madkaw

Actually I looked at the engine calculator and it was right around 8.65:1, but a good number for someone with programmable engine control. You won’t get away with flat tops- that’s 10.5:1 - that’s what I’m getting ready to run. That’s based on 41cc chambers, which is what I measured the at. I’ll be at 39cc chambers so I’ll be at 11:1 Ive got one more MN47 with some 44mm intakes if your looking.

So I’ll share my drama from my last couple of months . Engine just wasn’t running right and I swore I had a miss, but engine acted like it had a hunting idle. I knew my MAP sensor was questionable since I got it from the JY. I decided to buy a genuine new GM from Rock auto. Received it and checked it before install and it was bad out of the box. Sent it back and got another, this one has been working correctly. My Map Daddy that is on my board is bad also. I think it ruined from gunk running down the vacuum line. Current MAP sensor is installed above the intake! Engine still ran like poop, and I knew it had a misfire for some reason. Bought one of those HEI spark testers to test the coils . Found a coil that wouldn’t jump the spark - BINGO- I thought. Bought some used ones to replace my used ones and it still wasn’t right. Examined my GM plug wires with less than 10k miles and they didn’t look that great . Had a couple of extra wires and swapped some out. Ran slightly better but didn’t trust them. Because if the bad weather , most of my troubleshooting was idling in the garage. When I finally got out on the road the car sputtered up any hill at low rpm. WOT she still got it , but any low rpm loading caused major issues. All this time I was checking everything else on the engine; timing , tune , software updates , wiring , I just had re- wired the whole fuse box. Did a lot of reading and read how easy these logic coils will fire off. Little over 2 volts across the logic side and boom. I broke down and ordered MSD wires and new plugs. FIXED! Have to keep all the spark in the boots or these d585 will fire off. Pretty scary if you are running a turbo ( Gollum -are you reading ?) Hopefully the drama is over .Time to get my cam sensor working . Side note: Timing light is NOT an effective tool to troubleshoot spark with wasted spark and d-585 coils. The flash is erratic . I saw wasted spark flashes on 3 of the cylinders and half that speed on the other cylinders

Gave up and found a Nissan TPS to try, let you know.

Cool stuff. I thought that engine combo would have been good for an NA at best, but looks like you are making it work. You figure about 9.5:1? We wont even bring up the exhaust liners - lol. I hope you you relieved the short side radius before you put it on, they need some work there- especially for flowing a turbo . I had a MN-47 that I bought from someone that ran a blow thru turbo and it looked great .

If ever in Btown - come see the Z studio!

Did you end up in Indy Bob? Sweet -2 Z’s are better than one . Still in school?

Back in the game ?

You have double checked you have the correct throw out bearing -collar to match the clutch you have installed ? Just throwing out ideas. Maybe you aren’t getting full engagement ?

So doing all those checks - was flatness of the flywheel checked again? Looks like burn marks on the flywheel

What size hose runs to the IAC? 550 rpm is really low for an L motor and really low for a large cam engine . You should be closer to 900 rpm. Cold timing advance will help idle a lot . Tuning warm up idle is not easy and factors in a lot of things . What timing are you running at idle , should be at least 15-17 degrees . You could set in about. 7 degrees advance at cold start up . You could try setting your idle adjustment for engine to idle with IAC clamped off when at tempature , then try and tune in a fast idle at warm up

Have you cleaned or replaced the thermistor next to the temp sensor ? Is the AAR working ? If it is you should be able to pinch the hose when it’s cold and it should effect the idle . Sounds like your not getting the additional air during cold warm up . You could also visually check the valve is working . Almost sounds like your engine is idling off of the AAR valve , so maybe your butterfly is closed ?

Interesting . I did actually try to “preload” the TPS, but I might need to revisit that procedure . I don’t know if I did it like you exactly- if that was you in the video. thanks either way!

It’s almost more like there is slop in the fit of the TPS over the shaft. Once it engages it looks to be fairly accurate . I just need to get a real Nissan one and compare .

Remember what year you used?

Interesting . I’ve tried every which way to adjust it, but there’s not enough accuracy off idle.

So the engine is running pretty good. What I’ve noticed is that the TPS is not as sensitive as I would like it to be. It does not register off-idle as accurately as it should. I can move the throttle enough to bring the rpms up from 1k to 1500 and TS won’t even show movement. I’ve tried adjusting, calibrating , but it seems to be an issue of the TPS not being sensitive enough to small inputs. It is an aftermarket for my 240sx TB. And I have replaced it recently. I probably should have ponied up for a Nissan one. What I think it is doing is showing me at idle when I’m not . I guess I need to check voltages everywhere. I did verify that my sensor voltage coming from the MS is 4.95v. I need to test this at my sensors. Ordered a new O2 gauge . Ordered the Spartan gauge to match my Spartan wideband, maybe my numbers which match each other now.

Have you ever noticed the timing light issue I mentioned . Definetly a diffferent pattern on last 3 cylinders

I’ve been redlining my motor ever since I had these coils- 7200 rpm. Ill try and get a better pic of mine , but the coils are “ notched” into the square tubing. Hard to believe that small in set makes a difference over mounting on flat stock, but maybe my coils aren’t being loaded as heavy as yours with a smaller displacement motor ? You said there was a direct correlation to loading ?

I actually contacted him and he decided to keep it for now. It was rebuilt .

So were those originally d585’s you were having issues with?

I’ve noticed when checking timing, that the coils on 4,5,6 flicker twice the speed of 1,2,3 ?

So maybe you were having CAS issues from the noise ? My CAS is on the flywheel on opposite side of motor .

There was someone on FB selling one just a couple of days ago.

I keep reading your first post , but not sure I understand your symptoms . So basically the engine wouldn’t go past 6k because of noise from the coils? I haven’t had issues -except lately, and I’m not ready to blame my coils. I’ve been running my D-585’s for years . But maybe my mounting design helps me? Interesting!

Yes - I did some reading and realized that it needed to be mounted on top of the intake- which probably isn’t going to happen. I don’t think I’m ready to give up on the IAC . Besides - I’m having other issues right now I’m pretty sure my CAS is giving me issues - so I’m troubleshooting it right now. Found greasy condensation mess in my PCB coming from my MAP sensor . Also checking voltage for my VR sensor circuit.