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Rb25de not starting has everything

Dougy1997

By Dougy1997,
in R Series (R30, R31, R32, R33, R34)

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Dougy1997 Rookie

Dougy1997

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Hi people i recently bought an r33 that's been converted from a rb20e to a series 1 rb25de (was running before) and have just redone the head and it's not starting it has power to everything even while cranking it has fuel , spark ,heaps of compression has a brand new air flow meter , igniter module , new spark plugs but cheaper ones ,coil pack seals i've tried swapping throttle position sensor , clamping the return line in case was fuel pressure but it doesn't even start with starter fluid can only get the slightest pop out of it if i disconnect the afm  checked timing 3-4 times is spot on tried checking cas and get 5v on one spot but it's real touchy if turn it half a mm it will say 0.20v and it shows 3v constantly while cranking not sure if it's normal i have checked everything i can think of and i'm almost ready to call it a loss and just strip it for parts. anyone had this problem before or got any ideas ?

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GTSBoy Grand Master

GTSBoy

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33 minutes ago, Dougy1997 said:

tried checking cas and get 5v on one spot but it's real touchy if turn it half a mm it will say 0.20v and it shows 3v constantly while cranking

That's not how the CAS works. The CAS has a couple of optical switches in it that turn on and off every time a slot goes past the sensors. One pin is power in, one pin is earth. The other 2 pins are the output of the switches to the ECU. You should not be expecting constant voltages on any pin on the CAS that actually matters (apart from the power supply), and of course you should expect the output pins to change as you turn it. One of them will change state at every single degree of rotation.

Anyway, are the injectors actually pulsing?

Dougy1997 Rookie

Dougy1997

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Yeah i checked the 1 degree and 120 degree pins it was hard to find the spot where it has 5v constantly on them as it jumps around abit while in between them and if connect multimeter to one of them while cranking it shows 3v constant are they suppost to only show 3v constantly while cranking or pulse 5v or 12v ?

Dougy1997 Rookie

Dougy1997

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And yes injectors are pulsing an coils are sparking everything i've checked is normal just wasn't sure how to check the cas and it doesn't even start on starter fluid was thinking power while cranking and have no spark then but i checked and got power to everything even when cranking

GTSBoy Grand Master

GTSBoy

Posted
Posted
22 minutes ago, Dougy1997 said:

Yeah i checked the 1 degree and 120 degree pins it was hard to find the spot where it has 5v constantly on them as it jumps around abit while in between them and if connect multimeter to one of them while cranking it shows 3v constant are they suppost to only show 3v constantly while cranking or pulse 5v or 12v ?

If you are using a DMM to measure what's going on it's anyone's guess what voltage you would see. The optical switches will go from 0-5V every time a slot passes. A DMM is not fast enough racting to show these transitions, so on the 1° pin you will likely/possibly see a constant voltage between 0 and 5v. But....that's not great diagnostically. You're not getting the full story. On the 120° pin (actually, if you take the 1° pin to be 1°, then the other pin is actually 60°) frequency of switching is 1/60th of the 1° pin's, so depending on whether it's spending more time at 0v or at 5v, you will either see a lower or higher voltage on it than the 1° pin. I wouldn't know what to expect because I would never try to use a DMM tp probe the CAS pins while cranking.

Time for a compression test. And take the cam covers off and make sure you haven't broken a cam.

Dougy1997 Rookie

Dougy1997

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Not sure how to test them just read a post online to check if shows 5v when spin it and it does and the car wont start not sure if it has anything to do with it but everything else i've checked is perfect and still doesn't even give it a pop like it has no spark only way got the smallest backfire was when i disconnected the afm and have just replaced it with a brand new one and made no difference at all have replaced everything i can think only thing left is the cas and ecu then if that dont work will just strip it was wondering if anyone had any other ideas what it could be or are these cars just made to have a tiny problem and end up being parted out and scrapped ?

Ben C34 Grand Master

Ben C34

Posted
Posted
2 hours ago, Dougy1997 said:

or are these cars just made to have a tiny problem and end up being parted out and scrapped ?

Huh?

so you pulled it apart, put it back together and it does run so blame the car?

If I had to guess I would say you ha Ing the cam timing wrong. What is the spark timing like when cranking?

30ed32 Enthusiast

30ed32

Posted
Posted

If it has spark and fuel then your timing is probably wrong one way or another, I've seen it before where people have snapped the half moon in the CAS and don't put it back in the right place.  Take your CAS off and see if the half moon is still in tact and make sure you slide it back in at the proper position.

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

Take a spark plug out connect everything up and see if its sparking when you turn the key. have you got the furl supply to the rail connected correctly (don't laugh - many have done it the wrong way round)?

Don't stuff around with a meter on the CAS - pull it off as suggested and check the drive is ok and while you have it off turn the key on and turn it by hand and listen for the injectors. When you pull a plug out is it wet with petrol?

Finally if you can't get it going get a mechanic to have a look - its just another car and if its put together correctly and nothing is broken it will go.

WMDC35 Experienced

WMDC35

Posted
Posted
12 hours ago, Ben C34 said:

Huh?

so you pulled it apart, put it back together and it does run so blame the car?

If I had to guess I would say you ha Ing the cam timing wrong. What is the spark timing like when cranking?

I'd guess the cam timing is way off too

Dougy1997 Rookie

Dougy1997

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Was pulled apart when i got it as the old owner started to part it out and i lined the marks up on the cam gears and the crank when put it back together have checked it a couple times and they all line up have got fuel lines around the right way with the feed line going to the back of the rail and the return coming from the regulator but had to replace the exhaust cam gear is there a difference between the turbo an non turbo ones with just the pulley that bolts onto the cam ?

Dougy1997 Rookie

Dougy1997

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1 hour ago, Ben C34 said:

Oh, you bought a problem. There's no way internet diagnosis is going to work

You were right was the cam timing guy marked a white line on wrong tooth on exhaust cam gear and took cas braket off and noticed the little dot was like 9 tooth out and hardly visible and i lined the white lines up on intake and exhaust last time just redone timing to the little dot and it started up weird how they marked a random tooth on the gear though as the intake had the tooth with the dot marked white.

Ben C34 Grand Master

Ben C34

Posted
Posted
51 minutes ago, Dougy1997 said:

You were right was the cam timing guy marked a white line on wrong tooth on exhaust cam gear and took cas braket off and noticed the little dot was like 9 tooth out and hardly visible and i lined the white lines up on intake and exhaust last time just redone timing to the little dot and it started up weird how they marked a random tooth on the gear though as the intake had the tooth with the dot marked white.

Wow, lucky it didn't bend valves.

man I'm good, I should have stayed confident!

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