Engine won't rev and hunts

[ANDTWENTY]

Originally Posted by Laird Scooby

In that case, you need to look for the correct connector. Should be near/under the coolant expansion tank. I'll try and get a pic of mine later but bear in mind mine is a 1988 760, the exact place might be slightly different.







Orange signal cable to/from what?

Have to say, i'm not convinced the TPS idle switch is causing the problem , some monkey had been fiddling with mine before i got it and the idle switch wasn't working at all. It still ran passably well though. It was only other faults showing up that caused me to investigate it and sort it out in fact.

Looking at the pic further up of your MAF, it seems to be an 0 280 212 016 which is shared with several other 940s including a turbo version.

Have a look at this thread, someone else is also after the MAF but it might be worth a try :

https://www.volvoforums.org.uk/showt...48#post2551848

Not sure of any others being broken at the moment but worth remembering it might be the MAF still.

I'll try and get that pic shortly.

I had a good look around and under the expansion tank I couldn't see any other connectors than the one I saw but a picture may reveal something!

The signal cable from the TPS

The TPS went twice on my other Volvo, a 97 V40, the first time it just idles very low and I had to keep my foot on the throttle at lights and things, the second time was similar symptoms to this, the car would run for a while and then hunt and surge while driving, it wasn't this bad and it was intermittant but the car was still drivable, just not nice to drive!

I have sent a couple of messages on here and found a couple on ebay too so perhaps if they aren't to pricey ill grab one and see. Is there a way to test mine and see?

Originally Posted by kelvinp

I've never found that cable no matter how much I've looked for it (1990 740 with LH2.4)

Reading through this thread, it sounds similar to what I had with now my 740, it wouldn't idle or rev and this turned out to be the MAF. I'd checked everything else and so forked out an extortionate 99p for a BOSCH one on Ebay and it was good as gold. I found out that I had the diagnostics with the LH2.4 but I remember clearing the codes and because of another fault it didn't log the MAF error code if I remember.

I believe mine is the same (correct me if I'm wrong) but I am struggling to see anything, do you also have the wire on the air box side like mine? if so do you know what it does?

Dont suppose thou know of any others for 99p do you haha

[Laird Scooby]

The TPS on a V40 is a totally different animal, the 940 one is two switches or should be. The V40 one is a potentiometer and the position of it electrically is given by the position of the wiper on the track, with the ends of the track going to 5V and 0V respectively so the wiper taps off a voltage between 0.00V and 5V according to throttle position. In practice, they are usually adjusted so they read 0.7V with the throttle closed (but this can vary from car to car to car) and if memory serves, the V40 also has a MAP sensor - don't think it has a MAF but might be wrong.

https://www.ebay.co.uk/sch/i.html?_f...0+TPS&_sacat=0

S/V40 TPS sensors - also fit half the modern car parc including Fords, Rovers/Land-Rovers as well as all those stated in the listings!

Usually testing a MAF is done by substitution, especially if it's not showing a code.

Whereabout in Norwich are you?

[ANDTWENTY]

Originally Posted by Laird Scooby

The TPS on a V40 is a totally different animal, the 940 one is two switches or should be. The V40 one is a potentiometer and the position of it electrically is given by the position of the wiper on the track, with the ends of the track going to 5V and 0V respectively so the wiper taps off a voltage between 0.00V and 5V according to throttle position. In practice, they are usually adjusted so they read 0.7V with the throttle closed (but this can vary from car to car to car) and if memory serves, the V40 also has a MAP sensor - don't think it has a MAF but might be wrong.

https://www.ebay.co.uk/sch/i.html?_f...0+TPS&_sacat=0

S/V40 TPS sensors - also fit half the modern car parc including Fords, Rovers/Land-Rovers as well as all those stated in the listings!

Usually testing a MAF is done by substitution, especially if it's not showing a code.

Whereabout in Norwich are you?

yea the sensor on that is much cheaper too! I got one for about £7 first, said it had a 2 year warranty but went wrong after about 6 months, I got my money back and then got a proper one from euros which has been fine since but ended up replacing a few parts cos I didn't think it had gone again and it was intermittent so hard to pin point an issue.

I'm about 20 minutes south of Norwich by Loddon

[Laird Scooby]

Originally Posted by ANDTWENTY

yea the sensor on that is much cheaper too! I got one for about £7 first, said it had a 2 year warranty but went wrong after about 6 months, I got my money back and then got a proper one from euros which has been fine since but ended up replacing a few parts cos I didn't think it had gone again and it was intermittent so hard to pin point an issue.

I'm about 20 minutes south of Norwich by Loddon

A friend of mine paid about £7 for the same sensor for his Rover 820i and that cured the flat spots similar to what you were experiencing on your V40 and it's still going strong now as it's still on the forum.

Couldn't remember where Loddon was, looked it up and you're south-east of Norwich. I'm about 40 minutes south-west of Norwich or about an hour from Loddon.

[ANDTWENTY]

Originally Posted by Laird Scooby

A friend of mine paid about £7 for the same sensor for his Rover 820i and that cured the flat spots similar to what you were experiencing on your V40 and it's still going strong now as it's still on the forum.

Couldn't remember where Loddon was, looked it up and you're south-east of Norwich. I'm about 40 minutes south-west of Norwich or about an hour from Loddon.

ah thats pretty good! yea mine started off as flat spots and hesitation, thought perhaps it wasn't getting fuel

Yea I see it says Lakenheath, was trying to think where that was but thats not too far then haha

[Laird Scooby]

Originally Posted by ANDTWENTY

ah thats pretty good! yea mine started off as flat spots and hesitation, thought perhaps it wasn't getting fuel

Yea I see it says Lakenheath, was trying to think where that was but thats not too far then haha

That's how they usually show problems first. For £7 it was a no-brainer to not even try it as they're known to go.

