Ca18 Stranded, problem with Throttle body?

[romolus]

##SOLVED##
Hi, I'm new to the forum, always wanted to join but never quiet gotten myself to do it. Well today I found my reason:

-The Situation:
I'm driving a 89 S13 with a CA18det that's had the turbo replaced with one from a 300z by it's last owner. I have the car since half a year now. It's always been idling pretty roughly and the boost is shutting off rapidly at high 3 to 5 grand under full load. If it's hot, it often doesn't start before a cooldown period and I had a silicone hose pop off once.
2 hours ago I was doing a little shakedown cruise for an upcoming journey and I was doing a pull in 3rd up to 6000 with just enough throttle to not have the boost shut off.

-The Happening:
At 6000rpm I felt something give... it didn't apply power anymore and I immediately put it in neutral. This happened to me once before on the motorway, so I coasted into a backroad where it was safe and kept it running for about 20 seconds to not risk seizing the turbo. I had to gas it (tipping the pedal about 20-30% or so in 1-3 second intervals) to keep it from dying. It ran very rough, similar to a rotary engine at low rpms.

-The Assessment:
I shut it off and opened the bonnet, looking for a silicone hose that would have popped off (like the last time on the motorway (Blue circle)). And there was one that in fact came off the back of the throttlebody this time (Red circle). So I put it back on and tightened the clamp down (had a few tools on me).
I also noticed that the plug for this sensor leading into the center of the throttlebody (Green circle) had come loose due to the plastic retainer having broken off at some point in it's life (it's been like that since I have the car and I haven't found a spare plug or loom yet, electrical tape always melts off and it tends to stay on). I checked it for debris and plugged it back in.

I then checked all the other connections and hoses and tried to start it again. It hesitantly, after 3 seconds of starter and only with a fair amount of gas started to "brap brap" to life again but would die whenever I left off the pedal. It would have barely had enough power to keep the car going but I don't think I could have possibly bruteforced it ti limp it home over any terrain, so I repeated checking for loose stuff, looked for any oil under the car and on the dipstick with uneventful results. I also unthreaded the sensor without knowing it's purpose(Green), there was a bolt similar to a tire valve that was springloaded and didn't look or feel damaged, tried to start it two more times after unplugging and reinserting plugs around the sparkplugs and everywhere else on the engine. It never changed anything and with nothing else to do but to drain the battery, which still had 12.5v, I subsequently hitchhiked home.

-The 2nd opinion:
The guy who's been nice enough to pick me up also gave it a brief look, claiming not to be an expert either and after I showed him the hose and the plug, he put his money on the throttle body running out of rhythm, which sounds sensical to me. He also said it wouldn't have sounded like it was only running on 3 cylinders, which makes sense in my opinion because of how it happened and what came off, again around the throttle body

-The Conclusion:
Sorry if this is getting long, but I didn't want to leave out any potentially important details. I was reading this thread earlier, https://www.sxoc.com/vbb/showthread....-Control-Valve but it's not quiet solving my problem.
I hope somebody can narrow it down, there's probably 3 key clues in here to pinpoint it, but I've clearly run out of talent there. I'm going to tow the car home, or to a workshop on Tuesday, depending on if I can't fix it myself by then.
Thanks very much for your time, guys and have a better weekend^^


in case Gdrive doesn't work

[pointz]

That plug isn't iacv its ficd which is there to raise revs when ac is on.
(It won't cause your issues)

What spec is the car?

Pressure test intercooler and all boost pipes, sounds much like a hose popped off or split.

If you have blown the hose off pcv (rear of inlet) I suspect your pcv has failed and is allowing boost pressure into breather system.
The pcv is a one way valve and allows air into the inlet not out.

I would properly clean all breathers, specifically the one from intake cam cover to block (under the inlet)
Inspect pcv to see if it is sealing.

And do a compression test.

Also search hss removal, hot start solenoid removal.

