Friday, April 28, 2006 - 08:55 pm, by: Khan Quach(Kayman)
I would like to commend you all on your parts in creating such a wealth of information!
Symptoms having only arisin after some work had been carried out, my V8 sounds as if it has some lumpy cams below 800rpm. All above 800rpm, it drives fine and smooth, apart from having to use the throttle to maintain idle. Having just spent the Easter holidays replacing shims(intake only needed via intake cam removal), cam cover gaskets and bolt washer/seals, rebuilding power steering pump, pulley bearings, dizzy caps and rotors, air filter, oil filter, Idle Air Control bearings. On reinstallation, I ensured all timing sequences of gears and belts went in the same through paint marking, photos and double checking through rotation that the cam and crank marks align, as I have previously changed the timing belt without any problems. I also readjusted the Throttle Position Sensor to specification as I suspect it may have been the cause of my idle problems after replacing grounding leads, IAC bearing replacement/clean, checking for vacuum leaks, regapped and clean plugs(NGK BKREP?? to 1.1mm) and new fuel pump ecu. I presume the car's running lean now on idle as is tends to heat up quick in "lumpy below 800rpm" mode whilst idling and gives off quite an intoxicating exhaust smell. No such heat problems on gentle drives around the block though. Prior to this Easter revamp, idle problems were never as rough as idle could fall to 350 - 400rpm before getting rough through manual adjustment of disconnected/desembodied IAC. I know this may be a highly variable matter, but any clues/ideas to what causes this kind of behaviour will be greatly appreciated as I'm losing the plot over these last 3 days and nights.
Friday, April 28, 2006 - 09:43 pm, by: Khan Quach(Kayman)
Indeed Peter! If the ecu was to be the problem, should any errors show through diagnostics? I don't have any EFI## codes showing at all through E1 & TE1. I shall see anyway with access to a spare this weekend.
Not always. Our resident electronics Guru - Mark Paddick has started to experience some issues with V8 ECu's as they age, capacitors going dud and things like that.
As it's a relatively easy thing to swap, well compared to swapping a crank, and providing you don't have any dodgy wiring attached to it (blush) then it would certainly be worth a try.
91 V8's have a thick foam base attached to the carpet which apart from proving better noise insulation than on TT's and late model V8's, also makes it a bit harder to work in the footwell when doing this little job.
If it doesn't make any difference, and if the donor ECU is known to be working right, then at least you can add something to the "tested" list
Don Bagnall Moderator New Zealand I have LESS Soarers than Hayden :-(
Sunday, April 30, 2006 - 09:40 pm, by: Khan Quach(Kayman)
Thanks Don I dearly hope so too!
After taking time to locate an ECU, I finally tracked one down. Prices varied from $250 to $330 for a second hand unit. The wrecking yard assured me it was out of a working halfcut. They both displayed the same part number only having different serial numbers. I was told that it was from a 93 UZZ31 as mine is a 91. On removal of my old ECU, I deassembled it.
In the second pic, circuit tracks leading around that little brown capacitor and chip seemed cooked. Hence maybe why the car wouldn't idle before. After changing the ECU, I found the Idle Control Valve and ECU were willing to co-operate as one, it now idles without having to resort to the throttle. The 2nd ECU also seemed to have a yellow plug restrictor in the middle plug as my original had it on the left side. Same amount of pins(40 of them), so I just removed it and the plugs fitted fine.
So Peter, one variable out(Another dud ECU maybe?), The idle is still somewhat rough, but not as rythmic as a lumpy cam. More so missing now. I removed the plugs to find that they were quite oily and fouled, which may suggest spark issues. Though I'd just changed most of the ignition system(dizzy caps, rotors, leads, fuel pump ECU, coils as new OEM items). Suspecting ignitors, but is this how it'd behave? When lifting throttle from idle of 800rpm to 1000rpm, something on the fuel rail seems to click making the engine slightly smoother(Still few a slight few misses though). I hooked up my stethescope to the vacuum regulator on the right bank listening off the top centre screw and found the click to most likely be that.
I find it also quite difficult to maintain the throttle between the 1000 - 1200rpm range as it'll jump to either end when that click occurs when varying throttle. I've run injector cleaner through 2 weeks prior to this overhaul, although this probably wouldn't neccesarily suggest that they still would be at 100% operating efficiency, they all clicked though through testing with the stethoscope and it idled smooth before this workover.
20 days of not driving my baby and I'm starting to really itch everywhere and withdrawal. Nightmares too!
