psu_Crash Posted August 17, 2008 Report Share Posted August 17, 2008 So it has been doing this since the new engine went in and I was just hoping it would work itself out. Yeah like that was really going to happen. Anyways my engine rocks real hard a few times when I shut down. Like tries to twist right out of the engine bay! It did this with the stock ECU, cam, and injectors and it is still doing it with MS, trilogies, and a 284-H. The +12V for the coil is controlled by a relay I installed that is trigered from the old +12V wire that used to be connected to the coil. Shelby suggested to put a test light on the coil to make sure it is cutting power when i turn off the key so i will do that in the morning. Any other suggestions?? I don't like this ... not a bit Thanks Guys! (and girls ) Link to comment Share on other sites More sharing options...
Shelby Posted August 17, 2008 Report Share Posted August 17, 2008 yes bring the idle rpms down to 950 or less , i have run a 284 and it don't rumble that bad , sounds like plain ol run on to me and make sure the dist timeing is set with the engine rpms below 900 and no vac advance signal to the vac advance , if you have vacuum tot he vac advance it will cause over advanceing of the timeing at low rpms,,this will cause run on Link to comment Share on other sites More sharing options...
shift1313 Posted August 18, 2008 Report Share Posted August 18, 2008 i had a similar shake like you speak of. I had my ac fan wired in to the + side of the coil so it was on all the time a few years back. When i shut the car down and the fan was still spinning it would actually power the coil and keep the car running a bit(without fuel of course) and it would feel like it was dieseling. id be willing to be your relay powering the coil isnt shutting off right away with the key. Link to comment Share on other sites More sharing options...
psu_Crash Posted August 18, 2008 Author Report Share Posted August 18, 2008 The relay is a new addition. The problem came about before I had the relay in there. But I will check it out anyways. Having a hell of a time adjusting the idle... too high .. then too low ... try again tomorrow. Link to comment Share on other sites More sharing options...
shift1313 Posted August 18, 2008 Report Share Posted August 18, 2008 are you using ms to control the isc motor or are you doing idle control some other way? Link to comment Share on other sites More sharing options...
psu_Crash Posted August 18, 2008 Author Report Share Posted August 18, 2008 The isc is currently not connected at all. Haven't really figured out how to control the ISC with MS although I know it can be done. Just holding the throttle a little till it warms up and trying to adjust with the idle screw, which is all but stripped and a pain to work with. May be a project in the near future. Is our idle speed controller a stepper motor of is it just on or off? Also currently running fuel only with MS. My MSD is basically a stand-alone on it's own with the vacuum advance hopefully doing it's job. It holds a vacuum just fine so should be ok. I will be working on the car all of this afternoon/night if need be. I have to figure this out soon. Link to comment Share on other sites More sharing options...
Shelby Posted August 18, 2008 Report Share Posted August 18, 2008 the question was just how are you adjusting the idle rpms, sence the 86 has no fix'd sas screw ,nor an idle adj screw ,warning do not use the throddle cable to adjust idle it can't be done reliably Link to comment Share on other sites More sharing options...
psu_Crash Posted August 18, 2008 Author Report Share Posted August 18, 2008 what do you suggest Shelby? Figure out how to get the ISC hooked up in MS, I am going to have to eventually anyways. Anyone have some pointers for doing this with the '86 TBI? I need to just bite the bullet, get some injectors and get that Magna in there. Got one modded from Chad a while back with a 65mm TB. Really thought the screw I have been messing with was idle adjustment? That is how it's shown in the FSM ... although I may be looking at the wrong year ... Ok now i am really confused. Link to comment Share on other sites More sharing options...
