I've said before, lots of jenky things on this truck that I'm getting around to fixing. 

[datzenmike]

 The Z24 doesn't have that much top end power to begin with...

 

 

Going 60 MPH..

Annold: Dis is de veehickles dop speeduh

 

[Charlie69]

This seems to be a common problem in the last couple of years. 

Does your truck have a tac?

If it does what is the RPMs at what MPH?

 

When was the fuel filters changed last?  One at carb and one between tank and fuel pump.  If you have the stock electric pump there may be one inside the bottom cover of the pump.

 

When the gas pedal is pushed to the floor does the carburetor throttle shaft open all the way?

 

Check for vacuum leaks.

[PNW 720 97499]

I wish I had a working tach, it hits 2100rpm and stops climbing. Couldn’t tell you the last time the filters were changed. I just bought it a little over a month ago. Filters in the mail. Throttle fully opens the butterflies. Was just looking for vacuum leaks last weekend, didn’t find any. 

[Charlie69]

Did you spray starting fluid , brake fluid or WD40 around the base of the carb while idling.

 

Does it idle smooth or rough?

[PNW 720 97499]

Idle is smooth, haven't sprayed anything

 

[datzenmike]

If the Hitachi carburetor, only the primary will open with the throttle. The secondary is pulled open by an internal vacuum signal.

 

 

Vacuum diaphragm that pulls the secondary open is the rounded cone shaped thing on the left. You would have to rev it up and then hold full throttle for a split second to see if it moves.

 

With engine off and throttle at least half open push up on the linkage and make sure it isn't stuck. There's an interlock, that's why you have to hold the primary open to do this.

 

Guess I need to ask... is this the carburetor you have?

 

 

[Charlie69]

The reason for spraying one of the flammable sprays while idling is if you have a vacuum leak in the area you are spaying the engine rpm will increase.  if you have a smooth idle you do not have a vacuum leak.

 

Change the filters and put a can of sea foam in your gas tank and fill it up with premium gas.   I do this once a year. 

 

Does your truck have a stock carb?

 

Does your truck have catalytic converter?  Your cat could be clogged, this will give a tremendous loss of power.  Start your truck and have someone rev the engine while you check for exhaust pressure changes with your hand.  Be careful as the exhaust could be hot.

Edited March 1, 2019 by Charlie69

[PNW 720 97499]

Quote

It has a Weber 32/36... Came this way. been thinking putting back to a stock carb or 38/38

 

[PNW 720 97499]

Also, just welded a new exhaust up at work for it last weekend, no cat, and cherry bomb turbo muffler. Better than the garbage it came with: flexi pipe into a street bike muffler poking out beside the cab... don't care for the paceman header, but I can't find a manifold at the wrecking yard. Used a smoke machine for vacuum, will spray starting fluid and some seafoam next fill up

[Charlie69]

Weber DGEV 32/36 are great and simple little carbs. I run them on all my Datsuns and Nissans.

 

I need to see a picture of how the Weber is installed, be sure I can see in the pictures the fuel supply line.

Edited March 1, 2019 by Charlie69

[PNW 720 97499]

I'll post it tomorrow (how the hell do I add pictures???) when doing electric fan.

[Charlie69]

You have to use a picture hosting site to load pictures to Ratsun.  I use Post Image.

 

Here is a link to a write up on how to use post image.

 

Post Image and Ratsun

[datzenmike]

Well I'm out I know little other than the stock carbs. The stock ones are properly jetted. Webers? who knows what it's designed for V6 small V8??? Fits dozens of applications and probably needs the correct jets and correctors?

 

 

[Charlie69]

The Z24 is about the top engine size for the 32/36.  I run one on my Z24 stock out of the box from Pierce Manifolds.

 

The 38/38 does improve the pickup but it also uses much more gas as it is not vacuum operated secondaries, it has mechanical secondaries.

[Charlie69]

Also a picture of your fuel pump also if possible.  The Webers run on 3.5 lbs of fuel pressure.

[PNW 720 97499]

Will do. Also: fuel pump has a sheisty wire and toggle switch to turn it on. It runs mostly without using the switch; occasionally not pumping, which then requires using the switch. Ground issue or failing pump? 

[datzenmike]

Who can know how it was wired or how well unless you did it yourself. The '84 uses an automatic fuel pump relay. Maybe it failed and this was added or this is some half assed anti theft device.

[PNW 720 97499]

Fused wire from battery to switch, to pump. The wire is easy to trace because it wasn’t routed well at all. Is the relay by the fuse panel there?

[datzenmike]

Well if it's cutting in and out just run with the switch on.

 

The pump relay is beside the glove box on the right side above the kick panel about where the passenger side upper door hinge is. Looks like this...

 

[PNW 720 97499]

That’s the thing, it doesn’t really cut in and out. Typically goes out when it rains. Makes sense now though because I just found where water was getting into the interior: blower motor in passenger footwell. 

[datzenmike]

If you take the wiper arms off their pivots and unscrew the plenum cover grill and remove you'll find leaves or maple keys or pine needles plugging up the drain on either side. The outside air for the fan comes down a hole on the passenger side. If full of crap the water just spills over and into the fan and onto the floor.

 

Also possible the windshield is leaking near there but more likely leaves.