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Old 12-01-2012, 05:54 AM   #1 (permalink)
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Normal Idle Mixture?

I noticed that when I start the engine, I can smell a fairly rich exhaust. However, the exhaust tips seem fairly clean (but then I don't drive the car that often). Is this normal for idle or should I be concerned. It's possible that this could be a reason for slower startups after warm engine if the injectors are putting too much fuel in the cylinders.
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Old 12-01-2012, 12:40 PM   #2 (permalink)
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It would narrow down the possibilities if we knew what year the car was. And the approximate mileage. On the V-8's the answer is possibly yes. Especially if the mileage is near or over 40,000. As for smells, if you have a catalytic convertor (your year has one installed and it hasn't been removed) you will smell fuel on cold start-up because the cat hasn't warmed up and isn't working yet.
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Old 12-01-2012, 01:29 PM   #3 (permalink)
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The car is a July 2000 V8 with about 25k miles and yes, it does have the warm start issue. Not too bad but it seems like such a solvable problem.. I understand that it could also stem from faulty OXY sensors and fuel injectors. I personally think with my situation, it may be an advanced timing issue and or residual fuel in the cylinders(not sure what would cause either). I changed the CAM sensor myself and that didn't help. I have a new crank sensor but don't know how accessible it is on the engine to chagne it myself.
I didn't know that the V8s ran that rich on start-ups. For diagnostic work, I know the ECU is under the plenum, but can it be controlled through a more accessible port or plug?

Thanks.
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Old 12-01-2012, 03:17 PM   #4 (permalink)
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The ECU is not under the plenum, it's on the passenger side below the rear quatrer panel. The ECU will provide additional fuel when the engine is cold, (like an old style choke) but not for long and should not be enough to smell strongly. Get yourself a copy of the OBD2 software for the V8 and look at the O2 swithing times, they would indicate a O2 sensor going bad. Better yet buy an exhaust gas afr box, for about $200.00 and temporarily install it into the post CAT sensor bung. Eliminates all the guess work. You could have a leaking injector(s). There are two OBD2 ports one in the trunk and one under the dash on the passenger side.
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Old 12-02-2012, 05:28 AM   #5 (permalink)
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Wayne,
Thanks for clarifying the position of the ECU. I'll check the locations out.
I see Gendan out of England sells the hardware and software but will it it work on US models as mine is a July 2000 Esprit. There is also freeware on The Lotus Forum from a Peter Maeers but you have to buy the hardware through Amazon or Ebay. Do you have experience with either?

Mike
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Old 12-02-2012, 07:56 AM   #6 (permalink)
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Quote:
Originally Posted by mac2000 View Post
Wayne,
Thanks for clarifying the position of the ECU. I'll check the locations out.
I see Gendan out of England sells the hardware and software but will it it work on US models as mine is a July 2000 Esprit. There is also freeware on The Lotus Forum from a Peter Maeers but you have to buy the hardware through Amazon or Ebay. Do you have experience with either?

Mike

I use the Gendan on my '02 US V8 and it works fine. Not sure if it has limitations that result in me not seeing some of the things the Lotus ECU might provide, but it does show the primary stuff you'd expect and it does function fine.

Are you just trying to confirm your smell is as expected or is there an associated problem you're trying to address? I'm not quite clear on what the real problem is.

The O2 sensors have a warmup time and the ECU doesn't switch from open-loop to closed-loop operation until after a bit of warm-up (the OBD2 reader will tell you when it's running in open- vs closed-loop). Reading the O2 sensor values prior to the sensors coming up to temperature might give you some figures that are misleading. Also, prior to the ECU switching to closed-loop, reading the O2 sensor values only tells you about the open-loop behaviors (which things like leaking injectors would imapct). When reading sensor values the hardest part is making sense of what you're reading.

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Old 12-02-2012, 08:39 AM   #7 (permalink)
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I use the free Lotus OBDII software. Works great. Bought the USB cable from amazon that was recommended on thelotusforum thread.

Nice part is that you can log your data while you drive to a pc file. That way you can save a set while the car is running great so you can have something to compare to when the car goes wrong.

We can also create a store of people's logs so we can compare between cars. I'll post one of my logs when I get back to a PC.


