CA18 Hitting Fuel Cut??

[HellFire]

Alright, I havn't faced this issue before.

We have a CA18DET swapped S13. FMIC, BOV, stock everything else. It does have a SAFC, but nothing is tuned in it. KA24E MAF.

If you get on it, it will hit what seems like fuel cut, at about 4k RPM's. If you slowly go up in the RPM's it will sputter, but make it up to redline.

We went through EVERYTHING. MAF, Ignitor, Coilpacks, Spark Plugs, Checked SAFC Wiring, TPS, Timing, FPR, Fuel Pump, Fuel Filter, No ECU Codes, Injectors.

Also compression tested. 165,175,170,170 warm.

Finally, we pulled the wastegate actuator, and stuck the wategate open. Went for a drive, and no issues. So the problem must lie with the Wastegate Actuator. Correct? We replaced it with another one, same issue.

There is no boost gauge on the car, so I do not know what boost it hits..

ANY other idea's? I've run out. I do not have a spare ECU or CAS, so I could not check those. But the car does get proper spark, so I would assume CAS is alright.

[themadscientist]

You need to get a boost gauge in there before you do anything else. You could be pushing 2 kilo for all you know.

[HellFire]

I know, but a stock CA18 shouldn't have this issue. What would cause over, or under boosting? The wastegate correct? And I've already replaced that.

There are no boost leaks, or anything of that nature.

[themadscientist]

the point is you are not sure and that assumption could result in a melted piston if you are wrong. A boost gauge IMO is a MUST for any turbo car. When my actuator hose popped off I knew it. I knew it first because all of the sudden the car went sideways in the turn with the sudden spike in power, 1.1 on ye ole S14 turbo.

When you stuck the wastegate open you reduced boost substantially but probably still had some boost. You may be overboosting but you don't know without a gauge. It sounds to me like lack of fuel. That could be caused by a bad regulator or a weak pump. When you reduced boost you also reduced the fuel demand and it smoothed out. You will never know that without a gauge either.

[scato]

tyler did you change it to a 255? cause the stock fuel pump wont handle very well upto 14psi i hear. Same issue Cullen had on his CA until i told him to get a walbro.

[HellFire]

Fuel pump has already been swapped, twice now. From the RB25 fuel pump, to 2 different walbro's. Same issue. I'm going to find a boost gauge today and see if I can figure the issue out. I'll post up if I do.

Tyler

[HellFire]

Ok, little update. Put a boost gauge on there. Good vacuum. 20. Cuts out right at 7psi every time. If I shift earlier then 7psi, no problems.

I'm going to go through everything in the fuel system again, and I'll update..

Tyler

[Ca_Silvia]

MAF, When my CA MAF went on me it was the same thing. Swap on known good one in and take it for a drive.

Or turn down the boost to 12psi and see if it get better. Untuned 14psi does sound good to me, im guessing if you didn't have a boost gauge you probably dont have a wide band?

[viperbite]

idk anything about ca's but i know that on the fb turbo2 rx7 there is a sputter issue at 4000 rpm aswell. just made me think of it.

basically the fix was grounds. apparently theres a ground that kinda erodes away on those motors. and it causes the sputter. i guess bad ignition at 4000 rpm due to some kind of ground loop issue. try manually grounding anything around the ignition area ecu and other random grounds. manually ground the head and maybe fuel rail.

just a suggestion...

[steer from the rear]

HI JUST WONDERED IF YOU FOUND PROBLEM WITH UR CA 18 AS MINES DOING THE EXACT SAME THING

[float_6969]

Um, yea, chill on the caps lock. Totally rude. Make a new post about your problem. If it's in caps I'll delete it.

[Sideways s12]

what is this fuel cut you speak of I have yet to see it I'm stock other than t25g (stock boost) tubular ex mani and 3 in. exhaust and I can got through the rev range with one hiccup at 7000rpm in 4th but I can rev all the way to 8k no problem....