Jump to content
SAU Community

Recommended Posts

Alright, i give up. I've been under my hood for what seems like forever (which probably has alot to do with the weather finally shaping up) and i'm not making any progress here.

I need some tips/ suggestions, otherwise its gonna have to go to the shop and i don't want to the big money if i can avoid.

To make things simple, I'll just list everything i've done, and what i know it isn't.

Recent work (all done in one shot)

-New SARD 265 fuel pump & Deatchwerks 550cc injectors.

-fmic

-custom side feed plenum with Q45 throttle body.

-Z32 MAF

-Highflowed Neo rb25 turbo

-Ecu was mapped for Z32 and 550ccs to get me to the shop for a full Dyno.

Symptoms

-After everything was installed, turned the car over and it started but idled like hell, running stupidly rich, couldn't sustain idle or catch 1st. tried a couple times, figured the MAF was wired wrong.

-Came back the next day, turned out the MAF was correct, so we tried again, and boom, instantly hydrolocked b/c of flooding the engine with fuel. MASSIVE flooding. popped the plugs, saw that there was a small piece of silicon from gasket maker on the plug electrode in cylinder #1, which was the flooded cylinder.

thought maybe that was why #1 was flooding and pumped out the fuel, and put everything back, turned it over, locked right away. this time #6, and #3 i believe, point being that it was getting maybe half to one revolution before locking as the injectors are just DUMPING fuel into the cylinders. I mean i took out the plugs and covered the head with shop towels and turned it over and it was like niagra falls. (yes the pump fuse was removed and ecu unplugged)

-We tried 4 different ECU combinations from stock, to just the rb20maf and 550cc tune (put on the 20 maf) to even one chip tuned for bigger injectors just to try to suppress all this fuel.

-Nothing seems to change the result. it turns over for a fraction of a second (sometimes 4 secs if we really empty the cylinders) until BOOM, hydrolocked.

So at this point i'm rulling out maf as i've swaped in ones that i know work, Injectors as i see it unlikely that all 6 are broken, and plugs for the same reason. I also double checked the resistance on the injectors too.

My best guess is a wiring issue with the throttle position sensor that telling the injectors the throttle is open when its closed. I'll look into that and dbl check my voltage levels on the ingnition pack that tell the packs to fire. (anyone know where i can find those voltage specs?)

Ideas guys?? Please... i'm so close to having a ridiculously fast skyrocket here, its killing me.

No expert on this topic but it would be hard for injectors to pump enough fuel into a cylinder to hydrolic it in half a revolution. how much fuel pressure are you getting with new pump? and are the injectors constantly open rather than pulsing?

No expert on this topic but it would be hard for injectors to pump enough fuel into a cylinder to hydrolic it in half a revolution. how much fuel pressure are you getting with new pump? and are the injectors constantly open rather than pulsing?

Well when the cylinders are completely emptied it does take a few seconds of trying to turn over before it locks. Its when i just empty the one extremely full cylinder that i get about one rev.

Are they pulsin or pumping? i dunno. but the fact that certain cylinders are filling on certain strokes i would think pulsing no? how would i look into this as i don't see it being an ECU issue.

well if they are pulsing then you must have a huge fuel pressure to fill a cylinder so fast. I would try with the older injectors to see if the problem goes away, not a big job to swap those out first.

well if they are pulsing then you must have a huge fuel pressure to fill a cylinder so fast. I would try with the older injectors to see if the problem goes away, not a big job to swap those out first.

Yah i've been avioding that because the new plenum that i installed makes the fuel rail an absolute pain in the a$$ to get out. Thats my next step. but all it will likely do is get me to a shop to pay someone else to fix, the problem won't go away.

If he hasnt bent something already? Id be going the stock injectors for now, also how have you got the fuel pump wired up, and just a quick note what plenum is it? is it all fuel or water with it? thats why i asked what plenum it was

Im betting its either the injector o-rings or the diaphramin the fuel pressure reg, does it do it if you unplug all the injectors?Wont be tps, acell enrichment is nowhere near enough to causse this. Check the vacuum hose from the FPR to the inlet manifold(unplug it whilst cranking to see if fuel comes out there.)The reason why it is happening on different cylinders is because of the side feed inlet manifold.Might be good to do a compression test, this has been known to cause bent rods.

