Surge / Idle |
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Surge / Idle |
lsintampa |
Dec 22 2014, 08:53 AM
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#1
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Senior Member Group: Members Posts: 520 Joined: 28-January 13 From: Tampa, FL Member No.: 15,441 Region Association: South East States |
75 2.0 FI
I'm in Florida - so the weather outside is somewhat warm (50's maybe right now). I'll try to be as detailed as I can. I've had this issue since I started driving the car - about 8 months ago. It underwent a motor rebuild - along with some other mechanical repairs. All hoses are new (air supply, and fuel). ECU and other FI components are original - best I can tell. When I start the car - it starts right up. At idle RPMs go to about 1500 with a very slight surge (maybe 1450 - 1550). If I pull the air supply that goes to the AAR from the air filter and plug it, the idle goes down to what I'd expect - about 900 RPM still with a little surge. This is while the motor is "cold" - so to speak. Within like a minute of starting. As the car warms - just at idle, the RMPs start to come down and the vacuum from the AAR isn't as strong - but still present. However now the surge is crazy - like from almost a stall up to maybe 1200, back down, back up, etc. Pulling the hose from the AAR - does nothing - I can plug it or leave it and the air filter wide open and there is no change. I put the hose back on - again no change. I did not let it get to a full warm state - IE the temp gauge just started to move up. I've heard there are three states (cold, pre-warm, and fully warm) that come into play. Various tinkering, like turning the air mixture valve to a total closed state, and mucking with the ECU dial has had some success, but at BEST, I get like a 1200 RPM idle still with some surging. To the best of my knowledge there are no air leaks - at least not from any hoses. I've some concerns that the air plenum may have some stress cracks around the support studs. But I don't know that would cause the surging? I'd think the idle would just be high - period. YES / NO? I don't know where to begin to figure out why it behaves this way. Thanks, Len |
lsintampa |
Dec 29 2014, 09:12 AM
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#2
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Senior Member Group: Members Posts: 520 Joined: 28-January 13 From: Tampa, FL Member No.: 15,441 Region Association: South East States |
This is getting to the point of being a bad dream.
That middle "bolt" in the manifold that I found in place of a "stud"... well it came out just fine. But when putting it back on.. guess what? The thing was stripped (inside obviously). No way to get it tight. Builder used some thread glue to hold in it - so taking it out - I had no clue it was stripped. Putting it back however, well that was a different story. I'll deal with that at some point. I think the manifold is on tight enough not to leak. I got as much on that middle bolt as I can for now. I wanted to see what the results of fixing the cold start injector port leak would be. The surge is less but still persists. For grins - with the car at idle, I tried to adjust the TB switch manually. I noticed that turning it full CW or full CCW - the surging got really bad. So what I did was turn it full CCW the slowly turned it CW until the surging either stopped or should I say "got way better". Perhaps not the best way to go about it, but there did seem to be a "sweet spot" - anywhere else the surging was wild. I don't have a fog machine, but I'm gonna get me a 10 cent cigar to make some smoke and see if I can see where the leak is at. Maybe it's been the manifold all along? UGH (IMG:style_emoticons/default/headbang.gif) |
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