stephen Report post Posted March 2, 2010 hi guys some of you may or know me, but my dad had recently purchased a white 88 car out of ohio, and we are new here. we had a question about the cold start function of the injected cars. do you guys disconnect the vacuum hose letting it idol lower so it can warm up or leave it and let it idol at 3k? thanks guys i can tell more questions will arise. thanks again countachvirgin- Greg and Stephen Quote Share this post Link to post Share on other sites More sharing options...
Jalpa_Mike Report post Posted March 3, 2010 hi guys some of you may or know me, but my dad had recently purchased a white 88 car out of ohio, and we are new here. we had a question about the cold start function of the injected cars. do you guys disconnect the vacuum hose letting it idol lower so it can warm up or leave it and let it idol at 3k? thanks guys i can tell more questions will arise. thanks again countachvirgin- Greg and Stephen Does it always idle at 3000 rpm even after warmup? That seems very strange..... When I start mine cold, it first goes up to about 3000 rpm, then drops as the engine warms. It finally settles down and idles at around 1300 rpm. A bit too fast IMHO, so one of these days, I'll get myself a vacuum gauge and reset the idle to what the books says: 1000rpm +/- 50rpm. Quote Share this post Link to post Share on other sites More sharing options...
debriga Report post Posted March 3, 2010 hi guys some of you may or know me, but my dad had recently purchased a white 88 car out of ohio, and we are new here. we had a question about the cold start function of the injected cars. do you guys disconnect the vacuum hose letting it idol lower so it can warm up or leave it and let it idol at 3k? thanks guys i can tell more questions will arise. thanks again countachvirgin- Greg and Stephen Stephen, What vacuum line are you refering to? The cold start/warmup cycle (and warm up RPM) is controlled by the "warm up regulator" (regulates pressure to the injectors), the cold start valve" , (injects extra fuel for enrichment into the manifold after the throttle valve) and the "auxillary air control valve", allows a quantity of air to bypass the throttle valve). All of these are actuated by thermal (bi-metallic) electrical devices, not vacuum controls. If you need some info on the K-jetronic fuel system, I can send you a few pdf's of info if you give me an address in a PM. The start cycle does run the engine at a higher RPM for a bit of time, but it does that to help to ensure an adequate warm up cycle has been completed before you start driving and subsequently put a load upon the engine before it is ready. I know it is a pain when trying to run with modern cars, but just think of it as an insurance policy that keeps you from putting your foot into the throttle before the engine is ready for it. Let the engine warm up, then drive moderately until the transmission warms up also. Then ..... Have some fun!!!!. Dennis Quote Share this post Link to post Share on other sites More sharing options...
stephen Report post Posted March 4, 2010 Does it always idle at 3000 rpm even after warmup? That seems very strange..... When I start mine cold, it first goes up to about 3000 rpm, then drops as the engine warms. It finally settles down and idles at around 1300 rpm. A bit too fast IMHO, so one of these days, I'll get myself a vacuum gauge and reset the idle to what the books says: 1000rpm +/- 50rpm. yep thats what we were referring to Quote Share this post Link to post Share on other sites More sharing options...
stephen Report post Posted March 4, 2010 Stephen, What vacuum line are you refering to? The cold start/warmup cycle (and warm up RPM) is controlled by the "warm up regulator" (regulates pressure to the injectors), the cold start valve" , (injects extra fuel for enrichment into the manifold after the throttle valve) and the "auxillary air control valve", allows a quantity of air to bypass the throttle valve). All of these are actuated by thermal (bi-metallic) electrical devices, not vacuum controls. If you need some info on the K-jetronic fuel system, I can send you a few pdf's of info if you give me an address in a PM. The start cycle does run the engine at a higher RPM for a bit of time, but it does that to help to ensure an adequate warm up cycle has been completed before you start driving and subsequently put a load upon the engine before it is ready. I know it is a pain when trying to run with modern cars, but just think of it as an insurance policy that keeps you from putting your foot into the throttle before the engine is ready for it. Let the engine warm up, then drive moderately until the transmission warms up also. Then ..... Have some fun!!!!. Dennis rite rite we dont mind warming it up but the only thing is isnt 3000 a little high for the warm up idol? because with that little oil moving through the engine wouldnt 2000 be better? Quote Share this post Link to post Share on other sites More sharing options...
