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Drfatz

I am truely stumped on this one...still

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It has been sometime since I have posted anything on here! I have been busy working on the Esprit taking care of various odds and ends while avoiding the frustrating engine problems. Well she is almost ready to go through inspection and be placed back on the road, but before that can happen I have to finally confront the engine problems that have not been resolved since I first ran her several months ago. So here is the latest....

I originally had a problem with the idle being much to high that ended up being the throttle bodies not synced up together which was causing a vacuum leak and thus the car could not control its idle. Well I pulled all of it apart and reset the butterflies and now she seems to be able to control the idle just fine. However, she is (and always has been) running WAY to rich. So rich that the exhaust is really thick, black and smells strongly of fuel. I took some freescan logs and went over them with John from WC Engineering. It seems that the O2 sensor is reading 0.1-0.4 volts even though the car is spewing black smoke not to mention the MAP sensor is reading a consistent 0.7 volts (the Baro is 0.85) at idle. So I pulled out the new O2 sensor that I had just installed in the car only to find it was covered in a thick layer of black soot. I figured that certainly wasn't helping anything so I re-installed the O2 sensor that came on the car and I put in a new MAP sensor. I ran the car again and took another freescan log only to find that nothing has changed. The O2 sensor still reads that the car is very lean and the MAP is still around 0.7 volts (baro is at 0.85) at idle. I should also mention that the Engine Load parameter in freescan is reading a constant 10-11!!!! I am truly stumped and am ready to bang my head against the wall on this one.

Why would an O2 sensor read extremely lean when the car is obviously way to rich and the MAP sensor read to high? Again I have installed all new silicon lines and fittings to the MAP sensor. :) :) :) :)

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Upgrade today to remove Google ads and support TLF.

Could it be a bad injector? maybe the spray pattern is gone and you are burning short . . . not all gas burns, until it gets into the exhaust and then it cokes up . . . or maybe ring blow by . . . losing oil?

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Could it be a bad injector? maybe the spray pattern is gone and you are burning short . . . not all gas burns, until it gets into the exhaust and then it cokes up . . . or maybe ring blow by . . . losing oil?

The injectors are brand new RC racing units (370cc) from WC Engineering. When I look at the freescan logs it says that the ECU is running the injectors at almost full duty cycle! Its possible the bottom half of the engine is having problems since I have not stripped it down though she only has 30,000 miles on her. I did however recondition the head with a multi-angle valve job and I re-shimmed all the valves. So car as I can tell she is not loosing any oil.

I will try and post up the FreeScan logs later tonight.

Edited by Drfatz

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You could also have a clogged air/oil valve, the rebreather thing . . . maybe crankcase internal pressures are building up increasing blow by . . . or maybe that valve has failed and you are feeding more oil mist back into the intake . . .all guesses . . .sometimes a complete idiot like me can spur some ideas . . .

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You could also have a clogged air/oil valve, the rebreather thing . . . maybe crankcase internal pressures are building up increasing blow by . . . or maybe that valve has failed and you are feeding more oil mist back into the intake . . .all guesses . . .sometimes a complete idiot like me can spur some ideas . . .

Not a bad thought. The crankcase valve is cheap and easy to replace and its just about the only thing on the entire engine that has not been changed.

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Hi,

If both O2 sensors are giving odd data it does make you wonder about the circuit that is driving / measuring them. There is a page on my companies web site that may help http://www.picotech.com/auto/lambda_sensor.html

I would suspect the O2 sensor and circuit first. On some ECUs if you run the engine with the O2 sensor unplugged it will go back into open loop running off default values. Try this - if the engine then runs fairly normally other than a warning light (ie not way too rich) then you have at least confirmed its the 02 sensor and/or its circuit.

Alan

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Hi,

If both O2 sensors are giving odd data it does make you wonder about the circuit that is driving / measuring them. There is a page on my companies web site that may help http://www.picotech.com/auto/lambda_sensor.html

I would suspect the O2 sensor and circuit first. On some ECUs if you run the engine with the O2 sensor unplugged it will go back into open loop running off default values. Try this - if the engine then runs fairly normally other than a warning light (ie not way too rich) then you have at least confirmed its the 02 sensor and/or its circuit.