Shelby Posted August 18, 2008 Report Share Posted August 18, 2008 you can use the isc adjusting screw but maybe your going at this all wrong,, set the idle rpms as low as you can get it and have it still run,, now start fine tuneing your fuel mix in the soft ware ,, the mixture has blocks it runs in, you may have the next lower block too lean or too rich,, also you need to make timeing adjustments at a low rpm seting the ign timeing @1200 may cause the dist mechanical advance weights to swing out and throw your timeing off,, idle quality is the last thing you worry about,, the rpms are what you want to target , then do the fine tuneing ,, if you do not know how to change the fuel delivery at a spacific rpm,in tuneing open VE table , read the help with in the program ,if the FIP pro is the same as mega squirt , you hold the "shift key and hit + for more and - for less , the up ,down ,left , right keys will move you from block to block , you want to change the block you have highlight'd keep in mind that almost every thing effects the idle quality so any thing change'd one place will likely have an effect on the idle quality, so it may be that you will have to fine tune the idle mixture several times ,, ince you have a good steady idle , adj it up and down and check the mixture in several locations and rpms,, then set it back to where you want it to be,, this helps when the engine temps are warming upand not at full warm up,, the cold idle will be less then ideal most of the time but improve as the engine warms up the isc use'd aprox 5 volts on a reversing posi ,neg , not sure exactly how the FIP pro is configure'd Link to comment Share on other sites More sharing options...
psu_Crash Posted August 18, 2008 Author Report Share Posted August 18, 2008 Thanks Shelby! I believe my throttle cable is tight enough that it would keep the idle high. As far as tuning with MS I think I have a pretty good grip on all of that. At cruise and mild accel everything looks good. Just idle and shut-down. I have been tuning MS to give the lowest Kpa possible at a steady idle according to the megamanual and msextra manual. Going to try and tweak my injector PWM and Current Threshold too. Just need to make sure all bases are covered. Also going to degree my cam either tonight or tomorrow just for peace of mind and because i am sure it isn't perfect with a resurfaced block and all the other work. THANKS A TON SHELBY! see ... you aren't just a grumpy old man I'll let you know how it all goes Link to comment Share on other sites More sharing options...
Shelby Posted August 19, 2008 Report Share Posted August 19, 2008 durring low rpm you need to tune for the highest steady vacuum reading you can get , you should be able to pull 16-17 inches with that 284 if the cam is close to being in time , also try to run rich in the lower rpms and have a high steady vacuum signal,, and be in the pw1 when adjusting the fuel not 02 on the VE table and get some slack in that throddle cable and the grumpy old man stuff thats for the kids,, i don't always type like i have a sence of hummer , Link to comment Share on other sites More sharing options...
psu_Crash Posted August 19, 2008 Author Report Share Posted August 19, 2008 Ok so I am pretty sure the timing is the issue. Tried to get the idle as low as possible, still only just under 1k but it shut down MUCH smoother! Having a hell of a time with getting the idle where it should be. In the morning I have to investigate further .... Link to comment Share on other sites More sharing options...
psu_Crash Posted August 19, 2008 Author Report Share Posted August 19, 2008 At idle I pull about 18 inches of vacuum so I think that's pretty good. Has to be something simple I am missing. I've read that megamanual plus the stuff on ms-extra tuning front to back several times and I think at this point it is just a matter of mechanically setting the idle lower via the ISC screw. Expect an update mid day sometime. Progress ... it feels good Link to comment Share on other sites More sharing options...
shift1313 Posted August 19, 2008 Report Share Posted August 19, 2008 make sure you loosen that cable! you dont want a tight cable used for your idle adjustment. the isc is a stepper setup. It has different positions so the ecu can hit a certain rpm. good luck Link to comment Share on other sites More sharing options...
Shelby Posted August 19, 2008 Report Share Posted August 19, 2008 (edited) and don't over look simple places for vacuum leaks,, like the power brake booster or hose or even the mid houseing oring , and while doing this disconnect the vac adv hose and plug it , at idle there should be no vac signal on the hose as an after thought do you have Krank vents install'd , they require a restrictor in the pcv hose Edited August 19, 2008 by Shelby Link to comment Share on other sites More sharing options...
psu_Crash Posted August 19, 2008 Author Report Share Posted August 19, 2008 No Krank vents. Still using the PCV (recently replaced) and oil seperator Link to comment Share on other sites More sharing options...
