Ca18det bogging/hesitating at full throttle

Discuss topics related to the CA18DE and CA18DET series engines.
smiLey240sx
Posts: 26
Joined: Tue Nov 15, 2011 10:19 pm
Car: 1989 Nissan 240sx ca18det

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Hey guys, I've been searching for problems that could be causing bogging or hesitation at full throttle, won't go past 5500 rpm. Couldn't seem to find anything that could fix the problem. I've got an ECU code, #34, knock sensor. I'm waiting for the shipment to come in this week. One day, my boyfriend disconnected the wastegate rod, and it didn't bog at all, and revved to redline with no problem. When just normal cruising, it drives beautifully. But can't seem to get it to it's full potential. We did a boost leak test, and no leaks. Please help!! :frown:

MY SETUP:
Ca18det
Walbro 255
Gti-r t28
370cc injectors
248/248 intake/exhaust cams
fmic
arc bov
Apexi safc2
aem wideband


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themadscientist
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Disconnecting the actuator rod probably dropped your boost dramatically as the door just swings freely dumping exhaust pressure. Reset your computer by disconnecting the battery for a few minutes. While that's happening look under the intake and make sure your knock sensor is connected.

smiLey240sx
Posts: 26
Joined: Tue Nov 15, 2011 10:19 pm
Car: 1989 Nissan 240sx ca18det

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The knock is connected. But the ECU is giving off a code for it. So i assumed it would be bad?

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themadscientist
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It could be. Did you try resetting the computer? You might have been knocking and tripped some computer save your a** feature. I'm not the stock ECU expert, though; boost cut was my bane.

smiLey240sx
Posts: 26
Joined: Tue Nov 15, 2011 10:19 pm
Car: 1989 Nissan 240sx ca18det

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I'll ask my bf to reset it tomorrow, thanks for the help. Hope it works. It does feel like boost cut/fuel cut.

smiLey240sx
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Car: 1989 Nissan 240sx ca18det

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Also, would you know what would be the result of a bad knock sensor? I read somewhere that it would be running really rich.

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themadscientist
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Just a hunch, but I would suspect the timing would get rolled back.

blownhemi
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Car: S13 200SX CA18DET HX35
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themadscientist wrote:Just a hunch, but I would suspect the timing would get rolled back.
That's right. According to the FSM, the factory ECU only pulls timing if it detects a knock condition.

Had a real similar problem last summer. Happened seemingly from one day to another, car would bog down 4200-4500-ish under high load. Both my boost gauge and AFR gauge was acting up, so I couldn't exactly tell if it was overboosting or not, or over/underfuelling. But it was definitely fuel cut, that kicked in.
We investigated some, and it turned out that the wastegage's diaphragm housing was leaking boost. Not much, but probably enough to cause overboosting. My builder fixed the leak with some teflon tape, that took care of the issue.

Did you look for boost leaks in that area, too?

smiLey240sx
Posts: 26
Joined: Tue Nov 15, 2011 10:19 pm
Car: 1989 Nissan 240sx ca18det

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No, i haven't. We'll take a look at it. Thanks, any advice helps.

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float_6969
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What boost pressure are you running on that turbo? It doesn't take much with the T28 to hit the factory boost cut. Maybe 12psi.

smiLey240sx
Posts: 26
Joined: Tue Nov 15, 2011 10:19 pm
Car: 1989 Nissan 240sx ca18det

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blownhemi wrote:
themadscientist wrote:Just a hunch, but I would suspect the timing would get rolled back.
That's right. According to the FSM, the factory ECU only pulls timing if it detects a knock condition.

Had a real similar problem last summer. Happened seemingly from one day to another, car would bog down 4200-4500-ish under high load. Both my boost gauge and AFR gauge was acting up, so I couldn't exactly tell if it was overboosting or not, or over/underfuelling. But it was definitely fuel cut, that kicked in.
We investigated some, and it turned out that the wastegage's diaphragm housing was leaking boost. Not much, but probably enough to cause overboosting. My builder fixed the leak with some teflon tape, that took care of the issue.

