Cant connect engine running

[turbomart]

Hi guys, Im experiencing a strange problem. I can connect to tuner pro rt fine with ignition on and upload download etc but cannot connect with engine running. Strange thing is it worked fine with ecu sitting on passengers floor. I have mounted ecu to firewall on passenger side under the dash.
This is using a 808 with nvram , usb comms and ose 12p, its in a 78 jeep wrangler with a 351 cleveland. The Ecu controls timing , IAC and thermofan ( if I can get it to work).
Any ideas why this is happening, is the ecu picking up interference from the engine ? Can I shield it with some aluminium flashing or something ?

Other problem is getting the thermofan to work, Ive wired it up using pin c1 to earth the relay and when I earth this wire the fan works. Ive set hi speed fan to 95 deg but it didnt kick in even when temp gauge hit 3/4. I cant find a temp gauge in tuner pro rt to confirm the sensors output anywhere.
Is there any way to get a temp reading in tuner pro rt ? Any ideas why ecu is not triggering fan ?

Any help appriciated.

[antus]

You can see the dash by making sure you have the right ADX file loaded and hitting the buttons labeled 'F' in this thread.
http://pcmhacking.net/forums/viewtopic.php?f=3&t=590

It does sound like interference is getting in. Quite likely its on your power circuit, or one of the sensor circuits as the ecu itself is a metal box which creates good shielding. My bets would be on power.

What is the fan road speed set to? It cant be 0. Also when you can see the dash you can see if the ecu is trying to turn it on or not, then you know weather to check the physical wiring or the tune.

[turbomart]

Ah that may be the problem as I dont remember loading an adx file, how do I do that?

Yes I set road speed to zero cause I dont have a speed sensor, is that whats screwing it up?

I might have to run ecu off a ign trigered relay to ensure a clean power source.
Thanks for suggestions.

[VL400]

If it was ok when running on the passenger floor the power source is probably ok. On engines with dizzies at the rear its more of a problem, but still check the leads are not touching any part of the loom on the way around the front of the engine. Also confirm that the leads are spiral wound for electronic ignitions and your using resistive spark plugs.

In the 12P zip if you open the ADX "OSE_$12PV111_1BAR - Petrol with calcVE.adx" you can send a mode 4 command that turns on the cooling fan for testing. Enable the menu, select the high speed fan option and click send.

mode4.png

[antus]

Yes I set road speed to zero cause I dont have a speed sensor, is that whats screwing it up?

Yep. Set that back to 55, even without a VSS. The speed must be below that, and without a vss the speed always = 0 and is never lower so no fan.

I might have to run ecu off a ign trigered relay to ensure a clean power source.

I have seen issues due to having a noisy wideband power supply connected nearby. As VL400 says its not too likely, but it is possible.

[turbomart]

Ok I set the speed to 60km/h and the fan is now turning on thanks.
Still gota get to the bottom off the connection issue tho. I wonder if a power filter like for a stereo would work?

[VL400]

Not totally clear from your first post, but you mentioned it worked fine on the passenger floor. Was that with the engine running? If so then its not power related and a filter wont help. Its getting interference when closer to the ignition on the engine. What plug leads and spark plugs are you using? Is the loom clear of all ignition parts?

[turbomart]

Yeah it worked fine running when it was sitting on the floor but since mounting it to the firewall it connects ok ignition on but not when engine is running.
My first thought was interference from plug leads as they run very close to where the ecu is mounted albiet on the other side.
The leads are acl 8mm ,I think spiral wound. Plugs are not resistor type though. Leads dont touch ecu wiring except maybe iac wires but they are in convoluted tubing.
Ecu ign power is from ign switch which also feeds coil.
Originally I was thinking maybe a earthed ally plate behind ecu to block spark plug lead interference.
Thats only thing I can think off.

[antus]

is it an option to mount the ecu in the cabin, or move it further away in the engine bay from any possible source of interfearance? Its probably getting in via the wires that come of out of the ecu, so getting the ecu loom further away from any source of interference would likely help (either just the loom, or the ecu and the loom). VL400 is right, its not likely a power issue.

[turbomart]

Update: changed to resistor type spark plugs and can now connect ok.
Must have been picking up hv interference. The ecu is mounted to firewall inside the cab but is quite close to number 8 cyl spark plug.