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Old 12-02-2012, 10:01 AM   #8 (permalink)
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The main issue I have with the car is the warm/hot start lag in startup. I'm trying to use the old process of elimination to identify the problem. I changed the cam sensor myself and that didn't work. I have a new crank sensor but haven't installed it yet because I'm not sure if it's readily accessible as was the cam sensor. So when a friend smelled the rich exhaust plus the engine seems to start a little slower after the first start even though it hasn't warmed up, it got me thinking that it could be due to a leaky injector or injectors or advanced timing. I haven't checked the plugs since I got the car. I should see if they are fouled. What type of plugs should I use if I need to replace?

Thanks
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Old 12-02-2012, 10:21 AM   #9 (permalink)
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Here's some data. I had to chop pieces of the run out to fit into the 1mb size limit on here.
Attached Files
File Type: xls OBDIILOG 11-8-12 Full Run - clipped for space.xls (930.5 KB, 32 views)
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Old 12-02-2012, 03:35 PM   #10 (permalink)
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I have used both Peter's free version (+cable box purchase) and OBD2.com $180.00 version. About the same capability, with Peter's having capability to show O2 sensor switching in real time,but Peter's also samples at a slower rate.
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Old 12-02-2012, 05:03 PM   #11 (permalink)
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The warm/hot restart problem will not show up any error codes. You can try a bottle of Techron, it may help but what ultimately fixed my hard hot restart was replacing all 8 primary injectors. Another possibility is a leaky secondary injector because of a leaky "O" ring. After replacing the "O" rings in my car several times I figured that they were not causing the problem. You can see this with a fuel pressure gauge but all you can tell is that the pressure is dropping, it doesn't tell you where you are losing the pressure or why. Changing the crank sensor is pretty easy once you get the car up. One easy to access screw and the wires plug in. You should also measure the gap to the vanes on the pulley and set it per spec. I doubt that is your problem though, if the sensor is acting up you would have a "Check Engine" light. Same for the cam sensor. 25K miles is a bit "young" for the injectors to be a problem but you will only know for sure after you change them. Changing the injectors involves R & R ing the plenum, not a pleasant task. But not impossible either. fiveOmotorsports.com for the injectors.
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Old 12-03-2012, 04:51 PM   #12 (permalink)
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I think I will try a bottle of Techron. I know the car was stored for a while so it's possible some of the injectors could be a bit sticky. I also get quite a bit of crackling when I take my foot off the accelerator. Is this normal? I'm running straight pipes from the original cats.
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Old 12-03-2012, 05:13 PM   #13 (permalink)
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The cackling is normal especially when cold. Lifter ticking is also normal till it gets hot. Especially if it hasn't been driven for a while. When I first heard my car I was worried till I found out "They all do that, SIR!". If the Techron doesn't help your next step is to replace the injectors. You add the Techron to FULL tank of fuel and run it as far down as you can before refilling.
David Teitelbaum
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Old 12-03-2012, 06:51 PM   #14 (permalink)
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When you do a cam belt tension and you manually turn the engine a bunch of times, expect it to sound like your engine is completely hosed for 2-3 minutes with the dry lifter ticking! Scared me at first and had me double checking the that I didn't skip a tooth in the process.
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Old 12-07-2012, 02:25 PM   #15 (permalink)
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I've noticed that as I increased the rpm the crackling sound/muffled misfire can still be heard in my right exhaust pipe only. Could I have a bad plug?
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Old 12-08-2012, 08:46 AM   #16 (permalink)
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It is possible but the more likely cause is one or more bad injectors. It can't hurt to pull the plugs and check them. As jobs go in a Lotus this one is pretty easy. While you have the plugs out I would also do a compression test. If the plugs look good they can be cleaned and regapped.
David Teitelbaum
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Old 12-08-2012, 05:35 PM   #17 (permalink)
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Sure hope its not the injectors. It only has 24K on the odometer but I guess anything is possible. I did use the Techron and have noticed a difference even though I haven't even run a 1/4 of the original treated gas down. I really need to drive the car more but since I bought the thing I've been babying it too much. In the interim, I'm trying to find a station that doesn't use an ethanol blend.
Thanks again.
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