FI lurches at low rpm

[narfire]

Question. For the past little while, my car while in gear and idling/going slow, starts to lurch. EG., while driving down a street with a posted 30 kph limit, I put it in 2nd or 3rd and release the clutch and was hoping the car will idle and move without it starting to lurch.(around 1000-1500 rpm) I put the clutch in and try again and before long it starts again. I'm asking as I can do this in my clapped out VW Golf and no problems. The car is a bit lumpy at idle(especially at startup for a couple of minutes) as I have Marks 274 FI cams installed(and degreed to 109 centerline). I can feel it a bit as well when on the highway at 100kph/62mph. Timing was 12 deg btdc and 1000 rpm.
Any ideas as to where to start so I'm not chasing ghosts. AFM? (have new fuel filter installed), Goes/accelerates without any issues. Perhaps just the nature of the beast with the cams and should use 1st and gas to 2500rpm.
Chris

[TX82FIAT]

Chris you may be on to something with the nature of the cams. I could see the car lugging a little in gear at the low RPM in 2nd and maybe even 3rd. However, the same feeling at 62mph on the highway seems a little strange. If could be anything from fuel delivery up to timing.

[narfire]

Thanks for the reply. I'm now thinking it is the cams at lower speed. Guess what I found when mucking about with it this afternoon.... Smelled gas, so checked the hoses and sure enough # 2 had a loose clamp and was wet. I'll take it home tonight and see if tightening up got that "miss" at highway speeds. Plugs were all good.
Chris

[So Cal Mark]

there is no way those cams are causing your troubles. Those cams are designed for low and mid range. If you were running 40/80 cams are some other variation, it would be a possibility but most likely you've got a lean condition. Connect a voltmeter to your O2 sensor and see what the fuel mixture is doing at those speeds

[rlux4]

That's probably it Chris. I have had the same thing happen just as I left on a trip up to a Mirafiori Oregon campout. Mine was leaking at the hose to the cold start valve and it really affected how the car ran, even though it was just a drip. It must drop the pressure to a point where you don't get good spray out the injectors.
Ron

[narfire]

Don't get me wrong Mark, I'd recomend these cams to anyone wanting a bit more to their FI engine. I'm very happy with them. Great performance boost between 3200-5000 rpm.They are though a bit lumpy for the first minute , till the engine warms up and then absolutley no issues at traffic lights ect. I now suspect that the drippy fuel line could have been the culprit. Took the VW home because of thunder showers(moments of monsoon) so I'll run the spider tomorrow and see what transpires.

[So Cal Mark]

cams don't cause intermittent lumpy idle, I'd say your cold mixture is off along with the warm running issues you have.

[narfire]

it would be a possibility but most likely you've got a lean condition

Now that you mentioned it... I checked the plugs this afternoon and all were white. I'll check the O2 tomorow.
Going to have to read up on adjusting I guess.

[fiat218]

Don't get me wrong Mark, I'd recomend these cams to anyone wanting a bit more to their FI engine. I'm very happy with them. Great performance boost between 3200-5000 rpm.They are though a bit lumpy for the first minute , till the engine warms up and then absolutley no issues at traffic lights ect. I now suspect that the drippy fuel line could have been the culprit. Took the VW home because of thunder showers(moments of monsoon) so I'll run the spider tomorrow and see what transpires.

What cams do u have

[narfire]

What cams do u have

Marks 274 FI cams. I also have the head massaged and the adjustable cam wheels. Really lights up the FI engine.

[JConnerly]

One other thing to consider; I had a similar issue recently and it turned out to be my AFM. See my recent post on "the stumbles" and the advice I got. After adjusting the AFM my car runs smooth once again.

[narfire]

I had a similar issue recently and it turned out to be my AFM

I thought that as well. Just trying to get the gumption up to look at then possibly fiddle with the thing.