I'm pretty certain the injectors fire in response to a signal from the CAS. Are they high impedance or low impedance injectors?

To fill a cylinder to the point of hydraulicing the engine, the injector would have to be permanently open. Are you sure the re-map didn't put a huge time figure in the "start" fuelling parameter?

You are just going to have to pull the rail and observe what the injectors are doing. Refit the originals to get the car to the workshop (it will probably run a bit lean, but as long as it's low-load, it shouldn't be a drama).

Ok, thanks for the tips guys,.

so to answer some of the points here...

Used an fpr this morning. Didn't fix the problem. Did make the locking more consistent in that it takes about 1.5 full seconds for the engine to lock. However, this is a little bizzare. it no longer sounds like hydrolocking. It might have hydrocked the first time, but i'm fairly certain thats its not doing it anymore, Infact I'm able to continue turning it over while it cranks for 1.5 secs before locking, and sounds most definitely like something electrical is just cutting out and the starter just stops.

TPS is something i will look into tonight, but i'm beginning to wonder if it has anything to do with relocating my battery to the trunk. I had to with the position of the of the TB was pointing right at the stock battery location.

Wondering something isn't grounding properly maybe..

The injectors were brand new and should be ok, it would be odd for all of them to not be working, and even if 2 of them were malfunctioning, i think the symptoms would be different that just 1 sec of turning over then locking/shutting off.

As for all the ECU talk, i'm sure there is some truth to all that, but the one thing i can say is the tuner that did my ECU is a complete nerd with engine management/fuel management electronics. Every professional tuner has their aspects they excel at better than others, and this guy seems to be an electronic wiz for the most part, so if he tells me my ecu should run the car enought to get it to the shop, i have to take his word for it at this point.

if it was hydrolicking you'd wanna hope you havent bend a rod or 6 specaily seeing as you were doin it over and over...

No, i'm thinking not, it might have done it the one time, but its seems to be an electrical problem, i think the starter just keeps shutting off at this point. I really hope that nothing is bent. If so, i'll be sure to find the problem and kill the person responsible. (assuming its not me :kiss: )

Ok, i'd like to move the focus away from this end of the world bent rod scenario. I honestly doubt that happened, and if it did, then its already done. That still doesn't help me figure out whats wrong and i've got to get to that point first.

Pull the coils and plugs out, turn the key to on and watch what happens in the cylinder, if the injector is wide open you will see a constant spray. Hydrolocking a motor will do more damage to bearings than rods, especially on start. If it was at running revs then rod breakage would be a concern.

Because you are doing all this yourself, you also take on the risk of damage if something isn't working properly. Not someone else taking the risk.

James

Pull the coils and plugs out, turn the key to on and watch what happens in the cylinder, if the injector is wide open you will see a constant spray. Hydrolocking a motor will do more damage to bearings than rods, especially on start. If it was at running revs then rod breakage would be a concern.

it wasn't running revs and i'm almost certain its not hydrolocking, not anymore at this point, maybe once at first.

Because you are doing all this yourself, you also take on the risk of damage if something isn't working properly. Not someone else taking the risk.

