Installed Aeromotive FPR & 255hp pump and now car not running good, give me some tips

[ShadeTreeDSM]

1990 gsx is what i own, i just built the motor in it, had stock fpr and a walbro 255lph with 880cc's and somewhat of a tune on the greddy e-manage for my garret 57 trim. it was running pretty decent.

so today i installed my walbro 255 high pressure pump & the aeromotive regulator. i start the car up and with the fpr vacuum line disconnected i set the fuel pressure to 40psi. i rev the car a bit and the response sucks, engine chokes up top and backfires quite a bit, compression is fine and the crank & camshaft timing are dead on. car wont really rev up until i keep tapping the pedel. what can this be ? is that the right amount of fuel psi or what needs to be adjusted, whats going on, all i did was install an fpr & pump. ?WTF

 

[MidShipCivic]

1990 gsx is what i own, i just built the motor in it, had stock fpr and a walbro 255lph with 880cc's and somewhat of a tune on the greddy e-manage for my garret 57 trim. it was running pretty decent.

so today i installed my walbro 255 high pressure pump & the aeromotive regulator. i start the car up and with the fpr vacuum line disconnected i set the fuel pressure to 40psi. i rev the car a bit and the response sucks, engine chokes up top and backfires quite a bit, compression is fine and the crank & camshaft timing are dead on. car wont really rev up until i keep tapping the pedel. what can this be ? is that the right amount of fuel psi or what needs to be adjusted, whats going on, all i did was install an fpr & pump. ?WTF

Is it even able to idle ? My car doesnt even want to stay on.

That sounds like my car! The throttle response absolutely sucks and I get big ass balls of flame comming out of the exhaust and it will stay revving up randomly and slowly die down and stall if I tapped the accel at high rpm (4-5k) you'd hear the loudest pop in the world) .

I have a 255LHP Walbro and I'm using stock FPR, its for my TD06-20G/t3 upgrade.

It's driving me nuts I want to drive me car already.

 

[Dream On]

Change it to 37 psi with the vacuum line disconnected.

 

[DSMunknown]

^^ And make sure the fuel pressure gauge reads close to 43.5 PSI when the vacuum line is connected.

 

[Jst4Cyl]

Anyone know what a 255 hp should push out psi wise without the car running (just priming the system) Thanks Rich

P.S. I got about 20-25 psi

 

[gsxeclipse97]

Is it even able to idle ? My car doesnt even want to stay on.



I have a 255LHP Walbro and I'm using stock FPR, its for my TD06-20G/t3 upgrade.

It's driving me nuts I want to drive me car already.

hmm well that could be your problem you are using the stock fpr on a 255 pump. you need an after market fpr. you are clearly over powering the stock one you either need to get a new fpr or buy a 190 to use the stock one.

 

[tom04841]

^^ And make sure the fuel pressure gauge reads close to 43.5 PSI when the vacuum line is connected.

Please don't give mis-information.......with the vac line connected, fp should be around 30 psi, vac disconnected....37 psi. This is on a 1g

Even if it was a 2g, 43.5 psi with vac connected is too high.....it should be 43.5 with vac disconnected!!!!

Thanks and have a nice day!!!!

 

[kenamond]

So you had a kinda good tune on a 255 and stock fpr. This was overrunning the FPR. So fixing that problem by adding an AFPR just fixed your fpr overrun, but you're still using the same tune. My guess is you're running too lean now, as you're no longer overrunning the FPR. And I thought that 1g fuel pressure with vaccuum disconnected is 38psi, but that can easily be found with a bit of searching.

As a side question: With vaccuum connected, shouldn't it drop by the vaccuum you see on your boost gauge (~15psi lower = 23psi)?

 

[oldman]

1G is 37 psi, with vacuum line on, you should see 37 - (vac reading/2), if your vac is -18inHG, your fuel pressure should be 37-9 = 28psi. What is your vacuum reading at idle? What is the fuel pressure at idle with the vacuum line connected?

i start the car up and with the fpr vacuum line disconnected i set the fuel pressure to 40psi. i rev the car a bit and the response sucks, engine chokes up top and backfires quite a bit, compression is fine and the crank & camshaft timing are dead on. car wont really rev up until i keep tapping the pedel. what can this be ?

1. Did you re-attach the vacuum line when you revved it?

2. Did you tafflon both the vacuum fitting and adjustment rod? Did you test for boost/vacuum leaks yet? Fuel leaks?

3. Did you re-tuned your E-manage yet?

 

[DSMunknown]

Please don't give mis-information.......with the vac line connected, fp should be around 30 psi, vac disconnected....37 psi. This is on a 1g

Oh, nice catch. I was in "2G mode". Now I have to run outside and fix my AFPR, thanks to Bruce.

 

[thekellbeast]

2. Did you tafflon both the vacuum fitting and adjustment rod? Did you test for boost/vacuum leaks yet? Fuel leaks?

I'm sorry, but what's tafflon? Is it like teflon?

 

[oldman]

It's tougher than teflon.

 

[ShadeTreeDSM]

1G is 37 psi, with vacuum line on, you should see 37 - (vac reading/2), if your vac is -18inHG, your fuel pressure should be 37-9 = 28psi. What is your vacuum reading at idle?


1. Did you re-attach the vacuum line when you revved it?

2. Did you teflon both the vacuum fitting and adjustment rod?Did you test for boost/vacuum leaks yet? Fuel leaks?

3. Did you re-tuned your E-manage yet?

What is your vacuum reading at idle? after it warmed up it was about 30ish, i need to bump it up though

What is the fuel pressure at idle with the vacuum line connected? 30


1. Did you re-attach the vacuum line when you revved it? yes

2. Did you teflon both the vacuum fitting yes and adjustment rod? didnt know this needed teflon

Did you test for boost/vacuum leaks yet? Fuel leaks? no leaks

3. Did you re-tuned your E-manage yet?havent yet


but i did find the problem, i have MSD in the car and somehow one of the connectors came loose, luckily i found it, car runs good now !!

but what sucks is its leaking oil on the timing belt , seems to be it is my valve cover gasket, but the thing is every seal and gasket on this motor is brand new, i just rebuilt this engine and it only has 500 miles on it !!! when up at higher oil psi seems oil blows out of the valve cover, i think ill try and replace the valve cover gasket and hopefully that helps.