Esprit SE with Sad Idle

[chandrab]

I've got a 1991 Esprit SE and it's starting to act weird when I took it out of winter storage. In all honesty, I suspect this problem appeared this fall.  Basically, the car is idling very strange (all the time), feels it's very rich, feels like it's missing (some times), and I've heard it back fire once.  I'm afraid to drive the car  too far since the engine feels like it's going to cut out/stall.  There are no check engine lights (CEL) lights at all.  I used EspritMon to capture some of the logs and wanted to see if any ECU experts could tell me which sensor(s) are not functioning or where to look to diagnose this issue.  Attached are two zip files of the car warming up and a second one where it's a warm idle. Sad91SE.zip

I have reset the ECU and attempted re-calibration.  I noticed the TPS values are 0-84, but an issue for another day. 

Edited March 28, 2016 by chandrab

[Vanya]

Hey,

Are you running aftermarket injectors? Aftermarket 02 sensor? I don't see anything entirely out of whack in the above graph. The only time I've experienced extremely rich running and popping/banging as well as stutters etc was when I fitted FiveO Motorsport injectors. They overfuelled all the time, especially on idle, so I couldn't pass emissions...although that was the least of my problems (stuttering acceleration, cutouts at high-rpm etc).

An aftermarket O2 sensor can also act up in any number of ways, but I also ended up with quite a rich idle on closed loop, my engine would also pretty much cut out when I touched the gas pedal too...

[sailorbob]

What Memcal are you running? I ask because 0x6CE5 isn't an EPROM ID I've seen before.

Edited March 28, 2016 by sailorbob

[chandrab]

I'm running all stock fuel injectors, they were replaced with a used set of S4 injectors about 4-5 years ago. All the engine sensors are still original from 1991. The car is all stock with the exception of a BOV valve and upgraded memcal (S4S code?) that my mechanic gave me years ago. It's been running fine until recently.  I forgot to mention the car just sounds different when it idles, a different type of resonance in the house.  Maybe the clues are in the logs?

The car's problem just continue on when it's driving.  It just feels like the engine is going to stutter and die.  I should also mention this morning it took 2-3 tries for the cars to cold start - usually it's just one.

 

Edited March 28, 2016 by chandrab

[Barrykearley]

I had no end of running issues down to the aic valve - a cheap swap to try. 

[Chillidoggy]

11 minutes ago, Barrykearley said:

I had no end of running issues down to the aic valve - a cheap swap to try. 

 

I thought I'd have a look at the log (not that I'm an expert) but as usual I couldn't open it as it wasn't a .csv file. I agree with Barry though, an IAC is a cheap swap, and easy to fit.

[chandrab]

Hi Ian...Attached are the log files (CSV files).  If you could take a peek that would be great.

Thanks!

esprit91SE_warmup.log

esprit91SE_warmidle.log

[Barrykearley]

If the voltage on the o2 sensors is swinging about - that's a good sign

with the aic valve - it's showed nothing on mine bar a cel and bad running - the cel was something like revs higher than target if I remember correctly - along with some rich running errors.

take the aic off and check for wobble - make sure the o ring is nice - then do the correct warm up and relearn. 

 

http://www.thelotusforums.com/forums/topic/74755-air-idle-control-valve/#comment-577502

[Chillidoggy]

8 minutes ago, chandrab said:

Hi Ian...Attached are the log files (CSV files).  If you could take a peek that would be great.

Thanks!

esprit91SE_warmup.log

esprit91SE_warmidle.log

Hold up! Like I said, I'm no expert, I'm just curious, and there are plenty of others here who are, and can help you much better than me! Sailorbob, Travis etc.

[Qavion]

Is the fuel fresh (or did you add a preserver for the storage)?

[Bibs]

Barry, it's an IACV, Idle Air Control Valve on an Esprit, it's not called an AIC.

[Chillidoggy]

45 minutes ago, Bibs said:

Barry, it's an IACV, Idle Air Control Valve on an Esprit, it's not called an AIC.

Leave the bloke alone, he's got enough trouble on his hands.

[sailorbob]

0x6CE5 isn't an EPROM ID I've seen for an S4S either so I'm guessing the chip is modified.

I haven't looked at the logs in any detail but have you had a flat battery or reset the BLMs? The CL Correction Term and BLMs start at 100% and then start to change as the ecu leans the corrections. Your poor running might be as result of the previous BLMs being lost.

[Barrykearley]

4 hours ago, ian29gte said:

Leave the bloke alone, he's got enough trouble on his hands.

Anyone wanna buy a shagged v8 

[Chillidoggy]

40 minutes ago, Barrykearley said:

Anyone wanna buy a shagged v8 

 

Is it that bad?

[chandrab]

Hi SailorBob...I'm not sure aboure the BLM/CL....I did have a flat battery before and also reset the ECU by disconnecting from the battery.  So any correction terms could have been lost.  Not sure what BLM is.  I've had flat batteries many times and never had this sort of issue.  How do I see the BLM/CL from EspritMon.  I've done the correct reset sequence and let the car run for 20 minutes with headlight on.  

I did have a mix of old gas an new gas with some Stabil gas preservative.  I filled the car up before I put it away in Oct/November.

Can you suggest a course of next action?  Do the sensor look OK?

[Qavion]

Quote

The car is all stock with the exception of a BOV valve and upgraded memcal (S4S code?) that my mechanic gave me years ago.

 

So you still have your EBPV (exhaust back pressure valve)? I'm just wondering if your valve is stuck or that the rubber vacuum hose has perished or fallen off. When the engine has warmed up, the throttle jacking capsule will put the throttle back to a normal idle setting, but the exhaust will still be restricted.

Note that this line of thought is not based on your files. It's just a common Esprit SE problem.

Edited March 30, 2016 by Qavion
Added provision

[chandrab]

1 hour ago, Qavion said:

 

So you still have your EBPV (exhaust back pressure valve)? I'm just wondering if your valve is stuck or that the rubber vacuum hose has perished or fallen off. When the engine has warmed up, the throttle jacking capsule will put the throttle back to a normal idle setting, but the exhaust will still be restricted.

Note that this line of thought is not based on your files. It's just a common Esprit SE problem.

The EBPV is still on the car, but it's wired fully open.  I did verify that  it's open.  I have renewed some of the parts of the car all within the last few years: new MSD ignition coils, new spark plug wires, new fuel filter, electric charge cooler pump, newer S4S fuel injectors, BOV. I owned the car for 10 years and never had an issues until now.  

[sailorbob]

The BLM is the "Block Learn Multiplier" which is a long term fuel adjustment that the ECU learns as a result of the HEGO sensor feedback and it's used to adjust the amount of fuel injected to achieve the desired air/fuel ratio.

Had a bit more of a look at the "warmup" log and nothing else really stands out apart from the CL Correction Term and BLMs starting at 100%.

Without knowing what chip you are running my thoughts are that the VE tables are incorrect for the engine specification and it'll take a little while for the ecu to populate the BLM tables sufficiently to correct the fuelling to compensate.