tryign to do first start, problems
10-27-2008, 08:34 PM
#1
tryign to do first start, problems Got a new pcm with a tune and everything hooked up tonight, fuel system is all back in as well
The fuel pump signal wire from the pcm only stays on for a couple seconds, won't kick the relay over. I jumped power to the fuel pump and it runs, but real rough, have to hold throttle open and it is popping through the exhaust.
Fuel pressure holds at right around 60 lbs and I don't seem to have any leaks.
PCM will not communicate with the scanner still so I can't check for codes. What should I try now?
The fuel pump signal wire from the pcm only stays on for a couple seconds, won't kick the relay over. I jumped power to the fuel pump and it runs, but real rough, have to hold throttle open and it is popping through the exhaust.
Fuel pressure holds at right around 60 lbs and I don't seem to have any leaks.
PCM will not communicate with the scanner still so I can't check for codes. What should I try now?
10-27-2008, 08:57 PM
#3
I'll double check on the relay
As far as the other, I have to hold the throttle open to get it start and its really bad rough, and lots of popping.
Right now I don't have a source wire for switched power so I'm connecting them all direct, don't know if that would have any effect or not. We have the switched ones on a side post battery terminal and are disconnecting the wire that is supposed to be constant, probably not the best idea but would it cause considerable problems?
Does anyone know of a good source for switched power that's heavy enough to power all 4 circuits? I have the one that used to go to my coil but I don't think it would be good to connect 4 wires to that.
As far as the other, I have to hold the throttle open to get it start and its really bad rough, and lots of popping.
Right now I don't have a source wire for switched power so I'm connecting them all direct, don't know if that would have any effect or not. We have the switched ones on a side post battery terminal and are disconnecting the wire that is supposed to be constant, probably not the best idea but would it cause considerable problems?
Does anyone know of a good source for switched power that's heavy enough to power all 4 circuits? I have the one that used to go to my coil but I don't think it would be good to connect 4 wires to that.
10-27-2008, 09:10 PM
#4
You can run the wire that used to go to the coil to a relay that will handle the load of 4 wires. As long as it's not still a resistor wire. And as for the running rough, my car does that until it's been run for a while, when the battery is disconnected for long periods of time (over the winter) but once it's run for a while it's fine. Just a thought, hope this helps.
10-27-2008, 09:36 PM
#5
By running rough, I mean won't run at all basically. Just carries on while the throttle is held down then pops and dies.
Kinda more like dieseling than running.
I did find a pink/black wire connected to the fuel pump relay that looks like it needs to be connected to power instead if I'm reading my stuff correctly...but doing so does not affect the running at all.
I'm going to eat and take a break then go over it all again. This is very frustrating.
Kinda more like dieseling than running.
I did find a pink/black wire connected to the fuel pump relay that looks like it needs to be connected to power instead if I'm reading my stuff correctly...but doing so does not affect the running at all.
I'm going to eat and take a break then go over it all again. This is very frustrating.
10-27-2008, 09:39 PM
#6
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Just an idea, if you have a quick enough multimeter monitor your +power wire going into the pcm for low voltage or spikes, and or check the grounds, for high resistance i.e. between the pcm and your engine block.
10-27-2008, 10:17 PM
#7
You can run the wire that used to go to the coil to a relay that will handle the load of 4 wires. As long as it's not still a resistor wire. And as for the running rough, my car does that until it's been run for a while, when the battery is disconnected for long periods of time (over the winter) but once it's run for a while it's fine. Just a thought, hope this helps.
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10-28-2008, 10:20 AM
#10
anyone have any ideas as to why the pcm will not communicate to the scanner? this would greatly help since I could check for trouble codes and monitor the engine more closely
the only sensors not connected and/or connected properly right now are the TCC switch and the neutral safety stuff, but the car is starting without them
I pulled up a random VIN online for a 99 camaro with a 5.7 so I'm pretty sure that's fine to do correct?
the only sensors not connected and/or connected properly right now are the TCC switch and the neutral safety stuff, but the car is starting without them
I pulled up a random VIN online for a 99 camaro with a 5.7 so I'm pretty sure that's fine to do correct?
10-28-2008, 10:50 AM
#11
Put it on a battery charger and tried again today, it will run above 2k rpms but below that it tires to die and every time I let off the throttle to turn it off it backfires really bad
still sound like crank sensor needing to relearn? it did seem to miss intermittently on 1 cylinder a couple times, but other than that it ran smooth
still sound like crank sensor needing to relearn? it did seem to miss intermittently on 1 cylinder a couple times, but other than that it ran smooth
10-28-2008, 11:50 AM
#13
Maf is ducted with a filter and all
vacuum ports: large on rear of manifold to brake booster like stock, small on back of manifold to air/heating controls inside cab, small behind throttle body pass side plugged with a cap
one thing is when it's running it does sound really mellow and tame...don't know if that's any indication of anything like bad timing or something, but it sounds "weaker" and less "crisp" in the exhaust note than my old engine (same exhaust but different headers)
gonna come back from lunch and finalize the power wiring properly so the computer won't be losing power any more at all, also gonna try to hook up the scanner under "generic obdII" and see if I can get anything that way
the idea about voltage spikes seemed to help though, putting a battery charger on it has at least allowed it to run smooth above 2k rpm unlike before, so progress is being made it seems
so I'm definitely open to more suggestions, thanks guys!
vacuum ports: large on rear of manifold to brake booster like stock, small on back of manifold to air/heating controls inside cab, small behind throttle body pass side plugged with a cap
one thing is when it's running it does sound really mellow and tame...don't know if that's any indication of anything like bad timing or something, but it sounds "weaker" and less "crisp" in the exhaust note than my old engine (same exhaust but different headers)
gonna come back from lunch and finalize the power wiring properly so the computer won't be losing power any more at all, also gonna try to hook up the scanner under "generic obdII" and see if I can get anything that way
the idea about voltage spikes seemed to help though, putting a battery charger on it has at least allowed it to run smooth above 2k rpm unlike before, so progress is being made it seems
so I'm definitely open to more suggestions, thanks guys!
10-28-2008, 01:26 PM
#15
cam is a comp copy of the tr230, uses xe lobes and is supposed to be ground with the same +3 advance as the comp cam
it was installed straight up with an ls2 chain
i guess there's always the possibility comp messed that up somehow, but all in all I am leaning towards some kind of timing issue as well which is why i thought mentioning the pissy sound of the engine might have relevance
it was installed straight up with an ls2 chain
i guess there's always the possibility comp messed that up somehow, but all in all I am leaning towards some kind of timing issue as well which is why i thought mentioning the pissy sound of the engine might have relevance
10-28-2008, 06:25 PM
#20
tried a new coil and didn't help
checked them with a timing light and the middle 2 on the pass side keep cutting out
none of the coils will fire when I first try to crank it, almost like the throttle has to be held for them to fire
I'm out of ideas at this point
checked them with a timing light and the middle 2 on the pass side keep cutting out
none of the coils will fire when I first try to crank it, almost like the throttle has to be held for them to fire
I'm out of ideas at this point