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Discussion Starter #1
Hi all,

I have a 1995 Lotus Esprit Turbo S4 GT in which I have just bought with a leaking fuel tank so was not seen running when bought. Having replaced one of the fuel tanks with a aftermarket Alloy type and getting the car running there seems to be a few running issues.

The car struggles to drive under load and seems to misfire violently shaking the car with occasional pop and bang from the exhaust. I have currently tried the following:

Replaced Spark Plugs
Replaced HT Leads
Replaced Coilpacks
Replaced Lamba / 02 Sensor
Replaced Fuel Pressure Regulator
Replaced various vacuum pipes
Replaced Fuel Filter
Replaced Air Filter
Removed Catalytic Converter (In hope it was blocked)
Removed Exhaust Back Pressure Valve (Was seized)

Having recently bought the Freescan package. I was hoping I could find a fault but there are no fault codes been reported. I have however done a log which should help (Please see attachment).

When logging data with Freescan and monitoring AFR with a friends Innovate LM2 Wideband it seems that the car is running lean (According to the wideband) but shows as fine in Freescan.

Any help would greatly appreciated.

Many thanks and best regards,

Nick :)
 

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your MAT (Manifold Air Temperature) after the intercooler is high, you should service or rebuild your intercooler pump.

Your O2 sensor is going very low during boost, looks like you are going lean. Your BLM fuel trim also says you are going lean.

And you keep going to idle at around 100mph... which will definitely skew the results, since the ECU will cut fueling when you do that... Don't do that for a freescan run, it makes it hard to see what the ECU would do if the car were being driven normally.

Also, your wastegate is opening very early, but that is difficult to tell, it's probably due to you going to idle at 100mph often...

And your IAC counts are high at idle, you may have problems with the car stumbling or stalling before it is warmed up at idle.
 

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Discussion Starter #6
Thanks very much for the replies guys. Appreciate the help.

The 02 sensor is a new genuine item, but made no difference at all.

I also forgot to add that this log was made while on a friends dyno (Hence dropping to idle after a run). The car makes 182HP on the rolling road and the graph is hideous.

I shall do a couple of runs on the road tomorrow, what is the best way to make a good log?

I must also add that I added a fuel pressure gauge to the rail before the new fuel pressure regulator and was getting approx 3 Bar on idle.

Many thanks, Nick
 

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Discussion Starter #9
The car is lean enough that you don't want to drive it again until you get that part fixed. You could easily burn the head gasket or pistons.

the data you have so far is fine to be able to determine what I said above.
Thanks for the reply. Would you recommend having all the injectors ultrasonically cleaned or should they be renewed?

Its strange how the A:F reading from freescan seemed pretty normal 14's at idle and part throttle then showing 12-13's. Is this inaccurate on Freescan or should i be looking at something else to check if rich or lean on Freescan?

Thanks again
 

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The A:F column in freescan is NOT the A:F... it is the DESIRED A:F.

You need to look at the O2 sensor volts compared to TPS and boost, and then the BLM vs BLM Cell. If that graph averages at 128, then you are good. If lower then rich, and if higher than 128 you are lean. Yours is averaging higher than 128 in several places. The integrator is also a measure of the short term fuel trim, and can help determine if your ECU thinks you are going lean.
It graphs similar to the BLM vs sample in your case. Showing lean.

You should verify the function of your injectors, do a resistance test of all 6. The primaries should all be ~2 Ohm, and the 2 secondaries should be ~12-14 Ohm. You should see if your fuel pressure can rise 1:1 with boost, with the pressure drop of all 6 injectors. There is a balance test in the EMH manual that you can perform with some special equipment to trigger the injectors and measure if the pressure drop is the same from each primary injector.

So if you have no pressure drop... that injector isn't working well... hard to see if the spray pattern is good or not though. I built a simple circuit to activate my injectors with a push button for cleaning and so I could see the spray pattern.

Replacement injectors are not too expensive. I went with BOSCH, PM me for details.

Seems like a bunch of esprit fuel pumps have been failing lately (getting to be that age), and you had rust... so it wouldn't hurt to change the pump. Took me an hour.
BOSCH 69218 pump fits
[ame]http://www.amazon.com/Bosch-69218-Original-Equipment-Replacement/dp/B001LRMK2C[/ame]
you'll just need to get a new strainer (TS-9)
[ame]http://www.amazon.com/ACDelco-TS9-Fuel-Pump-Strainer/dp/B000C9QSGY/ref=sr_1_1?s=automotive&ie=UTF8&qid=1341005681&sr=1-1&keywords=ts-9+strainer[/ame]

Don't forget to leave out the pulsation damper above the pump. The GM pulsation damper has been a point of failure, and serves absolutely no good purpose in the Esprit.
This thing, it can leak fuel pressure at the pump outlet, and cause the lean condition all by itself.

Seen here above the pump


The BOSCH kit comes with a hose to replace it
 

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Discussion Starter #11
Travis,

Thank you for all the great advice.

I shall order a new Bosch 69218 and strainer ASAP, fit that and go from there. Fingers crossed that should sort the problem.

I am in the UK and struggling to find more than one supplier of the pump and stainer. I shall have a call around on Monday.

Thanks again
 
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