High idle on 1989 Esprit non-SE

[jkorvette]

My 20,000 mile 1989 non-SE Esprit has a high idle condition which has gotten worse. It now idles around 2000 - 2200 RPM and may drop lower after warming up. It has always had a high idle near 1800 - 2000 RPM but would drop to a pleasant 800 or so by cycling the key after warming up. This issue seems to be getting worse. I just realized that the battery disconnect that I installed to avoid a dead battery after weeks/months of not using is likely causing the ECM to relearn every time I start it!

Is this the case? Please advise on best steps to correct this annoying issue. Thank you

I suppose I should leave the battery connected and maintain a trickle charger on the battery when not in frequent use. (Someday I'll track down the power draw!)

[Escape]

Disconnecting the battery will mean the ECM needs to learn every time, so that could explain the high idle. But then it should be fine after a (decent) drive.

The idle air valve is known to give trouble (several topics with detailed info and replacement parts). Could be getting worse over time and the effect more noticeable as well because of the ECM losing it's memory. Do you have Espritmon or Freescan to check the idle settings?

[Barrykearley]

You defo need a computer hooked up to figure out what’s going on.

could be the tps is set wrong - idle valve is a common issue. Don’t guess though - you need that car scanned.

[jonwat]

5 hours ago, jkorvette said:

My 20,000 mile 1989 non-SE Esprit has a high idle condition which has gotten worse.

So, if it's a non SE & doesn't have carbs does it have Bosche FI, does it have an ECM? 

[jkorvette]

It has Delco fuel injection and an ECM.

[Barrykearley]

14 hours ago, jonwat said:

So, if it's a non SE & doesn't have carbs does it have Bosche FI, does it have an ECM? 

It’s basically what they sold in the UK as an “S” - they only sold 5 though 😬

[jkorvette]

they only sold 5 through ???

[jkorvette]

@Escape@Barrykearley I don't have Espritmon or Freescan to check the idle settings. Where can these be purchased? Thank you

[Escape]

You can find the software for free (search the forum), but you'll need to buy or build a cable. Don't worry about the ADSL connector, that can be replaced by any 4-way connector (as I did) or you can use pigtails to connect to the car.

[jonwat]

1 hour ago, Escape said:

You can find the software for free 

Does Espritmon or Freescanwork with the Delco ECM? 

[Escape]

From what I know it's basically the same ECM as for the SE, just with less possibilities. It is strange it has different connectors though. Maybe because it needs less wiring without the added complexity of the chargecooler and secondary injectors, so could use a simpler base layout. It is after all a generic ECM also used in some GM cars.

According to the wiring diagrams, the ALDL is wired the same for both, so it should work.

[Barrykearley]

It’s a slightly different ecm - one has three plugs the other 4.

yes Freescan works a treat.

5 hours ago, jkorvette said:

they only sold 5 through ???

Yes they did in the UK - sold a lot more in the USA

[jkorvette]

I wanted to provide an update on my issue (sorry for my tardieness). Since I stopped using a battery disconnect, my high idle condition has gone away. Seems making the ECM relearn everytime the battery is hooked up is not the way to go! Car idles quite well now.