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I got a huge hesitation between 3500 and 4500 rpm with my ze.

The tach also goes funky too so It leads me to believe its HEI related, which I do have installed with a msd coil.

The distributor is a ze disty, but it is almost all the way advanced just to run good... its been like that for 3 years but now its acting up.

I got brand new bkre5e-11's in there with brand new ngk mx-6 wires.

I am fresh out of ideas

some are saying its fuel related, but if it was fuel my tach wouldnt go crazy between 3500 and 4500

any ideas?

Have you checked your 1K ohm resistor?

nope... if it was the resistor it would only be the tach... but it hesitates too

man same problem here. The whole car just slows right down, then at about 5k it goes hard.

Check VRIS maybe?

this problem still exsistys, a little help please

First the simple things -
Check clean all the HEI connections - solder joints where necessary and clean other connections with some electrical cleaner and abrasives....

If that doesnt help - try another HEI

Mist some water over the sparkplug wires (at night) - if you can see any arcing then the wires are bad/leaking....

How do the plugs look?

Have you changed the cap & rotor?

Is the crank sensor connector clean and seated properly?

.......

new plugs, new wires, new disty, new hei, new resistor, redid all the hei wiring all nicely, tried different ecu's, we checked timing belt marks and are all dead on. the crank sensor was a lil dirty/oil but no ckp code. checked timing with a timing light.

Does it miss when you push the throttle in neutral? If it does hold the throttle where it misses and start wiggling wires to see if there are any loose connections...

Also check for vacuum leaks - remember VRIS 1 opens at 3250 RPM.....

its not only hesitation the tach goes crazy in that range

Did you take out the stock ignitor?

shameem wrote:Did you take out the stock ignitor?

He has a klze disty so there is no ignitor. The orange wire for the ignitor goes dierctly to the HEI.

Hows the cap and rotor man? Also why is the timing advanced so much, set it back to stock and see how it works,
I also find our cars run better on the bkr6e-11 plugs.

kp2t wrote:The distributor is a ze disty, but it is almost all the way advanced just to run good... its been like that for 3 years but now its acting up.?

Well just because it's been wrong for 3 years doesn't mean it's right. As well, you got you're motor rebuilt, so it's not the exact same motor, so it may not react and require the same things as before. I know you're suspecting that the timing is off, I would look into that. There was a new timing belt put on after all.

When your tach goes all funky, does the motor act funky too. I know when my tach was jumping all over the place, the motor was steady and didn't give any sigh that it was related to the tach.

Speaking of plugs, have you pulled them to see if they show anything odd?

You know, I just thought of something. Although the tach pulse is driven off the coil, which is triggered from the ECU, I betcha that the ECU gets the signal from the camshaft position sensor to know where to set the timing, cause the ECU realisticly would NEED that sensor to know what the mechanical timing if the motor is. If that's wonky, I would suspect it would cause the ECU to trigger bad pulses, which would affect both the spark and the tach. Pulling the plugs *may* show something. It could be 1 or all of the following: bad cam position sensor 2) internal mechanical assembly to the sensor inside the disty is bad 3) the wiring for the cam sensor, which I believe you needed to cut and splice to use the 4-pin connector on the ZE disty, is bad.

the camshaft sensor has nothing to do with timing. It just happens to be located inside the distributor. The distributor just rus off one of the cams. The crank sensor has alot to do with timing as it tells the ECU when each cylinder is at TDC. and then at that point it fires the plug.

You're right, I got mixed up and forgot about the crank sensor...unless there's something wrong with that sensor and/or it's wiring. I was thinking the cam sensor because I know that's been cut and wired for the ZE disty, thinking it could be that, and it still could be, people have has the exact same symptomes that Krish has.