coolant temp fault?

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01-02-2019, 10:48
Hugh Janus

coolant temp fault?

got a bit of a weird fault can anyone throw some light?

ok so the engine is an S15 SR.

From cold and allow the engine to warm gradually by driving slowly and after 20 mins of driving (slowly) if i suddenly put my foot down it'll splutter, lose power sound like its running on 3 cylinders i then lift off and coast for a few seconds and put my foot down again its absolutely fine.

i regularly go to a local jap meet, when at the end of the night means pulling out on to a busy road and having to put your foot down.

This happens EVERY time, i pull out and it splutters as outlined as above, again lift off or slow down its absolutely fine.

now the last time i went, we arrived with no issues (after a spirited drive) whatsoever parked up went inside for a drink came out maybe 2hrs later, started the car and sat there for around 15-20 mins chatting, so the engine was warm, again pulled out same thing happened.

the only thing i can think of is could a dodgy coolant temp sensor cause the effects above?

what i have noticed this doesn't happen if after 15 from cold (to allow coming up to temp) i kinda gradually allow boost to build for the first time the above doesn't happen
01-02-2019, 11:02
jj205mi16

I suppose buying a consult cable and watching the sensor operation would be the easiest way to check it.

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01-02-2019, 12:12
green_rs13

unplug it see if they fault changes.
the ecu calculates its own values if the sender is knackered. s15 will most likely be an s14a round plug one. conceptua do them for about £30
01-02-2019, 23:21
shikari chaos

Strange..
You checked fuel Pressure?

Electrical connectors? Maybe somethings loose, Such as CAS, coils, plugs, ECU, fuel pump, O2 sensor, main battery terminals or engine grounds etc.
02-02-2019, 01:07
Hugh Janus

Quote:

Originally Posted by shikari chaos

Strange..
You checked fuel Pressure?

Electrical connectors? Maybe somethings loose, Such as CAS, coils, plugs, ECU, fuel pump, O2 sensor, main battery terminals or engine grounds etc.

fuel pressure is fine (as far as i can tell) i have an inline gauge, the problem is it only happens once during a journey under exacting conditions, if something was loose id expect it to happen more frequently. as i say other than this it runs like an absolute dream
02-02-2019, 10:45
kingk

I've got a consult cable still if you want to see if it brings anything up?

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02-02-2019, 21:26
shikari chaos

So does it do it every time you initially accelerate hard?
e.g If accelerate hard, go back down to the same speed and accelerate the same again does it react the same?
If it “splutters” then spark.. On these cars, coils.
02-02-2019, 22:29
Hugh Janus

Quote:

Originally Posted by shikari chaos

So does it do it every time you initially accelerate hard?
e.g If accelerate hard, go back down to the same speed and accelerate the same again does it react the same?
If it “splutters” then spark.. On these cars, coils.

it only does it on first start on cold, i can go somewhere for 30> mins it'll be fine its just when the engine has cooled enough the problem comes back but again only for a few seconds. as for coils it would do it all the time, plus i have VAG conversion too

Quote:

Originally Posted by kingk

I've got a consult cable still if you want to see if it brings anything up?

Sent from my iPhone using Tapatalk

i have a cable already, ill have a look when it comes out of hibernation.
04-02-2019, 15:00
hooky

Could it be your wastegate sticking shut when cold and initially over-boosting and going lean? Or the over-boost causing the intake pipe to collapse?
Once the initial overboost has popped it open it stays free until cooled down again perhaps?
05-02-2019, 22:27
Hugh Janus

Quote:

Originally Posted by hooky

Could it be your wastegate sticking shut when cold and initially over-boosting and going lean? Or the over-boost causing the intake pipe to collapse?
Once the initial overboost has popped it open it stays free until cooled down again perhaps?

no it doesn't go lean at all, as for the intake...hard pipe.
06-02-2019, 09:00
R3K1355

How much is a sensor? like 20 quid or so?
Throw one in and see if it fixes the problem, original one has gotta be 20 years old now anyway.

I just did the same on my MX5, replaced both temperature sensors and the fan switch, only about a tenner each.
06-02-2019, 12:40
Hugh Janus

Quote:

Originally Posted by R3K1355

How much is a sensor? like 20 quid or so?
Throw one in and see if it fixes the problem, original one has gotta be 20 years old now anyway.

I just did the same on my MX5, replaced both temperature sensors and the fan switch, only about a tenner each.

yeah although finding the correct one can be problematic (from memory they are not the same as UK 200SX SR20's) and indeed i did have a new one laying about which i cannot find, yeah once she's out again ill do that.