Roman Report post Posted March 5, 2010 Im taking my car out in a minute..... Im going to pay attention to the various idle numbers for you.... I very much remember being a new countach driver thinking "Damn.... THis idles high..." Quote Share this post Link to post Share on other sites More sharing options...
Roman Report post Posted March 5, 2010 OK.... Idle when the car is off- 500 (I have no idea WHY this is, but its like this on every countach Ive seen....) Cold start Idle- 2200 Warm idle 1500~1600. (I think it goes a BIT lower when it REALLY gets warmed up... But any much lower and I think it would stall) Air temp is about 65 degrees.... warm idle took about 5 minutes or so to kick in. Quote Share this post Link to post Share on other sites More sharing options...
debriga Report post Posted March 6, 2010 My '87 turns at 2000 RPM on high idle and dops to 1200 on low idle. The low idle is still a touch too high for me, and when I am able to once again do a little work on the old girl, I will be taking it down to about 1000 RPM low idle. The car will actually idle quite nicely at 900 RPM (the cams are really not all that agressive!) but takes a little more finesse with the clutch to get rolling in tight spots. One does NOT adjust high idle by disconnecting a vacuum line!! Quote Share this post Link to post Share on other sites More sharing options...
GURSLO Report post Posted March 6, 2010 debriga, I want to thank you for the info! I sent a reply email last night after 9pm. Its nice to have a community of people helping each other. This is a view of owning the car I never thought about. THANKS AGAIN ! Quote Share this post Link to post Share on other sites More sharing options...
debriga Report post Posted March 7, 2010 OK.... Idle when the car is off- 500 (I have no idea WHY this is, but its like this on every countach Ive seen....) Cold start Idle- 2200 Warm idle 1500~1600. (I think it goes a BIT lower when it REALLY gets warmed up... But any much lower and I think it would stall) Air temp is about 65 degrees.... warm idle took about 5 minutes or so to kick in. If your normal idle is 1500-1600 RPM in the climate your car runs in, something is out of tolerance or mis-adjusted. Your injected engine will idle quite nicely at 900 RPM's with optimum being around 1000 RPM's. If you need your injection serviced, do not go to Lamborghini. Find a good reputable shop that has been around for ages and sprcializes in "80's vintage Mercedes six cylinders. Why Mercedes? Because you have two six cylinder Bosch designed Mercedes fuel injection systems on your pride and joy. Even a Volvo shop should be able to sevice the injection as they used this system also. Quote Share this post Link to post Share on other sites More sharing options...
debriga Report post Posted March 7, 2010 debriga, I want to thank you for the info! I sent a reply email last night after 9pm. Its nice to have a community of people helping each other. This is a view of owning the car I never thought about. THANKS AGAIN ! Thank you for your kind words. I am very happy to know that I had some knowledge or resources to share with another that might have helped them. Quote Share this post Link to post Share on other sites More sharing options...
Roman Report post Posted March 7, 2010 If your normal idle is 1500-1600 RPM in the climate your car runs in, something is out of tolerance or mis-adjusted. Not likely. However, the tachometers (and spedometors for that matter) on these cars are notoriously inaccurate.... If the car runs well, isnt stalling out in traffic, and isn't burning through clutches... I dont worry about it.... Quote Share this post Link to post Share on other sites More sharing options...
Steve400S Report post Posted March 7, 2010 Not likely. However, the tachometers (and spedometors for that matter) on these cars are notoriously inaccurate.... If the car runs well, isnt stalling out in traffic, and isn't burning through clutches... I dont worry about it.... I agree the tachs and speedo's on these things tend to be off for sure. Quote Share this post Link to post Share on other sites More sharing options...
Roman Report post Posted March 8, 2010 I agree the tachs and speedo's on these things tend to be off for sure. Yeah, I mean HOW ACCURATE could they be if it reads 500 rpm with the engine OFF? Before I replaced the ignition, I would routinely go from 3000 to 12,000 RPM... In a half second.... Glad I got that gremlin worked out.... After a while, I just stopped paying attention to what the gauges said and now I drive "by ear". I know what "sounds right" and I know what sounds "unusual" and beyond that I dont sweat the small shit. Quote Share this post Link to post Share on other sites More sharing options...
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