Engine not idling right

[Jezza_hr]

Okay. I've finally got my 20V back in and connected up, but it doesn't seem to want to idle properly, it's running between 500 and 1000 revs at idle (it seems to level out a little when running the throttle higher) and it pops and bangs both out of the exhaust and the intake. Also, when I switch off the engine there is a little bit of engine run-on.

I've sent a log over to Omex and they have said that all my calibrations are right and said that the issue I'm facing is likely down to fuel pressure, however I know that the fuel pressure is high enough, it built up enough pressure recently to cause a leak in the fuel line that needed attending to, also the spark plugs are being fouled by the fuel and it smells of fuel when running after a while. This leads me to believe that the engine is running too rich or it's not sparking strong enough, despite having not changed the calibration since removing the engine last.

The only other possibility I could think of was that the fuel sitting in the tank over the past year has lost it's integrity and isn't burning right. So I changed the fuel filter, topped it up with 99 octane fuel and put in some injector cleaner...no change.

It's coming to the point where I'm running out of ideas. I've tested the crank trigger sensor, tried running extra grounds off the engine in case it wasn't grounding correctly, cleaned the plugs. Yet it just still seems to be running rich.

Here's a video of the OMEX screen and how it sounded while I was trying to save a log to E-mail over for consideration.
http://www.youtube.com/watch?v=Cd33pLgqwNE

If anyone can think of anything else I'm missing, please let me know.

[jondee86]

MAP value does not seem to change ? Assuming you are running a MAP
sensor, if the hose is off that will get it running pretty rich

Cheers... jondee86

[Jezza_hr]

Unfortunately I'm not running a MAP sensor for this setup

[jondee86]

Has the engine been apart ? If so, check the cam timing.

Cheers... jondee86

[Jezza_hr]

Nope, the cam covers have remained on during it's time out of the car. But checking the cams is on my list just in case the belt has slipped somehow.

[Jezza_hr]

One other thing worth noting. when the engine is running, if I disconnect any singular HT lead to have it running on 3 cylinders there is no noticeable change in the engines running condition.

[jondee86]

You said it runs on after you turn off the ignition. Maybe there is some
auto-ignition going on from hot spots in the combustion chambers. What
do the plugs look like ?

Engine usually needs around 43 psi fuel pressure in the rail, but if the
return is blocked, the pump can put 75-80 psi in the rail. Make sure you
have fuel flowing back to the tank, and that you don't have a crimped
hose or bent hard line on the return side. If the leak you had was in
the return (low pressure) line, there could be a blockage, and that would
be a possible cause of running rich.

Cheers... jondee86

[Jezza_hr]

When pulling the plugs they are pretty well carbonised, I cleaned them up and put them back in again. When I took them out a second time they were heavily carbonised again, much as you would expect from a pretty rich running engine.

The return you're explaining does sound like a possibility. The leak was on the inlet line though and not the return line. But if the fuel pressure is too high due to a blockage in the return line then I guess that could have still caused the inlet line to leak. I did pull off and look over the return line and there didn't appear to be any kinks. I did try blowing into it (with the fuel cap off), which seemed hard work, but I don't know how much pressure there should be in there for reference.

Annoyingly I don't have a fuel pressure tester to check what PSI I'm running, I may need to see if I can borrow one, since they're about £30 new from what I can see.

[jondee86]

You could try experimenting if the OMEX has a master fuel trim setting?
Reduce the fuel by 10% and see if it cleans up at all ? If you are running
a wideband O2 sensor, you should be able to see the difference, as well
as hearing the difference in the way the engine runs.

Doesn't solve the problem though. You didn't change the injectors while
the engine was out by any chance?

Cheers... jondee86

[Jezza_hr]

I just had an E-mail back from Omex saying a similar thing to yourself about the trim settings, so I'll give it a go.

Nope, the injectors haven't been touched. When I next get to the car I will see if setting the trim works at all to give me an answer. If it does and it turns out the return line is blocked, I'm trying to think of how I can sort out that issue