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 Post subject: Any ideas? Now fixed!
PostPosted: Mon Jan 16, 2006 9:31 am 
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Joined: Mon Oct 24, 2005 10:04 am
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Location: Auckland, NZ
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Got everything baak together this morning (engine rebuild), filled up with the relevant lubricants etc and cranked the engine over with the fuel pump disconnected - oil pressure reached after a few cranks.
Then connected pump and fired up motor which started without any issues and then idled quite nicely. Let it run for a few minutes to get up to temp and then noticed water dripping down. Investigation showed seveal leaking hoses due to the cr@ppy OE hose clip. So, swapped out the coolant hose clips and pressure tested the system until no more leaks.
Started car up again (still warmish at this stage) and car refuses to idle and cuts out. Try again and same problem. Will still run with throttle open, so drive car up the road to get a WOF (MOT) and see if it'll sort itself out. No such luck. Runs even worse when you start to come onto boost.
Get car back to workshop for further investigation.
Only fault code which shows up is 54 - WAI system which is cleared. Then, Air Control Valve shows problem up on the diagnostic tool which is then cleared. Still no idle. TPS is checked and found to be out so is altered to correct setting, but still won't idle. Have checked to ensure all the plugs are attached and no obvious vac pipes etc left off.
By this time, motor is cold and when re-started, it seems to run fine. However, as soon as the temp starts to rise, the idle goes to pot once again. Ignition is spot on and good flow of fuel. Diagnostic sensor shows the 'mixture' reading as alternating between rich and lean. No more fault codes are coming up on either the diagnostic tool or the dashboard.
At this stage, I am completely stumped. Anyone have any ideas? :(
Cheers
Gary

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1994 Toyota Celica ST205 GT-Four Group A WRC - running in rebuilt engine....


Last edited by GT4WRC on Tue Jan 17, 2006 6:16 am, edited 1 time in total.

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 Post subject:
PostPosted: Mon Jan 16, 2006 11:46 am 
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Hi Gary

Not what you needed.

Have you tested the ecu water temp sensor for correct resistance/ temps, could also be air trapped in cooling system, especially in the sensor location?

Maybe worth testing the air intake temperature sensor

Surely, if any sensors are outside of the factory limit range, they should come up on diagnostic, or generate a fault code.

I know on occasions, on rebuilds, that the oil used on assembly gets on the plugs, sometimes after a short run period, oil burns onto the plugs, leaving a carbon deposit, or film, thus causing the spark to be all over the place which can lead to poor idle and general running problems.


What reading you get, when on idle for air intake pressure.

Yes the standard sprung OE hose clamps are pants, once removed, the bin is the only place for them…lol

Bet you wished you used jubilee clips 1st time round.

Hope you get to the bottom of it..

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 Post subject:
PostPosted: Mon Jan 16, 2006 12:08 pm 
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Joined: Thu Jul 14, 2005 12:44 pm
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Location: drinking devil fuel
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Could be the ECU coolant temp sensor is not properly connected or is fubar. I have seen this cause horrible problems where the car runs fine when cold and bag of spanners when warm

Although if the mixture is cycling (about every second or two??) between rich/lean then the ECU thinks the engine is over the real cold idle stage

It's the two wire sensor in the water elbow connected between the top radiator hose and the block

If this fails then I'd re-check the dizy/rotor then whip out the plugs for a visual in case that throws any light on the subject


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 Post subject:
PostPosted: Mon Jan 16, 2006 8:29 pm 
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Location: Sunny Fareham, UK
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Just a couple of thoughts in addition to the ones above...

The Throttle Position Sensor must be set correctly. The tolerances quoted to setup this gizmo have to be followed or weird stuff happens! Did you use a feeler gauge to set the TPS?

Fuel pressure regulator - is the vacuum/boost hose attached to it?

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 Post subject:
PostPosted: Mon Jan 16, 2006 11:29 pm 
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I agree with Kris, should leave the TPS alone unless you have already moved it.

You said you had a air control valve problem present its self and then you cleared it and changed the TPS position.

I would return the TPS to how it was and investigate the air control valve problem that your diagnostic machine showed up.

This may have something to do with the idle problem.

Temperature related faults are pointing towards NTC's.

Check them out.

HTH


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 Post subject:
PostPosted: Tue Jan 17, 2006 6:33 am 
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After much head scratching (or rather banging our heads against the wall :lol: ), the problem has been resolved.

Tried restarting the car first thing this morning, but it just didn't want to idle. So first thing was to whip the top cam cover off to ensure that the adjustable wheels hadn't moved. All good there. Next stop was the plugs. Pulled these out and they were all as black as a lump of soot. Hmmmm.
Put some new plugs in, fired it up and while it did run better, it still wouldn't idle - all seemed better when the revs were above around 2k. So we disconnected the map sensor and connected a vacuum pump and set it to 15mmHg and cranked the motor over. And it ran fine making us point the finger at a vacuum idle issue, possible cam related.
Rather than alter the cam timing which we knew was set up exactly as per HKS spec sheet (Inlet - 110 deg duration / Exhaust - 103 deg duration), it was decided to try altering the TPS again (previously set to factory setting). Doing this yielded an immediate result, the engine running much smoother, but still not happy under 1000rpm. So the ignition was advance by 14 degrees in total. With this done, the engine was much happier. However, blipping the throttle caused issues when the revs dropped usually resulting in a stall. To help prevent this, the throttle stop was altered to keep idle at 1000rpm.
Everything was put back together and the car taken for a spin round the block. Back to the workshop for a check of fluid levels before going out for a decent road test. No leaks were evident.
I'm pleased to say that there were no issues whatsoever. Car was extremely smooth all the way up to 5k and despite keeping away from full throttle openings, the motor felt very strong and eager to unleash a lot of torque - especially when the cams started to come into action.
It has been a very frustrating and tiresome period trying to get it running, but all is now well. Another 920kms to go before an oil change and then another 4k before the boost can be turned up. In the meantime, sensible driving and a trip to the dyno shortly to check that the fuelling is as it should be.
Gary

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1994 Toyota Celica ST205 GT-Four Group A WRC - running in rebuilt engine....


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 Post subject:
PostPosted: Tue Jan 17, 2006 2:43 pm 
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Location: Perth, Western Australia
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Phew!.....I bet that's a relief now its running. Just think, if it had fired up and run perfectly first time we wouldn't have found out all this interesting stuff (ducks for cover!)

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 Post subject:
PostPosted: Tue Jan 17, 2006 6:48 pm 
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Location: Auckland, NZ
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:lol:
While it was extremely frustrating at the time, at least some useful info, like you say was discovered :D

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Gary

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1994 Toyota Celica ST205 GT-Four Group A WRC - running in rebuilt engine....


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