insanely rich; won't hold fuel pressure when I cut the car off
#1
insanely rich; won't hold fuel pressure when I cut the car off
Alright I posted before about how I got my T2 started.
Here is my fuel setup: 720/1680, Aeromotive FPR, stainless steel lines with KG aftermarket rail, Supra TT pump rewired. I am not running a parallel FC3SPro system.
Well it's running really rich and won't stay on without me holding the gas. This is being caused by likely a few things:
1. my thermosensor is reading too cold. I have a new sensor that I am about to put in.
2. I need to tune my Power FC. I am not using the idle speed control because I have no BAC, so I have to lean out the map some. But first I need to get that thermosensor in because I know it's dumping way too much gas. It's reading literally 50 degrees C too cold.
3. My fuel pressure may not be set correctly. I initially set it with the fuel pump check connector at I think 40psi with the car off. Doesn't the FSM say 37 or something?
When I start the car and try to hold the throttle open to like 900rpm or so (to keep it from dying because it's so rich), I had an assistant check the pressure and it said it was around 35psi. This is with the vacuum source hooked up.
Should it be that high? I think the car was pulling like 10-12 vac on the autometer boost gauge, that's with a street port and me holding the pedal down. I have heard it should be around 35-36 at idle with the vacuum source hooked up and I have heard it should around 30. So which is it?
The final issue is, when I turn the key and the pump primes, it immediately registers fuel pressure and then it drops to 0. The same thing happens when I cut the car off. Is the Aeromotive regulator just different than the stock one in that regard? I am positive have no fuel leaks. Positive. I jumpered that check connector and checked every single connection and fixed all the little leaks. I'm also sure my fuel pump is good. It came out of a VR4 making over 500 at the wheels, and before that it was on a Supra TT with like 30k miles. The pump definately has 60k miles on it max, although it has obviously been pushed.
Here is my fuel setup: 720/1680, Aeromotive FPR, stainless steel lines with KG aftermarket rail, Supra TT pump rewired. I am not running a parallel FC3SPro system.
Well it's running really rich and won't stay on without me holding the gas. This is being caused by likely a few things:
1. my thermosensor is reading too cold. I have a new sensor that I am about to put in.
2. I need to tune my Power FC. I am not using the idle speed control because I have no BAC, so I have to lean out the map some. But first I need to get that thermosensor in because I know it's dumping way too much gas. It's reading literally 50 degrees C too cold.
3. My fuel pressure may not be set correctly. I initially set it with the fuel pump check connector at I think 40psi with the car off. Doesn't the FSM say 37 or something?
When I start the car and try to hold the throttle open to like 900rpm or so (to keep it from dying because it's so rich), I had an assistant check the pressure and it said it was around 35psi. This is with the vacuum source hooked up.
Should it be that high? I think the car was pulling like 10-12 vac on the autometer boost gauge, that's with a street port and me holding the pedal down. I have heard it should be around 35-36 at idle with the vacuum source hooked up and I have heard it should around 30. So which is it?
The final issue is, when I turn the key and the pump primes, it immediately registers fuel pressure and then it drops to 0. The same thing happens when I cut the car off. Is the Aeromotive regulator just different than the stock one in that regard? I am positive have no fuel leaks. Positive. I jumpered that check connector and checked every single connection and fixed all the little leaks. I'm also sure my fuel pump is good. It came out of a VR4 making over 500 at the wheels, and before that it was on a Supra TT with like 30k miles. The pump definately has 60k miles on it max, although it has obviously been pushed.
#2
HAILERS
Join Date: May 2001
Location: FORT WORTH, TEXAS,USA
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28-32psi at idle.
Water thermosensors that have an open to the ECU, cause the water temp to default to 176*F.
On the stock fuel system, the fuel pump does not work by just putting the key to ON. You have to HOLD it to START or have the engine running, for the pump to work.
The stock fuel pump has a internal check valve to hold pressure in the system after the key is turned to off.
Water thermosensors that have an open to the ECU, cause the water temp to default to 176*F.
On the stock fuel system, the fuel pump does not work by just putting the key to ON. You have to HOLD it to START or have the engine running, for the pump to work.
The stock fuel pump has a internal check valve to hold pressure in the system after the key is turned to off.
Last edited by HAILERS; 12-06-07 at 10:59 AM.
#3
Thanks for the reply. I will probably drop the fuel pressure about 5 psi. I presume the Aeromotive regulator does not have a check valve so everything should be ok with that. As far as the thermosensor goes, well it does not have an open to the ECU. It's just inaccurate, and that's why I got another one (OEM Denso unit). On my Power FC Commander it was reading 45 degrees C when the car had heated up to 200 F (on my aftermarket gauge tapped into the water pump housing) due to another problem I am attempting to track down. 45 C is like 115 Fahrenheit, at which point the PFC is still pumping an extra 30% fuel in there for cold start enrichment.
#4
HAILERS
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If it's reading 45C which is 113F, then that can cause it to run a touch rich.
Just rambling........I've notice the water thermo sensor TO ME, just has two temperatures that effect the ECU. I notice at 120* degrees and below the afr will be rich, and at over 120* it will lean out a full afr at least, and then at approx 150 degrees it'll lean out another little bit. After that I don't see the rise in water temp do much of anything at all.
And the 02 sensor won't go close loop until the 150* temperature.
Just rambling........I've notice the water thermo sensor TO ME, just has two temperatures that effect the ECU. I notice at 120* degrees and below the afr will be rich, and at over 120* it will lean out a full afr at least, and then at approx 150 degrees it'll lean out another little bit. After that I don't see the rise in water temp do much of anything at all.
And the 02 sensor won't go close loop until the 150* temperature.
#5
You probably haven't messed with a power fc much, but all those warmup enrichments are controllable via a separate map (if you have the datalogit box necessary for a laptop interface). that's how I know it was dumping in about 30% more fuel. and I have O2 feedback disabled.
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