new stroker 4.6 idles fine till 2500

[Jor2010dan]

So I started my stroker yesterday. Ran good at idle, and let it run for 20 mins as per my manual. Then when we went to go seat the rings, it would'nt go above 2500 rpms. as soon as you get there, the engine starts to stumble. I was messing with my distributor afterwards, and now it wont run. I'll re-index the distributor but is there anything else that would'nt let it run past 2500? I tested the injectors before I put them in and they are all in spec.

[dwg86]

Turning the distributor will not change spark timing. Turning the distributor changes when the fuel injector sprays and effects fuel injector to spark sync.

Here is a description of the distributor taken from a service manual. This is for a fuel injected Jeep 4.0 with a distibutor cap and wires...


DISTRIBUTOR

All engines are equipped with a camshaft driven mechanical distributor containing a shaft driven distributor rotor. All distributors are equipped with an internal camshaft position (fuel sync) sensor (Fig. 2) . This sensor provides fuel injection synchronization and cylinder identification.

The distributors on both engines do not have built in centrifugal or vacuum assisted advance. Base ignition timing and all timing advance is controlled by the Powertrain Control Module (PCM) . Because ignition timing is controlled by the PCM, base ignition timing is not adjustable on any of these engines.

The distributor is locked in place by a fork with a slot located on the distributor housing base. The distributor holddown clamp bolt passes through this slot when installed. Because the distributor position is locked when installed, its rotational position can not be changed. Do not attempt to modify the distributor housing to get distributor rotation. Distributor position will have no effect on ignition timing. The position of the distributor will determine fuel synchronization only.

All distributors contain an internal oil seal that prevents oil from entering the distributor housing. The seal is not
serviceable.



CAMSHAFT POSITION SENSOR
The camshaft position sensor is located in the distributor on all engines (Fig. 2).

The sensor contains a hall effect device called a sync signal generator to generate a fuel sync signal. This sync signal generator detects a rotating pulse ring (shutter) on the distributor shaft. The pulse ring rotates 180 degrees through the sync signal generator. Its signal is used in conjunction with the crankshaft position sensor to differentiate between fuel injection and spark events. It is also used to synchronize the fuel injectors with their respective cylinders.

When the leading edge of the pulse ring (shutter) enters the sync signal generator, the following occurs: The interruption of magnetic field causes the voltage to switch high resulting in a sync signal of approximately 5 volts .

When the trailing edge of the pulse ring (shutter) leaves the sync signal generator, the following occurs: The change of the magnetic field causes the sync signal voltage to switch low to 0 volts .

[Jor2010dan]

k.. How about the not going past 2500 thingy?

[Jor2010dan]

K so I got the distributor back in where it idles fine. Still wont go past 2500. It also backfired out the exhaust once and out of the intake once when I was trying to floor it a couple times.

Any Ideas?

[dwg86]

What year Jeep?

[Jor2010dan]

1992

[Cheromaniac]

K so I got the distributor back in where it idles fine. Still wont go past 2500. It also backfired out the exhaust once and out of the intake once when I was trying to floor it a couple times.

Any Ideas?

Plugged up cat.

[SilverXJ]

Low fuel volume/pressure

[doc65]

Personally my money's still on the distributor, mine was the exact same, dizzy was 1 tooth back, moved it 1 clockwise and all was good.

[Jor2010dan]

K so I got the distributor back in where it idles fine. Still wont go past 2500. It also backfired out the exhaust once and out of the intake once when I was trying to floor it a couple times.

Any Ideas?

Plugged up cat.

Took off the exhaust from the header back. Sounds cool, but no difference

Low fuel volume/pressure

31psi, 40 with the vacuum off. Tried flooring it at both, No difference

Personally my money's still on the distributor, mine was the exact same, dizzy was 1 tooth back, moved it 1 clockwise and all was good.

Go my HB keyed. Put a timing light on it. 12* Distributor is fine. I will post up a video tonight

[Jor2010dan]

Humor me and watch the video. (no, I will never get a job reading books.)
http://www.youtube.com/watch?v=blLC2SzFnPw
I checked my injectors, they all clicky.


What am I missing?

[Missourian]

Let's see...

Crank /cam relationship, distributor position, distributor cap, rotor, spark plug wires, spark plugs, coil, fuel injectors, burnt valve, broken spring, throttle cable/linkage issue, compromised computer?




Perhaps your muffler bearings have gone bad?

Levity, it's an awesome thing when you understand "it was a joke".

[Muad'Dib]

Sucks...


What size injectors?? Stock?

Maybe you wiped out the cam already???

[BDD]

Is this a brand new motor? Did you break in the cam properly by running the motor above 2000 rpms for twenty min,before letting it idle?If you did not,you have flat cam lobes,and a motor full of metal.I think your post said something about letting it idle for twenty min? I never let a fresh motor idle,untill it has a few hundred miles on it.

[Jor2010dan]

Yes brand new, I broke it in right. By Idle, I meant I let it sit at 2000 for what felt like 20 minutes. It was really like 10.

Anyways. CPS was bad. Go figure