Engine Hesitation

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Engine Hesitation

Postby Wortho » Thu 17.10.2019, 11:52

I have a 1990 SE with 70,000 miles only mods are a Miltek exhaust and an Alpha air filter.

Yesterday the engine started to hesitate when accelerating under load from around 3500 RPM the only other symptom i can find is a slight rattle from the CAS.

Elan Scan gives an error code of 4000 but I cannot find anything that corresponds with this on WikiLEC.

Anyone any ideas please?
Lotus Elan SE 1990 x 2, Porsche 911 C4S, Mazda MX5 NA, Mini Cooper RSP, VW Scirocco, VW Golf TDI.
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Re: Engine Hesitation

Postby John_W » Thu 17.10.2019, 15:41

I recommend checking:
  • plug gaps
  • static timing is correct and not wavering
  • HES
  • Plug leads
  • Coils
But it sounds like plugs to me, which is the simplest and cheapest of the above.
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Re: Engine Hesitation

Postby GeoffSmith » Thu 17.10.2019, 16:30

Pretty sure error code 0x4000 is wastegate related. Open out the fault codes to see what the individual flags mean - press the [+] next to Faults and see which flag is set ON.

PS I had a similar problem just before it went to bed for the winter (but did not scan it) and I suspect I have a sticking wastegate.
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Re: Engine Hesitation

Postby Wortho » Thu 17.10.2019, 17:07

Thanks I’m away with work for a few days, I’ll start investigations when I get back.
Lotus Elan SE 1990 x 2, Porsche 911 C4S, Mazda MX5 NA, Mini Cooper RSP, VW Scirocco, VW Golf TDI.
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Re: Engine Hesitation

Postby Wortho » Thu 24.10.2019, 16:23

Plugs swapped no change. Waiting for new leads to arrive.

I have opened up the errors on Elan Scan (thanks Geoff I didn’t know how to do this) item 14 Wastegate over boost is on.

I have just “enjoyed” doing the wastegate wiggle with the turbo and heat shields in situ the bottom bolt is a sod to get back in for sure! Everything feels free and I have lubed it up with copper slip.

How do I clear the wastegate fault on Elan Scan please?
Lotus Elan SE 1990 x 2, Porsche 911 C4S, Mazda MX5 NA, Mini Cooper RSP, VW Scirocco, VW Golf TDI.
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Re: Engine Hesitation

Postby John_W » Thu 24.10.2019, 16:56

Disconnect the battery to reset fault codes.

Did you set the new plugs to the correct gap? If not, they will still cause a misfire when the turbo kicks in.

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Re: Engine Hesitation

Postby Wortho » Thu 24.10.2019, 17:41

Hello John

Yes the gap is set at .8mm.

Thanks

Dave
Lotus Elan SE 1990 x 2, Porsche 911 C4S, Mazda MX5 NA, Mini Cooper RSP, VW Scirocco, VW Golf TDI.
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Re: Engine Hesitation

Postby Wortho » Thu 31.10.2019, 17:52

Now sorted! :D It was a dodgy coil pack.

The waste gate over boost error is a separate problem, I think I may need to port the wastegate or adjust the rod (mine has an adjustable actuating rod) so that it opens earlier.

Thank you for your help gentlemen.
Lotus Elan SE 1990 x 2, Porsche 911 C4S, Mazda MX5 NA, Mini Cooper RSP, VW Scirocco, VW Golf TDI.
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Re: Engine Hesitation

Postby John_W » Thu 31.10.2019, 21:24

:smt023
Glad you're sorted.

It can sometimes take a while to locate the reason for a problem like this, but you did it pretty quickly. I hope it wasn't too expensive!

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