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'90 740 GLE [ALL/1998] posted by Osamu on
Monday, 30 June 1997, at 6:55 a.m.
The my own volvo is 1990 740 GLE 16v Estate. ( i.e. the engine type is B234F 16v)
I have a trouble on the own car that the idling is not stable. So, the car is like as coughed.
Then, I have cleaned up the throttle bidy and replaced the fuel pump and it's relays. But, the car condition kept the before condition.
Does anyone have similar problems or suggestions of what the cure might be ?
Re: '90 740 GLE 16-Valve[ALL/1998] posted by Dave on
Tuesday, 1 July 1997, at 8:14 p.m.
My '89 740 16-valve similarly suffers from idling and stalling problems. The best I can achieve is temporary relief with one or more of the following techniques: a) using top grade fuel (94 RON), plus periodic use of an
injector cleaner additive b) using top grade spark plugs (NGK platinum), cleaned regularly c) cleaning the idle auxiliary air valve and throttle body d) disconnecting the battery to reset the computer e) avoiding stopping and starting the car with the A/C turned on.
I know many others have similar problems with their 16 valves. Anybody else got any experience or comments?
Volvo has Tech Service Bulletins that address these sorts of problems for the B230F and B230FT. The closest symptom match is where the LH 2.4 inj computer module ROMs were revised for use with the newer low volatility fuels, but no ROM upgrade is listed for the lower production B234F engine. Ref TSB's GR23-#26, GR28-#102, GR28-#105, GR37-#907 (from your dealer or available on the Popular Mechanics Volvo CD-ROM which you can order from www.ipdusa.com).
Re: '90 740 GLE 16-Valve[ALL/1998] posted by Robert on
Wednesday, 2 July 1997, at 9:22 p.m.
Dave, I have never been impressed with idle quality on B234 engines, but it should not stall. The throttle cleanliness is important but even more important is throttle adjustment. The throttle stop screw has to be adjusted correctly. The throttle swich has to also be adjusted correctly, (you should hear a click from it as you open the throttle slightly), and finally the link rod has to be adjusted correctly. The link rod can actually change lengths very slightly during temperature changes and throw off the other adjustments. This can create an intermittant problem. If the throttle switch does not close at idle, the idle valve will not work and you will not have idle compensation. These adjustments are best done by a qualified technician familiar with the process. It should not be very expensive. Another thing to check is the wiring connectors under the right side strut tower supports. I have seen a few where the idle valve wire was pulled out of its connector or just making poor contact. One other possibility, check the pcv hose. I have seen a few B234s with the pcv hose disconnected where it connects below the flame trap, causing a vac. leak.By the way, there are no E-prom upgrades for the B234. Good luck, Robert