As in the title really!

I have had the dreaded P1518 DTC on my 52 plate ST170. As said in a previous thread, the cable was mechanically moving when starting the car, but then moved back. I assume this was because it wasn't getting a signal when moving into position.

So last night I decided to remove the IMRC box, clean the gearing, clean the copper contact and replace the transistor.

Anyway, broke my solder pump and had a complete nightmare with transistor replacement. (Wish I never replaced it as it was probably just an oxidised copper contact that need cleaning!)

The EML has gone off and stayed off, which is great! But when accelerating over 5k revs, the car hesitates and stutters. I am assuming I have caused an issue with the shit job I ended up doing on the transistor replacement? Has anyone had this and can confirm please?

I have another transistor which I plan to replace at the weekend, but would just like to know if it's worth it.

Thanks!

 

have you tried taking the battery off for a bit to reset the ecu?

 

I haven't, is this something I needed to do when doing this repair?

 

Its just something free which is easy to do. As you've got no error codes you'll have to start delving a little deeper into things.
Leads are a common issue on the ST, might be worth checking when the plugs were last changed.

Could even be something as simple as a collapsed cat. Mine makes a bit of a noise at 5k revs, but doesn't stutter.

 

That's great, thanks. I will disconnect the battery tonight for a bit and see if that cures anything.

I will be re-doing the transistor solder at the weekend when I can spend more time on it.

Plugs were changed in May this year, so haven't covered many miles as yet.

Collapsed cat sounds expensive...!

 

cable tugging and releasing on start up is normal but at around 5k it should tug the cable again allowing throttle increase but sounds like thats your issue its not doing it

 

It's normal for the DSI clip to move towards the front of the car (when started) and then return?

I was under the impression that it moved forwards when started and held there until the revs hit 5k...? Is this not the case?

 

its releases after start up which is normal, it does not hold it and only pulls again around 5k

 

Have you cleaned the inlet manifold seen many getting same issues, and its sticky flaps (Ooooooer misses) take throttle body off and spray carb cleaner down into the inlet, manually move the flaps back and forth a few times, should clean them up, I now clean mine every 6 months just to stop them becoming sticky in the future

 

Ok so mine was probably working then. I do not have the EML on now and there are no codes when reading the ECU. Only the hesitation when over 5k revs, which I thought was because the Manifold Flaps were no opening properly?

 

That's something I am yet to try too, thanks. Throttle body valve is clean on mine.

How much carb cleaner should I spray down the inlet? Just a little spray or is there no damage that can be done by too much?

 

even though its working at start up it does not mean its working higher up the rev range, suggest you warm the car up and either rev it by hand on the throttle body or get someone to rev the car past 5k and look for operation , if not pulling again then the gearing inside the imrc is worn etc or other issue, the 170 has way too many sensors for my liking but you simply need to work through them making sure things like the flaps are clean etc

 

Thanks for your help.

I know the gearing is fine within the IMRC control box but will re-check that when replacing the transistor (again!).

I will disconnect the battery for a while tonight and spray some carb cleaner in the inlet before retrying.

Can you advise how much carb cleaner is too much? Will it just need a gentle couple of sprays while I'm pulling and releasing the cable?

 

carb cleaner is way more pressurised than normal sprays so as long as straw is attached simply aim and squirt and let it evaporate, simply do it until your happy its clean

 

Thanks, will give this a go after work and post the outcome!

 

I use wyns carb cleaner, and at a guess the 1st time I done it. I used about a quarter of a can, but now not so much, as its more just maintenance than actually unsticking them.

Good luck,