Author Topic: help: ka24 e corsair surges under 3krpm  (Read 6917 times)

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Offline crazy2287

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help: ka24 e corsair surges under 3krpm
« on: Aug 29, 2011, 09:00AM »
Greetings.
I have a 89 ford corsair with the ka24 engine. Under 3k rpm it surges slightly.
From my experience i would suspect the ego sensor. The surge has the charactistics of a closed loop ego screwup. As soon as you want power or run above 3k the circuit openloops and problem gos away. Under 3k at cruise it reduces power of the car a bit. If i hook up my exhaust sniffer the fuel mix varies around staoch (14.7:1)
The engs just come out of a rebuild. The problem existed before the rebuild. Its definetly an ecu or sensor issue?
Have changed the ego sensor with a second hand one. Problem remained. No guarentee if the replacement sensor was serviceable though.
 Any ideas guys? Anyone had experience with this on these cars?
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Offline Pure_Sincerity

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Re: help: ka24 e corsair surges under 3krpm
« Reply #1 on: Aug 29, 2011, 12:04PM »
I've heard bad swirl control valves can make your car run like a dog under 3k rpm.
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Offline crazy2287

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Re: help: ka24 e corsair surges under 3krpm
« Reply #2 on: Aug 29, 2011, 09:02PM »
Nah, It's running a different intake manifold from when it originally started surging. Cheers though.

Anyone know where i can find the diagnostics bridge plug? Reading the manual here. It's the plug you insert the shorting link in to bring the ecu into diagnostics mode. have NFi where this plug is?
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Offline Kranzy

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Re: help: ka24 e corsair surges under 3krpm
« Reply #3 on: Aug 29, 2011, 09:14PM »
In behind the centre console. Where are you located?
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Offline FuzzyDropbear

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Re: help: ka24 e corsair surges under 3krpm
« Reply #4 on: Aug 29, 2011, 10:58PM »
Hey mate, if you're running a KA you'll never find the bridging plug, cause there is none.

ES-119 of the FSM will show you how to get the computer into diagnostic mode, you just have to turn the little selector on the side of the ECU.

Cheers.
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Offline crazy2287

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Re: help: ka24 e corsair surges under 3krpm
« Reply #5 on: Aug 30, 2011, 04:49PM »
Kranzy: Yeah i found the 16 pin (6 populated) header in the center console last night but couldn't initiate diagnostics form it.
I'm at The southcoast

Fuzzy: Thanks for the reference!!! Spot on, I'll go out and see what i can do with it now, this might really help me find the surging issue.
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Offline crazy2287

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Re: help: ka24 e corsair surges under 3krpm
« Reply #6 on: Aug 30, 2011, 09:06PM »
No go, the computer was error free and the o2 sensor was operating within limits. When i disconnect the o2 sensor the hunting/surging stops so im till thinking the o2 sensor is out of cal. i guess i wont know for certain until i put a brand new one on there.
re-gapped the plugs and it's taken the miss out. checked timing, Its about 19BTDC (where i purposely set it) and idle is good. starts eazy and god pretty quick if i put the foot down. It's just that cruise area where it surges a bit and lacks power.

Any ideas guys?

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Offline Burga

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Re: help: ka24 e corsair surges under 3krpm
« Reply #7 on: Aug 31, 2011, 08:31PM »
No go, the computer was error free and the o2 sensor was operating within limits. When i disconnect the o2 sensor the hunting/surging stops so im till thinking the o2 sensor is out of cal. i guess i wont know for certain until i put a brand new one on there.
re-gapped the plugs and it's taken the miss out. checked timing, Its about 19BTDC (where i purposely set it) and idle is good. starts eazy and god pretty quick if i put the foot down. It's just that cruise area where it surges a bit and lacks power.

Any ideas guys?



Fuel pump, fuel pressure regulator, or possibly air leak. Are you chewing up the fuel too?


Offline crazy2287

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Re: help: ka24 e corsair surges under 3krpm
« Reply #8 on: Aug 31, 2011, 11:30PM »
Hmm maby air leak. have checked but i guess i should have a realllyyyy good check. whatever it is its still there after an engine remove and install.
Maby a fluctuating fuel pressure but it stops above 3000rpm and dose not stutter when i give it the balls right up to 6k
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Offline Burga

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Re: help: ka24 e corsair surges under 3krpm
« Reply #9 on: Sep 1, 2011, 09:22PM »
Hmm maby air leak. have checked but i guess i should have a realllyyyy good check. whatever it is its still there after an engine remove and install.
Maby a fluctuating fuel pressure but it stops above 3000rpm and dose not stutter when i give it the balls right up to 6k

I have the same thing going on. Haven't had the time to go through some checks yet tho, but it's most likely one of those 3 things.

