Date: Tue, 11 Jul 2000 05:31:56 GMT From: "Larry Palmer" <palmerlnopsam.com> Subject: Re: Poor idle, sluggish 900S
Nate, Thanks for your suggestions. Since the car runs well in 1st up to 5000 RPM I'm starting to think it is not the Cat but maybe a fuel problem. The air filter has been replaced and the fuel filter is next. I have a fuel pressure gauge I made for my 80 900T and I'll check the fuel pressure after I read up on the specs. I got an email from TW about the idle. His thought is the problem on the initial start up is the "hybrid circuit in the control module". He also does not think the cat would cause the hi speed problem. Larry "Nate t. G." <ngoddardnopsamnect.net> wrote in message news:396c3c80.0nopsamy.powercom.net... > hello, > the poor idle may also be caused by the AIC (Air Idle Control) unit. it > is a valve that is supposed to open or close slightly to keep the idle in > trim (kinda-sorta similar to a choke) when it is still cold. the valve is a > rotary valve, and is only supposed to turn 1/2 - 3/4 of a revolution. > generally the behaviour (when the valve is bad/sticky) is a low/rough idle > that wants to stall for the first couple of minutes. not quite the same, > but there may be mitigating factors in your case(s). > as for the poor performance above 3000 RPM - it souds like the engine is > starving for some reason or another. have you checked the air filter > element - is it clean? could also be a fuel delivery problem (possibly a > plugged filter). you might see about having the fuel pressure checked. > also, as you mentioned, a restriction in the exhaust could also be a > problem. given the number of miles, even if the "cat" was replaced once in > its life, it might still be plugged. run the engine at idle for a while, > not going anywhere, and look under the car at the cat and exhaust pipe. > check to see if they seem hotter than expected. one other thing to check is > (in guessing whether it might be fuel or "cat"/restriction related), is if > the engine freely and rapidly revs in neutral it is more likely fuel > related, because the fuel requirement when not in gear is lower than when > actually doing something - thus a a fuel flow restriction has less effect on > it. on the other hand if it seems to be at all "unhappy" about reving up > high (around 5k RPM) then it is most likely a "cat" problem since flow > volume is more directly related (but NOT "only related") to flow volume > through the cylinders. to me it sounds like a "cat" problem. > > -- > Nate t. G. > > '87 900 Turbo 16v > Athlon 650 - NT > > > "Brett and Tracey Kimmel" <bert.kimmelnopsam.net> wrote in message > news:%woa5.864$K04.463665nopsamoon.snet.net... > > Mine does the exact same thing. From what I understand, this is suppose > to > > be normal at start up. Mine however stalls the first couple of times so I > > am going to replace the fuel pressure regulator to assist with that. > > Larry Palmer wrote in message ... > > >I recently bought a 87 900 S with 150k. All is well except for two > things. > > >On the first start of the day with the temp 50f to 70f the engine hunts > for > > >an idle speed for 30 seconds to 1 minute or two. The idle speed ranges > > from > > >1500 rpm to stall unless I give it a little throttle at the right time. > > >After two minutes it runs and idles fine. > > > > > >The other problem is a lack of power above 3000 rpm. It is increasingly > > >noticeable in each gear from 1st to 5th. The car has more power at 60 > mph > > >in 5th then at 60 mph in 4th. It feels peppy at speeds up to 30 but > feels > > >sluggish as the speed increases. A new muffler (the one after the > > catalytic > > >converter) helped some. Could a bad catalytic converter cause this > > problem? > > >Gas mileage is about 29 mpg. > > > > > >Larry > > > > > > > > > > > >
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