Start Up Problems

[FearNoFish]

I'll be the first to admit that I have more guts than knowledge. I just lit my 4.6 for the first time. It ran about two minutes really fine and then just shut down. Afterwards, it was hard to start and when it did start it would run rough but when it got up to about 2000 it would smooth out for about 30 seconds and then start poping and backfiring and shut down. I did this about 3 times and decided I would quit before I did any damage.

I don't know if it is a timing issue or fuel. I hope the cam didn't destroy itself already. To compound issues, the configuration is not the most common. Right now I am running a stock ECM but I am running 45 lb injectors with a Kenne Bell supercharger and a Hesco aluminum head. THe SCR is about 8.8:1 with 5.5lbs boost at the super charger. Damn it sounded and felt strong for that first two minutes!!

A little direction as to where to start diagnosing the additional problems would be appreciated.

[SilverXJ]

Do you have spark?

[FearNoFish]

Well I assume. It started and ran and it will start if cranked enough.

[4.whoa]

Did you switch the map sensor for/with the SC?

[FearNoFish]

No. It is the OEM MAP sensor for the XJ 4.0 liter. Kenne Bell has been pretty much uncooperative since they no longer produce the Jeep blower. I purchased the SC used and have been pretty much playing by the seat of my pants. I need to and I will look into sensor options and such.

FNF

[SilverXJ]

The stock sensor does not read boost.

[FearNoFish]

I am looking into Megasquirt. I would still need the services of a Jeep Mechanic or someone with much much more knowledge than I to set it up. I have built the engine, completely rebuilt the AW4 with shift mods, rebuilt the NP231 With 1-1/4 chain and 6 pinion planitary gears and set up my F & R ring & pinion but the computer stuff is beyond me. I come from the pre-smog era of engine mods.

I am also going to make one more appeal to Kenne Bell for a reflash of my ECM. They quit making this SC several years ago and supposedly don't make the "Optimizer II" any more but I will appeal to their business reputation.

FNF

[gradon]

The split second psc1-002 that I have has a built-in 2-bar map sensor(can read boost). I use that built-in map sensor when I have it in circuit, instead of the stock map sensor. They make a ftc1-019b that has the the ability to retard timing as well(good for boosted apps). http://www.splitsec.com/spike/jeep/spikejeep.html

[FearNoFish]

I'll give Split Second a call in the AM.

Thanks

FNF

[FearNoFish]

Going with an AEM F/IC. Fellow NAXJA member has provided me with a base MAP for inital start up. I can tweak the tune from there. At least that is the plan.

FNF

[unlimitedrubicon]

The AEM unit is very nice looking. Let us know how it works out and what your impressions are once it is in.

[banipal19]

Going with an AEM F/IC. Fellow NAXJA member has provided me with a base MAP for inital start up. I can tweak the tune from there. At least that is the plan.

FNF

How did it go?