2eighTZ4me

Mostly occurs under very light throttle/cruise while going over bumps. The car will miss for a split second (AFR's go rich) and then pick right back up. I pulled datalogs and the guys at DIY said that I have a 'sync loss' condition. This has also happened a couple times under full boost - so it's not relegated to just light throttle/bumps - it's happened during a bunch of different conditions - but MOSTLY light throttle going over bumps. I have the 83 turbo dizzy with their (DIY) Hall effect wheel in it. No shaft play in the dizzy that I could feel - car only has 2200 miles on it now. Put in a new dizzy pickup/sensor as well. This is a 78 S30 turbo BTW... Just replaced the relay board - thought it may have been a bad fuse holder - that didn't help. Anyone ever encounter this? The DIY folks said I need to put an oscilloscope on it. Doubt I would even know how to hook one up - much less what to look for in the data. Curious if this has happened to anyone, and if so - what you did to fix it.

Well howsaboutthat..... I had a spare dizzy and went to put it in. Upon removing the old one, I noticed the sheathing around the red and green wires was melted. Upon closer inspection, it turns out it burned through the green wire jacket all the way down to the copper. It was obviously resting on the header and when the green jacket yielded - it shorted and shut the car down. The new pigtail has been routed far away from the header now. All is well....stupid me.....despicable me......

Sorry NewZed - I have 3 - this is the NA car that I've had for 18 years. Is there a way to test the tach adapter? I doubt that's the culprit though. I will search around for the GM HEI setup and see what all needs to be done to accommodate that....but with GM - I just don't want it to 'shut off' !!! (Bad joke in there...) MegaJolt will ONLY work with a 36-1 trigger wheel. So much for that....

That's what I thought you meant - but the black box is on a 79-81. Mine's a 78 - so that function would probably be handled by the Transistor Ignition unit in the passenger side footwell under the dash. ??? When you say magnetic input of the MSD - is that the green and purple wires coming off the MSD box? I don't have a manual here in front of me.

Six_Shooter - not sure what you mean by using the original ignitor. I'm using the star wheel/reluctor in the dizzy to trigger spark. Red and green wires. Course - now that you mention it - it's been so long since I wired that thing in - i'll need to go back and find where the red/green from the dizzy go to. I did try bypassing the MSD box and ran straight coil (B/W wire to +, and blue wire to -) and got NO spark either. I have to think it's something in the trigger setup as NewZed stated. I do have a spare distributor, so I may try that this evening. The MegaJolt looks very cool - are you able to trigger from an existing stock distributor setup, or do you HAVE to go crank trigger?

78 280 - carbed - running MSD6AL with a stock dizzy through a Jacobs coil. Just fired it up after a refresh - ran for about 6 minutes, long enough for me to set the timing, and then quit when I locked the dizzy down in place. I could hear the MSD box shooting random sparks with the car off (but key still in the run position) - and then it just quit making noise altogether. Tested the MSD box by grounding the white wire - got plenty of spark, yet when I spin the motor over - no spark. Like it's not even reading the pulses from the reluctor in the dizzy. Shaft has minimal play. Transistor Ignition box?? I had noticed, prior to the refresh, that the tach would jump randomly all over the place while at idle, and you could hear/feel 'misses' in the ignition when the tach needle was bouncing. I was suspicious of that behavior back then as well. This particular MSD box has failed on me twice now. I'm sick of this POS. Maybe I just got a lemon - but that has left a bad taste behind regardless. I'm leaning towards it being the issue now - yet the test shows it is generating spark. From what I've read - the two popular ignition setups are the ZX E12-80 or the Mallory. I would 'like' the Electromotive XDI system - but can't justify a grand on ignition for a car that doesn't get driven a whole lot. Yes - i'd like to fix the current issue, but my fears of the MSD failing again have overtaken the desire to continue screwing with this setup. Open for suggestions...

Sorry - it's Jon Coffey's writeup. http://forums.hybridz.org/topic/38589-strut-sectioning-faq/

Nelsonian - I took apart the old booster and glued the disk to the rod and put it back together. I have not had a chance to swap it back in yet. That is on the docket for this weekend. I'll let you know how it goes.

Here's how it's fed. The fitting maybe sticks up 1/3" inside the tank.

Well - ok. A little testing/wiggling revealed that indeed my MS relay board has bad posts for the fuse. As I'm trying to get a reading - and jiggling the fuse in the process, I can see sparks in the fuse holder, while listening to the pump turn on and off. Fuse was hotter than a firecracker after about a minute of the pump being on (and off and on and off etc.... Long enough to hook up the meter....and have a swig of beer...... I'll be replacing the relay board and a 12ga wire to the pump before I even bother you guys again. This has GOT to be it...bad fuse connection as NewZed stated - causing my fuses to burn up....before they blow...... due to crappy contact. Could also be the cause of my intermittent miss when I go over bumps..... a two-fer would be nice.....I don't get many of those....

