Went to the track...
checked the fuel pressure with the key on engine off and at idle. pressure is 40psi with the vacuum off 45 with it on. going to have to wait until later today so that someone can give it some gas to see if it drops.
okay so i'm trying to find out the source of my problem. i still need to check fuel pressure while giving the car gas. should have that checked out before the weekend is over. in the meantime i decided to take a look at my old opti just to see if it could reveal anything. so below are the pictures. i did notice three out of the ordinary things.
First it looks like one of the metal points looked weird:
Second the rotor was cracked:
Third there was some gunk or oil like substance on the rotor side cap as well as some discoloration on the other cap:
Are these trouble signs? Does it look like there was an issue. Currently I have an MSD unit on the car and I'm tempted to open it up as well.
First it looks like one of the metal points looked weird:
Second the rotor was cracked:
Third there was some gunk or oil like substance on the rotor side cap as well as some discoloration on the other cap:
Are these trouble signs? Does it look like there was an issue. Currently I have an MSD unit on the car and I'm tempted to open it up as well.
personally i don't know what the opti is "supposed" to look like, but that looks pretty nasty. I went with an opti from thepartsladi on ebay and it was pretty reasonably priced. but that's my .02
anybody else have any thoughts or comments on the condition of the old opti? looks like it was had some issues but the car didn't have any of the classic opti failure signs.
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So you are pinning you belief that this is a potent setup on one freak dyno run????
I see nothing about your build(not that you gave much info) that would suggest 450rwhp, that is a pretty lofty number for a hydraulic A4 car. Possible but everything would have to be perfect.
Bet the 370rwhp number is accurate. People these days think any randomly thrown together parts will meet or exceed 400rwhp and that is not the case.
I see nothing about your build(not that you gave much info) that would suggest 450rwhp, that is a pretty lofty number for a hydraulic A4 car. Possible but everything would have to be perfect.
Bet the 370rwhp number is accurate. People these days think any randomly thrown together parts will meet or exceed 400rwhp and that is not the case.
C_,
The old Opti looks like normal wear.
You need to verify your fuel pressure under a load @ wot.
If you are trying to check pressure it won't be accurate with the car stationary.
Can you hook the gauge up with some tubing so you can see it while driving?
Don't have any experience with the MSD opti.
Good luck.
Brad
Edit: It would seem that if you are commanding a richer mix than you are seeing on the wideband it would relate to a fuel issue.
The old Opti looks like normal wear.
You need to verify your fuel pressure under a load @ wot.
If you are trying to check pressure it won't be accurate with the car stationary.
Can you hook the gauge up with some tubing so you can see it while driving?
Don't have any experience with the MSD opti.
Good luck.
Brad
Edit: It would seem that if you are commanding a richer mix than you are seeing on the wideband it would relate to a fuel issue.
Last edited by bmax; Oct 4, 2009 at 11:52 AM.
So you are pinning you belief that this is a potent setup on one freak dyno run????
I see nothing about your build(not that you gave much info) that would suggest 450rwhp, that is a pretty lofty number for a hydraulic A4 car. Possible but everything would have to be perfect.
Bet the 370rwhp number is accurate. People these days think any randomly thrown together parts will meet or exceed 400rwhp and that is not the case.
I see nothing about your build(not that you gave much info) that would suggest 450rwhp, that is a pretty lofty number for a hydraulic A4 car. Possible but everything would have to be perfect.
Bet the 370rwhp number is accurate. People these days think any randomly thrown together parts will meet or exceed 400rwhp and that is not the case.
The FP @ idle seems a little low, IMO. It should be more like 43.5 or so, at idle, and with the vacuum line off, it should be a little higher, something like 45-47psi. Does the pressure bleed off on the gauge, when you shut the car off? Or shortly after you turn the key on to prime the system?
43.5 is minimum spec with the line off.
People make the mistake of blindly believing "upgrades" always add power. SSSOOOOOO many people make bad choices and endup not getting the upgrades they wanted.
If the dyno said 370 twice and 450 once then the 370 is accurate even if this setup should have been better.
All it takes is cheap pistons with thick parasitic ring packs and a mediocre bore job and all of a sudden a full build makes less power than a stock shortblock did.
People make the mistake of blindly believing "upgrades" always add power. SSSOOOOOO many people make bad choices and endup not getting the upgrades they wanted.
If the dyno said 370 twice and 450 once then the 370 is accurate even if this setup should have been better.
All it takes is cheap pistons with thick parasitic ring packs and a mediocre bore job and all of a sudden a full build makes less power than a stock shortblock did.
Mine was a little higher, due to a AFPR.
You could always put your fuel pressur gauge on, and zip-tie it to your wiper cowl, facing the windshield, then you could have a passenger watch it as you go down the road.
You could always put your fuel pressur gauge on, and zip-tie it to your wiper cowl, facing the windshield, then you could have a passenger watch it as you go down the road.
okay checked my fuel pressure. its dropping to about 30 psi under load. took the vacuum line of the aeromotive fpr and it was steady at 47. so i ust plugged the vacuum hose up and left it like that for now. anyone have any thoughts as to why with the vacuum line on its dropping like that while without it the pressure is steady?
the consensus seems to be that the bladder in the fuel pressure regulator is bad. will either buy a rebuild kit for the aeromotive unit on there now or just go back to the stock unit. funny thing though was that even with the vacuum hose plugged at WOT it was still running lean. either way hope to have this fixed with enough time to get back to the track and put down some better numbers.
i also ordered a digital fuel pressure gauge to monitor it just in case i change the regulator and the problem is still happening.
i also ordered a digital fuel pressure gauge to monitor it just in case i change the regulator and the problem is still happening.