Omex Start Up Issues

[Richie-Van-GTi 70 2 Cars]

Lookng t 2.0 16v with jenvery bodies and omex management. Its always had an issue with cold star, as though its mapped backwards. When you start it at cold it kind of ticks over mega low, often stalling, then as it warms up the revs increase to a nice tickover. The only way to help with the cold start is to hold the throttle open slightly until warm, or raise the idle by adjusting the throttle stop but this then means a very high tickover when warm.

Does anyone have any experience with omex stuff that can give me some pointers on what the cold start setting data should look like? Last person to map it says he couldnt change the cold strt, I think he forgot and wanted the space back in the garge for other work as he is mega busy.

[welshpug 1,621]

it'll just be poor mapping, cold start is notoriously difficult to get right, as you only really get one shot at it every day, so it helps to find someone who has done engines of your spec before.

[Miles 331 1 Cars]

What omex is it?

[chris 417 mi 24 2 Cars]

As far as im aware its the 500 ecu (only 1 output), its been on the car since 2001 and was fitted and mapped by richard the (then) owner of omex at powerstation in gloucstershire. However since then the map has been adjusted to different engines fitted over the years.

[Miles 331 1 Cars]

I'll try and have a word with my man tomorrow see what he says

[Richie-Van-GTi 70 2 Cars]

To clarify, this is Chris's car I was posting about

[Simes 248 2 Cars]

Although mine is on Emerald....I feel your pain, especially as it's getting colder...which is incidently a good time to get around to sorting this out.

[Richie-Van-GTi 70 2 Cars]

well just seen a link welshpug posted on nother thread to the omex 500 manual. That gives me a good idea on whats needed. Also shows me I think that something is wired wrong to solve another niggle with the car.

[Richie-Van-GTi 70 2 Cars]

It is definatley an Omex 500 system.

Well Ive rewired the other niggle so the fuel pump now runs via the ECU, and it shuts off when ign on and not started! Or at least it will when I get a better relay that isnt sticking.

Ive tried tweaking the warm start up but there is literally no difference. Even if I change it between 0% up to 60% it doesnt make any difference at all to start up idle.

[Richie-Van-GTi 70 2 Cars]

Sussed it a few days back, it now starts and idles from cold no problem. Fuel pump primes etc via the ecu and the rev counter is fully functional again. Also changed the cam so the engine isnt rattling its nuts out.

[chipstick 382 1 Cars]

I've 'suddenly' the same problem as you describe in your first post.

 

My car was mapped back last summer and always started fine.

 

Would always start fine with a bit of throttle and then idle properly.

 

I then put the car into storage for several months and only started it once during that time in which it popped, banged and wouldn't idle without throttle being applied to keep it alive. I put it down to not being run for a while so wasn't too concerned.

 

Now the car is back with me and has it's MOT next week so I started it earlier to blow out the cobwebs and again it wouldn't stay running if my foot was let off - the revs would drop and it would stall. Admitidly this time after just 30 seconds it woud idle without throttle, just very low. Displayed as about 550 rpm, but I take the gauge with a pinch of salt anyway. It certainly didn't feel much higher though tbh.

 

I'm wondering if the blast up the road to the MOT will clear it out and from then it may behave with regular use. I'm just concerned it's going to be a mission getting to the station with revs dropping off when coming off the throttle. Hoping it will sort itself out.

[welshpug 1,621]

plug the laptop in, check the throttle settings and check the live readings, seems to be a relatively common complaint.

[chipstick 382 1 Cars]

Bugger never bought a cable When I saw they were £60 with little view to ever needing to plug I in I never bothered. Odd that it's suddenly forgotten something from being left stood a little while. Does anyone on here make the cables?

[welshpug 1,621]

Isn't omex a standard Serial cable?

[chipstick 382 1 Cars]

Sorry I forgot to mention, I'm using a DTA S40.

[Anthony 1,000]

Cables aren't too difficult to make Dan - I've done a few of them now, and it's only a few quid in parts to do

 

Welshpug posted a topic recently where he made one (and had unrelated computer trouble)

[kyepan 291]

Mine did the same thing, check the throttle stops are what they were set to when it was mapped, and you've not developed a tiny air leak over the winter, bodies are quite sensitive to this, and it will throw the idle out massively. in my case, i had an air leak, and the throttle stop had unwound itself a bit.. once sorted it was back on song.

 

you're not far from sandy, perhaps go see him in saltash.

 

Cheers

J

[welshpug 1,621]

What those guys said!