Hit 3K and there's no probs.. only getting 130 km/half tank, too :(

Offline Cheezel

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Re: help: ka24 e corsair surges under 3krpm
« Reply #10 on: Sep 1, 2011, 11:03PM »
My car has absolutely no guts before 3k. Wanna trade? :P

Offline Cheezel

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Re: help: ka24 e corsair surges under 3krpm
« Reply #11 on: Sep 3, 2011, 12:09AM »
My car has absolutely no guts before 3k. Wanna trade? :P
Well shit. Jinxed this, didn't I. Developed a surge. And a whine from the fuel pump. Guessing a dead fuel pump? It's about 70,000km old anyhow, so it's time for a new one regardless. FYI for anyone else..

Edit: LOL! 11 hours since posting this. Exactly.

Offline crazy2287

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Re: help: ka24 e corsair surges under 3krpm
« Reply #12 on: Sep 3, 2011, 11:36AM »
Had a good look for vacuum leaks. I found a crack in the pipe between the rocker cover and the intake tube. replaced. No change though, I guess it's on the wrong side of the butterfly so there's bugger all vac on that pipe and i doubt it would be moving enough air to throw the mixture out. MAF setups are shit, MAP based all the way. If i was serious about keeping the car i would probably but a MS ecu on it and make it MAP based.

Here's something that stumped me, the engine is not maintained at a vaccume (im assuming that's just how the ka24 is). When i pull the oil filler cap off it [language filter smackdown] out air which i would usually assume is blow-by. But the mean average of the movement of air actually produces a vacuum if i block the hole with my hand... Normally id just say the rings are shot but would it really draw more past the rings then gets blown past?

ill be having another look at it today anyway.

Good luck with your fuel pump issue!
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Offline crazy2287

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Re: help: ka24 e corsair surges under 3krpm
« Reply #13 on: Sep 5, 2011, 01:09PM »
Disconnected the EGO sensor and the surging has stopped. Going to drive it a bit and see how the fuel usage is. Will prolly fit the EGO sniffer today or tomorrow and check mixtures.
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Offline Burga

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Re: help: ka24 e corsair surges under 3krpm
« Reply #14 on: Sep 6, 2011, 08:45PM »
Disconnected the EGO sensor and the surging has stopped. Going to drive it a bit and see how the fuel usage is. Will prolly fit the EGO sniffer today or tomorrow and check mixtures.

Any luck working out your issue?

Offline crazy2287

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Re: help: ka24 e corsair surges under 3krpm
« Reply #15 on: Sep 7, 2011, 12:30AM »
not yet, didn't have the car today. will update tomorrow after i get the o2 sensor on and check the mixtures.
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Offline crazy2287

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Re: help: ka24 e corsair surges under 3krpm
« Reply #16 on: Sep 8, 2011, 12:14AM »
hooked up the sniffer with the ego sensor disconnected. Mixtures were 14.5-15.5:1 at cruise below 3000rpm.
light acceleration above 3000rpm ~13-14:1
~12:1 at WOT.
0-100 in 8 sec flat.

All sounds normal to me. It's seems to be only when the o2 sensor is connected so i'll try a different oxygen sensor and see how that helps at some point.

Whats typical fuel usage for these. I'll try and monitor fuel usage and see if it's within the average. highway would be the preferred value if anyone's worked it out here before.
« Last Edit: Sep 8, 2011, 12:16AM by crazy2287 »
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Offline Cheezel

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Re: help: ka24 e corsair surges under 3krpm
« Reply #17 on: Sep 8, 2011, 08:35AM »
10L/100kms is fairly average for our cars. Factory specs claim 6L, but i dont know if anyone has actually got that.

Offline crazy2287

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Re: help: ka24 e corsair surges under 3krpm
« Reply #18 on: Sep 8, 2011, 01:36PM »
Thanks Cheez. ^.^
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Offline crazy2287

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Re: help: ka24 e corsair surges under 3krpm
« Reply #19 on: Oct 2, 2011, 01:03AM »
o on highway was getting about 10ltr per 100k. all good.
I also paid a bit more attention to the swirl control system and noticed it wasn't functioning.

Was also going over the pneumatic solenoids. i know they were the same way as when i pulled them off during engine r+i as i labeled them on removal. But i noticed a lot of them were cracking around the ends. The hose was cheap so i got a meter and a half, printed out the assy diagram for the solenoids from the FSM, pulled all the hoses off and redid them in new hose as per the manual. I noticed when i was refitting them i put a couple back in different locations... Dah.
Took me this long to find it, Looser. Whoever said SCV you are winrar.
Reconnected the EGO sensor and the surging is gone. It runs better and the SCV works now. I think the SCV and the fuel pressure reg may have been mixed up? dosent explain why it only surged when ego was plugged in but whatever. It's going now.
I drive like i screw..... illegally =D... wait O.o WHAT?? O.O