I was referring to the individual who fabricated my plenum with a Q45 TB and failed to inform me of several specifics, its already been an issue twice. Now its alteast a possibility that the TPS is one too.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Hey Dave, welcome aboard! Good to see another soon-to-be Stagea owner here. The wagons are awesome — plenty of space, still got that Skyline DNA, and loads of potential if you’re into mods. Definitely post up pics when you get it, everyone here loves seeing new builds. What model/year are you looking at?
    • See if you can thermal epoxy a heatsink or two onto it?
    • The other problem was one of those "oh shit we are going to die moments". Basically the high spec Q50s have a full electric steering rack, and the povo ones had a regular hydraulic rack with an electric pump.  So couple of laps into session 5 as I came into turn 2 (big run off now, happily), the dash turned into a christmas tree and the steering became super heavy and I went well off. I assumed it was a tyre failure so limped to the pits, but everything was OK. But....the master warning light was still on so I checked the DTCs and saw – C13E6 “Heat Protection”. Yes, that bloody steering rack computer sitting where the oil cooler should be has its own sensors and error logic, and decided I was using the steering wheel too much. I really appreciated the helpful information in the manual (my bold) POSSIBLE CAUSE • Continuing the overloading steering (Sports driving in the circuit etc,) “DATA MONITOR” >> “C/M TEMPERATURE”. The rise of steering force motor internal temperature caused the protection function to operate. This is not a system malfunction. INSPECTION END So, basically the electric motor in the steering rack got to 150c, and it decided to shut down without warning for my safety. Didn't feel safe. Short term I'll see if I can duct some air to that motor (the engine bay is sealed pretty tight). Long term, depending on how often this happens, I'll look into swapping the povo spec electric/hydraulic rack in. While the rack should be fine the power supply to the pump will be a pain and might be best to deal with it when I add a PDM.
    • And finally, 2 problems I really need to sort.  Firstly as Matt said the auto trans is not happy as it gets hot - I couldn't log the temps but the gauge showed 90o. On the first day I took it out back in Feb, because the coolant was getting hot I never got to any auto trans issues; but on this day by late session 3 and then really clearly in 4 and 5 as it got hotter it just would not shift up. You can hear the issue really clearly at 12:55 and 16:20 on the vid. So the good news is, literally this week Ecutek finally released tuning for the jatco 7 speed. I'll have a chat to Racebox and see what they can do electrically to keep it cooler and to get the gears, if anything. That will likely take some R&D and can only really happen on track as it never gets even warm with road use. I've also picked up some eye wateringly expensive Redline D6 ATF to try, it had the highest viscosity I could find at 100o so we will see if that helps (just waiting for some oil pan gaskets so I can change it properly). If neither of those work I need to remove the coolant/trans interwarmer and the radiator cooler and go to an external cooler....somewhere.....(goodbye washer reservoir?), and if that fails give up on this mad idea and wait for Nissan to release the manual 400R
    • So, what else.... Power. I don't know what it is making because I haven't done a post tune dyno run yet; I will when I get a chance. It was 240rwkw dead stock. Conclusion from the day....it does not need a single kw more until I sort some other stuff. It comes on so hard that I could hear the twin N1 turbos on the R32 crying, and I just can't use what it has around a tight track with the current setup. Brakes. They are perfect. Hit them hard all day and they never felt like having an issue; you can see in the video we were making ground on much lighter cars on better tyres under brakes. They are standard (red sport) calipers, standard size discs in DBA5000 2 piece, Winmax pads and Motul RBF600 fluid, all from Matty at Racebrakes Sydney. Keeping in mind the car is more powerful than my R32 and weighs 1780, he clearly knows his shit. Suspension. This is one of the first areas I need to change. It has electronically controlled dampers from factory, but everything is just way too soft for track work even on the hardest setting (it is nice when hustling on country roads though). In particular it rolls into oversteer mid corner and pitches too much under hard braking so it becomes unstable eg in the turn 1 kink I need to brake early, turn through the kink then brake again so I don't pirouette like an AE86. I need to get some decent shocks with matched springs and sway bars ASAP, even if it is just a v1 setup until I work out a proper race/rally setup later. Tyres. I am running Yoko A052 in 235/45/18 all round, because that was what I could get in approximately the right height on wheels I had in the shed (Rays/Nismo 18x8 off the old Leaf actually!). As track tyres they are pretty poor; I note GTSBoy recently posted a porker comparo video including them where they were about the same as AD09.....that is nothing like a top line track tyre. I'll start getting that sorted but realistically I should get proper sized wheels first (likely 9.5 +38 front and 11 +55 at the rear, so a custom order, and I can't rotate them like the R32), then work out what the best tyre option is. BTW on that, Targa Tas had gone to road tyres instead of semi slicks now so that is a whole other world of choices to sort. Diff. This is the other thing that urgently needs to be addressed. It left massive 1s out of the fish hook all day, even when I was trying not too (you can also hear it reving on the video, and see the RPM rising too fast compared to speed in the data). It has an open diff that Infiniti optimistically called a B-LSD for "Brake Limited Slip Diff". It does good straight line standing start 11s but it is woeful on the track. Nismo seem to make a 2 way for it.
×
×
  • Create New...