Couple Problems..... Soft Code???

[Joel5.0]

Originally Posted by BowTie Eater 5 Liter

my problem is after 5000rpm the car doesnt like to work, it backfires and gets really stoopid... i just changed o2's, fuel filter, fuel pump relay(was getting a code for that). i get a "soft code" if i tromp on it through the first 3 gears(or more). the check light will come on and stay on until i let off, and i can not pull a code up for it. i was thinking the o2's were the problem, but now im leaning towards mass air sensor??? i havnt found a way yet to actually test to see if the meter itsself is screwed? does this sound like a condition of a bunk mass air meter?

another q, what should i have the fuel pressure set to running my combo(as ive just got the stock injectors for now) or should i leave it at 39psi?

thanks

That's the problem....anytime the CEL turns on, there should be a code registered in memory, not having a code means there's a problem with the EEC-IV...what kind of problem?.....anything from a bad EEC relay, wiring, VPWR supply, ground, fubar'ed PIP signal, bad TPS, bad alternator (bad rectifier causing electrical noise) or,.......fubar'ed ECM.

How did the voltage check on the MAF go? , did you get rid of code 56? LUK

[vristang]

As stated directly above, it could be a ground issue. The EEC is pretty sensitive to ground/power issues. It may be worth the time to double check the grounds in the engine bay.

I don't think you can get the 5.0 dist "a tooth off." You can easily get 180 out (which I have done more times than I care to admit). If you put the dist. in off center by a few degrees, you simply rotate it until it is where it should be. It is possible to have the dist hit the manifold or something and still be out of range, but other than that the dist is fine unless you get a full 180 out.

jason

[Unit 5302]

The two problems may be unrelated. I would tend to agree with the comments about the engine being lean as a likely source for your top end backfiring. With the kind of horsepower I'd expect that combination to be capable of achieving with a decent tune, you'd need about 60psi on the stock injectors to simulate the stock injection cycle. You're running 39, which would be spot on for 24lb/hr units.

As Jeff stated, getting it to a dyno might not be a bad idea, considering you could easily blow the engine if you're as lean as we suspect you may be.

[rwhite65]

Jeff and Unit offer reliable advise. I would stay on the safe side and look into the lean issue.

I know very little about fuel injection, but it makes sense with the better heads, the stock injectors might have trouble keeping up.
Ryan