cvan1976

Hey Experts,

I recently purchased a second hand s2001. It has a Comptech Super Charger on the car. Well after dogging out the engine or driving it for along distance, I come up to a complete stop. My engine then starts to die (but it doesn't) as if it's not getting enough fuel.

When my engine goes into that "near death" experience, I pop my hood and check the fuel gage that the I had recently installed to measure the fuel pressure. I notice that the gage was jumping from 50-53psi. Normally, it's 30psi when you start the engine.

Also when I drive, I try to accelerate so that I can shift into the next gear. I don't feel the "boost" that I would normally feel. You can feel the engine drag. That alerts me that I will have the problem when I come to a complete stop, that my car will die or choke. Once it dies, I have to shift into 1st gear and start the engine. Right when my engine starts, I quickly apply tons of gas and take off before my engine chokes again.

Can anyone tell me if I have a bad FMU? Am I not getting fuel? Bad MAP Sensor? Is there any upgrades that I need to make? I do not have an intercooler on the car. Just dual apex exhuast, comptech sc and header.

I also read up on "Comptech SC bypass valve" by AUSs2000's article. It feels like I may have the same problem. xviper also try to help me out but I am accepting all kinds of help cause the place that installed the SC doesn't know the problem themself. They ordered me a new FMU from comptech but haven't installed it yet.

Please help a newbie....

AzNxKuKu

Wow, sorry to hear that. Hrmm... I really don't know what is wrong.. I am guessing maybe not enough fuel or maybe a surge of back pressure? I don't know how a supercharger really works.

cvan1976

The shop that installed adjusted the fuel pressure to 50psi and comptech told them that it's suppose to be at 30psi. So they readjusted it back.

AzNxKuKu

Hrmmm.... so my question is this does a supercharger has a surge of back pressure? Cause my friend's auto 94 TT Supra had an HKS SSQV BOV put on it and after he has the rev's up and idles it feels like his car is about to stall/ idle really hard. So I don't know if the supercharger can have a surge of back pressure.

02spas2k

maybe the 02 sensor i had a bad 02 sensor and it made my car run boggy. the car would not get out of its own way. just a suggestion

matt

CRX 18

Does the supercaharger use the stock fuel pressure regulator? If so it may be malfunctioning from the increased wear due to the high pressure fuel pump. That may cause the incresed fuel pressure you reported at idle. The excess fuel pressure at idle and low RPM's would cause the engine to flood making it sluggish and cause it to stall. If you have a buddy with an S2000 you could do a quick FPR swap to test it.
Just a thought, but I am by no means an expert.
Good luck

Slows2k

There are to many variables to accurately diagnose you problem.
I would suggest going over you wiring conections on the ESM. Unless, you have an early Comptech kit that does not have one, Then I would suggest getting an ESM. 50 psi of fuel pressure is not low enough to cause a power loss from lack of fuel. Go over the install directions to make sure nothing was missed. The foam Comptech air filters can be over oiled and cause running problems as well.

cvan1976

I don't have any knowledge about an after market fuel pressure regulator unless you are referring to the comptech Fuel Management Unit. I dont know to much about racing or the terms. But I would like to learn cause I love the ride. I just purchase the car cause it was a hot ride for a good price. Just my luck, I have these problems now.

The fuel gage tool i used to measure the fuel looks round with a needle that is installed on the engine (looks like those tire pressure gage). Nothing special about it. When I first start the car in idle, it reads 30psi. When it has that problem, it reads 50-53psi.

Slows2k: what is ESM? And do you plan to visit New Orleans or Biloxi, MS any time soon? Perhaps you can take a look at my car? I don't know what I have on my car...but I was told by the shop who installed the parts, say that my car run low 13s in a quater of a mile.

Thanks for all the feedback fellas.
Do any of y'all have AIM? Let me know, I would like to chat with yall. Mine is "CHUONG76". Feel free to message me....I need all the help I can get!

Slows2k

ESM is "electronic signal modifier" or a map signal clamp. The first comptech kits did not come with them. You can download the install instructions here www.comptechusa.com Did the car come with the blower, or did you have it installed?

AusS2000

From Joe Sierro at Comptech:
> The static fuel pressure 46-50psi and at 20" of vacuum is 30-34psi.
> You might want to turn it down a little. Thanks.

You set the static pressure by disconnecting and plugging the vacuum line (thin tube that connects to the FPR on the top/side) and setting to 46-50 whilst idling.

As mentioned by Slow, you should check to make sure you have an ESM rather than the check valve. The check valve was a dodgey mechanical device to hide boost from the ECU. The ESM is a more sophisticated electronic method. I believe the check valve sat between the throttle body and the MAP sensor. The ESM is connected to the ECU wiring beside the drivers foot.

All that said, it is also possible your problem is Intake Temperature. The ECU reacts very badly to increased intake temperature and pulls timing quite drastically.

I would recommend a tuning session after a hard drive. Just arrange some dyno time at a remote location and drive there pretty hard. If they can replicate the problem and have all the correct sensors on hand they should be able to pinpoint the real issue.