Maybe the new ECU is faulty but that would be unlikely and unlucky too. The old one has one of the more common faults with that capacitor being leaky and corroding the surrounding tracks. I can fix that for you. This fault does often manifest as missing at idle and rough running at low revs. The other capacitors in the ECU will probably be starting to leak too. There were some changes in ECU over the years. I thought the major one was in 1994 so the ECU you are using should be fine. The plug restrictor thing makes me wonder though.... Perhaps you should check the new ECU for signs of the same leaky cap. ECU faults can be very hard to track down as the fault code are generated in the ECU. This means that the fault codes may be completely wrong or nonexistant. Quite often diagnostics will show a fault that is not correct because the ECU is faulty. Often you will get a code for the airflow meter when it is the ECU that is faulty; an expensive excercise as airflow meters are in the $500 region. My experience would point me in the direction of the idle speed control valve, they are painful things at the best of times with only the slightest spec of dirt causing them to stick. New bearings usually fixes them but it still doesn't take much to stop them working.
Tuesday, May 02, 2006 - 01:21 pm, by: Khan Quach(Kayman)
Oopsy guys! My mistake, no need to wonder about the plug restrictor, I removed the 2nd ECU to my surprise there were two more where they weren't before! They must've popped off the actual plug itself and swapped themselves over. Duh! By the way Peter, forgot to mention earlier, another excellent preliminary prognosis!, I would've never have guessed it to be the ECU, and yes, just noticed the wiring attached to have been tampered with sometime in its life, using those plastic crimp wire taps. Will check them though.
The new ECU has just been checked with no visual faults, although while attempting to do "Test Mode Diagnostics" using E1 and TE1 pins, the malfunction indicator lamp doesn't appear to flash to show test mode. So presuming there may be a circuit fault, I grounded TE1(Green/Yel) output from the ECU plug to bypass any possible open wiring, even trying to multimeter the malfunction indicator output(Blue/Yel), and still nothing. This "Test Mode" worked before the coil changeover 2 months ago. I hear Miles Baker had a similar problem on this? Anyone know whether that was ever resolved?
Will recheck the Idle Speed Control Valve Mark, although it has been cleaned rigorously many times finishing with a blast of compressed air. Also hooked up a timing light yesterday, and the flashes seemed inconsistent off some of the leads but regular on the others. Timing mark on the balancer also seemed quite jumpy at idle(Up to 10degrees back in forth from one flash to another). So I'll try what you have noted too Mathew. So many possibilities for the same cause. Cheers on your input guys, I shall keep you all posted.
Wednesday, May 03, 2006 - 11:03 am, by: Mark Paddick(Sparks)
Scotch locks are an evil curse, aren't they Peter?They can be soldered which makes them OK or ripped out, and the wires joined properly (solder, tape and cable ties....most people leave out the cable tie. This results in the tape eventually losing its' adhesion and falling off. It may take a few years but it WILL happen and then you have uninsulated bare wires. A cable tie around the taped connection is cheap insurance).
The timing variations sound like the root of the problem. The fan belt rubbing on the wiring is a common problem with the crank angle sensor.
Wednesday, May 03, 2006 - 06:07 pm, by: Khan Quach(Kayman)
Howdy Cihan, I've tried setting TPS as mentioned in the TPS maintenance thread and achieved the outputs at those throttle stop gaps, quite touchy to set though, trying also adjust through minute rotations using trial and error too. Both without much success of improving in a big way. I have restored it as specified in the meantime though, which seems to allow the best compromise for sudden throttle back-off without awkward stalling through its rough idle. Thanks for the thought though
I have also tested the Distributor Caps with an Ohmmeter to test for continuity together with light tapping/shaking to ensure any loose paths don't show their faults, they seem fine too.
However as you've mentioned Mark, if timing variations occur due to a problem with Crank Angle Sensor wiring, this seems to be a possible cause as timing variations occur at lower revs where most vibrational disturbance exists, whereas higher revs, the problem in my case seems to level out to a more acceptable manner. Yesterday night, I removed and cleaned the Crank Angle Sensor, following the wire back up, it seemed quite tight between the body of the A/C Compressor and Fan Pump/Cylinder Block, but nowhere near the Serpentine Belt which rules out chaffing. I may have lightly squished the sensor wires during the A/C compressor refit. However with both ends unplugged, I will check for short/openings in the wiring, although not too sure about the white wire as other ignition components seem to share this wire on the Wiring Diagram. I may also be thinking too hard about a single cause/problem But, an idea is always better than none. I'll see, hopefully... Appreciate your time guys! Thanks again.
