Problem with cartech FMU

[hooper]

I got one of the Cartech 20005 FMUs on the group buy last month, and have been very pleased with it's performance. However, I just ran into a problem with it. I had it set to raise the FP to a certain max pressure under full throttle (~80psi), which worked very well. I recently changed my fuel filter from a K&N inline to a Paxton inline. The K&N was shot, and I needed more filtering capacity.
Now, the FP will rise to (at least) 100psi, even with the bleeder screw all the way out.
Logic would dictate that the filter would be the cause (and I plan to change it back to find out), but this one is actually less restrictive, plus the fact that it still works as it did before when not in boost (idle FP at ~25 and 0 vac FP at ~50).
What I need to know, is if there have been any others with any problems that may be similar. I think I remember somebody here had one that leaked, and had to take it apart to fix the diaphram, or something.
I'm trying to figure out if is the FMU itself, or something I've inadvertantly done.
Any info you guys might have would be helpful.


------------------
Phil
93 Civic, ENDYN-built D16Y7, ENDYN-modded JRSC, ENDYN/Thompson intake tube w/ cold air "bath tub", Bosch fuel pump, Kamikazi, test pipe, GReddy 2.25, J&S, MSD 6BTM, RC 310s, Field SFC, Clutchmasters stage 3 & aluminum flywheel, Quaife, Moroso oil separator

[NuSiEr]

It was me who had the problem with the Cartech. My problem was my fuel pressure wasn't dropping with the restrictor installed. I found that one of the seals on the Cartech wasn't aligned correctly causing a vacuum leak.

For your problem.. Did you install the restrictor? I would think you did since it was running fine before the filter change.

Somebody with more experience than me will have to jump in.

[lundgren]

Did you install the restrictor?

[hooper]

Yes. It worked fine until the fuel filter change. I've tried with and without the restrictor to see if that made any difference. I will try the other K&N filter again to see if that is, in fact, the problem. But I have to clean/replace the element first. But, I just can't see how it could make such a profound difference.

[JRCivic]

Hooper,

I have heard rumors about the difference in fuel filtration rates changing the peak fuel pressures of a rise rate regulator... however, I am a bit surprised that it did not change the fuel pressures ALL OVER. I would suggest swapping back to the K&N first to eliminate the possibility of that being the culprit... if there is no change, lets take a good hard look at the regulator then.

Jim


------------------



'93 Civic Si H/B with B18C1, JRSC @ 8psi
Best 1320: 12.68 at 110 mph

[JRCivic]

You wouldn't happen to have the check valve on backwards (inadvertantly of course) currently would you ???

I have seen a case where a guy took the small rubber hose off of the bleeder barb... and when it was re-installed, he placed it on backwards, thus pointing the check valve in the opposite direction.

Just a thought.


------------------



'93 Civic Si H/B with B18C1, JRSC @ 8psi
Best 1320: 12.68 at 110 mph

[hooper]

I plan to change the filters back to the way they were, now that I've got the replacement element for the K&N. The old filter was trashed. The Cartech FMU worked perfectly until the filter was changed. It's put together properly. I'll do some diagnosing today...

[hooper]

Update:
I re-installed the K&N filter. It made no difference. BTW, that particular filter had been on the car for maybe 2years with no trouble. I do not believe that the new filter is the cause of the problem. It was merely coincidence that this started at the same time. I have gotten a CEL code in addition to the high FPs. 43 (OBD1 "fuel supply problem")
Just to let you know, the entire fuel system has been changed from stock: Bosch pump plumbed with -06 line all the way to the engine bay. Paxton filter, fuel rail modded to fit -06 fittings, 370 RCs, no OE FP regulator, -04 return line to Cartech, and -04 line return line to the tank.
Again, any help is appreciated...
Phil

[waveoff]

Did you try resetting the ECU? There's been a couple of times that my car would act funky after a change. After an ECU reset everything would be back to normal. Perhaps your car is acting up because the ECU is using fuel flow parameters that were suited for the shot K&N. Just a thought.

------------------
Fred G.
'97 Civic EX supercharged http://www.geocities.com/motorcity/track/4059
Beech 1900D driver...2,558 shp, 10,000+ ft./lbs. tq., top speed 331 mph
THE MOST USEFUL LINK HERE...USE IT!!! http://www.hostboard.com/cgi-bin/sea...tro&default=40

[hooper]

That would make sense if the ECU controlled the fuel pressure, or at least had a fuel pressure sensor of some kind. When it throws the code 43, it knows something is wrong but not what. The manual describes the cause of that particular code as the "fuel supply system" (OBD1), which is everything from the pump,up, back to the pump. That's alot of stuff. There's not a leak. That would be easy to find. The manifold pressures haven't changed, according to the vac/boost guage. So, that's not it. The pump pumps like a MF. The filter(s) is(are) not the problem, the lines are clear, other wise the FP would be high all the time. It almost has to be the one mechanical device that varies the FP...the Cartech FMU. It does the same thing with, and without, the restrictor. Adjusting the bleeder valve has no affect, and the one-way valve on the bleeder seems to be working, and IS on properly.
The next test, is to change it back to the JR unit to see if that makes any difference. Of course it's going to raise the FP way high, because of the rate of rise. But it's the next logical step.
Oh, and did I mention that the Cartech pegs 100psi with only a moderate amount of manifold boost (~5 psi)?
Phil