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Shooting lean >4k rpm


X64v

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Interesting...Seems we have one problem after another, and not the same recurring problem.

 

The fuel pump definitely wasn't getting enough juice before with the original wiring set up. My new wiring set up is now adaquite for the pump's needs.

 

I had checked ignition before, and it was working just fine up 'till as far as I could go, ~4500rpm.

 

Well, now that I could rev higher (and on Mario's prompt), I checked the ignition system again. Hooked up my timing light...showing 10 degrees timing at idle...rev to check full advance...get to ~34 degrees (all mechanical, no vacuum). All is fine, right? Well, I floor it, revs are climbing....and then BAM no more flashes from the timing light. At a certain rpm (revving by hand so I can't tell, I would guess around 5000-5500) my spark is cutting out completely. To make sure the spark isn't falling off the end of the rotor or anything, I dropped timing back 10 degrees...still doing the same thing. So, I'm guessing coil. I'm still running an original type coil with the ballast resistor and all that crap. I have an '82 n/a zx coil, I'll throw that on and see if I can get it to work right.

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Heh yeah...I did do it the next day though.

 

Well the zx coil did the trick! Went out and hit 70 before I even knew how fast I was going (zx 5 speed with a 3.364...redline in 2nd is like 75). Definitely needs some tuning, but now at least I can.

 

Tach stopped working when I wired up the new coil though. I have the longer black w/white stripe wire feeding the + on the coil, with the green/white and shorter black/white just sitting there. I can probably figure it out, but if anyone knows off hand which wire goes were to get the tach working, please share.

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Got it. Longer b/w to g/w (where the old ballast resistor was), shorter b/w to + terminal (like stock).

 

Anyways, thing runs great. Was able to get WOT o2 to around .6v or .7v up through 7k. I'm up in the high 120's for ve on my fuel map though, so I'm not sure of the accuracy of the o2 reading (stock exaust manifold, have had head pipe sealing issues, so maybe it's sucking in a little outside air). I'll probably get it on the dyno for 20 minutes to check that and get it tuned real well before the MSA show.

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bpr6es I think is platinum. bKr6es-11 is what I'm using, they are the 280zx NA plugs. The 11 at the end just means it has a 1.1mm gap, which as about .042" if I remember correctly. I just loaded a derivation of BRAAP's fuel settings into my VE table, and it seems like it ran better up to about 4500rpm, and then started to break up again. I've only got a few gallons of gas in my plastic fuel cell, and even though it has the foam I suspect it may be sloshing away from the pickup under load...maybe I should just go fill 'er up and see if that doesn't help. Also I haven't tried free revving it to see if the problem is only under load or not, let me go try that too.

 

*edit* Well, mine revs fine in neutral all the way up to 6500rpm. Guess I'll fill it up with gas and see if my 4k problem goes away or not. If so, guess that means I'll be needing a surge tank...

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I've always thought and used BPR6ES-11 since I believe that's even in the manual as being OEM.

 

There used to be a nice chart showing the naming but all I can find is these crummy text only ones:

http://www.kaila.net/tl125/tl125ngkcode.html

 

http://www.math.uwaterloo.ca/~rblander/NGK.txt

 

Anyways it shouldn't be a problem with nice resistor plug wires (which I'm sure the NGK are).

 

Veritech, what spark plug gap are you running? If you have a weak ignition system (like X64v), you could be blowing it out under load. Or you could be so rich under load that it causes it to blow out.

 

Mario

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I've got a stock 1977 ignition module, but I'm using an MSD Blaster II coil with Accel Super Stock 8mm wires. I don't remember what the gap was, I'm pretty sure its .044", but it might have been .043"? Somewhere around there anyway...I'd have to pull one out and check it to be 100% sure.

 

*edit* Mario, this is the link you were looking for:

http://www.ngk.com/sparkplug411_ngk.asp

 

Looks like I was mistaken, the P means "projected insulator type" when it follows the B, but platinum when it leads off the part number string, and it seems that 1.1mm is .044"...it's been awhile since I was fooling around with spark plug catalogs.

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I've got a stock 1977 ignition module, but I'm using an MSD Blaster II coil with Accel Super Stock 8mm wires. I don't remember what the gap was, I'm pretty sure its .044", but it might have been .043"? Somewhere around there anyway...I'd have to pull one out and check it to be 100% sure.

 

*edit* Mario, this is the link you were looking for:

http://www.ngk.com/sparkplug411_ngk.asp

 

Looks like I was mistaken, the P means "projected insulator type" when it follows the B, but platinum when it leads off the part number string, and it seems that 1.1mm is .044"...it's been awhile since I was fooling around with spark plug catalogs.

 

I tried looking for that chart! I knew it existed somewhere...

 

Also, I believe it was Mack that had a "rev limiter" type problem and it was indeed his ignition module, not the coil. Its something to check for sure though...

 

X64v, setup were you using for spark control?

Mario

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