Wednesday, May 03, 2006 - 10:14 pm, by: Khan Quach(Kayman)
Yes, tried that Peter. I've actually bought myself a spare to play with, chose best parts from both(ie. Least play, corrosion, etc) including new bearings and giving them a fastidious clean, light lube(WD40), anti seize spray and air blow. I've had a third one too to check resistance between pins and they've all come up the same as what's specified on the Planetsoarer page. It seemed obvious when the Idle Air Control didn't want to work few months ago when I'd take it out, give a quick spray with WD40, couple of turns of the magnet on the shaft to clear any particles and put it back in, to have it start straight away. Few days later it'd slowly seize up on start up again with change in idle control speed slow and unresponsive but rpm would work it's way down to 400 at some stages during a drive without much roughness at all. 350rpm would seem to be the point of roughness if it got there. I'd try to wiggle the steering wheel while parked and let the power steering pressure switch signal more power to the IAC to try and free it's stickyness and it'd work for the majority of the time until one day recently, it really seemed as if the IAC didn't want to work again. When I changed the ECU as you suggested, it's been controlling it's idle ever since every start, lifting to a rough 1000rpm down to rough 800 once warmed(approx. 3mins).
Probably totally unrelated but worth noting ....I had a similar problem recently with rough idle at 600/650 and I was having to put the transmission into Neutral at the stop lights to keep the revs up, but all was ok at higher revs. All this happened when I recently replaced my alternator. I disconnected a grey sensor plug going onto the bottom of the radiator left side (battery side) in order to get the alternator into position easily. The next evening I woke up in the middle of the night and remembered I had disconnected it. I reconnected it the next day and the engine idles " normal " again, no rough spots. So it maybe worth checking this connection / wiring.
Thursday, May 18, 2006 - 05:15 pm, by: Khan Quach(Kayman)
Thanks Blaine, I'll keep that one in mind for any further idle issues that may arise in the future.
Trying to remove the jammed Crank Angle Sensor wiring out, I cut it off for inspection, only to find that a crushed wire was not the problem, so having to resolder,re-sheild and reinsulate the wire, I smacked myself in the head for good measure.
However, as the absolute fuddy dud that I am, I've found the problem to be plain silly negligence. Thinking back through after a few long nights pondering, I wondered why the Exhaust Cam drive gears were split, which lead me to do some reading on it and ask around. "Split Helical Cam Drive Gears" they're called. Gears being in two sectional halves providing opposing cog teeth tension when mated to the Intake Cam drive gear to reduce noise and wear, ie. Play between both gears. One side of the split gear is fixed to the Camshaft whereas the other rotates to a degree under tension. Having being a silly billy, I'd marked the rotating side in reference to the intake cam. And when I had gone to put them back in, any kind of click or rotation on removal went unnoticed, the Split Gears had rotated three teeth out causing me to align with the wrong side of the gear. Having been oblivious to alignment marks on the other side of the gears facing the rear of the car until a second inspection. So feint they were too. The marks were out, which got me abit but at the same time. Finally a promising resolution I thought!
On reinstallation of everything, I cranked her up and then "Vrooooom!burble..burble..burble..burble". Ecstatic I was as the lumpiness in her throat had gone and smooth she greeted. Fifteen minutes later I'm test driving at a damn freezing 2am with a massive grin on my face frozen in. Smoothness that's nevered so impressed me until now. Mind it was quite deteriorated in the time that I've had it. The standing coin on roof, start up and rev to 4000rpm trick working too finally. Strange it didn't seem so bad when reving above 1200rpm with timing out, suppose adjustable cam gears(HKS adjustables, etc) rotate to a certain degree too to optimise certain ranges of valve timing for certain rev ranges. I should also thank Toyota for designing these as Non-Interference Valve/Piston setup(ie, Valves and Pistons don't act like they're in a mosh pit), else, bigger headache!
But oh well, having almost gone back to square one, I have learnt a hard lesson being so experimental with this car, whilst on the verge of just getting another one(yes I love em) if I'd not figured the problem. Anyhow, not a bolt or nut left orphanage, She's all A OK! So remember, Split Helical Cams!!!. And the ECU!! And get the Soarer Bible for this kind of work!
Cuz the old Sigma school of thought ain't ever the same if that's where you grew.
Thank you all for your time! I will keep them in mind for future references to similar problems.
Khan, You may have noticed a hole in the side of the tensioning gear ? You screw a 10mm bolt in through this hole to the other half of the gear to hold the gearset together. What you may have noticed when removing the cam's..that they *popped* up when you undid the holders ? The reason behind this setup is to stop the cams *chattering*.