Ok all done with the engine work, put in new injectors, 87 waste gate actuator, and reworked everything I thought was even remotely questionable. Looks great and hold 10psi on the fuel rail after almost 2 days, ready to crank it up.....what I found is when the fans kick on idle drops off significantly, I would concider that normal, the duals have a serious current draw...but..fuel pressure drops as well, now that should not happen...should it????? I mean I can imagine that causing my WOT issues after the car warms up...If the fuel pressure drops because the fans are on then the engine will starve at WOT, I mean am I thinking correctly?????
voltage issue
- Thread starter tenright
- Start date
Hey Jerryl.......IAC does correct the idle if it is in gear, but in park it does not. I haven't looked at the scanmaster voltage to see if it comes back up yet, I wanted to see if it was normal first. What concerns me most is the fuel pressure dropping while the fans are on....
I have dual flex-a-lites on a racetronix dual harness, it's all brand new so I know it's not relay contacts, it is grounded to the bottom rail of the radiator mount but I am going to change that today to rule out grounding as an issue. I will check the voltage and post later
thnx.....
I have dual flex-a-lites on a racetronix dual harness, it's all brand new so I know it's not relay contacts, it is grounded to the bottom rail of the radiator mount but I am going to change that today to rule out grounding as an issue. I will check the voltage and post later
thnx.....
ok..IAC does drop and then comes up to about 28-30...it is normally set to 22, so lets say the IAC is doing it's job. Voltage really does not drop, if it does it almost immediately goes up to 13.9....which is awesome concidering it is also powering 1000 watts worth of amplifiers.
I reorganized the grounds, and grounded the fans to a bare fender spot that I have grounded other stuff to like the heated O2 sensor, the previous owner also had the neg side of the battery strapped to this spot. I never did understand that and figure it would do just about nothing but create noise since the neg bettery cable is already grounded to the frame, so I disconnected it. This seems to have improved the FP drop somewhat, it still drops but only about 2psi or so..not the 7 or 8 psi it was dropping before.
Actually I think my FP gauge is wrong because at 40 psi my BLM's are 116 or so....
I reorganized the grounds, and grounded the fans to a bare fender spot that I have grounded other stuff to like the heated O2 sensor, the previous owner also had the neg side of the battery strapped to this spot. I never did understand that and figure it would do just about nothing but create noise since the neg bettery cable is already grounded to the frame, so I disconnected it. This seems to have improved the FP drop somewhat, it still drops but only about 2psi or so..not the 7 or 8 psi it was dropping before.
Actually I think my FP gauge is wrong because at 40 psi my BLM's are 116 or so....
Jerryl
Tall Unvaccinated Chinese Guy
- Joined
- Dec 14, 2004
tenright said:
Well, there may have been a grounding issue since you picked up 5 PSI by just changing the ground cable. I picked up 0.5V just with a good ground when my car was running. :tongue:
Does your fuel tank have a good ground and what is your voltage under load?
Your BLM reading may be an indication of something else.
Jerryl- Like I said earlier I really think my FP gauge is off by a good amount and that is why I have low BLM. The reason I think this is the case is because I don't have knock at 17lbs no alky...At 40 psi fuel, 17lbs boost and no alky it should be pegging the knock gauge on a WOT run, should be at least 4-7 KR.....It's just very hard to tell with this car because even with these problems it is a monster...
The fuel tank has a strap in the corner to the rear quarter...no it's not very good, I will sand the spot down later and reattach it. Been working on the new heavy duty springs I just got from JaysGN....
Picked the car up a good 2-3 inches...add to that my blistin shocks should be an awesome ride. but man what a bitch gettin those in there....
The fuel tank has a strap in the corner to the rear quarter...no it's not very good, I will sand the spot down later and reattach it. Been working on the new heavy duty springs I just got from JaysGN....
Picked the car up a good 2-3 inches...add to that my blistin shocks should be an awesome ride. but man what a bitch gettin those in there.... BRAD_PADGETT
Well-Known Member
- Joined
- Jan 22, 2004
Tom- As I recall your fans are not controlled by the ECM. I just converted to the electric fan as well but mine is controlled by the ECM via a relay setup. Maybe your fans are drawing all the power from the alternator and undersupplying the fuel pump. If I can be of help let me know. Brad
Finally done with the springs....its a whole new car, bout the only things left are the frame itself and some sheet metal parts lol.... well and of course that damn freakin stock elbow.....
So back to the voltage issue...
Brad- Mine are controlled by thermostat, it is set up to connect the ignition trigger at a certain temp. They are all controlled by relay...I believe the ECM grounds it though...bottom line is it doesn't matter how you turn them on...the problem lies in the dual fan setup. Where you have one 30 amp relay kicking over I have two. The draw of current is significantly more. Where you may get away with a bad ground, or some little electrical boo boo I cannot. I do need you to check something for me..how long do your injectors hold fuel pressure???? Hook up your pressure gauge to the fuel rail turn the ign on engine off, let the rail charge, you will hear it kick on then kick off. Turn the ign off and check it every so often.....I need to know how long and how much FP your rail holds....
Jerryl- I am gonna fix the tank ground wich has a bit of rust under the tab, it is grounded to the fram not the rear quarter. Then see if this makes a difference. I suspect that this will slowly get better as I fix minor grounding issues and electrical junk. I don't think it is one thing....
So back to the voltage issue...
Brad- Mine are controlled by thermostat, it is set up to connect the ignition trigger at a certain temp. They are all controlled by relay...I believe the ECM grounds it though...bottom line is it doesn't matter how you turn them on...the problem lies in the dual fan setup. Where you have one 30 amp relay kicking over I have two. The draw of current is significantly more. Where you may get away with a bad ground, or some little electrical boo boo I cannot. I do need you to check something for me..how long do your injectors hold fuel pressure???? Hook up your pressure gauge to the fuel rail turn the ign on engine off, let the rail charge, you will hear it kick on then kick off. Turn the ign off and check it every so often.....I need to know how long and how much FP your rail holds....
Jerryl- I am gonna fix the tank ground wich has a bit of rust under the tab, it is grounded to the fram not the rear quarter. Then see if this makes a difference. I suspect that this will slowly get better as I fix minor grounding issues and electrical junk. I don't think it is one thing....
Update---Cleaning the ground to the fuel tank brought the voltage up to 13.8-14.2, when the fans kick on it drops to 12.8 or so hard to tell because it goes right back up to 13.3-13.8...FP drops 2 psi and then goes back up within a sec or 2. I would say this is about as normal as it gets...yes??
BTW Jerryl, good call on the fuel tank strap, I never would have messed with it had you not mentioned it......
Tom
BTW Jerryl, good call on the fuel tank strap, I never would have messed with it had you not mentioned it......
Tom
BRAD_PADGETT
Well-Known Member
- Joined
- Jan 22, 2004
Tom- I hooked up the fuel pressure and got 42 psi. Left it on and one hour later the pressure dropped to 12 psi. Brad
BRAD_PADGETT
Well-Known Member
- Joined
- Jan 22, 2004
Tom-Contact me anyime for reference checks. I got the 2 1/2 inch downpipe an Jays uppipe installed yesterday. I haven't done any testing yet(spent the day screwing with the pool). I did have one a**hole try to beat me from a red light- two lanes into one-i was in the left. I didn't get into it like spooling the turbo-but the tires broke loose in first gear. Needless to say the guy was toast. I will do some more real testing tomorrow and post. Brad
Similar threads