Do you need the charcoal can for emissions? Are you UK?
If you don't need it then I'd remove it as removing this and hss removes a whole lot of crappie vac lines and tidies up the bay.


Throttle body is very unlikely.

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[romolus]

I suspect your pcv has failed and is allowing boost pressure into breather system.
The pcv is a one way valve and allows air into the inlet not out.

Thanks for the reply, does that mean the valve is just in the wrong position or that I broke it and now probably need a replacement?

What spec is the car? - Do you need the charcoal can for emissions?

It's a German car (bought it in Ger and it came with a German user manual at least), Is charcoal can slang for catalytic converter? I'm really painfully green, I know. I think it should have a kat and that TÜV would be very angry with me if I hacked it out.

Also, do you mean this breather?



I just bought a compression tester (and new spark plugs) but I have no idea how I could compression test the intercooler without driving the car into a pond (I mean It's not running rn) I'm not supposed to just take off the air filter and blow into the intake till loosing consciousness, right??

Thanks a lot!

[pointz]

Well this is going to be a long one.

Do you have ac?

No charcoal canister is located behind slam panel to the right of radiator.

It is a one way valve, you should be able to blow through and not suck through. Take the hose off and blow/suck lol.


What is the spec of the car??


If you are able to blow 1bar of pressure and hold it crack on but no ideally you need a compressor and some bungs to block inlet pipe at throttle body at least

[romolus]

No ac, the cabin air isn't working overall, but according to my memory there is no condenser behind the radiator.
gotcha on the charcoal canister, my inspection is due in a few months and I'm gonna ask the inspector. I'd be happy to eliminate some of the vacuum lines.

Spec, I mean it's a 89 original 1.8 DET, it has electric windows and an open diff, manual 5speed, ABS. Originally had the seats with non modular headrests, No hicas chassis sn is JN100RS13U0008310 Hope that answers your question. Uhhh I don't think edm cars had the J,Q and K's designation, if that's what you want to hear, right?

I'm gonna hike down to my car tomorrow and do my dirty on the PCV Valve.
Thanks for your patience^^

[romolus]

I just remembered having a miata engine kicking around in my basement and figured I could double my chances both for success and catastrophic failure, so I nicked the PCV from that one. Maybe I'm lucky or 'll make it fit with some electrical tape. From my understanding it's an on/off type of deal so it should be fine.

[pointz]

I just remembered having a miata engine kicking around in my basement and figured I could double my chances both for success and catastrophic failure, so I nicked the PCV from that one. Maybe I'm lucky or 'll make it fit with some electrical tape. From my understanding it's an on/off type of deal so it should be fine.

The ca18det pcv is a threaded fitting in the rear of intake plenum that the breather hose connects

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[romolus]

Thank you VERY much, I just rescued my car. I managed to bridge the threaded gap with electrical tape, the old valve was a bit gunky and didn't work as direct as the one from the miata. I also found what was the actual issue. A... a boost leak. Yeah I missed a clamp before the intercooler, that was obstructed by the bumper. Gave the original valve a short clean with hot water and brake cleaner, back home and put it back in. Again, thanks a lot! Maybe this is the tipping point for me to learn what all these hoses actually do ^^

[pointz]

Thank you VERY much, I just rescued my car. I managed to bridge the threaded gap with electrical tape, the old valve was a bit gunky and didn't work as direct as the one from the miata. I also found what was the actual issue. A... a boost leak. Yeah I missed a clamp before the intercooler, that was obstructed by the bumper. Gave the original valve a short clean with hot water and brake cleaner, back home and put it back in. Again, thanks a lot! Maybe this is the tipping point for me to learn what all these hoses actually do ^^

Thats great but please may I suggest you look into cleaning all the breather hoses properly specifically the one at the back of inlet side cam cover that goes down into a hard pipe then to the block by oem oil filter location

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[romolus]

Will do. The one you wanted me to blow through was a bit oily, thought about replacing them anyways because the previous owner picked a tacky camouflage theme and I'll get some proper, uniform hose clamps while I'm at it.