Well I'm almost close to throwing the 730 in the trash in light of the problems I've been having with the wiring/ecm/car. Ya, it's possible that the ECM/Wiring are not the cause, but, hey, at least it will make me feel better.

My question is this...
I have no idea what was put into my eprom (and honestly I do not really care) when it was on Ed Wright's dyno. IF i choose to go DFI, can I carry the fuel maps / VE, etc data pretty much directly over to the new system? I'm sure this depends on what system I choose to go with. Does anyone have any experience doing something like this? Ho Hum.. I just want it to run again.

Oh, and FYI here's the link to the problem I was referring to...
https://www.thirdgen.org/techbb2/sho...hreadid=233541

Theres nothing wrong with your computer. The tach going all over the place is what says otherwise. The fluctuating tach points to, with a very high probability, an ignition problem somewhere. There is either somthing overloading the module, like a spark leak near the dist., somethign possibly starving the ignition system of voltage, or interfierence somewhere. For starters, thoroughly check the spark plug wires. That means take them off the car one by one and inspect each wire for tracking through the insulation and for cracks or internal break down. After that, make sure all connections are clean and tight and do a run in the dark and make sure there isnt any cross-arcing. I had a very similar problem that was caused by carbon tracking that worked its way up the wire and eventually shorted out to the firewall and dist. Ruined the coil and module. The wire looked fine until it disinigrated into dust when I touched it. After that, its a matter of pouring over the wiring to make sure that there arnt any loose grounds, lacks of voltage, or what have you in the ignition system. Replacing the ECM will probably fix nothing as its very unlikely the cause of the problem.

It can't be the plug wires. The car has the exact symptoms with my taylor wires and my new MSD wires. The car has the exact symptoms with the stock coil and my accel coil. The car has the exact symptoms with a new set of plugs. I have linked every single grounding point in the engine bay with aligator clips and used a jumper cable to ground the engine block to tihs link. Surely it's in the wiring harness or some piece of hardware, but i cant find it. Replacing the wiring harness would best solve my problem. And while I'm at it, it might as well be a DFI system if it's fairly simple to tune. And that leads me to this discussion...

Just as a wild guess try a new TPS.
An RPM miss takes a certain amount of throttle opening, and you might have a bad spot in the TPS.
Might redo the battery and chassis grounds.
I wound up running the battery ground to the front of one head, and then a cable from there to the starter. Then the normal battery to sheetmetal ground. And then a braided engine to firewall ground. And the ecm grounds get cleaned regularly.

The DFI VI is easier to tune. And can be disappointing. There's a number of guys going to the newer ones, but that means getting more difficult to tune. Having a car that drives well, and makes HP takes a fair level of sophistication. The later the aftermarket, the close they approach oem. The new Accel had PE, and the BS3, AE stuff very similiar to oem. By the time the aftermarkets get it correct there just isn't going to be that much difference, for a real well mannered streeet car.

If you want aggravating, think about swapping to the new ecm and still having the same problem.

Just had a thought, disconnect the tach lead at the coil. Check if that corrects the problem. May be a bad tach.

RBob.

TPS voltage varies linearly with throttle position as verified with Moates. The original tach was removed (literally) and the problem still exists. I replaced the tach with an in-dash autometer, still the same problem. The only thing I havent done is cut the OEM tach wire. I will try that and report! Thanks for the information on DFI. I did not realize DFI was inferior to OEM in regards to drivability. You're right about the agrivation. AND a lighter wallet.

your engine has the hei distributor? follow the tach wire and locate the tach filter which looks like a capacitor, it is shorting out i bet. I have seen it many times before

Where is the tach filter? I've never seen or heard of that before. Perhaps it doesnt exist because we have two windings in our factory coils. Or perhaps it's under the dash?

$$$$ to doughnuts its on the on/in the cluster itself, prolly on the back of the tach :-)

Mine wont work with msd box tach drops at 3k and goes dead with the msd hooked up.............

cluster is only place ive traced the wiring on both my 91's

later
Jeremy

You can still have a bad spot in it. With a scanner your only looking at it, at the update rate of the ALDL, not as often as what the ecm is looking at. I had one play this game on me, and it took forever to find it.