Rb25/30det Issues :(

[Finny]

Hi all,

I put a Botch 023 fuel pump in my car about a week ago. When we first drove the car afterwoods it went like a dream. After it recieved a fair flogging the car refused to run any more. After a while the car cooled down and it would start again but was having a big winge under load. it would splutter and carry on.

I checked that the fuel pump was working fine and its holding pressure well so the pump is working fine.

Since then I have replaced the Crank angle sensor and the AFM with a Q45.

It is still doing it after that but it wont do it until you have driven it for about a minute until it warms up.

Basiclly it revs until about 2000rpm on a flat. from about 1500rpm onwards in drops power drematicly until at about 2000rpm were it just compleatly cuts out. if you put your foot flat to the floor it will back fire once it stops cutting.

Up hills is imposible it just wont do it at all.

it seems like a ignition problem to me as the fuel seems to be getting in there hence why it burns all that unburt fuel that it has been dumping in while while cutting. It blow massive flames when it cuts.

Any ideas?

I have changed the air fuel ratios but it seems to make no difference.

[Adriano]

Sounds like ignition module

[Finny]

Ok here is an update:

I hate replaced the AFM, the ignighter, the spark plugs, checked the coil packs I still have no idea why the car is spluttering and running so rough.

It even splutters on idle now

Kinda important as I have no car to get to work.

I have brought a new set of injectors (800cc) to see if that fixes it.

[BoostdR]

Ok here is an update:

I hate replaced the AFM, the ignighter, the spark plugs, checked the coil packs I still have no idea why the car is spluttering and running so rough.

It even splutters on idle now

Kinda important as I have no car to get to work.

I have brought a new set of injectors (800cc) to see if that fixes it.

I hope you are adjusting your tune to support your new mods......

[infamous_t]

What ecu? Have you checked sensors for faults thru Consult or your tuning software?

[FATGTS-R]

After it recieved a fair flogging the car refused to run any more.

You have changed all of these parts, adjusted the tune etc but have you checked the simple things first?

i.e intercooler piping?

Classic symptons of a cooler pipe coming loose, split join etc..

[Finny]

Yes is seems just like an air leak in my intercooler piping but I have checked all my piping and there is no air leak.

AFM is reading steady readings 2.8% air during idle which is about right for my air hungry engine. Stock engine use to be 1.7% I think.

Tune is fine.... if I increase or decrease AFR it makes no difference.. to the spluttering any way.

cars idle at 14.7:1 and I can't even free rev the car over 4000rpm because it splutters too much. If I richern my mixtures up to 20% it makes no notisable difference while free reving and if I lean it heaps it makes no difference either.

If I adjust my fuel pressure... makes no difference.

I am running out of things to replace....

I am going to replace my intercooler and I am getting a Microtech LTX12s soon so I will see if that will make any difference.

I am also going to replace the intake manifold with a greedy one and a 90mm billet throttle body.

It sucks because I leave in Tasmania so I can't take it to a macanic because there is no gregory's for RB30DETs so they can't read it to find out whats wrong.

[Cubes]

Get it on a dyno.

Surely there's a dyno in tasmania? A car is a car; your only diagnosing a simple issue.

Also with regards to the airflow thing.

My and others afm volts hardly increased on idle so something is up with yours if that is the case.

[Finny]

I disagree...

Stock RB25DET against a heavilly modified RB30DET with cams etc. there is going to be a difference in air flow at idle.

Also the car is idling a tad higher, engine is very tight and new still, needs a fair big of air to keep it turning over.

Longer stroke etc. the engine is doing a fair ammount more.

Dyno is not going to tell me any thing....

It wont even get one run on dyno as you can't rev it... they will just be like umm we can't dyno run this car cuz you can even give it any throttle.

Whats it going to tell me.... AFR while idling... thats going to help heaps.

I have an exhaust leak as my dump pipe isn't real tight because the exhaust and dump was make for an RB25DET which sits 1.5 inches lower than my current engine. I took my car to a local performance shop (one with a dyno) and they said yeah theres your prooblem you have an exhaust leak there... WTF!! IDIOTS!!! what the hell is an exhaust leak going to do. I can run my car with out an 02 sensor as its only used for open loop when highway driving and I still have the same problem when my 02 sensor is disconnected.

[Chris_A31]

A dyno is used to diagnose problems just like this one. Just reving the engine while it's just sitting there isn't going to tell them anything so they put it on the dyno to load it up. Much more chance of finding the problem when its put under load.

