Limp mode troubleshooting Q

[paulc]

I just finished rebuilding the motor on my car (2.1L T4 Porsche 914 motor).

I had it running before the rebuild fine. i have not changed anything to do with MJ.

i took it for it's first spin last night and man was it a dog. could hardly get it home.

i would have thought it was the MJ in limp mode, but the tach worked fine.

If i plug it into the laptop when the car is running (lumpy), should i see a flat 10° BTDC map?

Essentially how do i know it's in limp mode?

I'm pretty sure it's the timing because it's harder to start and a dog under power.

thanks.

edit: sorry, this is a V3 MJ unit

[NITROPIXIE]

Sorry don't know my porsches?? Is it a flat four as they have a different firing order to a normal 4 cylinder engine and this could be your problem.

Does the engine sound rough with popping, etc???

In limp home mode you will only see 10 degrees on the engine timing marks. If the MJ was still recieving a PIP signal and there was a loss of connection in the SAW wire then the computer software would show an advance of X degrees (according to map) but you would still only see 10 degrees on the engine timing marks. This is because the EDIS module is not recieving a signal from the MJ to alter the advance.

To test if it is in limp home mode properly you need a timing light to shine on a timing mark, if the timing mark does not move when the engine is revved then it can be considered to be in limp home mode.

You could also turn on and off the mj unit (pull the lead out, it wont damage it) and listen for a change in engine note to indicate.

Are all your ignition parts new and are you using resistive plugs?????? as it could be interference.

Ryan

[paulc]

I've confirmed it's not in limp mode. it's doing everything it should be doing.

i did put new Bosch spark plugs in, but i am not sure if they are resistive plugs.

i also tried out DannyP's latest config and it runs better. i think it's just time to fiddle-fart around while driving.

[DannyP]

FYI, using NGK DP-8-EA9 plugs for years, no interference on 'Jolt or dizzy. These are non-resistor plugs.

Glad you're running again Paul.

A quick Google and a few false links, then eureka, NGK decoder ring:

http://www.ngk.com/sparkplug411_manufac ... cturerID=1