Did you look for boost leaks in that area, too?
I drove the car today and wot it bogged and what happen to you happen to me.
"car would bog down 4200-4500-ish under high load. Both my boost gauge and AFR gauge was acting up, so I couldn't exactly tell if it was overboosting or not, or over/underfuelling"

smiLey240sx
Posts: 26
Joined: Tue Nov 15, 2011 10:19 pm
Car: 1989 Nissan 240sx ca18det

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float_6969 wrote:What boost pressure are you running on that turbo? It doesn't take much with the T28 to hit the factory boost cut. Maybe 12psi.
Right now i don't know but my bf is going to test the wastegate pressure on the wastegate with a pressure gauge and see what psi its set on and i'll let you guys know. thanks guys

smiLey240sx
Posts: 26
Joined: Tue Nov 15, 2011 10:19 pm
Car: 1989 Nissan 240sx ca18det

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Hey guys, I found a boost leak on the throttle body where the TPS sensor bolts on. We're gonna try to get a new throttle body and see what happens.

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float_6969
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Thanks for the update, let us know what you figure out.

boostedgerman
Posts: 20
Joined: Tue Mar 08, 2011 3:58 pm
Car: 1989 200sx
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did you find what fixed the problem i having the same probem on my car

Sc0oByDo0RaCeR
Posts: 113
Joined: Fri Aug 19, 2011 3:40 pm
Car: 240sx s13- ca18det.

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It was a lot of things. You really have to go step by step. first thing you should check for boost leaks. We found that it was leaking from the manifold, like o rings, tb. That helped a little. and also, check your CAS and timing with a timing gun. It's bound to be one of those things. we had to go through all those problems and little by little it improved. Now it runs beautifully.

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s13drifter88
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T28 and its cutting at 5500, sounds like the MAF is reaching peak resolution. Wastegate unhooked it prob made very little boost which didnt peak the MAF so it didnt cause the issue to present itself. Wire up a Z32 MAF and use your SAFC to translate it, I had this same prob with an SR T25 at 14psi. MAF swap and SAFC-1 later and it pulled all the way out to red at 14lbs

Sc0oByDo0RaCeR
Posts: 113
Joined: Fri Aug 19, 2011 3:40 pm
Car: 240sx s13- ca18det.

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s13drifter88 wrote:T28 and its cutting at 5500, sounds like the MAF is reaching peak resolution. Wastegate unhooked it prob made very little boost which didnt peak the MAF so it didnt cause the issue to present itself. Wire up a Z32 MAF and use your SAFC to translate it, I had this same prob with an SR T25 at 14psi. MAF swap and SAFC-1 later and it pulled all the way out to red at 14lbs
true what he said. we end up getting a chip ecu and now the car runs perfect! lol.

Sc0oByDo0RaCeR
Posts: 113
Joined: Fri Aug 19, 2011 3:40 pm
Car: 240sx s13- ca18det.

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but you you still have to go step by step to get the car running right lol.

Sc0oByDo0RaCeR
Posts: 113
Joined: Fri Aug 19, 2011 3:40 pm
Car: 240sx s13- ca18det.

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like the last drift event me and my girl went to, the car just dies. i keep cranking the key and noting and the first thing that pops in my head is the cas. the lucky thing is that i had a spare one in my tool boxs at the pit and i ran to go get it and i even brough my timing gun with me because you never know when you need it , and guess what i needed it lol. put the cas in car started up, set the timing and went back in line to drift it again lol. that the ca owner life if you ask me never ending , but i love the motor once it run lol.

Sc0oByDo0RaCeR
Posts: 113
Joined: Fri Aug 19, 2011 3:40 pm
Car: 240sx s13- ca18det.

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Image

ill try to post some videos.

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harukisan
Posts: 46
Joined: Fri May 31, 2013 12:40 pm
Car: 1989 Nissan 240sx coupe right hand drive, sr20det and 1989 JDM Silvia Ks model w/CA18DET

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Sorry I can see this is an old post but I wanted to ask the question; someone said that they went to a chipped ECU. Id like to know what brand of chip was that?

Sc0oByDo0RaCeR
Posts: 113
Joined: Fri Aug 19, 2011 3:40 pm
Car: 240sx s13- ca18det.

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There a member here name srt4 something, I forgot his full s/n but he burn me a chip. But I did ran a apexi safc that you have to get the setting right, the in and out , thr for running bov so the car don't stall out.


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