Indiana Posted August 19, 2008 Report Share Posted August 19, 2008 you have a minimum rpm value in megatune right? how about cranking rpm and its timing? are those over lapping and causing the timing to jump from run to crank? I see you said this was before MS so how about motor mounts? Link to comment Share on other sites More sharing options...
psu_Crash Posted August 19, 2008 Author Report Share Posted August 19, 2008 (edited) Motor mounts are new, doesn't mean they are great but they are new OEM mounts. Kept debating going with poly mounts but the amount of shaking on shutdown is more than mounts. I am 99% sure the MS settings for cranking are right set at 300 RPM since that is about what the engine cranks at. Minimum running RPM is set at 800. I am not controlling ignition with MS so I haven't really payed much attention to that part. I don't think that should be effecting anything though. As I get the idle closer to 850 is shuts down much smoother so I believe that is the problem. Going to work on it right now so I will update later on. Edited August 19, 2008 by psu_Crash Link to comment Share on other sites More sharing options...
psu_Crash Posted August 20, 2008 Author Report Share Posted August 20, 2008 So I now have the idle speed right. I adjusted the ISC screw and got it stable at 850 RPM. Idle AFR looks good at high 14 to low 15's but it still shakes a good bit on shut-down. Didn't have time to degree the cam today but that is my next step. Base ignition timing is fine and the vacuum advance is fine too. I checked for vacuum leaks and can't find anything. All of the vacuum lines have been replaced in the last couple months. I connected my digital multimeter from the neative of the battery to the positive of the coil and at no time to i ever get 12 volts there. Sits right around 180 millivolts (0.18V) Still a little confused by this, I don't know what could be causing it. Link to comment Share on other sites More sharing options...
Indiana Posted August 20, 2008 Report Share Posted August 20, 2008 That minimum running rpms seems awfully high to me Link to comment Share on other sites More sharing options...
Shelby Posted August 20, 2008 Report Share Posted August 20, 2008 (edited) you need to lower that min idle rpms to 500 or so,, then make sure the min cranking rpms signal is low enought for the ecu to know the engine is being crank'd 150-200 rpms and add fuel to get 13-13.5 on the 02 sensor signal , 14.7 is too lean for a good idle Edited August 20, 2008 by Shelby Link to comment Share on other sites More sharing options...
psu_Crash Posted August 21, 2008 Author Report Share Posted August 21, 2008 Changed cranking RPM to 175, min running at 500 about to go burn that to MS and get the idle AFR 13 - 13.5 Let you know in about an hour how it works out! Link to comment Share on other sites More sharing options...
psu_Crash Posted August 21, 2008 Author Report Share Posted August 21, 2008 (edited) Ok so the shut down is still far from great but it is slightly better. On a brighter note i spent about 4 hours last night going through datalogs and tuning my VE tables. Now there is no more hesitation and no spitting when i romp on the gas a little. Today is the first time i have really been able to pull any boost with it. I figured I have about 600 miles on the new engine and it seems to be running great with nice safe AFR all through the spectrum so I had to get on it a little and see what happened. WOW .... I am so freakin' excited right now! Let me tell you what even at about 7psi it starts to pull REAL HARD! Can't imagine what it will fell like at 15, and more when I get the meth/water injection set up Now I just have to save up some $$ and get injectors and piping for that magna I have sitting in my living room. Probably won't happen for a while yet though. Trying to save up some cash to drive to South Carolina for the starquest club beach bash sept 5-7. If you don't know about that check the meet forum. Still have to degree my cam ... I mean I have an adjustable cam gear, a degree wheel, and a dial indicator. No reason not to get that done. Any other suggestions about the crappy shut down? I have just been riding the clutch a little to get it to shut down smooth. Edited August 21, 2008 by psu_Crash Link to comment Share on other sites More sharing options...
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