Alan

Good idea. I will have to give that a shot tonight. I looked over all of the connections to the O2 sensor and nothing seemed suspect.

Interesting article. I read over the website Alan posted and it mentions that the O2 sensor will read lean even if the engine is running rich, if there is a vacuum leak or extra air is getting into the engine some how. This seems like it must be the problem since the O2 sensor is reading very lean AND the MAP is saying there is to much air going into the engine. Both these conditions would cause the ECU to dump more fuel into the engine. Now I just need to figure out why there is more air getting into the engine!!! This has been a problem for months now. I have taken the entire intake manifold off multiple times and checked all of the fittings and hoses. I reset the throttle bodies and made sure all of the linkage was okay. So far as I can tell there are absolutely no leaks in the intake system. Also I should mention I ran a compression check and got between 145-150 psi across all cylinders so it seems the rings are in good shape.

Edited by Drfatz

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Graham,

Did you check the vacuum T under the Chargecooler hasn't broken? I had a similar issue but not as bad and when I removed my CC to clean it and repaint it I found my T was cracked off one side(to the Fuel pressure regulator YIKES!) good thing I hadn't been driving the car hard. Also, are all the gaskets intact? I've torn mine a couple of times getting things on and off.

Artie


89 White Esprit SE

...a few little upgrades....

93 RX7.....Silverstone

....slightly modded...Muahaha...

New Addition:

1990 300ZX TT......Hmmm

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Graham,

Did you check the vacuum T under the Chargecooler hasn't broken? I had a similar issue but not as bad and when I removed my CC to clean it and repaint it I found my T was cracked off one side(to the Fuel pressure regulator YIKES!) good thing I hadn't been driving the car hard. Also, are all the gaskets intact? I've torn mine a couple of times getting things on and off.

Artie

All of the vacuum fittings are intact and I replaced all of the gaskets with new ones when I stripped down the top half of the engine. Forgetting vacuum lines for a moment, is there anyway one of the channels inside the intake manifold is leaking? I'm just grasping at thin air at this point.

What is a normal MAP reading for a good running car at idle?

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As promised I have attached the freescan.

I have looked at a few logs for the Elan but it's the first time I've looked at a Freescan run so I'm feeling my way around the data. The following might be useful:

The engine appears to be cool at start up - coolant temperature starts at ~30 and rises to ~40. The target idle is 1200 (which I guess is the cool elevated value). The ECU goes closed loop at ~72s but the O2 sensor does not start toggling (between ~0.25 and ~0.65V) until ~90s when the A/F ratio is ~13.5. I'm afraid I don't know anything about the Esprit MAP readings, sorry.

Could this just be normal for a cool start i.e. higher idle speed and running slightly richer (the Elan runs very rich until it's warm). The O2 sensor appears to be starting to operate correctly and it would be better to see what it is doing when the engine is warm.

Hope it helps.

Geoff


Geoff Smith

LotusElanCentral.com and BOLLECKS† founder

[†Bristol and Outlying Lands Lotus Elan Central Knowledge and Support]

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Graham,

When I compare your files to some idling freescans of mine your TPS V at idle is .61 on yours and mine is around .39 at 0 tps %. Also, my map at idle is around .45-.5 and baro is .8 or so. Maybe you need to adjust the tps and see if that helps. THe two screws should allow you to retard the tps some and see how your values change to get it close to .4

Artie


89 White Esprit SE

...a few little upgrades....

93 RX7.....Silverstone

....slightly modded...Muahaha...

New Addition:

1990 300ZX TT......Hmmm

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Cheers guys! I can try adjusting the TPS, but I thought so long as it is under 0.67 you were okay however, that may not be the case. As for teh MAP I am really stumped as to why its not dropping down to around 0.5. I think that MAP is the heart of my problems.

