Turbocharged Crx surges at low boost, can anyone h

[Crx 91]

I've asked alot of people of what could be wrong with it. So far nothing. I was hoping that maybe you guys or gals could help me out with this. Here's my setup 91 Crx, b18b motor, MSD fuel pump, vortech FPR, Fastrax t3/t4 turbo, spearco intercooler.

Now the problem is that when I am at low boost 1 to 4 psi the car starts to surge. but once it reaches 7 psi everything is fine. Even when I am dragracing. That is with the fuel pump on. Now if I turn off the fuel pump the car runs fine problem solved but I have a good chance of leaning out. I already changed the FPR, got a new but still I had the same problem. Do I have the FPR hooked up right? PLEASE help he out with this problem, nobody can seem to solve this problem that I am having. Thank you very much

Marc

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91 Crx
B18B turbo

[G3-TEG]

hmm interesting.. my friend turbocharged his 98 Jetta with the first production kit from GUDE...

his did the same thing.. ended up blowing the motor.. ouch.. not saying that yours will.. but umm not enough info..

describe the surging? what RPMS? whats it do?
fuel pressure? what injectors? ignition setup? what wastegate? please list what you got and what your running...

[Crx 91]

Thank you for responding. The surging is like back and forth. I can't really descibe it. At about 2000rpm to 3000rpms the surging happens. But once I am at 3000rpms or above the surging is gone. I am running stock injectors. The wastegate is from Turbonetics with the spring set at 7psi. The ingntion that I am running is MSD 6al with a Blaster 3 coil. I have a 95 b18b motor, Fastrax t3/t4 turbo, Msd fuel pump, Revhard manifold, sperco intercooler, 2 1/4 intercooler piping. Could it be the fuel pump? Maybe the I need a lower psi rated fuel pump. Remember this problem only occurs with the fuel pump on. Please help!!!!!

[plumvtec]

I would guess you are running overly rich at that low boost which is fouling the plugs causing it to surge. When you finally do get up into higher boost, the problem goes away because that is the required amount of fuel.

Do you have an Air/Fuel ratio gauge? Get one if you do not.

Do you have a variable rate fuel pressure regulator? Instead of running 10lbs fuel (off of baseline pressure) per lb of boost you can change the rate to a different ratio at higher boost.

basically your choking the engine with too much fuel at low boost.

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'96 JR6 GSR Sedan
'93 Honda CBR 900RR
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4Sale:New Holley 255 fuel pump kit
#12-906 (Integra/civic)
$200 shipped COD

[G3-TEG]

I agree with Plumvtec... do you or are you running a FPR of any kind? at 7psi, you should have one ar 6:1 or 12:1 Fuel pressure per psi of boost...

Too much fuel down low would have similar effects..

does it only happen at WOT? what about half throttle? are you at full boost from 2-3000rpms?

Whats your timing at?

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.99 GSR
.TO4e power
.Plate# V8 THIS
.ICQ# 27569229

[CROM]

You're running way to rich down low, happens all the time with turbo cars, you are leveling out in high RPM's because you are getting more air in the mixture and evening it all out! But down low you are running way to rich and bogging the hell out of the engine.....

[MarkC]

Describe your check valve setup Crx 91? Do you have a CEL coming on?

Mine acted exactly as you described when I was playing around with my MAP sensor/check valve setup the other day. I threw a code-3 and the car acted all crazy. Do you have an EGT? Because altho mine pulled good at full boost/WOT my EGT's went skyrocketing to past like 1000C!! Normally never gets above ~850C.

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Mark - Darth Boost - Turbo Mafia
98 Pearl Black GS-R, DRAG Gen. 3 Turbo
13.2 at 114MPH (GTech/Pro w/Drag Radials)

[Crx 91]

Thank you guys for replying. Yes I do have a A/F meter and it read at WOT rich, and when I am normaly driving around it reads rich. Yes I do have a 12:1 FPR by vortech. At 2000rpm to 3000rpm I am not at full boost, thats when I am just starting to just build boost. But once it reaches 5lbs and over the car runs fine. My timing is retarded 1 deg. below stock timing. I had these same effects even when my timing was at stock. Also I forget to tell that I am getting a code on my ecu. It is code 43 which is (fuel supply system), do know what that means. My map sensor setup for the check valves is fine because my ecu doesn't give me any map sensor codes. Again thank you for replying. Please respond back!!!

Marc

[plumvtec]

Well if we are barking up the right tree, I would suspect the O2 sensor(s) may be done if you are/were running too rich for lengthy periods.

I do not have my helms handy to look-up that code. Anyone?