Brent

iTrader: (1)

I can't figure this out. 350 TBI, 747, manual, no EGR installed. It idles at 750rpms and 40KPA. Slight lope, 214i/224e @ .050. Drives fairly well. Will accelerate in 6th gear at 1200 RPM.

Trouble is, it surges in some cases. I don't know if its timing related or fuel related.

For example, if you try to hold the engine @ 1600rpms in neutral, it will surge 200-300rpms. The INT is 128 and BLM is 108. That tells me it is alittle rich. I ran out of time so I didn't get to lean it out any farther.

The other thing that confuses me is the aftermarket chip that I replaced was so pig rich according to my nose and the INT/BLM, yet it still surged like I described.

Anyhow, I just don't know what to look at next. The cam isn't wild and it drives pretty nice, except this surge in neutral and the lower gears.

Any thought?

Grumpy

The 747 is the dead simplest of the ecm lot.
There is no nortmal operating condition where your going to be just holding 1,600 rpm in neutral, least that I know of.

Kinda like why is there no lean druise in the stock prom. Just cause they didn't need it. they had x amount of room and just did waht they had to do.

When the calibration guys are out doing a new calibration, they just call home to get patches, and do what they need to do. So some program just read funny, and some cars have weird glitches in them

Brent

iTrader: (1)

I agree with you here. My example is not all of the problem unfortunately.

It also surges in 1st, 2nd and 3rd gears. The surge is less noticeable the higher the gear. It would be nice to be able to drive in heavy traffic and parking lots without the engine making the car buck.