Popping a crack sensor code when over 3k to... New build

[Sean295]

So I built a 4.6 by going . 060 over.. 4.0 block.. 4.2 rods and crank... All in my 97 TJ.,.. the original motor was fine.. no issues... Installed this set up and now I get a crank/ cam sensor code if I turn 3000 RPM... Still runs fine.. no miss.. no other codes... If I drive easy.. No p code..... Changed the crank sensor and the pick up sensor in the distributor.. yes it has the distributor..... no problems with the original motor.....Any suggestions?

[Cheromaniac]

Did you index the distributor?

[Sean295]

Don't index the distributor... Mine is the cap and rotor type... As far as I know anyways.... Rotor points just past number one when it's on TDC for cylinder 1

[Sean295]

Sooo... Took your advice to heart.. read more... Snapped the ears off the distributor... Turned it ever so slightly counter clockwise.... First test ride.. no code....... Strange thou... From looking at the rotor I turned it the other way first... Started popping out the intake.... Turned it towards the block and went away... Almost feels like less power thou.... Time for a larger throttle body next... And cooler plugs

[Sean295]

So that leads to another question......how do you know how far to turn the distributor? Just get it close and the PCM takes over? From what I read it controls the injector timing and not the spark.....

[Cheromaniac]

Correct. The cam position sensor commands the ECU to synchronize the injector pulse with the spark.
The rotor should be at 5 o clock when looking from the passenger side with the no.1 cylinder at TDC at the end of the compression stroke.

[SkylinesSuck]

The "proper" way to do it is to take it to the dealer and let them set it with a special scan tool. Not saying it won't run fine without it.....

[The Beast]

If you have to turn it a little by chopping the tabs I'm wondering if the cam gear is a little off. Aftermarket cam, aftermarket distributor? Sometimes that's just how it is.

[Sean295]

The cam is a Comp Cam 68-232-4 but the dizzy is stock.....I moved it a little more counter clockwise....seems better...I can't index it like on the angelfire page cause my cable is way smaller where they measure it from.....should I go with the comps reading for fuel air mixture?

[The Beast]

I'm wondering if your distributor gear is 180 out. That's why I asked about the aftermarket distributor as well. But it's
also possible that the cam has a certain valve timing built in that would need you to set better fuel sync.

[Cheromaniac]

The engine wouldn't even run if the dizzy was off 180*. Seems that the Da Vinci code would be easier to crack than this one.
If it's off, it'll be by no more than a few degrees. You might need to fiddle with it to find the sweet spot. Shame my Angelfire page didn't help. If the cam timing was off even by one tooth, the engine would run poorly at all rpm.

[The Beast]

The dizzy itself is not off 180, I'm saying the gear on the shaft could be off one 180. Also aftermarket cams aren't perfect either,
also a lot of cam advance/retard can mimic fuel sync issues. You can set up the engine to the angle where injection timing starts.
Then check the rotor on the sync generator to see if it's at the beginning or the end of the injection cycle looking at the window
and magnet.

IF you have to move the dizzy a lot say like what looks like 15-20 degrees, likely will be out one tooth of the gear.

If you check this you'l know if your out of sync is either valve or dizzy gear related. The quick fix/band-aid is to twist the distributor,
if you like that then do if you feel it works well enough. I did it for 8 years and didn't have any problems running really it was satisfactory.

Currently I adjusted the sync generator to give me no sync issues and my valve timing via MS3 but someone else will need a tune to
account for valve timing. Which most will be flashing the ECU (if possible) or using aftermarket controllers.

[Sean295]

So turning the dizzy counter clockwise seems to have cleared that up....I turned it more and it really...REALLY woke it up...BUT ...after it's warmed up if i turn it off (or stall it) and try to strat it right away i get that kick back..hard to start cranking...like the timing is advanced to far......how can I get rid of that and still have it advanced for the power? I have heavy cables to ground and the starter...starter is a bit old ...do they make a heavy duty starter for higher compression motors? I'm running 165 PSI compression.

[The Beast]

I'm thinking one possibility could be that you are advancing so far that the rotor on the distributor just gets too far
out of spec and you get those issues. You have no advance in reality just injection timing. SO when you go too far
and it "wakes up" is because the fueling is better at that given RPM injector timing but will suffer at the bottom end.

You need to be able to independently adjust timing for injector and ignition while keeping your sync, is the only way
to fully utilize an aftermarket cam. Since your only adjustment at the moment is to twist the distributor, I'd say
find the sweet spot in between power and drivability (that includes starting) and just leave it there.

A new starter will do the job fairly well. Make sure that you have large short runs to the starter and good ground.
Also a decent battery will let that starter live longer. Loading and lugging a starter will burn the comm and brushes
faster and start to lose it's power to crank. You'll know you burnt a comm when you got to start smacking it lol.

[The Beast]

As a site note I should mention is that you can put a little bit of adjustability in your distributor by changing the arm that holds
the sync generator inside. I don't know what version of dizzy you're using but you can get a little bit of adjustment just shortening
or lengthening it (depending which way it's mounted). But that can be used to offset it and get a little more out of it. I made mine
an adjustable turnbuckle to get it perfect.

If you got the stupid plate one then your boned.