High rpm when idle and at speed

[timcoleman420]

I have a 2.0ltr 1993 non-turbo engine and I have a few concerns with the way it is running. This is the first big engined car I have owned so my concerns maybe unwarranted, I don't know, so I thought I would ask some guys in the know.

When idling in neutral the engine stays at about 1300-1400rpm. Second gear seems to over rev too easily when i'm trying to overtake. When I am on the motor way at 70mph in 5th the car seems to be doing 4000rpm. Is this right for this engine? It feels a bit high. I get the feeling if i were to go flat out to 100 I would be over revving the car and possibly cause a breakdown.

The fuel economy also seems to be pretty poor, around 28mpg according to the trip computer.

Can anyone point me in the right direction please?
Would this be something I could fix myslef with my limited knowledge and armed with only a tool box and a haynes manual?

Thanks in advance guys!

[jamesy12345]

Hi Tim, that sounds to high to me 4000 rpm at 70 mph in 5th

Mine is an automatic and I've never driven a B20F Celebration, but my 440 had the same engine and gear box

According to the site below you should be doing 3100 rpm........

http://www.endtuning.com/gearratios.html

That is with 195/55 R15 tyres that is. I got the gear ratios from here:

http://www.volvo-480-europe.org/volvo48 ... ngine17=on

Common culprits for the high idle are the coolant temp sensor(s), lambda or inlet control valve, just for some ideas. These wouldn't change your gear ratios though!!

edit: just a thought, what does the rev counter read when the engine is not running......?

[timcoleman420]

I can't check right now because the Mrs has taken the 480 to work today but i'm pretty sure when the engine is off the counter is at 0.

I guess the lambda sensor and coolant temp sensor are fairly cheap and easy to replace?

*edit* I'm pretty sure the tyres are standard sized for this car. I bought the yellow 480 from user 480clone on this forum, he's got some pictures posted on here somewhere. It's all pretty standard config as far as i can tell.

[Van]

The engine has a rev-limiter at 6000rpm. Maybe your rev counter is a bit optimistic. The V1000 for your car is 34.3 kph, this means at 1000rpm in fifth gear it is doing 21.3mph. So 3000rpm = 64mph and 4000rpm = 85mph.

Idle at 1300-1400 is to high.

Fuel economy should be in the thirties. Unless you floor it all the time.

There can be several reasons why the engine takes to much fuel. I recommend to have it checked on a diagnostic station at a workshop.

[jamesy12345]

^^^^^^what Van said - maybe the rev counter is reading high!

28 mpg is not that bad but I have heard of people getting better, it depends on your driving style.

Lambda is more expensive than the temperature sensor but neither are big money (IMHO) or unexpected for a car that is 20 years old now

but

make sure the idle really is high first before worrying too much about it - it may be just a dodgy connection making the rev counter read optimistically. Do you know anyone near you with a similar car/engine to compare sounds...? Add your location so we can tell where you are.

Be careful you are not actually doing 4000 rpm and 85 mph!!!! No good getting a speeding ticket over this (check your speed using a sat nav for example).

Did the previous owner mention anything?

[timcoleman420]

As soon as i've got the spare cash lying around I plan to replace the lambda and cooling temp sensor any way. Couldn't hurt, right?

Unfortunately I don't know wnayone near me with a similar engine, haven't even seen a 480 in Wolverhampton since I was 17

I don't own a sat nav but I will borrow one and check. The car just "feels" like its over doing it at high speeds, feels like it's kind of straining if you catch my drift...

I'm pretty sure the speedo is correct, I travel the M6 by Birmingham most days so I would have been had by the average speed cameras for sure by now if it was on the fritz.

Would you know how much work it would take for a garage to have a look at the idle and sort it out? Money is really tight so I'm hoping to get most of these issues sorted without having to take it to a garage.

If it seems like I'm fretting, I know absolutley nothing about cars, my previous 2 cars were work horses, they just ran and ran with no issues so I never really had to do any work on them apart from cosmetics. I absolutley love my 480, I just want to make sure it runs well and doesn't conk out on me.

Thanks again, guys!

[glasgowjim]

Clean the idle control valve first there is a how to on this one.
next check out and clean the distributor cap again dead easy just 3 screws or bolts and a wipe with a rag.

Next check if the engine temp sensor is goosed start the engine and let it warm up then disconnect the engine temp sensor and so what happens there should be a big difference if not then I strongly suspect that you have found the problem.

When the engine is turned on at first it will rev rather high and very quickly drop down to 800-900 revs/min.

I had a similar problem but it turned out to be the engine management system unit which only cost £20 + postage to change over and it solved my problems.

Lambda sensors can cost from £30 to £80 and can be an absolute pig to replace.

Oh and a second hand rep[lacement rev counter is only about £20 inc UK postage but TBH I would be very surpried if that was at fault.

[glasgowjim]

I have a spare engine temp sensor and engine management unit available if you are interested but I would clean out the ICV (idle control valve) and the distributor cap just to be sure first .

then disconnecft the engine temp sensor . then consider whether you want to try the lambda sensor or the engine unit.

For what its worth it I dont think it is due to the lambda sensor.

[jamesy12345]

I have a spare engine temp sensor and engine management unit available if you are interested but I would clean out the ICV (idle control valve) and the distributor cap just to be sure first .

then disconnecft the engine temp sensor . then consider whether you want to try the lambda sensor or the engine unit.

For what its worth it I dont think it is due to the lambda sensor.

Yep, the lambda sensor could not make the rpm higher at 70 mph!

As has been said, it would be a good idea to at least have a garage take a look at it and give you an opinion of what is wrong. There are not many reasons why a rev counter could be reading high at a certain speed assuming everything is standard - broken rev counter or slipping clutch are the two main ones that spring to mind! The latter of these would not explain the high idle.

High idle could be a different fault altogether, but since I assume Tim you are diagnosing this by rev counter then it does make me wonder if they are related somehow.

If you have no chance/funds/wish to visit a garage maybe you could post a video of the car idling?? At the very least I would be no help whatsoever but at least we would see the nice yellow colour!!

[timcoleman420]

Thanks for all your help guys. Next time i'm on the motorway with the wifey I shall ask her to video the revs while i'm at 70 and post a link.

I'm going over to my mechanically minded friends house tomorrow to pick his brains and borrow some tools to clean the ICV and the dizzy cap. I'll post back and let you know how it went.

I will take it to a gragae at some point. I want a complete fluid flush and change so i'll ask them to have a look if i haven't sorted it by then.

Glasgow Jim, thanks for your offer mate, I may take you up on that depending on how well i do.

[timcoleman420]

Welp, I cleaned out the Idle control valve yesterday. Quite a bit of carbon type crap came out of it. I put it back on and it "seemed" to run a bit slower while idle. Will have a better look on my way to work today. Thanks again for your help!

[jamesy12345]

Good news everyone!! Keep us posted

[timcoleman420]

It's idling at about 1200 now but I haven't really put it to the test. It's only 10 miles to work. Will have a play on the motorway on the scenic route home tonight!

[Captain Slow]

The motorway is the scenic route! where on earth do you live

[timcoleman420]

Well, after cleaning out the ICV and road testing it over the last 2 weeks, the idle is still at 1200 once it's warmed up and still at around 4-4400 when doing 70mph in 5th. Fuel consumption is still really bad.

Next step: Check out the coolant and engine temp sensors!