"We can't dyno your car..." pfft, dont you think this is what they do most days? find problems with engines?

[Finny]

YOU CAN'T LOAD UP MY CAR BECAUSE IT SPLUTTERS ITS FACE OFF WITH ANY ACCELLERATION!!

its not going to tell them any thing.

I have dyno tuned cars before....

the car bearly idles.... any load and it doesn't fire at all.

I can stick it on dyno pull the clutch out and the car would stall.

The car runs like it has 2psi of petrol pressure but I have checked that and it has 42psi of petrol.

I don't trust the dyno tuners here any way, last dyno I watched the idiots used the dyno brakes and put a VZ-SS into the dyno fan because it jumped off the rollers and they didn't strap it down.

[TTT]

has this engine ever run fine before the fuel pump change?

have you changed the fuel filter?

when you say you tested the fuel pump, how did you test what happens when you place load on it? (not free rev)

have you got the old fuel pump you can put in to test?

[bubba]

What management are you CURRENTLY running?

[Revhead]

It sounds like the ECU has gone into a limp-home type mode. If you're confident it's not the ECU (can you swap it?) then there are a couple of other things you may or may not have already checked...

* blocked fuel filter/line

* dying fuel pump (but it's new, so doubtful) - check voltages to it?

* wiring to AFM - unlikely as you're getting readings from it

* ignition - coils, ignitor, plugs. Not sure if you've checked any of these? Throw some cheapo copper plugs in, for a couple of bucks a plug it's worth checking

* sensors? TPS, CAS (which you've changed), AFM (ditto), O2 (ditto again), temp etc

Dunno if any of that helps but it always pays to check the basics!

[Cubes]

YOU CAN'T LOAD UP MY CAR BECAUSE IT SPLUTTERS ITS FACE OFF WITH ANY ACCELLERATION!!

lol.

Get it on a dyno with wide band shoved up its tail pipe and see whats going on.

Shop around and find a workshop that has the nisscan or what ever the std ecu plug in monitor thing is called. There will be a work shop that can work on your car. Hell even if you have to tow the car 90minutes who cares. Beats having no car to drive.

Also.. an rb30det with big cams etc is unlikely to use considerably more air at idle simply because the motor is not efficient at idle.. why do you think cam'd cars make less power at low rpm.. because the motor is pumping LESS AIR.

I went from an rb20det to an rb30det. A good few years ago; std ecu, std afm, inj etc.. and have slowly built it up.

[cjmcholm]

hi guy, Im winging alot of attitude and I dont need ur guys flack. So im giving you all the stiff arm. Recognise that shit.

[SmittyR33]

YOU CAN'T LOAD UP MY CAR BECAUSE IT SPLUTTERS ITS FACE OFF WITH ANY ACCELLERATION!!

its not going to tell them any thing.

I have dyno tuned cars before....

the car bearly idles.... any load and it doesn't fire at all.

I can stick it on dyno pull the clutch out and the car would stall.

The car runs like it has 2psi of petrol pressure but I have checked that and it has 42psi of petrol.

I don't trust the dyno tuners here any way, last dyno I watched the idiots used the dyno brakes and put a VZ-SS into the dyno fan because it jumped off the rollers and they didn't strap it down.

wtf? Take it to a tuner dig. Somethin tells me your still running the stock computer? If not then take it to a tuner for a tune

[Finny]

The bosch 023 is that strong that it was sucking the bottom of the fuel tank up and blocking the pump off.

On idle it wasn't doing it so when I checked fuel pressure I thought it was fine.

Ripped the 023 out and placed it in so it couldn't suck up the bottom of the tank and its fine now.

[Cubes]

Replaced all those bits when a quick run up on the dyno would have shown what was up with it

Its all good. Glad you got it sorted. Nothing worse than a gremlin that you can't track down.

[Finny]

A quick run on dyno wouldn't have shown that as dynos don't have fuel pressure readouts. I had to remove the fuel gauge off my fuel pressure regulator as it filled up with petrol and leaked :S.

Used a mates Mallpassi to test fuel pressure. Also dyno guys here are stupid and wouldn't have worked it out any way.

Now I have to fix it all over again because the 023 keeps sucking up stuff off the tank and clogging its self so I have to pull the pump out and clean it ever 10km.... wish they had a better filter on the back of them.