Not sure if this is an issue of the fuel pump or reflash. The car has a Saab kit runs 91/93 octane and has racetronix w-body pump.
First off it takes @!#$ tons of cranking to start. I have to crank it for probably 10+ seconds to start it
second, it does the typical reflash thing, where if you blip the throttle it dips down, then rpms go up
Third when you get on it really hard it feels jerky. Like its running out of gas feeling.
Any ideas what could be wrong. I personally blame the tune. Opinions?
What does your wideband say?
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Do you let the pump prime for 3 seconds or so before cranking over so it builds pressure?
Yup, sounds fuel or spark related. What's the fuel pressure and plug gap???
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Im going with spark. I have NEVER let my racetronix prime.... thats just me. I just never have. Sounds like either spark blow out or fowled plugs. Thats my guess as to why its cranking so hard, it cant ignite the fuel.
I was commenting on the 10 second start up. I had maybe 1 or 2 times where it took 5 seconds to fire up without letting the pump prime. Idk what the sabb kit guys are gapping plugs too but I had good luck with .032 on my blower
yeah i knew what you meant. I just never had to let it prime for mine. as soon as i put the key in and turn it, it fires right up.
yes i let it prime, every time i attempt to start it (about 2-3 times each startup) gap is at .035 on one step colder plugs. im going to pull them later today and see how they look
Sounds like plugs...
My car would run like crap, and sound like a 2 step launch when the plugs were going to crap on the saab setup
.035 could be a little much for in boost, but start up issue. Maybe too much fuel.
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Well I pulled the plugs yesterday. They had minimal wear, but it was obvious I'm running rich. I re-gapped them down to 30 and cleaned them up. It seems to have cleared up my sputtering issue, however, im still having a hard start issue and there's the whole thing where it wants to cut out when you mat it. But I believe that's a tuning issue with the reflash
try gapping them to 28 or so. what plugs are you running?
try gapping at 28 and if that doesnt work, replace them if they look bad.
Get a fuel pressure tester and test your key on/engine off fuel pressure.
Also, what injectors do you have?
Also wanted to add, that I remember reading on here someone installed the racetronix pump and it dropped their AFR nearly one point over the stock pump.
I know the GM tune runs rich as it is, it could be possible with the racetronix pump that it is running even richer, something to look into.
i was having a similar issue with my setup w/ the LNF, and the fuel pressure being to much. i have a walbro pump and it would sputter in high boost cause the pressure was set to high, fauly guage on my fuel rail, turned it down 10psi or so and its all but gone.
That is exactly what I think is happening.
From what I've been reading, the Racetronix pump flows enough fuel that the stock fuel pressure regulator can't keep up, only real explaination for people having richer AFR's under WOT with the only differance being changing the fuel pump.....unless their stock pump was going bad that is.
If it were JUST sputtering going into WOT I'd say plugs were the issues, mostly because that's exactly what was happening with my homebrew turbo setup. The plugs were gapped to 55 or so, closed them up to 28 like I used to run on my 1.8T and it cleared the problem right up.
However, your cranking issue would indicate to me that something else is going on. Could be fuel pressure thing, could be something in the tune with cranking pulsewidth or warmup enrichment... If it was dumping too much fuel on cranking though my guess is that the longer you cranked it the less likely it would be to start at all, since it would be flooding. I'm guessing you're just using the straight reflash and no HPT? If that's the case I think you're going to have to start looking for a better tuning solution...
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Thanks for the replies all, but as I said before the sputtering issue cleared mostly up over last weekend. Every now and again I feel it chug a fraction of a little bit. But nothing I'm worried about since I know it runs super rich especially with the reflash. And its already in the works to be tuned this winter after I do some more work. Only issue I'm struggling with now is the hard start. I haven't had time to work on it much, but I will hook up my fuel pressure gauge today and check it key on/engine off. Though while I was messing with it over the weekend I do vaguely remember it being on the low end
I checked fuel pressure with key on engine of and initially it was 0. after letting the pump prime about 5 times it went up to about 8. after 10 times it went up to 15
That is strange, is the pressure normal with it running?
Thats very strange it won't build pressure with the key on, engine off, but yet makes pressure with the engine running
