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1995 Esprit S4S
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206 Posts
Discussion Starter · #1 ·
So my 95 esprit s4s is running rich. So much so, I have a hard time keeping it running until the engine gas warmed up and then it runs fine. Any ideas?

Thanks!

Bill
 

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So my 95 esprit s4s is running rich. So much so, I have a hard time keeping it running until the engine gas warmed up and then it runs fine. Any ideas?

Thanks!

Bill
Take some data with freescan.

These cars always run rich, but stumbling problems at idle when cold have a particular cause of either an air leak in the manifold or a problem with the minimum air rate bleed screw adjustment. Look for air leaks in the manifold, clean your IAC valve pintle, and take some data with freescan and send it to me.

Start recording freescan logs at 100ms data rate, with a cold engine, let it idle to 80C deg coolant temp without touching the throttle and then take it for a drive. Use all 5 gears and use 100% throttle and boost if possible.
 

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1995 Esprit S4S
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206 Posts
Discussion Starter · #3 ·
Take some data with freescan.

These cars always run rich, but stumbling problems at idle when cold have a particular cause of either an air leak in the manifold or a problem with the minimum air rate bleed screw adjustment. Look for air leaks in the manifold, clean your IAC valve pintle, and take some data with freescan and send it to me.

Start recording freescan logs at 100ms data rate, with a cold engine, let it idle to 80C deg coolant temp without touching the throttle and then take it for a drive. Use all 5 gears and use 100% throttle and boost if possible.
will do. thanks!
 

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Take some data with freescan.

These cars always run rich, but stumbling problems at idle when cold have a particular cause of either an air leak in the manifold or a problem with the minimum air rate bleed screw adjustment. Look for air leaks in the manifold, clean your IAC valve pintle, and take some data with freescan and send it to me.

Start recording freescan logs at 100ms data rate, with a cold engine, let it idle to 80C deg coolant temp without touching the throttle and then take it for a drive. Use all 5 gears and use 100% throttle and boost if possible.
is there a easy way to detect a air leak in the manifold?
 

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1995 Esprit S4S
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206 Posts
Discussion Starter · #7 ·
does anyone have any constructive comments on the data attached to my last post other than "hmmm the cars running rich?"

:)
 

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Looking at your data now.

On "startup"

your IAC is hunting and a bit high. You either have an air leak, a dirty pintle, or an incorectly adjusted minimum air rate bleed. Your engine wasn't cold though when you started. Your idle is still high when warmed up, so you definitely need to look at those points above.

You stalled it a few times, you also touched the throttle... Did it stall because you touched the throttle? Or did it stall and you tried to save it by touching the throttle?

When recording the data, it is VERY important to start recording data with the engine from cold, and let it idle without touching the throttle until the IAC stabilizes above 80C coolant temp.

Your O2 sensor signal looks really weird. Is it original or a replacement?

Your wastegate duty cycle is 100% even at very low RPM. Not normal.
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On your file called "on a run" Your battery volts are very low.

Your O2 still looks weird.

Your IAC is a little high, which could cause drivability problems. Like stalling when the engine is cold and you touch the throttle.

You BLM vs BLM cell says you are rich, which is better than lean. Do you have big injectors on there? Your injector duty cycle is pretty low.

Your wastegate is still opening way too early, up to 100% duty cycle at very low RPM's.

However I have never seen anybody drive they way you did in this data. You pretty much don't use any gear except 4th at mid range RPMs... I think, the data makes it look like you drive around only in 4th I think with some low rpm shifts to 5th, and a few higher rpm shifts to 1st, 2nd, and 3rd. basically it looks like you always shift before 2500 rpm??? Are you lugging the engine for a reason?
 

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1995 Esprit S4S
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206 Posts
Discussion Starter · #9 ·
I'll redo the data. On startup the engine wouldn't stay running I tried to save by hitting gas and killed it. In the interest of full disclosure, I'm running a catfree down pipe with a replacement O2 sensor I got from Marcus at puk esprit. I'm also running one if his high compression turbos, 1.25bar wastegate pod, remapped ECU chip, high flow primary and secondary injectors, and the ram air conversion. My issues didn't start until I replaced the exhaust with the cat free down pipe.
 

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1995 Esprit S4S
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206 Posts
Discussion Starter · #10 ·
I'm lugging the engine cuz my exhaust is so damn loud it's bugging the neighbors and I'm trying to avoid being called in since the exhaust I'm running is illegal...
 

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1995 Esprit S4S
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206 Posts
Discussion Starter · #13 ·
That Bosch sensor is pretty cheap, maybe I'll just pick one up and swap it in to see if there's a difference.
 

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O2 sensor is usually the cause for running rich in closed loop mode, it's generally the default position the ECM would take if it doesn't like the input signal from the sensor.

It also sounds like you have an air leak somewhere in the intake manifold or throttle body. For turbo cars, I've always had good luck making a boost leak tester out of plumbing PVC from Hope Depot in the same size as your turbo inlet, then connecting the two with a rubber coupler and clamps. The other end gets a quick disconnect fitting, air pressure gauge and regulator. That way you can pressurize your whole intake without the engine running and listen for leaks. There's a lot of places for air to escape that you might not have thought about. Mine looks a bit like this.

 

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Wow that is a lot of good info to read.

Opposite is happening for me. Ever since I bought my Esprit I have been running poor...:facepalm:shrug:

But it's cool I love this car!
 

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1995 Esprit S4S
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206 Posts
Discussion Starter · #16 ·
So Vulcan..... I disconnected the O2 sensor , started the car and all my troubles vanished. I plugged the O2 sensor back in and my troubles immediately returned. I think I have a defective O 2 sensor :)
 
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