Unusual starting problem

[SimonW]

Hi,

This is my first post and looking for some help (surprise)!
I've read many of the posts and the Wiki, which has been a massive help! Although, I'm at a loss with my starting problem.

To start the car it takes around 5-8 seconds of cranking and full throttle followed by a strong smell of fuel, then it runs fine.

If I turn the car off and start without the fuel pump priming it will start straight away hot or cold. If I wait 10 seconds or reinsert the key so that the fuel pump will prime again, it has the starting problem again.
Basically, the more the fuel pump primes the longer it will take to start.

As part of my mission to have the car on the road this year, the following parts have been replaced:

Injectors
FPR
Fuel filter
Coil packs
Spark plugs

Elanscan and paperclip, show no faults. My next step was to purchase a timing light and check the timing but it's a job I haven't done before.
This is my first Lotus Elan and hoping that someone can provide some guidance!

[Brit-Car-Nut]

Still sounds like it is excessively rich - especially as soon as the fuel pump runs.

Which injectors did you get / use?

[SimonW]

Hi
I purchased the Delphi ones from eBay US. The car runs the same as it did with the old injectors

[Brit-Car-Nut]

I have used those and had no issues.

The fuel system "pressurizes" the circuit when you hit the key the first time.

If the fuel pressure is too high, it would probably flood since more fuel gets past when the injectors open the first time.

It is also possible that one of the injectors is damaged and not closing completely thus allowing excess fuel into the intake.

I would check the pressure first and then if it is still flooding, I would remove the injectors and test them to see if any are sticking open.

Unfortunately, even new things arrive defective. The seller has sold many sets, so it is not a normal result for those injectors

[SimonW]

At idle the fuel pressure is 33psi it increases about 10psi if I remove the vacuum line from the FPR.

If I prime the fuel pump with the ignition a couple of times without starting the pressure increases to 38psi which makes it more difficult to start.

Turning off after idle, then turning the car back on without priming: starts around 28psi with no problems.

I hope this makes sense, thanks for your help.

[Brit-Car-Nut]

Unfortunately, without any other data, it appears one (or more) of the injectors is/are not fully closing and that is allowing excess fuel into the manifold causing the excessive rich mixture.

When I got my first M100, it did the same thing and was a bear to get started and worse to re-start it after it got warmed up. I sent the injectors away to be cleaned and when I got them back, the problem was solved.

I installed a set from eBay in the other M100 I bought when I found one of the injectors was physically broken into two sections.

Remove and test is the only suggestion right now.

What is the specification for fuel pressure? Is it possible the car has a higher volume/higher pressure pump installed?

[esprit888]

I'm going to state the obvious because, well, you never know You mention you are cranking and at full throttle, as its fuel injected you should not need any throttle at all to start the engine, the ECU takes care of the fuel. I'm assuming that you already tried that and she will only start with full throttle?, but does no throttle application give you the same result? Like i said, obvious but.....

[Brit-Car-Nut]

I got the impression that he could only start it with full throttle otherwise it was flooding.

[SimonW]

The new injectors were tested before fitting and didn't appear to have any problems. They were only changed as the car had been stood and were part of the recommissioning, but it didn't effect the starting/pressure issue.

I don't know the pump spec or if it has been changed in the past or what the psi should be.

[SimonW]

Sorry, I didn't make it clear. The car will start without applying the throttle too after about 5-8 seconds, although it will bog slightly before the idle is smooth.

[Brit-Car-Nut]

Does the car have any "improvements" like a Mountain chip or different ignition coils or anything like that?

The correct fuel pressure would be found in the closed loop manual

[SimonW]

Nope, the car is standard.
I'll take a look at the closed loop manual.

[SimonW]

The manual states the fuel pressure when priming should register 40-47psi. Mine only registers 34psi on the first prime then 38psi on the second and subsequent primes.

Could this cause the problem?

[Brit-Car-Nut]

I honestly don't know. I hope one of the ElanScan experts jumps in and joins in with some help or suggestions.

I am lucky. Except for terrible cold starting issues, my car seems to be functional. It has been sitting in and around the shop for almost 10 years waiting to be reassembled after being repaired and then repainted - twice.

Is still starts as expected and occasionally gets driven up and down the block.

I have no other direct experience with running problems except what I have read here and around other sites. My second car needed injectors and the fuel tank was full of water when I got it home. I replaced injectors, plugs and pumped the tank dry to put in some fresh fuel. It runs OK and shifts OK but I haven't done much else except to see what I actually got when I bought it.

Come on, Injection gurus, give us a hint and hopefully help Simon get his car running correctly

As an OPEN question, could the CTS be way off and "telling" the ECM falsehoods? What other sensors/senders could be responsible for his issues?

[Simon_P]

With the engine fully cold and not running.

Plug in elan scan turn the ignition on but don't start the engine. Are the CTS and Mat temperature close to ambient and almost the same ? Are the ambient and Map pressures the same?

How old is the fuel?

[SimonW]

Fuel is new

Barometer 1.00bar
Manifold press 0.99 bar
Injector pulse width 18.4ms

Ambient temp:22.9
CTS: 21.5
MAT 25.1
Op. temo.-temp 57
Coolant Raw 115.0

I've also attached the screenshot.

Is this within spec?

[SimonW]

Thanks to everyone for the help.

Does anyone have any idea or a recommendation of a suitable garage in Nottingham/East Midlands I could use to diagnose the problem?

[Saltire]

No personal experience of either, but Kelvedon Lotus near Spalding and Paul Matty in Bromsgrove are very well recommended on these pages and reasonably close to you.

[SimonW]

Thanks for the recommendations. If I can't fix the issue I'll look into how I can transport the car to the nearest as a last resort.

Is there anyone that can check my Elanscan data?

[Simon_P]

The data looks OK, next is to do the same thing and then start the engine.

Have you checked the idle?
If you are buying a strobe, make sure that the cables are long enough. The pickup wire comes from the near end of the engine, then you may need power. It has to go over the wing and allow you to aim the gun at the crank pulley.