LWillmann

I've been trying to track down the cause of this slight surge I've had since installing the new Opti, coil and waterpump...

I've done the following:
-New plugs
-New wires
-Idle Vacuum check 20" at idle
-Fuel pressure check (drops by 1psi at high RPM)
-Fuel filter
-Swap Injectors (slight improvement felt at the time)
-Compression test 200-210 psi all cylinders
-Put stock coil back on car
-Replace ground wire from coil to frame rail
-Swap entire coil/module assembly
-Spray starting fluid all over intake manifold and on elbow after MAF with no change in idle.
-o2 sensors have less than 5k miles on them. Replaced 2 months ago if that. They are GM units also.


Last night I was watching my rear view when I got on it after swapping the coil/module assembly onto the car (Thanks for the loan Marvin).

When the car got to 4500 RPM it started surging, and I noticed puffs of smoke (couldn't really tell the color) that seemed to coincide with the surge.

The surge seems to always happen from 4500 and up. The car spends so little time above 4500 in 1st that you don't really notice it, but in 2nd and 3rd it becomes more noticeable. 3rd is where it's most noticeable because it takes longer to accelerate through the gear.

Autotap scans show nothing, no miss, nothing at all when it's surging.

In the garage, at night there's virtually no arcing going on. Slight glow around the coil and at the end of a single plug boot. Just a glow though, no sparks are visible. At one spot on the passenger side by the motor mount where my wires come together before going through the accessory bracket you can occasionally see a glow also. These glows are associated with just stabbing the throttle, and it only happens once per throttle opening. If I move the throttle from idle to 50% instantaneously, I'll get one glow and that's it, it goes away, until I let off and the hit the throttle again.

Anyone got any ideas?

LWillmann

Bump... anyone?

LWillmann

ttt one last time...

Dave Feerst

do you have a rich smell when it is missing?
check for a vacuum leak around your vented opti fittings...
Check to make sure your ICM is properly grounded.
Make sure your coil is not cracked. try another coil if your old one still works.
Make sure your coil wire is not touching the waterpump.

LWillmann

I have run 3 different coils on the car, and a completely different ignition module.

I don't think the coil wire is touching the waterpump, but I'll check it this evening.

The only time it surges is above 4500, so naturally I wouldn't smell a rich condition.

On the dyno recently it did it right at 4800 RPM.

Dave Feerst

Check resistance between Ignition post and batter ground.

LWillmann

Made sure the coil wire isn't touching the water pump this weekend.

By Ignition post, you mean the one under the plastic cover on the fender well?

Dave Feerst

sorry it took so long for me to foid this thread again.
no, I meant the post where the ignition module grounds, it is a stud right next to the coil.

LWillmann

The ground wire that I'm using from the coil bracket to the frame is .002 on a 200 ohm scale.

I'll go measure the resistance to the battery post though to be sure.