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S4s hot starting problem.

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the throttle cable is ok

I do not have a close friend with the esprit

Meanwhile, I bought a new crank sensor I get in 10 days

give me the recordings FreeScan, your esprit

thanks

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hi Travis
I saw your registration FreeScan
your "Knock Count" are many, is this normal?
Your IAC is very high?
your TPS reaches 100%?

I have to check my TPS for high voltage

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yes in that file, I was just driving around and didn't go to 100% throttle, there were no issues with the car.

 

Since I just drove and didn't let the car idle to full temperature, the IAC didn't settle to 20-40.  When you are driving the IAC won't drop down to 20-40.  Which is why I always ask people to start the car cold, let it idle to 82C and then drive, when recording freescan data.

 

That file did have some knock, up to 37, which is high for my car, I normally only get ~7.  The engine had a pretty recent rebuild, and a new knock sensor.  But we have bad gas here, only 91 Octane and with ~10% Ethanol.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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hi Travis
now is the crank sensor tomorrow I try
I saw your TPS voltage "0" is 0.35 is low!?
what is the best voltage to "0"?
thanks

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88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

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hi Travis

now is the crank sensor tomorrow I try

I saw your TPS voltage "0" is 0.35 is low!?

what is the best voltage to "0"?

thanks

 

Yes, my TPS voltage is a little low at .35V and only goes up to 3.25V. That is low but not too bad.  The ECU will learn the point where the throttle is at 0% and scale the range to make that the new 0%.  However I have bought a new TPS to put in, since that data was taken, since I didn't like the throttle response at the low end of the RPMS.

 

The link that Bibs posted will help you learn some of the Freescan data.

 

The manual says that a closed throttle should have a TPS V of 0.47V to 0.70V.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Alex and Nick, do you both have the same problem?

 

That is difficult to start when car's at normal temperature and after switching off eg buying petrol?


DanR

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adjusted, TPS 0.55 to "0" - 4.53 to "100"
installed new crank sensor!
same problem :no
I can just try new spark plugs NGK standard
yet disappointment 
  :wallbash:

:help: 

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Hi Travis
injectors were tested in bench specialists are ok
do not lose, and inject the same amount of gasoline

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Hi again! Well my car came out of hibernation finally this week, and of course the same problem remains. After driving in traffic the other night, I had to stop to pick something up from the shop, and as I returned to the car with all eyes on me.........that's right, would it hell start again!! Only slightly embarrassing then :blush:

The difference this time however was that it was a good 6 or 7 mins wait to fire up again. On trying it a few times in this period it sounded like it was really trying to start but just not enough fuel? Then finally it fires up perfectly normally as if nothing was ever wrong??

I have just checked the valve at the end of the fuel rail having just turned the engine off (still cold) and if I manually press the needle in I get one little squirt of fuel then nothing, so guessing its hardly retaining any pressure at all-but then again I understand they only run about 6/7 psi anyway?

 

Has anyone got any more clues as to this embarrassing little problem-seems to be dragging on a while this one!!

 

Thanks guys, Nick.

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hello friends
I received the new NGK spark plugs
what electrode gap?

thanks

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Nick,

As sailorBob says, you should have ~43psi at the rail at idle, and the pressure should stay for a while after the pump is shut off... hours at least. You could have a bad pump or fuel pressure regulator, since you only have a small squirt of fuel from the Schrader valve on the rail.

Does the engine stay better if you prime the fuel pump several times before starting the engine?


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Travis.

I was talking about the pressure remaining a while after the engine was switched off. It doesn't make any difference what i do when its in non starting mode.

It seems to me it is directly to do with the temperature of the engine/amount of time its left before it will fire up again. I have to assume its temp related eg.as soon as it drops below a certain temp it fires up straight away, which pushes me towards thinking it must be some sort of electrical sensor problem ie. lets say it won't start when engine temp is 81deg but will start at 80deg ??

 

If it was pump/pressure related, then why would this only manifest itself when the engine is hot, or should I say above a certain temp?

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Nick, 

 

After the engine is switched off, the rail pressure should remain high for many hours.

 

If yours is not, then the pump or pressure regulator is not holding pressure in the system. The pump has a check valve to prevent fuel from draining back into the tank.

 

Do this test when the engine is cold. Prime the rail by turning the key to the point before cranking the engine. Prime it 3 times. Check trail pressure with a gauge. Don't spray it into your eyes. ;)  then check it a bit later and again later. It's the pressure decreasing?

 

Things expand as they get hot, so internal clearances also open and could be allowing fuel to drain back into the tank.  I'm focused on this since you said you had no pressure at the rail. There are many other causes for not staying when hot, but start with the simplest first.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Also, remove the vacuum hose from the top of the fuel pressure regulator, and turn the key on without cranking. If any fuel comes out of the port where the hose was attached, the regulator is bad. Note that this is not the only symptom of a bad regulator.


Visit Sanj's Lotus Esprit Turbo SE pages

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hello
try new spark plugs .... the problem remained
next step?
Travis coolant temprature sensor with FreeScan looks good
What do you think?

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Hi again.

Have now checked the fuel pressure over the weekend, and can happily report no problems here! At tickover it held 43psi which increased gradually on blipping the throttle, and held for a good long while once the engine was switched off.

So having eliminated the pump/pressure reg, where do I start looking next?

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