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God Help Me Pls, Overfueling...hydrolocked

Paradis v.1
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Paradis v.1 Enthusiast

Paradis v.1

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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.

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tacker Mentor

tacker

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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?

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Paradis v.1 Enthusiast

Paradis v.1

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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.

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tacker Mentor

tacker

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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.

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Paradis v.1 Enthusiast

Paradis v.1

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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.

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Devils_Advocate21 Mentor

Devils_Advocate21

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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

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Adriano Grand Master

Adriano

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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.

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blind_elk Grand Master

blind_elk

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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).

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Paradis v.1 Enthusiast

Paradis v.1

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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.

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Paradis v.1 Enthusiast

Paradis v.1

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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: )

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Paradis v.1 Enthusiast

Paradis v.1

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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.

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heller44 Mentor

heller44

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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

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Paradis v.1 Enthusiast

Paradis v.1

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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.

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