BTW I finally have some pictures!

dsc00019tc6.jpg

dsc00023hi9.jpg

dsc00022cr6.jpg

Edited by Drfatz

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This is very interesting... Aerobat's S4 has similar issues. I ran the engine with just my wideband hooked up and I've ran it with the o2 and my wideband.... nothing changes. This MAP system is a little different than most because of the ITB's. Most engines only have one throttle body and therefore intake manifold leaks have VERY minimal effect. If it were a MAF (Mass Air Flow) system, then even the slightest leak anywhere between the MAF and the head will cause a very significant change in AFR. When I step on the throttle in the S4 the AFR goes down to 9.4.... which is sufficient to blind anybody behind me (or at least give their paint a new black-hue)

I'm going to spend a bit more time on the S4 soon (the v8 only requires an oil change and it's CB antenna to be mounted) and I'll check the throttle plate vacuum and see if they are properly balanced. I'm also beginning to think that the RC injectors are, in fact, the problem. They may be too good and over-fuelling.. i dunno yet. gonna have to spend some time on this one.


Modifying esprit's.. now that's fun..

PS... I AM NOT A CERTIFIED MECHANIC.. I Have chosen to help those in need, in the past and must not be construed as being a certified technician.

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Hi,

Your Freescan-file does not look right to me. There is too much data simply missing, IMHO. I would suspect that there is something wrong with your ECU/MemCal/Chip.

Maybe you should get a complete ECU from another SE/S4 for a test.

Marcus

As promised I have attached the freescan.

Marcus

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Mark, I have actually had someone else suggest that the RC injectors may be the source of the problem. I would be interested to know what you find out!

Marcus, when you say data is "missing" what data are you referring to?

Edited by Drfatz

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Graham,

I was wrong ... it just looked too static for me at first sight. You chose a very high sample frequency. Thats why it looked to me like frozen ...

It definitely is running way too rich. You can see that by looking at the "integrator" value. Once the ECM goes into closed loop (line 345) the integrator value which should stay around 128 is constantly dropping. This means that the ECU is trying to reduce fuel, without luck.

Interestingly the O2-sensor is not showing too much odd data. With these overly rich conditions it should constantly read high voltage.

- is the MAP-pipe/hose to the fuel pressure regulator attached properly ?

- what primary injectors are you using ?

- the MAP figures also look a bit too high

- the baro is OK (they all show these low 0,85)

- The IAC counts are also too high. When warmed up this should be around 20-40 counts. This indicates a not properly adjusted minimum air rate setting (= throttle bodies, butterflies !)

- maybe the main problem is just a faulty O2-sensor ... who knows ?

Good luck hunting

Marcus


Marcus

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Cheers Marcus. As far as I can tell the MAP hose is connected properly. Just to confirm, where is the MAP connected to the manifold? Towards the front (firewall side) at the single fitting or towards the rear at the T fitting?

As for primary injectors I am using 370cc RC racing injectors which are brand new.

I checked the throttle bodies by pulling the entire intake off and noticed that the linkage connecting the throttle bodies was not properly put together which means at some point a PO had taken it apart. I attempted to fix them and it seemed they were correct which I verified with a flow meter while the engine was running. However, I still have my doubts about the throttle bodies and may end up removing the intake manifold and sending it over to WC Engineering.

The O2 sensor has also been a concern. I pulled off the brand new one that I just installed and it was caked in dark black soot which is probably why it had failed. Perhaps I will go pickup ANOTHER one :-(

- Graham

Edited by Drfatz

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Graham,

please have a look at the diagram inside your rear hatch. there you can see all the proper hose/pipe routing. Or have a look here:

ENGINE%20SCHEME.JPG

You can see, that the MAP-hose is connected at the rear.

RC injectors are fine. No doubts here.

Your flow might be balanced now, BUT the butterflies might be too much closed when TPS=0. You have to adjust the minimum air rate screw in a way that the TPS-counts are 20-40 counts when the engine is warm and TPS=0.

I personally would check all the pipes/hoses first. Please also check the fuel pressure regulator's function. With idle there should be some vacuum present at the connector. Check that and also check the reaction of the fuel pressure when you disconnect and reconnect that hose. There has to be a significant difference.

