Rb25de Starting Woes

[FTO]

Thought I'd run this by you guys in case it's a common issue.

Engine won't start after shutdown, happened a few times, otherwise it's normal.

Leave the car sit half an hour and it starts and runs normally. Seems to happen hot or cold startup attempt.

Idles normally, has normal power when running..just won't fire up at all, until it sits awhile.

I haven't checked error codes yet, but there's no CEL comming up. Thought it might be a leaking injector or AAC problem..maybe even a ECU temp sensor, but running fine after startup has me puzzled.

Any ideas..........

[TwoCents]

Thought I'd run this by you guys in case it's a common issue.

Engine won't start after shutdown, happened a few times, otherwise it's normal.

Leave the car sit half an hour and it starts and runs normally. Seems to happen hot or cold startup attempt.

Idles normally, has normal power when running..just won't fire up at all, until it sits awhile.

I haven't checked error codes yet, but there's no CEL comming up. Thought it might be a leaking injector or AAC problem..maybe even a ECU temp sensor, but running fine after startup has me puzzled.

Any ideas..........

Checked the starter motor?

[mad082]

does it turn over if you try and start it, or does it just do nothing when you turn the key?

[FTO]

Starters fine, good battery, cranking speed is normal.

Go to start it and it cranks rormally, just no indication of any attempt to fire.

Acts as if there was a problem with the CAS or ign problem..half hour later it fires up on first attempt and runs normally..bit strange to say the least. Once it's running, there's no indication of any problem, idles normally, runs fine.

I thought it could be leaking injectors after shutdown, tried starting at WOT, but still no indication of trying to fire, plus you'd expect the problem to be constant if it was injectors.

Tried a reset on the ECU..still the same.

There's no alarm or ign cutout fitted either.

Edited February 10, 2010 by FTO

[mad082]

well it only needs 3 things to start, 1 of which is hard for it not to get. that is air. the other 2 are fuel and spark.

do you have an alarm system or immobilizer in the car? may possibly be that it is causing the problem if you do.

if not, next time after you have been for a drive, have a spare spark plug handy, pop the bonnet and remove the spark plug from number 1 cylinder. screw in the spare one (to stop fuel coming out) and then put the old spark plug bag in the coil and earth the tip of the plug on the motor and have someone turn the car over. you should see a spark as it turns over. if you don't then you have a spark issue. if it sparks fine, then you more than likely have a fuel issue.

also be worth trying to let the fuel pump prime before you start turning it over. see if that makes any difference.

[FTO]

yup, just looking for something more specific..

Same deal happened the other day, won't start, the fuel pump wasn't running prior to cranking, checked the pump relay..all ok.

I expect the problem is either the pump itself or the ECU (ECCM) not responding to the start signal..doesn't explain the normal start after waiting an hour though.

I don't want to replace the ECU and then find there's something up with the pump, or something else.

You'd expect either the pump or ECU would be working or not..coming good after a delay seems a little weird.

[mad082]

you could try just borrowing someones ecu to see if it works. or even just make sure that the loom is plugged into it properly

[FTO]

update: just in case someone runs into the same problem..

it turned out to be the fuel pump. E10 was the cause, it might be higher octane and run a tad leaner for better perf (cheap)., but stay away from it.

The pump seals had swollen so much it was stopping the pump from running, intermittentaly.

Also, might be of interest, hunting through circuit diagrams, I noticed the ECU self diagnostic doesn't monitor any outputs except to check it's own signal is outputed. In other words it only monitors the relay output ie. it's got no idea if the pump is running and there's no fuel line pressure monitoring..same for the IGN. and EFI. So don't put too much faith in a code 55, you could have leaking injectors, ign arcing, no fuel pressure etc.

[mad082]

most people on here will be aware that the ecu doesn't check things like that.

as for E10, i've been running it for about 3 years now in my SSS pulsar and it has never missed a beat. my in laws run it in their cars (have been for about the same, maybe longer), also with no issues.

[FTO]

Not so sure about that, in most cases the ECU has a feedback loop. Should the ECU indicate the pump is faulty, for instance, then a lot of people would think that is the case, conversely if the ECU indicated no problems, then again some people would think the pump is fine..both cases being possibly wrong.. (using the pump as an example).

As for E10, I've run it for 6-8 months now and the pump seals swelled to twice their size. It appears the fuel lines, and possibly injector seals also, have softened & deteriorated as well, maybe not as critical because they aren't submersed..but yes fact not opinion. Can't speak for pulsar's or anyone elses car, but if you choose to run it in a '95 RB25DE R33 Skyline you can propably expect the same result, sooner or later.

[mad082]

Not so sure about that, in most cases the ECU has a feedback loop. Should the ECU indicate the pump is faulty, for instance, then a lot of people would think that is the case, conversely if the ECU indicated no problems, then again some people would think the pump is fine..both cases being possibly wrong.. (using the pump as an example).

As for E10, I've run it for 6-8 months now and the pump seals swelled to twice their size. It appears the fuel lines, and possibly injector seals also, have softened & deteriorated as well, maybe not as critical because they aren't submersed..but yes fact not opinion. Can't speak for pulsar's or anyone elses car, but if you choose to run it in a '95 RB25DE R33 Skyline you can propably expect the same result, sooner or later.

my pulsar also has nothing in the ecu to indicate faulty fuel pump as far as i'm aware. or if it does it would only be to say that the fuel pump isn't recieving the correct voltage, etc. not to say what the fuel pressure is like. i don't think you will find too many cars the same age as most skylines that actually monitor fuel pressure. some newer cars might, but not the older stuff.

as for fuel, i think you will find that there are plenty of people also running e10 in some for or other in their car who haven't had issues. how can you be sure that it was caused by the ethanol and not old age? how do you know that they simply weren't faulty seals? the reason i say this is that there are a hell of a lot of ethanol blend fuels out there and plenty of people on this forum are using them. hell some are even running e85.

[FTO]

Quote: "how can you be sure that it was caused by the ethanol"

Because the pump seals & in-tank fuel line were soft and swollen badly when removed, and when left to dry out, returned to normal size..that's what alcohol fuels do to standard rubber components.

Nobody in their right mind would run E85 on a stock fuel system.

"Ethanol blends may have a deteriorating effect on the rubber components of an engine. Other additives, such as benzene may also have an effect.

In older models, deposits in fuel tanks and fuel lines are occasionally loosened by E10, and the fuel filter may become plugged. This is remedied by a fuel filter change.

If very Ethanol rich fuel is used this may cause an engine to stall.

Laboratory tests have shown that blends of 20% pure Ethanol in petrol can damage some conventional automotive paint."

RAA report on E10.

No point in debating it, it's just there to help anyone that might encounter the same problem.

Edited February 28, 2010 by FTO