If you drive down the A11 it's not far past Thetford.

Not many secondhand donut tanks on fleabay at the moment, just this one really :

https://www.ebay.co.uk/itm/Toroidal-...UAAOSwi-9dIyI4

Depending on the postal cost, it might be just as easy to get this :

https://www.ebay.co.uk/itm/Lpg-Tank-...2/163814971100

Or this :

https://www.ebay.co.uk/itm/650-250-6...S/322993846746

Just a few ideas for when you get the wee beastie running again.

[ANDTWENTY]

Originally Posted by Laird Scooby

That's how they usually show problems first. For £7 it was a no-brainer to not even try it as they're known to go.

If you drive down the A11 it's not far past Thetford.

Not many secondhand donut tanks on fleabay at the moment, just this one really :

https://www.ebay.co.uk/itm/Toroidal-...UAAOSwi-9dIyI4

Depending on the postal cost, it might be just as easy to get this :

https://www.ebay.co.uk/itm/Lpg-Tank-...2/163814971100

Or this :

https://www.ebay.co.uk/itm/650-250-6...S/322993846746

Just a few ideas for when you get the wee beastie running again.

might have to drop by and give you some beers when this is going then asa thanks for all your help! my brother lives in Cambridge so I come past every now and again.

Yea I saw a few of those, just not sure how I feel about a second hand gas tank haha. I got all my stuff from a company called Tinley tech. Extremely helpful people and reasonable prices, I converted my v40 about 7/8 months ago and its been fantastic so was going to take the kit off that and put on this once its going, was going to get a slightly smaller tank so I don't have to sculpt the boot so much... On that I got a full toroidal tank instead of the 'donut' type, gives a few more litres but does mean a 70mm whole has to be drilled in the floor to put the multi valve outside.

[Laird Scooby]

Originally Posted by ANDTWENTY

might have to drop by and give you some beers when this is going then asa thanks for all your help! my brother lives in Cambridge so I come past every now and again.

Yea I saw a few of those, just not sure how I feel about a second hand gas tank haha. I got all my stuff from a company called Tinley tech. Extremely helpful people and reasonable prices, I converted my v40 about 7/8 months ago and its been fantastic so was going to take the kit off that and put on this once its going, was going to get a slightly smaller tank so I don't have to sculpt the boot so much... On that I got a full toroidal tank instead of the 'donut' type, gives a few more litres but does mean a 70mm whole has to be drilled in the floor to put the multi valve outside.

That would be nice, thanks!

If the tank looks in good condition, you're onto a fairly good bet even with a secondhand tank. They're made of 10mm thick steel so unless they've corroded badly (surface rust can be wire brushed, Kurusted and painted easily)

You'll be surprised how big the spare wheel well is in the 940 compared to the V40, even that last tank won't look out of place without sculpting as you put it. I've got a (from memory) 640 x 220 donut tank sat in the spare wheel well of mine at the moment, awaiting plumbing and fitting properly with plenty of room to spare. If you have a towbar you can use one of Tinleys towbar filler mounting plates bolted to the towbar mount. Saves making holes in the wing which is a big flexible sheet of tin at the end of the day.

[ANDTWENTY]

Originally Posted by Laird Scooby

That would be nice, thanks!

If the tank looks in good condition, you're onto a fairly good bet even with a secondhand tank. They're made of 10mm thick steel so unless they've corroded badly (surface rust can be wire brushed, Kurusted and painted easily)

You'll be surprised how big the spare wheel well is in the 940 compared to the V40, even that last tank won't look out of place without sculpting as you put it. I've got a (from memory) 640 x 220 donut tank sat in the spare wheel well of mine at the moment, awaiting plumbing and fitting properly with plenty of room to spare. If you have a towbar you can use one of Tinleys towbar filler mounting plates bolted to the towbar mount. Saves making holes in the wing which is a big flexible sheet of tin at the end of the day.

Yea I had a little measure up today in between pulling my hair out and measured around 650 wide by 270mm if I went right up to the interior floor, giving me a 77 litre tank so not bad, think the one I have is 750 wide, they have the jack in by the wheel so got a bit more room.

yea I have a tower, fitted my other to the tower, its handy for filling because its in the middle of the car so can fill up either side. I found a nice bit of stainless in the scrap bin at work so made my own which i'll reuse I reckon.

[Laird Scooby]

If you look at the size of the spare wheel/tyre, that's about 640 x 200 give or take and there's plenty of room round that so a 650 x 250 should easily fit with a bit of breathing space above between it and the boot floor. Less chance of compromising the gas tight seal on the tank lid that way.

If you've already got a stainless mounting plate for the filler on the towba not much need for this but i'll post it incase anyone else who happens to be reading wants to know :

https://tinleytech.co.uk/shop/lpg-pa...el-for-filler/



Pic shamelessly stolen from Tinleys website but as i've already linked to it i doubt they'll complain!

Handy having a workplace like that where you can find such things in the scrap bin! Really need to get on with mine, i've been doing a bit of wiring work on a loom for someone which in fairness has taken me a lot longer than it should have done but that's how life is for me these days.
Hopefully be able to get on with mine soon, looking forward to getting it gassed!