ak95ta

Go get your car from him, the above statment makes no sense. How long has he been tuning?

Edit:BadAssed beat me too it..

dr97z

He says it sits at about 96kpa then when he hits it, it falls to 89kpa. He's been tuning for a while, but Bryan from PCMFORLESS said that it could be the valves to tight statement.

WS6T3RROR

It does make sense, if you build vacuum under wot (from a restriction) the kpa value will drop because its absolute pressure you're dealing with.

dr97z

This is Bryan's email

that is a big cam, but if he is seeing MAP pressure variations (basically seeing Vacuum) there could be some inlet restrictions choking it, or the valve lash could be too tight not allowing all the valves to seat and blowing off compression.
thanks,
Bryan

dr97z

What do you guys think about the valve lash?

Just so you know, I have Morel lifters and I went 1/4 turn past 0 lash.

WS6T3RROR

1/4 turn 1/2 turn shouldnt make a diddle worth of difference, I have seen people swear up and down that it does. What makes a difference is how good you are at finding zero lash some people are just not good at it. If you think thats the problem, set the lash with the engine running.

I'd be looking at fuel pressure, air fuel ratio, and a datalog of what the engine was doing during a run, your tuner has the logs because he is talking about absolute pressure and kpa. I have the software and will take a look at it if he will email the logs to you. The dyno graph will probably tell the story though.

On your bad optis, have you taken them apart and made sure the rotor screws are still tight, that is an issue i have seen many times. Also check the harness out to the opti and the condition of the wires all the way back to the pcm.

Might have them pull the filter off to see if thats the problem. What kind of throttle body is on the engine? How much power or airflow (grams/sec from maf) are we talking about here?

dr97z

Fuel pressure is solid after getting rid of the aeromotive AFPR. Air Fuel ratio, I'm assuming is good, since that's usually the first thing he gets right when tuning. I'll try to get the logs from him and the graph.

As far as opti sparks. The last one I had on there was a dynatech with the old motor. This one is a brand new MSD and I did take the rotor screws out and put thread lock on like everyone suggests. Harness is brand new with MSD. As far as I could tell the wiring back to the PCM was good, because I did check it out before starting the new motor.

It's a Holley throttle body 58mm. Don't have the answers to your other ?'s. I will email him and see if I can get the info you're requesting.

Thanks for helping out.

SS RRR

So refreshing to read good sense like this!

dr97z

Here's the link to my dyno run, tell me what you guys think is going on.


http://www.cardomain.com/member_page...jpg?544918-014