OK, so here's a new one...low idle, help me please!, also timing questions |
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OK, so here's a new one...low idle, help me please!, also timing questions |
porsche735 |
Sep 8 2003, 10:39 AM
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#1
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Member Group: Members Posts: 189 Joined: 10-January 03 From: Los Altos, CA Member No.: 127 |
We just finished rebuilding our engine and it started right up the first time...
We set the timing at 27 degrees with both hoses removed at 3500 rpm. After the engine had warmed up and the aux air valve shut (even tested by plugging air inlet to valve), we tried to set the idle. The idle is way too low, about 500 rpm max. The adjustment screw is making almost no difference. I played with the mixture screw on the ECU both directions (refresh my understanding, it is backwards, right? CCW is leaner, CW is richer). Adjusting this did not make a huge difference. I adjusted this to achieve highest rpm and richened one click (CW). We cleaned out the air bypass hole to make sure it was not plugged. We also played around with the TPS by shutting the butterfly valve all the way to make sure the ECU "thought" it was in idle mode. I also have another question about advance. I have been told that we should see a total advance (with hoses on) of around 33-34 degrees. We checked our's after setting the 27 degrees the normal way, it was around 39 degrees. Does anyone have any specs on the mechanical advance and vacuum advance (retard as well, I guess)? My understanding is that at WOT that vacuum advance should be close to nil. We should basically only see the mechanical advance. However, we are seeing about 12 degrees advance due to the vacuum advance (39-27=12). Does this make sense? We played with the advance all over the place and were not able to get the idle to go higher. Please help me with these questions.... Your help is much appreciated. Chris |
porsche735 |
Sep 8 2003, 03:04 PM
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#2
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Member Group: Members Posts: 189 Joined: 10-January 03 From: Los Altos, CA Member No.: 127 |
The parts are matched fine. The engine was working on most cylinders before we pulled it out..;-) I can check for kinked hoses, etc. But, we have run the car and it runs well. It is just the idle that is goofy. The fuel pressure is at 29 psi. I can raise it a little, but adjusting the mixture screw on the ECU should change it at idle.
I don't have any furry friends around my house except for some squirrels and skunks. Neither of which make it into my garage very often... Notice, I did not say never.;-) Injectors were flowed and rechecked just bit ago. We can pull them and check the pattern, but I suspect they are OK. There is probably some dumb-ass thing we have done. I just can't figure it out. Maybe reflecting on the relative intelligence of my buttocks. Chris |
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