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The mkiv Supra Owners Club

Solenoid click location


Ian C

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All,

Using a long extension bar as a stethescope I've narrowed down a click to, oddly, the fuel rail around injectors 3, 4 and 5. It's solenoid type click, it's audible at idle and you cause it by cracking the throttle open. I don't know what is causing the click as there aren't any VSVs or anything nearby!

 

I'm hunting this down as I'm STILL trying to get a stable liftoff-idle, and as this click every time I open the throttle and then when I close it the idle stumbles I want to investigate it. Especially as I've investigated everythign else ever on the bloody car. Anyway.

 

Try it yourselves if you want, I've found the the click is strong enough that you can feel it in the extension bar, never mind hear it. The fuel rail around injector 4 was strongest I found, and yet the cylinder head, manifold, intake runners, FPR, knock sensors etc etc weren't "connected" to the click, couldn't feel it at all. It's bizarre because the fuel rail has nowt but the injectors hanging off it (and I tried disconnecting 4, 5, and 6 in turn and the click remained). Any clues? It would also be good to hear if there actually is a click or not on other people's cars :)

 

There is mention of something called an APIC VSV around that area in the component locations part of the electrical manual but I've no idea what that is or if it's even on a jspec.

 

-Ian

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First off it's an ACIS VSV, dunno where I got APIC from :)

 

Dude - no, I haven't, do they let you narrow the location down a lot? The click is strong enough to feel in the extension bar, I don't even bother listening, so would a det can be any better? Thanks for the offer btw, much appreciated - this problem is driving me nuts :)

 

Matt - the MAP sensor is plumbed in fine, one Apexi unit is tapped into it's signal and it shows what it's supposed to show. Car is now running great apart from the lift off, I doubt it would with a bad MAP sensor :) I swapped in another one anyway and checked the connection a fiar few times, ho hum.

 

The symptoms now are - poor idle with clattery noises when cold, and a large amount of overfuelling (or under-airing). Good idle when warmed up. Lifting off throttle while driving in-gear can result in intermittent excessive engine braking, you know, the sort of slight jolty-chuggy sensation as the engine misses a beat and the drivetrain keeps it going. Lifting off throttle out of gear has the revs drop below 500rpm and it either recovers or doesn't - usually it does but it's not pretty. Seems to me whatever controls the off-throttle loop is buggered in some way - wasn't there an ECU strategy specialist on this BBS?

 

Ooh - one other thing I noticed was that first start from cold it works *perfectly* for a few seconds - 1100rpm, no noises, nice and smooth, and then it goes downhill over about 5-10 seconds to 650rpm and missing and overfuelling. I know the HEGO sensor needs to heat up, if that also only takes a few seconds I suppose it could be that (especially with overfuelling) but I tried Brian Duff's fairly new CW supplied one and it didn't make any difference? Should I try another? Does this sound like a bad O2 sensor problem?

 

This problem has driven me to the desperate attempt of going to see the local Toyota garage tomorrow :eek: This is to see if they have a big fat diagnostics machine that will plug into the diag socket and tell me a sensor is giving spurious readings or something.

 

The click is intriguing, especially as you don't have one Matt. It's really bizarre. May be a red herring though...

 

Thanks for sticking with this guys :) Sorry it's a long post but it's gotta be better than "My engine goes funny what's wrong" style posts :D

 

-Ian

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sounds like idle air control problem,lost or corrupted signal to ecu

could be any of the following sensors; water temp,rpm signal,throttle position sensor,air con clutch,brake light s/w

you could measure resistances from ecu to sensors but this would

be a pain to do and require a warm engine,plus figures to compare ,probably best get toyota dealers to plug in diagnostic

unit. do air con and brake lights work properly? hth

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Dude - no, I haven't, do they let you narrow the location down a lot? The click is strong enough to feel in the extension bar, I don't even bother listening, so would a det can be any better? Thanks for the offer btw, much appreciated - this problem is driving me nuts

 

You wont believe what you hear thru them , in fact you wont wanna hear what you are hearing thru them !!!

 

Dude:flame Dev

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the hoe2 :) sensor is pretty well covered by fault codes. do u have any stored? the o2 sensor may b fine it might b the heater circuit thats funny.

 

yr gonna have to watch any signals that affect fueling during that transition from fine to crap.

 

i dont have a click neither, just the rythmic injector ticks.

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Guest Terry S

Ian with the electronic Det cans you get say 4 x channels. Each channel can have a crocodile clip attached, so you place them at various places the flick through to try and Isolate the problem. They are very handy, and the ones I have come with a directional mic that has an extension that will go into the dip stick hole! You are always welcome to borrow them.

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Originally posted by jagman

sounds like idle air control problem,lost or corrupted signal to ecu

could be any of the following sensors; water temp,rpm signal,throttle position sensor,air con clutch,brake light s/w

you could measure resistances from ecu to sensors but this would

be a pain to do and require a warm engine,plus figures to compare ,probably best get toyota dealers to plug in diagnostic

unit. do air con and brake lights work properly? hth

 

What I've done so far:

I've swapped the IACV and the MAP sensor out, as well as cleaned the IACV with brake cleaner. I've cleaned out the throttle body.

Swapped out the O2 sensor with one off another car.

The TPS gives a rising resistance as it opens and the idle switch mechanism works. It also reports percentages to the Apexi AFC.

Water temp sensor reports the correct resistance on a cold engine.

Apexi units report the revs correctly.

Brake lights work as I've seen them light up stuff behind me at night.

Idle speed goes up if I switch on the rear heater, aircon, and/or lights, so that loop is working.

Changed spark plugs - twice.

Checked all hoses, even replaced a split one.

Checked all fuses

No check engine light comes on, no codes are stored.

 

I spoke to the local Toyota today and the bloke there was reasonably helpful. He seemed to think that if the O2 sensor went wrong it would store a fault code, I tried to explain to him that the manual says it's only under certain circumstances like a short that it logs a fault, and that Brian Duff had his go and thus failed emissions tests yet nothing was logged, but he wouldn't have it. However, he gave me the card of a guy who is in tomorrow that is their ECU wizard, so I'm gonna persuade him to hook the car up to the diagnostics just to check all the sensor outputs I can.

 

And I'll ask him about the mystery click :)

 

-Ian

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