EGI wont idle after rebuild

[BarryB]

Hi guys, some of you might remember me and my rebuild exploits
state of play is now she starts ok and revs smoothly and evenly, but she wont idle, just dies imediately once you get below 1500-2000 rpm, depending on how warm the engine is.
Anyone got any suggestions on how to isolate the problem?
A series of steps to take to check things one by one.
And firstly how do you deal with an engine problem when ya cant fiddle with things under the bonnet \'cos ya have to sit in the cab with ya foot on the loud pedal?
Its been two years since I\'ve driven the ol\' gal and I miss it!

cheers

Barry

[Big Stu]

And firstly how do you deal with an engine problem when ya cant fiddle with things under the bonnet \'cos ya have to sit in the cab with ya foot on the loud pedal???

I can help if you lilke. Im in and around peterborough. Send me a PM if you like.
(P.S. i am a crap mechanic, but i can keep a foot on a pedal!)

[Gman]

Have you searched or posted on //www.teamfc3s.org/forum

[Carl]

When you get some help you need to see if you have an inlet manifold leak,that will prevent the engine from idling well.
Kind regards
Carl

[Brett]

Do you have all the vacuum hoses in the right place? Also check to make sure the ones that are not used have the caps fitted.

 I remember when I was messing around with the air/vacuum hoses to get the emissions down at idle, one setup caused the same prob\'s you are experiencing.  Trouble is I cant remember which one!!!

[BarryB]

Many thanks guys for your replies.

I have checked for air leaks reasonably thoroughly, and also have experienced in the past the poor idling you get when a hose falls off, and this is much more severe. It doesn\'t just idle rough or a bit lumpy, it dies imediately the revs drop below 1500-2000 rpm.If you catch it quick enough it will rev up again.

So if its not air leaking in, whats the next likely cause?

Cheers

Barry

[Carl]

next logical thing is a compression test.
Kind regards
Carl

[antnicuk]

The 2nd gens have an airflow meter, make sure this is connected and there is no way for air to get into the engine bypassing the AFM.   I had this problem on my TII and it was due to the fact that the ducting from the AF meter to the engine was leaking and the engine was sucking in un metered air.  f the AF meter doesnt register any air going through it i wont supply fuel.  Worth a try
good luck
regards
tony

[BarryB]

Ok, quick update,

compression seems good, as best you can tell using a standard compression tester

BACV checks out

air intake seems airtight

I\'m tending towards what Tony is suggesting, air metering is out of whack or the TPS is out. I think these two work together, the TPS in control at idle and low revs, then the air flow meter takes over.

The air flow meter is free to move ok

The TPS works ok but not sure if its set right.

Difficult to find time to work on the old girl atm, decorating :/

cheers Barry

[antnicuk]

if the afm doesnt read any vacume or movement of the plunger it wont idle so i assume that it controls something at idle, as the tps would be in the shut position.

[Brett]

If you think the AFM is dodgy buy a 2nd hand one (Grinder ans sean may still have one) and fit that.  Should be pretty cheap.

[BarryB]

I\'m not so sure the AFM does do anything at idle. With the very low air flow at idle the AFM is likely to be very inaccurate and also suseptable to movement of the car. This would make steady idling and low emissions difficult to achieve.
So the TPS is used at low revs until the airflow is good enough to use the AFM. Bear in mind the TPS has run out of travel at about 1/3 throttle.
I\'m suspicious that my problem may be the TPS signal is not getting to the ECU

Barry

[Brett]

True, but if the pot\' on top of the AFM has been damaged/disturbed it may well be sending off incorrect signals.

 BTW, I\'m assuming you have adjusted the idle screw. (On top of inlet plenum)

[BarryB]

There\'s a pot?

Would that be the thing fixed to the inner wing near the air filter box? Marked "L <-> R" ?
Wondered what that was.

Barry

[Brett]

No, thats the Lean>Rich idle mixture adjustment.

 Inside the AFM is a pot type thing. (I dont recommend playing with it unless you have a spare AFM and dont mind damaging the engine if you get it wrong...)