Thread: Possible tune, Possible Fuel pump problem

So like the title suggests I have a problem that I can't seem to figure out. So for a little background before the problem, Last month i switched my 04 comp g over to E85. I did this by switching my stock injectors out for 42# ones and added a zzp fuel pump rewire to make sure my pump could keep up. Contrary to a lot of the talk here on the site, this method actually worked(s) pretty well for me. My Ltft's were pretty high cruising (anywhere from +3 to +13) but on any WOT pulls i'm pegged at 0. Car runs great on E85, i see no knock and she's faster than ever.

So now to my problem. The car cold starts hard. And by hard i mean she doesn't want to start at all. None of that it takes 10-20 seconds and then cranks crap. Today, in probably the coldest weather we've had all year (Raleigh, NC), it took me about half an hour to get it to start. Now i'll admit i wasn't cranking it over that whole time, but i probably cranked it over 50-75 times in that span to try it. On a normal day it takes between 5-10 minutes and about 20 or so cranks to get it started. Once it starts and runs for a few minutes it's golden. I can go to school, spend 6 hours there, and then come out and it starts, normally the first try, if not then definitely the second.

So i've grown tired of these starts over the last month and thursday I ordered a new AVT box and got the DHP software from Bill(thanks again for that Bill). Yesterday i got the box and after getting everything setup I got my tune downloaded, made a backup just in case, and tried changing the cold start vs coolant temp table as indicated in this guide: http://www.grandprixforums.net/threa...ur-car-for-e85.
So after uploading my updated tune with the aforementioned tables changes as directed i expected my car would start easier.
It does not.
So that is where i'm at now. I tried tuning the cold start out. Didn't work. So what could be my problem?? Possibly fuel pump related? Still maybe tune related? I was thinking maybe something in the crank spark tables but it tries to start right off the bat, it just doesn't sound like it's getting fuel.
Yes, the pump primes everytime I put the key in the on position. Yes i prime it sometimes as many as 10+ times before i try starting it. Nothing works. NO, I haven't got a fuel gauge and tested the pressure at the rails, that will be next (ie, tomorrow).
Has anybody experienced any kind of hard starts on E85 to this degree? Getting up 30 mins early to make sure my car cranks is getting old. Any help would be great and just fyi, tomorrow i will take a few videos of it trying to crank and not succeeding.

Sorry for the long post, but it's a complicated problem.

Pump the pedal like a carb is my only advise lol.

My 215,000 mile SSEI you crank and give it a constant 25% - 35% pedal. It starts up with only a little hesitation. Keep giving it 25% pedal for 30 seconds and it runs good from then on.

Powrtuner isn't going to be able to make the changes you need. You will need to download tinytuner, and change your cranking fuel. The table you changed is used after the car starts but is still in open loop.

I used tiny tuner to make the changes. I followed frosty's writeup to the t, and even went back and changed it to more fueling for the 5 to -20 cells. 125%. No help

OK. You said you changed cold startup only so I was confused. Next step IMO is get a fuel pressure gauge on it. How cold does it get there in the mornings?

Today it's about 25. Normally anywhere from 25-45. Even on the 45 days though it takes a while to start since the switchover. I'm going to go buy/rent a gauge today. I'll post what the reading is.

Yeah, it should start fine at those temps. I usually don't see problems until it's below 20 around here.

Started poorly again. 20+ cranks. 10 minutes. As always ran great after that.
Neither my autozone nor my advance had a fuel pressure gauge in stock. I did do a self check on the valve on the fuel rails when it wasn't starting this morning. A bunch of fuel squirted out. So i'm not sure if fuel pressure is the problem. Still worried my pump just might not be strong enough for the added E85 and larger injectors with it. Suggestions besides fuel rail psi?

You might need to step up the heat range in your plug. why dont you post your tune file so we can take a look. But if the average temp in your place is below freezing alot i would stick to has in the winter

Update. It snowed Monday so I've had a few days of ultra cold temps to play with it in. I had not thought about it until the Bonne guy said something about having to give his gas to get it started, so I tried that yesterday and today. Surprisingly, it started much quicker with me throttling the gas pedal a bit. Still took about 4 or 5 cranks, but much quicker than without.

Originally Posted by Sven The Baldman

...who the hell would tune only for above 40* though?

Desert rats like me.

My car does run pig rich pretty much all the time according to the LTFT values i see on torque and now on dhp scanner. So where should i make any changes in dhp? PE Rpm vs Time A/f?

I say that cause on my overkill tune the table is zeroed out. Stock has values going in the negative numbers.