Then I would disconnect the O2-sensor and let it run on a fixed value (the CEL will come on).

BTW, is there maybe some silicone in your engine intake or exhaust path ? JFYI, silicone contaminates O2-sensors and destroys them.

Cheers

Marcus


Marcus

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Marcus, interesting point about the silicon in the intake. So far as I can remember there isn't any silicon in the intake, but there is some gasket epoxy.

Indeed I have my air lines hooked up exactly like the diagram. What alarms me is when you say when you disconnect the air hose to the fuel pressure regulator there should be a significant difference. Well on mine I have done that and there is no change at all in the fuel pressure. I know this because I have an Aeromotive fuel pressure regulator with a fuel pressure gauge installed on it. Currently the fuel pressure is set to 42psi at the regulator. I set the pressure by disconnecting the air line and adjusting the regulator. However, when I install the air line back onto the regulator there is no change in fuel pressure. Could this be because there is no vacuum coming from the manifold (ie a leak) or is my regulator malfunctioning?

Thoughts?

Cheers,

Graham

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Graham,

I hope you are using the correct fuel pressure regulator (or the original one). With the engine running (idle) and everything correctly assembled you should see something between 31-55 lb/sq.in

With the engine NOT running you should get a static pressure around 60 lb/sq.in

If you cannot get these figures then either your regulator is faulty (or the wrong one) and/or your MAP-hose is not giving the correct information (= no vacuum = leak somewhere)

Cheers

Marcus


Marcus

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Your car looks very sharp Graham! The repaint turned out sweet. Any pictures of your exhaust set up....I am about to fabricate a new one out of stainless, and wanted to get ideas about routing.

As far as the fueling issues, if your O2 sensor checks out, I think it is time to try to start swapping back the stock components...first FPR, then injectors, etc. Esprits are very sensitive to aftermarket parts. Your TPS definitely needs to be recalibrated if you are .6 volts at 0%/ idle....that will likely affect the IAC counts. Also be sure to reset the ECU each time you do an alteration...as any "learned" fuel curves are likely one's you don't want to keep because of the overly rich running. Good Luck!

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Marcus... what's missing? The issue here is that the freescan has been completed when the engine is quite cold. The engine starts at 31*c and cools off to 30.6*c. So, his thermostat isn't working, or his coolant sensor is shot, or his fans won't turn off.

I might be wrong.. now that i've seen more input... but i'd check that too.


Modifying esprit's.. now that's fun..

PS... I AM NOT A CERTIFIED MECHANIC.. I Have chosen to help those in need, in the past and must not be construed as being a certified technician.

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Thanks for the paint comments, she certainly looks pretty now if only she would run like she looks! I have pictures somewhere of the exhaust being fabricated. Currently it is a 3" turbo back exhaust with a high flow cat going into a magnaflow muffler. Unfortunatly the company who fabricated the exhaust swears by Magnaflow even though many people on here said they do not like the sound. Well I should have trusted the LEF people because I went with a magnaflow and I absolutly HATE the sound. As soon as she is running well enough to drive I will be removing the Magnaflow and installing a aeroturbine muffler.

As for the FPR I can no longer revert back to the stock unit as I have installed nice AN-6 lines to coup with the eventual high demands of my GTR3071R turbo. I am running the Aeromotive 13109 (Aeromotive) which was recommended to me by John at WC Engineering to go along with my setup. As mentioned before there is no change at all in the fuel pressure when the vacuum line is on or off the regulator which says to me there is a problem with the manifold. I am going to get a vacuum tester tonight and see if there is any vacuum at all going to the FPR and MAP.

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You can just suck on the vac line and watch you're fuel pressure change... if it doesn't change by sucking on the line with your mouth... then there's a problem with the FPR, fuel filter or pump.


Modifying esprit's.. now that's fun..

PS... I AM NOT A CERTIFIED MECHANIC.. I Have chosen to help those in need, in the past and must not be construed as being a certified technician.

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