Symptoms: after car sits for multiple hours (3+ hours and especially in the morning) It needs a long crank (2-3 full seconds) to fire. After it starts it runs normally and starts normally. This has been going on since it got cold (2 weeks or so). I doubt it’s cold related though. Car: 2003 bugeye wrx that I’ve daily driven for 1 full year. All maintenance is up to date. New battery and spark plugs. Battery was replaced after this issue. Spark plugs replaced about 2 months ago with a new radiator and air/oil separator. No other changes to the car this year. Spark plugs are stock heat range. Any thoughts?
I think the right way to proceed would be to hook up a fuel pressure gauge and see what the system reads during start-up. Then leave it connected and see how fast pressure bleeds down after the engine is shut down. I'm sure there are specs for both of these, but I have no idea what they are.
Out of curiosity, do you turn the key to "run" and hold it there while the fuel pump primes before turning the key to "start"?
Yes, I have been doing that for a long time. Any e85 car generally starts better that way and this is my 2nd e85. No key gimmicks have helped this situation.
This is common with cars tuned on E85 in cold weather. Some have issues and some don't. Talk to your tuner and mention the issue you are having and they will be able to tweak the tune in.
My bugeye has been getting difficult to start lately too, even sputtering a bit before it really fires. In my case I'm fairly certain it's a combination of running e85 (with little remaining in the tank) and having TGV deletes.
Well today was warm. I went out to the car afterwards 8 full hours and (almost) hoped it would long crank. But it started right up instantly. Looks like cold is the issue. Is it possible the air-oil separator would cause cold weather start problems?
Aos, probably not. I tuned cold start on my own and it's amazing how a few minor adjustments can make a world difference. Do you have any rpm oscillation (up and down) while it's cold or is it just the starting part?
Short version: I would guess the tune can be adjusted... It sounds like crank inj pulse width needs to be increased, and possibly the inj scale to help smooth close looped idle. I'll try not to ramble but.. cold crank and rpm "swinging" were the trickiest things to tune for me. The RPM "swinging" happens when the car is either too rich or lean before the O2 warms up, and when the ECU goes into closed loop mode it tries to match the target AFR by adding/removing fuel. It overshoots and it swings. Ethanol % and temp multiplies the affects, which is why it gets worse when you change either. Cold crank is the same way, where cranking will take longer because the cylinders need more E85 on colder days to fire and its not getting it. I think this has to do with E85's change in viscosity at lower Temps and how that changes inj latency and pulse width. When I fixed it, I leveraged the Flex Fuel blend maps a lot. I used my high ethanol and added extra injector pulse width to the crank maps (plural). I also set the high ethanol crank maps (plural) closer to each other (unlike stock) so the cranking behavior was more consistent. Then I would add non-oxy to get different ethanol % and adjust my blend map as needed... If you don't have a flex sensor, you might fix it on a certain % of ethanol but not the whole range. If you didn't have the issue last year but do now, it could be that we still have higher % of ethanol at the pumps (aka, summer blends), then what the cold crank was originally tuned on. For example, cold crank @ 30F on 65% starts fine, but 30F on 80% may take longer.
Weeeellllll. I did NOTHING and this problems looks to have basically disappeared. Just leaving an update as I hate it when you have an issue and you never see the conclusion. It could have been bad gas? It could be that the e85 station has diluted the mix for the cold. It could be that its been ever so slightly warm? (but even on 40 degree days the car doesn't seem to have the same problems anymore)
Winter blends usually result in better cold start even if the scaler is set to higher content because it's adding more fuel than it needs to fire. The crank issue sounded like it wasn't enough fuel and not too much. (smells rich or fires if the peddle is put to the floor). This aligns with the theory that a summer blend + cold weather = crank no fire. Wait until we get back into 30 +-5 degree weather again. I noticed that's like a tipping point for e85 where one day can be perfect and just a few degrees less and the issue returned. Again I'll reiterate, it's amazing how the results skew within a few degrees around that tipping point... It's been a while since I've worked on it but last year I was collecting data that suggests change in viscosity of e85 at those Temps warrant an additional injector latency map based on temp/ethanol. Too lazy to continue research. I'm sure there is a trick map that can be used as a substitute so I just gave up. It's such a minor issue tbh. If you got the time, test the ethanol content from the pump.. Google +a few measuring cups and a glass should do the trick. If it's in the 75+, drops in temp may bring crank issues back until winter blends (55-70) hit the pump.
Just a follow up. Car runs perfectly now. I'm guessing it was a cold weather related E85 gas issue (or possibly just a crappy batch of gas that needed to be worked out). Starts up without any drama every time now.
