I've been having problems recently with my 2000 M45 2.4 LD9 Cavalier. Noticed its been taking about 5 seconds to crank and finally start up. Have the Aeromotive adjustable fuel pressure regulator been jacked up to as high of 80 psi- which might have made the fuel pump get hotter. The last owner had the Walbro fuel pump installed. Has a PO300 random misfire code and idle its not so much of a miss but sounds eratic. I read that running the tank low on gas causes the pumps metal vanes to heat up and im also thinking the check valve in it is bad possibly. When idling I heard the pump make a wierd noise when the tank was low with the gas light being on. During acceleration it takes a very long time to rev with no power and air fuel ratio numbers at 12.5 with the CEL blinking yet no hesitation. Has lean air fuel ratio numbers when idling. Taking off from a line itll cut out, backfire sometimes and when changing gear into second. Now it cranks and wont start. Has spark, timing, and compression. Swapped ecus, same. With the key on the fuel pressure primes up and than drops to zero in a split second-Not sure if this is normal with the Aeromotive regulator or the check valve is bad in the pump... Reading about Walbro in other applications and in the J bodies they all seem to have problems and dont last very long. Disconnected coil and cranked engine for while and the plugs had little bit of fuel on them but not wet.
Just because it's easier I'd attempt a stock regulator first. I just recently ditched my automotive regulator for similar reasons (this is on an ecotec). It wouldn't hold any pressure at all, even for a split second, without the pump running and at wide open throttle it was bleeding off pressure. Changing to the stock regulator helped a lot and definitely fixed my WOT fueling issues.
The walboro pump, is it from racetronix? If it is, it definitely doesn't have a check valve. I don't know if other walboro 255s come with check valves or not but the racetronix units definitely don't.
"In Oldskool we trust"
He is correct no aftermarket pump for our cars has a check valve.
12.5 is a little lean at WOT, but isnt that far either. Swap regulators and see what happens.
FU Tuning
Installed stock for. Still wont start. Changed fuel filter since the one seemed somewhat hard to blow through. I seriously am scratching my head on this... Tried swapping dodge neon coil pack, icm... Tested coolant sensor, had good resistance vs temperature. I dont know what the hell! Timings good, compression, injectors pulsating....I have no idea. Just rebuilt this motor and has maybe 60 miles on it. Fired up and sounded great. After few start up its started hesitating at idle, than the loss of power...
Installed the stock fpr I meant. Damn autocorrect.
O.
I hate to say this but it might be time for a compression test.
I forget, you checked the fuel pressure correct?
"In Oldskool we trust"
Compression is good. Went up in pressure as well since rebuild. Fuel pressure was at 50 when cranking and when key on
Like said. It started taking about 5 seconds of cranking the motor over before it would start before this crank no start condition. I don't get why the fuel pressure would instantly drop after the key being on when the pump shuts off.... I thought it should stay primed!?
It will NOT stay primed with most aftermarket fuel pumps.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
