Microtech on aussie six

[Unfalconbelievable]

Hi there, just after a little help with my Aussie 4.0l. I have a microtech lt10s hooked up and was runing fine but now it misses under high load/ high revs and the log indicates maximum rpm achieved was 15980....! Obviously not the true rpm reading. I'm guessing the miss is my rev cut kicking in when the ecu thinks its doing 15980 rpm, the dizzy is relatively new and the wiring is only a couple months old. I'm going to run 2 new wires to and from the tfi module and double insulate them. Has anyone had any problems like this? electrical interferance maybe? A short would be the obvious place to start as the sensor runs a variable voltage to give it its crank angle and this is the only way the ecu could reference rpm. Or does the ecu read rpm off of ignition pulse and thus if ignition dropped out or coil shorted, it would read a high rpm...?

Any ideas?

 

[fordconvert]

When I did my MS system I had the random rpm blips also. I figured they would not hurt anything but was wrong, they really mess things up. With MS they give you some possible component swaps on the MS board. Their plan B was to get a second spark module and use that one to drive the computer. In my case it was the GM HEI module. I just got a second module and paralleled it to the pickup coil in the distributor. It also needed a loading resistor on its output. What dizzy and spark module do you have?

 

[Unfalconbelievable]

I have the stock motorcraft dizzy with vane type pick up and tfi module. The crank signal is routed from the tfi to the microtech where it is interpreted and then the microtech sends signal back to tfi where coil earthing is done. The revs read spot on for the most part, just a random glitch and only ever when its getting curry, can drive it around like a factory work horse all day with no dramas at all... Got me confused

 

[Unfalconbelievable]

Ok so i found sumthing interesting when i poked about a bit. Checked timing and it was 10 degrees too advanced all around, static timing in the ecu was set to 00 deg but the dizzy was at 10, adjusted that all back to spec. Should be able to bost her even more now, was pinging at 14psi before. I have devised that the problem only shows itself when hot, hence the drive thismorning didnt have any dramas as ambient temp was only about 3 degrees c and the coolant temp didnt get to its max of 84c, only reaching 74c before i got to work. I have replaced the ignition module as i had one in my tool box anyhow. The tfi modules often give troubles when hot though normally the engine just stops all together but the symptoms may vary with an other than stock ecu? Will let you know the results tomorrow...
Cheers

 

[fordconvert]

I wonder if the issue is that the spark is happening with the rotor too far away from the terminal on the cap? That would make for a big spark that could easily get into the computer and perhaps cause that glitch. What I would do is hack up a distributor cap around one of the terminals so you can see the rotor. You then use the timing light connected to that terminal to see if its fairly centered on the terminal when it sparks. If its not you should be able to physically rotate the dizzy then change that offset in the computer to keep the timing the same.

 

[Unfalconbelievable]

Thanks fordconvert, that sounds like something i'll try for sure. If rotor phasing was out it definately would cause some issues. Though the dizzy was moved 10degrees crank timing the other day and made no difference. The ignition system is at its peak anyhow so that may just be the issue

 

[Unfalconbelievable]

Sorry its taken so long, the ignition module didn't fix it but i have sorted it out. Decided seeing as my wiring had checked out and the ignition module did not fix it that it was either dizzy or ecu. I had a dizzy, brand new in box (I have alot of ford spares lol, been messing with this vehicle for 4 years) so thought id replace it. When i pulled the old dizzy (only 12 months old i might add) the roll pin had shattered but still remained in there and holding the gear, but allowing it to turn about 2-3mm back and forth. Cheers for all the help people. The big girl gets a wade 977b-14 camshaft and a custom short runer intake plenum this week and then its off for the final tune. Should snag in excess of 400rwhp providing the dizzy can keep the spark up