http://www.brickboard.com/FORUMS/uid=46256 The Volvo owner's resource since 1997. en Copyright 1997-2009, Jarrod Stenberg Sun, 22 Nov 2009 13:27 GMT Sun, 22 Nov 2009 13:27 GMT brickadmin@denizen.net brickadmin@denizen.net volvo 1440 http://www.brickboard.com/images/logo_b_25.gif http://www.brickboard.com/ 25 25 The Volvo owner's resource since 1997. Well my son came to visit with his tools and his 740 and we fixed it!! I'd like to thanks Dave Stevens for his help because it turned out to be the throttle body after all. What I couldn't see until we pulled the throttle body off with my sons no.30 torx screw, was that the TPS was missing a lower screw and was maladjusted to the extent it was holding the throttle open slightly. It still functioned ok as a switch but Dave was right, this throttle has to be adjusted correctly. Thanks everyone for your help. http://www.brickboard.com/RWD/?id=1360374&rss=1 Fri, 17 Jul 2009 07:55 GMT I've given up on this very frustrating problem for the moment. I'll wait for my son to visit soon with his 740 so as I can swap parts and see if I can find the fault that way. I will keep the forum posted as I'm sure when I find the fault, the solution could be useful to others. http://www.brickboard.com/RWD/?id=1358346&rss=1 Mon, 6 Jul 2009 05:24 GMT Checked O2 sensor voltage at ECU pin 24 - varying between .3 and .7 volt at idle, no change here when engine jumps to high idle. AC on/off voltage is correct on ECU pin 14. Have tried three other ECUs - high idle fault persists. Throttle body - I cannot fault. Disconnected and plugged manifold, brake booster hose and aux vacuum hose - fault persists. I have observed that when the idle valve is plugged, idle drops to 600 rpm and then slowly rises to 900 rpm. is this normal? Is it the ECU compensating or is this telling me something? Thanks for all your suggestions so far. http://www.brickboard.com/RWD/?id=1358208&rss=1 Sun, 5 Jul 2009 04:53 GMT Dave, thanks for your massive input into my problem. I will check the throttle plate thoroughly tomorrow (its evening here in Australia at the moment) and I do have a new o2 sensor in the cupboard and I'll install that now that you have suggested it. But I'll do one thing at a time so as I can see which fixes the fault. Regards, Peter http://www.brickboard.com/RWD/?id=1358083&rss=1 Sat, 4 Jul 2009 09:13 GMT OK, I connected the CRO and started the engine. Idle speed ok. Square wave with about 60/40 mark/space ratio. 10 seconds later the mark/space ratio changes to 95/5 and the idle speed is up at 1600 rpm. Looks like something is telling the ECU to open the idle valve more. Checked the coolant sensor (again!) and is in spec. TPS ok. Swapped with two other ECUs and the fault persists. Darned if I know! http://www.brickboard.com/RWD/?id=1358078&rss=1 Sat, 4 Jul 2009 06:28 GMT Yes its a 16 valve. By chance I do have a CRT scope, I'll dig it out and put it on the idle valve as you suggest. I'll report back with my findings. http://www.brickboard.com/RWD/?id=1358050&rss=1 Sat, 4 Jul 2009 02:49 GMT Thanks for suggestions--- just went out and checked TPS and coolant temp sender as per FAQs and both were in spec. Beginning to think that new idle valve IS faulty! Still high idle. http://www.brickboard.com/RWD/?id=1357921&rss=1 Fri, 3 Jul 2009 05:15 GMT Persistent high idle - 1600rpm. I have bought a new idle control valve, made no difference. Disconnected valve and plugged pipes, idle drops to 600 rpm. Tested TPS, even at ECU connector, no fault,(shows low ohms, touch accelerator and goes high). On starting engine, idle speed correct for about 1 minute and then abruptly goes to 1600rpm and stays there. Does this consistently as if there is a timer controlling it somewhere. Could the new idle valve be faulty? (not a Bosch but a substitute 0280140516). Have performed test at pin 2 of test button and I can hear the idle valve clicking as it should. I have run out of ideas! http://www.brickboard.com/RWD/?id=1357755&rss=1 Thu, 2 Jul 2009 05:58 GMT Thanks for help, I've ordered a new switch but I'll check it on my bench jig before I install it. I suspect the gas might need topping up as well. Been over the system with a UV led and cannot find any leaks (there is UV dye in the system). http://www.brickboard.com/RWD/?id=1313689&rss=1 Wed, 12 Nov 2008 05:38 GMT Hi, I've been having strange problems (white smoke from vents, erratic cooling) with the air cond. on my 940GLE and have just discovered that some previous numbskull deliberately shorted out the wiring to the Pressure switch!. I removed the short and now the compressor is cycling on and off rapidly. I removed the switch from the accumulator onto the bench, tested it with an ohm meter and it is 'open'. I rigged up a test jig using an air compressor and the switch does not 'close' until the pressure reaches 41psi.I did a google on the switch (1259519) and eventually ascertained that it should be normally 'closed', 'open' at 21psi and 'close' again at 41psi. Has anyone any experience of the switch and can confirm that it should be normally 'closed' on the bench, ie at zero pressure? Thanks :) http://www.brickboard.com/RWD/?id=1313269&rss=1 Sun, 9 Nov 2008 05:14 GMT Use the text input below to search brickboard.com query http://www.brickboard.com/FIND/