Rb26Dett Problem Starting When Warm

[BoostedBarge]

I have a Stagea 260RS with a RB26DETT. It's had a Vipec V44 fitted for 5 years or so now. One thing that has always bugged me and I haven't been able to solve is engine starting when warm. If the engine is cold, it starts straight away. If I shut the engine down and start it 10s later, it starts straight away. If I shut the engine down for a few hours (sometimes up to 8 hours) it always takes a lot of cranking. At first I thought this was a tuning problem and my tuner added more cranking fuel. It may have made a minor difference. A friend and I had another go at it 6 months ago and added more fuel. It seemed to improve the case where you shut down for 10s, but still if the car has been left for a while I have the normal problem. When it does eventually splutter to life, it pumps out a bit of black smoke, so I'd say we've gone too far with the fuelling now. I'm beginning to think this is not an ECU problem, so I was wondering if anyone on this forum might have some ideas of what else I can check. I was thinking it could be an injector that is slowly passing when the engine is off. I had all injectors cleaned and tested when the ECU was fitted, but perhaps they didn't pick or test for this. Any other ideas?

[Ben C34]

I think it would be tune issue. It's hard to set up all of the parameters, and to get it nearly as good as factory is really hard.

I am suprise the cold start is good, usually that's the difficult one to get right.

[GTRPSI]

How does is sound while cranking warm, does it sound like the starter struggles a little to turn the motor over, sort of like the battery is losing its balls a little? If so pull some timing out and try again.

Of course if you have a leaking/stuck open injector thats another matter......

[Shoota_77]

As per above I would look at injectors as a possibility. A dribbly injector/s could cause that. Are you running a higher fuel pressure than standard? Could be forcing fuel through the injectors when parked. Does your oil smell really fuelly??

[Dose Pipe Sutututu]

I would play around with the temperature vs. injection correction table...

when your car is hard to start, pay attention to the water temp logged, then go to that point and try tweak the cranking injection & also the fuel correction for that temp

[BoostedBarge]

Cool. Thanks for the feedback guys. The starter motor never seems to struggle. It cranks quite easily, but just takes a while to eventually start. Fuel pressure is standard. The oil doesn't smell fuelly, but I might check it again.

I'll check out the coolant temp correction, etc.

[Dose Pipe Sutututu]

Also if it starts easier with a little throttle applied, I would have a look at the AAC or IACV and give them a test/clean.. there should be some high idle dwell on start up.

I'm not too familiar with your ECU but other ECUs there's an idle dwell which you can adjust which applies a little throttle on startup and dwells a little before dropping to your predefined idle setting.

[BoostedBarge]

Also if it starts easier with a little throttle applied, I would have a look at the AAC or IACV and give them a test/clean.. there should be some high idle dwell on start up.

I'm not too familiar with your ECU but other ECUs there's an idle dwell which you can adjust which applies a little throttle on startup and dwells a little before dropping to your predefined idle setting.

That's quite a good point about the idle up on startup. I might look into that..

[West]

Thread revival but did you ever had this fixed?
Thanks

[BoostedBarge]

Sadly I sold the car in 2016. I honestly can't remember if I fixed this problem. I don't recall doing the AAC or IACV. Maybe we tuned it out on the Vipec.

[West]

On 4/28/2022 at 11:03 AM, BoostedBarge said:

Sadly I sold the car in 2016. I honestly can't remember if I fixed this problem. I don't recall doing the AAC or IACV. Maybe we tuned it out on the Vipec.

Ah ok thanks
I'm having the exact same problem, cold/hot start like a dream, when its mildly warm she struggle and when start, RICH as fk.

[Dose Pipe Sutututu]

On 28/04/2022 at 11:26 AM, West said:

Ah ok thanks
I'm having the exact same problem, cold/hot start like a dream, when its mildly warm she struggle and when start, RICH as fk.

Your cranking table and prime table needs work.