Running too rich now?

[Tjn182]

I installed the Powerdyne RRFPR today when I was in Charlotte. I had it on full pressure and drove around and it felt just fine. The top end seemed a little smoother and there were no extra problems.

Yet on the way up to Boone I would start buckling (stuttering) when I would give it some gas(with boost) to accelerate up a hill.

Am I running more rich with the thinner mountain air? Should I turn it down?
The only problem is that the regulator sees boost through a bleed screw. When you back it out-- it vents air to the atmosphere. I backed it out a little and now I have some idling problems -- Yet the stuttering turned from long hesitations to short but many jolts.

TIA.

-Tj

[Craig -535i- Seattle]

I had something similar happen, the fuel pressure was way too high. Todd suggested turning down the FMU a lot, and that made it dissapear. Unfortunately I didn't have my fuel pressure gauge installed so didn't know what it was set too but whatever it was it was hydrolocking the injectors and making the engine buck like you describe.

Turn it down and see what happens.

[Justin in C'ville]

I don't know if the thin air is as much of a problem for you as the fact that you've been running to rich and your plugs may be getting fouled. i would pull one out and see what it looks like. what plugs are you running btw? get your hands on some W7DC (1.50 each from steve) they should help with any detonation you are getting from being alittle lean. then you can turn your fuel pressure back down a bit. What you really need to do is rig up a fuel pressure gauge, you could build one to work under the hood for about $10, at least you could figure out your base pressure (which is most likely the problem since you are fine under boost)

[Bill in MN]

Mine acted the same. I found it to be two issues.

At first I accidently had the input and output lines wrong to the FMU. It acted normally until the turbo got some load on it and ran like crap thereafter.

Secondly, I had the meter cranked up too high, same as Craig. Once I pulled my head out of my butt and got the connections right it still did the stuttering thing but nothing as severe. A few less lb. of pressure took care of the issue. It takes some hit and miss for sure.

Ditto on the meter issue. It's a must.

[Tjn182]

Well I'm back up in college now -- I guess I'll have to go buy a spark plug socket. I'm running the W6DC plugs right now. But you could be right -- It might just be fowling. It really only does it under boost.

I'll go get a check valve and open up that bleeder some more and see what happens.

[Tjn182]

Ok I went to advance auto and did some vacuum line work. I put the line to the RRFPR on the plenum chamber (it was on a charge pipe) after noticing on the boost gauge (which I've had connected to a charge pipe and the plenum chamber at seperate times) that on the charge pipe, I'll have boost when just giving a little bit of gas... which would increase fuel when I don't need it. Yet on the plenum chamber -- it only shows boost if I floor it... which is the only time I need extra fuel.

I took it for a spin and I riched out a little near redline.. so I'll back it down a little more. But otherwise I think I got it fixed.

Oh i also installed a check valve so the RRFPR only sees boost -- not vacuum (which would cause an air leak)

[Tjn182]

Well this past weekend I went down to my girlfriend's at the beach. I was able to put the RRFPR at full fuel and I had no rich problems -- the car pulled hard to redline.

When I got back to the mountains I had to back it out all the way and it's still running rich.

I guess elevation makes a big difference?


[Edit by Tjn182 on [TIME]1109267950[/TIME]]