My relay board is mounted in the engine bay right next to the clutch master cylinder - where the dropping resistors used to be. Just to be clear - I'm using MegaSquirt relay board to power my fuel pump. It is where the fuse and pump relay live. I bypassed ALL the stock 1978 wiring - save for the one that goes back to the pump. Spliced it in to the relay board. NewZed - yeah - I need to update my signature file. My 73 has a fuel cell and nothing stock about it. This is my 78 that I'm trying to make a DD. You did have a great point about the fuse socket though....mine looks pretty trashed as mentioned before, so maybe the fuse is heating up there from a bad connection....Good call! This weekend, I will replace the relay board AND the wire going from it back to the pump....providing Mother Nature doesn't dump rain on me all weekend...

My pump is mounted horizontally in the exact same spot/position that the stock (1978 EFI) pump was. It even fit right in to the stock mounting bracket. No need to reinvent the wheel. If it was good enough for the Nissan design team for mass production - I have to think that it would be sufficient in my case as well. It's not close to anything hot. Unless the diff heats up in stop and go traffic I have an inline pressure gauge (and an Aeromotive pressure regulator) and it reads 40psi spot on all the time (except when it dies!) Again - the car has roughly 2100 miles on it now - the parts are still pretty much brand new. The pressure gauge is plumbed in just before the fuel rail. Being that I pull fuel from (what used to be) the tank drain plug - it's nearly impossible for me to mount the pump lower than the tank, which is why I try to always keep at least 1/2 tank in it at all times. I have a sneaky suspicion that excessive underhood temps, coupled with minimal ventilation, are heating the fuel up - even though I have taken great care to route the lines as far away from anything hot in the engine bay as possible. I am running a -6AN line all the way from the pump outlet to the front of the car as well. I tried to look up the flow rate of the pre-pump filter with no luck. Filter is an Aeromotive 12304. Just throwing out as much info as I can to you guys....

When it first did it with the 10micron filter pre pump - the tank was fairly low. This time, however, I had nearly 3/4 of a tank. It was 86 degrees out yesterday and traffic sucked! Sucked even worse when the car died in it!! I have been conversing with the DIY AutoTune folks and I'm going to run a few tests tonight - namely a current draw across the fuse on the relay board that keeps getting smoked. I am convinced that running a single 12GA wire from the MS relay board straight back to the pump could not hurt anything. And it will give me peace of mind that at least that piece is out of the equation. I'll go after removing the pre filter next if this doesn't work I will also be replacing the entire MS relay board over the weekend. The one in the car now was bought off this site and have no history on it. Plus - the fuel pump fuse socket is nearly wasted from all the heat and pulling of fuses... Thanks for your help guys!

Return line is the factory hard line. Pump (and car) has 2043 miles on it. Brand spanking new. Fuel comes from the dead bottom right of the FACTORY tank. I mounted a -8AN 3/8" 90 degree fitting in the bottom of the tank where the drain plug is. The old 10 micron pre pump filter has been replaced with a brand new 100 micron filter less than 400 miles ago. The tank was boiled and sealed. There is no sh** being sucked up. The pump is mounted in the stock location. Pretty much dead even with the outlet on the bottom of the tank....maybe a wee bit higher. The problem is clearly heat related - and related to the heat of the fuel, as it gets hotter and hotter being pumped through the system. The pump is lubricated and cooled by the fuel - and when the fuel gets hot - there's a problem. Here's the deal. Everything I've read stated that the 044 pump is to be used inline with a feeder pump. I can see that making it the only pump would make it upset a bit. I don't want to replace it, but if I have to go with a 'single' pump - like an Aeromotive A1000 - and wire it with 12GA. - I will. Don't really want to go with a -10AN outlet out of the tank - that'd be a freakin' fuel mess...but I will do the 12GA wire directly first - that seems to be the sentiment echoing here . It's burning up the fuses on the MS relay board - so I have to think that excessive amperage is being pulled by the pump under hot conditions - causing the fuse to fail due to the pump trying to pull too hard on hot fuel... This is a turbo car with no hood vents (Carbon fiber hood) and gets dogged pretty hard daily with 16 intercooled psi. Air intake is underhood above the factory AC compressor. I know IAT's are probably a little hot -- not helping the situation any - but it is what it is.... And Nigel - many thanks to you for the 240SX tranny swap writeup!! I have one in this car, and in my racecar - and I have been completely pleased with the performance of them! Followed your Motortopia writeup to a T - worked like a champ!!

