[Gallagher]

Did a quick forum search with no luck, thought I'd throw a thread on here before I hit the garage and start digging...

Not a major issue, but took my '90 SE for a quick spin the other day. Left a stop light and had to get in the lead (hehehe) before two lanes turned into one. After a hard fought, yet convincing victory over my rival in the Buick LeSabre wagon beside me, I noticed that on lifting off the throttle in neutral the RPMs dropped to below 500 and the car stalled. Car runs perfect if I hold the pedal down slightly to keep it at a hair over 1000RPM....no other side effects.

Did I find a weak link in the throttle cable assembly? Anything to look for that commonly dies? Figured it was easy to ask in case somebody has done the same and could save me some looking.

Thanks in advance,

Jeff

 

[Gallagher]

Found it! Cable jumped out of the track on the semi-circular quadrant and was pulling from the wrong angle.

 

[esprit888]

Jeff,
Still shouldn't have stalled, just gone to idle. Also it shows your cable has too much slack, I would also pop it off the quadrant and check for fraying on the nipple end.
Colin

 

[Vulcan Grey]

The ECU controls the IAC valve (a stepper motor), which is what controls the idle. Even if your throttle cable weren't attached, you should still get a normal idle.

I'm assuming your problem will persist, so you'll need to see if the IAC needs cleaning, if you have air leaks in the manifold, and you should record data with freescan for the IAC counts as the engine warms from cold to 80C.

It is possible that the minimum air rate bleed screw will need adjustment, but that should only be done with freescan and following the procedure in the EMH manual. DO not try to adjust the idle by ear with a screwdriver! That will not work, due to the ECU control.

 

[OnAir]

Jeff,
Are you able to get 100% throttle with that slack in the cable? You can check with the help of a OBDII reader. Might explain the struggle against the Buick.

 

[MidLifeZ]

Jeff,
Are you able to get 100% throttle with that slack in the cable? You can check with the help of a OBDII reader. Might explain the struggle against the Buick.

Dont think 1990 cars have OBDII ports.. or did they on Lotus?

 

[OnAir]

Dont think 1990 cars have OBDII ports.. or did they on Lotus?

Good point Kenny. It's likely only the V8's that have this.

 

[sailorbob]

It possibly sounds like the cable was opening the throttle slightly before and the ecu had adjusted the IACV to such a small opening that it was not enough to maintain idle when there was some slack in the cable due to it jumping out of the quadrant.

Restore the cable with a bit of slack and then force an IACV reset so that the ecu learns the correct setting.

Check your throttle cable bracket to see if there's an obvious reason for the cable becoming dislodged.

The cars with the Delco ecu do not have OBD-II, this is only on the V8's.

 

[maxvelocity]

I've seen it slip off if the pedal pops or your foot slips the pedal. Almost seems like the cable tension was used to set the idle.

 

[Gallagher]

I should have known that the ECU controls idle speed....I guess I just got excited about finding something wrong so easily and had tunnel vision.

What side is the bias towards either Freescan or Espritmon? Also what's the best place to acquire the hard bits to run it?

In the meantime I'll go through and adjust the throttle cable and checking all brackets follow by doing the IAC replacement procedure in the manual and see if that gets me anywhere.

Thanks for all the helpful advice, always much appreciated!

Jeff

 

[esprit888]

I should have known that the ECU controls idle speed....I guess I just got excited about finding something wrong so easily and had tunnel vision.

What side is the bias towards either Freescan or Espritmon? Also what's the best place to acquire the hard bits to run it?

In the meantime I'll go through and adjust the throttle cable and checking all brackets follow by doing the IAC replacement procedure in the manual and see if that gets me anywhere.

Thanks for all the helpful advice, always much appreciated!

Jeff

Sanj sells the cable with either a RS32 or USB connector http://home.earthlink.net/~turboesprit/ALDL_Cable/index.html
If you need one right away you can borrow mine

 

[Vulcan Grey]

Espritmon gives more accurate readings for boost, and can do a few other things, however, in order to look at Espritmon data you have to rewatch it.

Freescan data is easy to graph in Excel, and see at a quick glance what the engine s doing. Once you get used to reading the freescan data, then the inaccurate boost reading doesn't matter.

Use both. If you want to send data to someone else to look at, the freescan is much easier.

 

[sailorbob]

There is also TunerPro is you want to datalog more data. The log files can be exported in Excel .csv format too.

 

[lotusdriver2001]

On both my son's '90 Esprit and my 03 V8 I have had intermittent problems with returning smoothly to idle after coming to a stop. Each has usually responded well with the IAC reset easter egg with the throttle. Later Esprits can also be pretty picky about the "learn" procedure after reset. It's free and easy so I'd try the IAC reset procedure first.

 

[MidLifeZ]

I have an extra connector like Sanji sells, thought I lost, bought another and then found it.. yeah, still connected to the car...

PM me with an offer if want it.

 

[jtrealty]

On both my son's '90 Esprit and my 03 V8 I have had intermittent problems with returning smoothly to idle after coming to a stop. Each has usually responded well with the IAC reset easter egg with the throttle. Later Esprits can also be pretty picky about the "learn" procedure after reset. It's free and easy so I'd try the IAC reset procedure first.

The '90 and the '01 have very different systems controlling idle so it is unlikely they both have the same problem. If you are having to reset the idle tables often you have something wrong, you should not have to do that. On the '01 I would remove the IAC and clean it's insides with carburetor cleaner, it is probably sticking. You may also have air leaks so check all of the hoses and connections. After doing that go over all of the throttle cable and linkage adjustments and make sure it is working smoothly.
David Teitelbaum

 

[mpesik]

Found it! Cable jumped out of the track on the semi-circular quadrant and was pulling from the wrong angle.

Hello.
Not contributing much to your Thread but I had that happen with both my 928's.

 

[Gallagher]

Hi all,

Thanks for all the tips, turned out that the IAC was dead. Put in a spare I had and the car ran perfectly again. Also did a little cleanup of the throttle cable....I'm still a little hesitant that both the cable hopping out and the IAC dying happened at the same time....seems like too much of a coincidence to me...we'll see

Thanks again,

Jeff

 

[Gallagher]

Hello.
Not contributing much to your Thread but I had that happen with both my 928's.

928's eh? Beautiful cars, obviously you're a glutton for punishment!!! Haha, my brother had one and I can honestly say that the car was awesome and I was glad it wasn't mine! I actually saw an absolutely perfect s4 the other day....anyways.

 

[Gallagher]

Sanj sells the cable with either a RS32 or USB connector ALDL-to-PC cable for FreeScan
If you need one right away you can borrow mine

Thank you very much for the offer! Now that I have it scoped ( so far anyways) I will pick up the proper bits in due time.

Really appreciate the offer though!