4 replies to this topic

[garrmark]

Hey folks, last year I started road racing with an 1984 ITC civic hb. Everything I read said buying a racecar is the way to go. So I, in my ultimate wisdom decided to build my own. Now I know for sure that buying a race car would have been the way to go.

Anyway, maybe someone can help me diagnose a motor problem I'm having. It has to do with the engine cutting out coming out of a corner, doesn't seem to matter whether it a left hand or right hand turn. It pulls pretty well at low RPM coming out, but once I get to mid RPM it falls over. It takes a probably two or three seconds to fire back up and get going again.

I had a Weber 32/36 and then went to a race prepped Honda carb, both exhibit this problem. I tried adjusting the float level on the honda carb, but that didn't seem to help. The motor bottom end has been freshened. The top end was given to me by another racer, he said it had about 10 hours on it since rebuilt. The carb was also given to me by the same racer, but I'm not sure what state it's in (It looks clean).

Are there other carb adjustments that might help? Should I look at an aftermarket fuel pump? Anybody, got any ideas?

[pmpicci]

I don't know the regs for ITC, but an electric fuel pump and adjustable fpr would be very useful to you for improving the performance of your car. Check your rulebook, though. As for your fuel supply problem, what sort of condition are your fuel filters (front and rear) in? The carb fuel tank is not baffled, and the fuel sloshing around could be your problem if you don't run with a full or semi-full tank. Just some ideas.

[Greg Gauper]

Before I converted to G-Production, I ran an ITC Civic (and an 84 CRX before that). I went thru all sorts of gymnastics to get a Weber 34DMTR to work and never completely liked the response and had issues with cutting out in left hand corners. I went thru every thing (float settings, FPR adjustments....everything!!!!!) Prior to that I ran a stock carb modified for IT rules (remove all the pollution controls & choke stuff). It ran fine for years so I sold the Weber to somebody that wanted a spare (and knows how to swear in Italian, I guess ) and went back to stock. After several years of trouble-free operation I started to have problems with it cutting out in left hand corners. The inside was clean. I sent it out to Rivergate to see if they could check it out. They cleaned and rebuilt it and put a new float needle and seat, but I had the same problem, no matter where I set the float height. Finally got ticked off at how bad I was running in a few races and so I broke down and bought a brand $panking new OEM carb. Not cheap (and thank god for my racer's discount!!!) I bolted it on and set the float to the stock settings and it ran great right out of the box. This was with the stock tank and stock fuel pump. I suspect that over time time, something in those carb's gets gunked up, or one of those teeny-tiny orifices gets plugged or knocked out of alignment....or something. A friend of mine who used to work at a Honda dealership indicated that they routinely tossed out worn out carbs and put new ones to cure weird problems after the cars were 3-4 years old, rather than try and fix the old carbs. The first two races that I ran as a G-prod, I still ran with the stock head and carb so I could focus on getting used to running on slicks vs DOT tires. The car had no problems in the corners with the higher cornering loads.

And yes, IT rules do allow you to install an electric fuel pump in place of the stock mechanical pump and add a reegulator, but the stock pump should work fine....though it might have slightly too much pressure for a Weber in which case a low-pressure FPR (like a Holley unit) set for about 2 to 2.5 psi is recommended.

That said, there are two things to try...

You can get a new float with a new needle and seat.

You can get a new power valve. This is the little thingy that sits in the bottom of the float bowl with the small pin sticking out. It has an 8mm hex body so you can use an 8mm socket to remove the old valve. It has a small o-ring on the base.

You can spray everything down inside with carb cleaner. Use new gaskets when you put everything back together.

Check the filters. Here's a tip...relocate the rear filter to the engine compartment and install it in the section of hose that feeds the pump. This way you can inspect and service it easier than the stock location. If your tank is old and rusty, you could have issues with the little 'sock' that fits over the end of the pick-up getting clogged, but generally that problem and plugged filters show up everywhere...on the straights and in the corners. I found I could run my stock tank pretty low (less than a 1/4 tank) and it still picked up the fuel just fine. This isn't the case with the FI motors. They had issues with pick-up and you had to run with a heavier fuel load to prevent starving in the corners.

Lastly....do you still have the PCV valve hooked up to the intake manifold? I spent half a season chasing down a seperate weird problem that I thought was carb related. Turns out that as I got the car to handle better, I was pulling higher g's in the corners, causing the oil to get sloshed around in the pan. This was getting sucked up into the PCV valve and dumped back into the intake. The simple fix was to plug the intake and route the hose from the PCV valve into my catch tank and all was well. Like I said, it was a weird problem....

Edited by Greg Gauper, 21 December 2004 - 02:52 PM.

[Doodson]

HHMMM ? Ive got to agree that its the CARB and not the tank or pump.
I had that problem but managed to cure it by playing with the float bowl adjustment, But Im talking a canadian carb which is a little different.
Because I was holding the carb wide open -It would drain the bowl down enough that in the corner the car would sputter.

[garrmark]

Thanks for the input guys, I'll keep looking at the carb, I've got four carbs to play with (One weber, one stock, and two race prepped stock). Maybe I'll put the stock one back on first as I never had problems with it.