"whatuptkhere" (whatuptkhere)
03/07/2018 at 15:34 • Filed to: Volvo, Auto, Horns, Horn, Fuel, fuel system
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"whatuptkhere" (whatuptkhere)
03/07/2018 at 15:34 • Filed to: Volvo, Auto, Horns, Horn, Fuel, fuel system | 2
| 18 |
The 740 Turbo is a big ol’ wagon, but it’s gone from using 11 L/100km up to 15 L/100km. I wondered if I was simply leaking fuel on to the road, so I grabbed a bike pump to investigate.
It’s also got two horns for interesting reasons.
!!!error: Indecipherable SUB-paragraph formatting!!!
I suspect my fuel issues might actually be due to a dying/slipping automatic transmission. Anyone got any idea how I can check?
PartyPooper2012
> whatuptkhere
03/07/2018 at 15:52 |
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air filter?
Spark plugs?
oil sludge?
uneven tire wear?
All those will rob you of fuel.
Akio Ohtori - RIP Oppo
> whatuptkhere
03/07/2018 at 16:09 |
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Talking (mostly) out of my butt here, but a slipping transmission would be getting much hotter than a non-slipping one. Also you could drop the transmission oil pan and look for friction material (“glitter”) or chunks in the bottom. A little glitter is to be expected (or at least that is what I tell myself) but more than a little is too much.
Dogsatemypants
> Akio Ohtori - RIP Oppo
03/07/2018 at 16:13 |
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Usually when my fuel consumption is up, i check my throttle cables and move the plate looking for anything out of normal. Then i check the air filter, intake and vacuum hoses.
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Akio Ohtori - RIP Oppo
> Dogsatemypants
03/07/2018 at 16:31 |
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Oh for sure. I figured if he suspected the transmission for other reasons those are the steps I’d take to confirm. Finding good info on transmission troubleshooting is hard.
But yeah, huge list of things to check before you condemn the transmission.
Then again if the transmission is going it is a good time to do a manual swap...
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Dogsatemypants
> Akio Ohtori - RIP Oppo
03/07/2018 at 16:38 |
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That is what i want when mine shits the bed. What year is the 740? s a ling shot but you may have a rudimentary control module.
Do you have cruise control? There may be a diagnostic test you can do with it. Also depends on the method of actuation.
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Dogsatemypants
> Dogsatemypants
03/07/2018 at 16:40 |
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Or.... bring it up to 60, shift into reverse, listen for loud clunk. Transmission is def broken.
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whatuptkhere
> Akio Ohtori - RIP Oppo
03/07/2018 at 16:49 |
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Thanks for the tips, y’all.
So the backstory is after I had it for a few months, the transmission started to shift poorly and would tend to really hang in gear way too long before changing with a small bang when it was cold.
I did a transmission filter change & put in fresh fluid which helped somewhat. It’s definitely better than it was. There was some brown/black gunk in the pan and on the magnets but no sparkly metal.
Funnily enough I have noticed that on hot days the footwell does get very warm/hot which is even noticable through shoes, which is another thing that has led me to suspect a dying trans.
I’ll add air filter & the other points to my inspection list. Cheers!
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whatuptkhere
> Dogsatemypants
03/07/2018 at 16:50 |
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It’s an ‘88 without cruise control.
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whatuptkhere
> PartyPooper2012
03/07/2018 at 16:54 |
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Thanks for the tips, I’ll start checking them out!
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Akio Ohtori - RIP Oppo
> whatuptkhere
03/07/2018 at 17:16 |
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Hmm well no glitter in the pan seems like a good thing... or you’ve already lost all your friction material... or I have no idea what I’m talking about. Could be any of those really haha
If the footwell is getting hot I would double check all your exhaust heat shielding is in place. If it isn’t, it could very well be overheating the transmission (and your feet) and causing problems? Maybe?
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whatuptkhere
> Akio Ohtori - RIP Oppo
03/07/2018 at 18:04 |
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Hm, good call. Will investigate some underbody shots to see if I’m missing anything.
GeekGirlKatie
> whatuptkhere
03/07/2018 at 21:33 |
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When you changed the transmission fluid did you do it as a drain and fill or did you do a power flush via the transmission fluid input line that go into the radiator? If you only did a drain and fill then there is still old fluid in the transmission which would cause the shifting issues to occur still. Also the transmission radiator which is part of the main coolant radiator might be clogged. I’ve seen that happen a few times in Volvo 240 and 740's which would explain the transmission possibly overheating.
Also another cause of the harsh shifting and sticking in higher gears is the overdrive relay or solenoid on the transmission might be sticking or starting to fail all together. That is also a very common failure on all 240 and 740 models but it’s an easy and very cheap fix to either bypass the solenoid or replace the relay if it’s failing.
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whatuptkhere
> GeekGirlKatie
03/08/2018 at 03:20 |
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I removed the drain pan and refilled. Didn’t do a power flush. You make a good point.
Can confirm the overdrive relay/solenoid works - checked by watching the tach and hitting the shifter button.
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whatuptkhere
> GeekGirlKatie
03/08/2018 at 03:21 |
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I might see if I can remove the trans cooler and inspect and clean it.
pip bip - choose Corrour
> whatuptkhere
03/08/2018 at 04:37 |
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where is the temp gauge sitting?
theory being, car runs colder so uses more fuel as the sender is sending an incorrect reading to the ECU
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whatuptkhere
> pip bip - choose Corrour
03/08/2018 at 16:38 |
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Dead middle on temp gauge, all day ‘erry day.
Mechanic reported that the coolant temp sensor was working properly, but I replaced it anyway just in case. No change sadly. :(
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pip bip - choose Corrour
> whatuptkhere
03/08/2018 at 16:54 |
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I was thinking maybe thermostat is the issue
However I’m clueless
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whatuptkhere
> pip bip - choose Corrour
03/08/2018 at 18:24 |
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Always good to get another perspective, thanks for chipping in :)