Thought the reason I was burning up fuses was b/c of the 10 micron filter PRE pump. Swapped that out to an Aeromotive 100 micron filter and a -10AN line from the filter to the pump (up from a -8AN). Problem got better....BUT....after sitting in a lot of stop and go traffic - the pump died. Once it gets hot after about an hour of driving - the pump starts to get loud. On cool mornings - I can't even hear the thing on the way to work - which is an hour drive each way. On the way home is a different story. Pump starts humming after about 45min. into the afternoon commute. On two occasions when it has died - I pulled the fuse and one side of the plastic was burnt. Fuse didn't blow - but it damn sure got hot. Replaced the fuse - and it fired right back up and got me home. Tested the fuse when I got home - it's still good. I am using the STOCK wiring for the fuel pump. I spliced into it under the dash. I'm guessing I need to run a straight 12GA wire from the relay board to the pump to drop resistance? Pump is mounted in the stock location. I know I'm missing some details - but that's the gist of it. Car/fuel gets hot, pump gets loud and just shuts down for a while. Not sure if replacing the fuse did any good - or whether the cooling down did the trick. I'm either looking at going to -10AN from the tank to the pre-filter, or straight wiring 12GA. from the relay board to the pump. I'd like to be as minimally invasive as possible - but just want to see if anyone else is running the 044 pump and has had any heat relate cutoff issues. Thanks in advance...

Yep - it was bench bled when on the car. I don't suspect there is air anywhere. If there were - I would be experiencing some sort of pulling to the left or right - even if a rear wheel, it would still put enough drag on one side to make the car feel funny during stoppage. She stops straight and dead on. I'm leaning heavily toward the reaction disk. Guess I'll know this weekend...thanks for all the help gents!

Miles - yes - I do have the aluminum spacer in place b/t the MC and booster. I did my adjustments to the rod as you stated. I have maybe 1mm of play in there. I will re-measure the rod in the old booster once I get the reaction disk back in there tonight and see if it is the 13-15mm you stated. The pedal still comes on fairly high up - so I have to think the rod is adjusted 'close' - as the pedal doesn't drop to the floor before activating the brakes. Pedal 'height' feels totally correct - there's just no pushback on the pedal. I can hit it with my big toe and the car will stop on a dime. It's not so much when/where they activate - it's how little pressure I have to use to get them to work. I'm used to having some pedal pressure to work with in order to stop smoothly - there's just no pressure and all stop....

Thanks NewZed!! That's the article I had looked at - but for some reason - the pics wouldn't come up. Thank you!!

socorob - you can easily detach the master cylinder (full of fluid) and push it forward and out of the way to get the booster out if need be. No mess. Did it last week.

John - I agree. Is there any way to verify for sure that it's in and seated properly? I saw an old post of Blue's where he took the booster apart and fished the disk out - but it was an old post and the pictures were long since deleted. How do I get in to the booster? I still have my old one to play with.

Since I didn't get any response on the Wilwood sticky thread - I thought I'd try my luck with a fresh post. Have an extremely touchy pedal. There is no 'pushback' from the pedal at all. It goes down with very little effort and the car stops on a dime. Heel and toe braking is a non-option - the pedal is just way too touchy. I thought I had dropped the reaction disk in the booster (which I did) - so I bought a reman booster. Still the same problem persists. I can shake the old booster and hear the reaction disk bouncing around inside. The new booster - I cannot hear anything when shaking it (after adjusting the pushrod). Leads me to believe the reaction disk is still in its' proper place. Brakes have been bled ad-nauseum - nothing but fresh fluid coming out - not a speck of air. I'm running the Toyota vented setup up front and the MM 240SX rear. I do not recall if I removed the cones from the Wilwood or not. Would they (or the lack thereof) cause my pedal to be so touchy? Scratching my head over this one...

Ignition/Accessory relay went bad. 25230-89958. Fabbed up 2 relays to function in the manner in which this 'dual' relay operates - everything works in all positions. So there we have it!

Well I'll be - just checked another box in the garage. Yep - sure does - at the back of the tailshaft housing at the top. Learn something new every day!

Actually - the 81-83 5 speeds only have the reverse switch as well. You must be thinking of an automatic. The 5 speed I just put in there is out of an 82 - only the reverse switch. My problem is that I'm not getting power TO the fuse block - so I can't pop fuses. I'm convinced the relay works b/c I have power to it in the Acc position. There's gotta be something upstream. Knee deep in the wiring diagram now. Do appreciate your help - let me know if something else hits you.

This is a manual 5 speed. The only wires going to it are the reverse light switch.