1991 940 2.3 Estate, Part Number Needed. Very High MPG!!!!

squealey · Post by **squealey** » 14 Apr 2008, 10:41

Hi All

Im a newbie here so be gentle, Please!

My wife has a 1991 940 with the B230F engine (non turbo). It has been running like a proverbial pig for ages now and uses so much fuel its just not funny any more (im talking

Post by **billofdurham** » 14 Apr 2008, 11:42

Wayne,

Welcome to Matthew's Volvo Site.

Im a newbie here so be gentle, Please!

We are always gentle on this site.

The only sensor I can think of in that location is the coolant temperature sensor. If it is faulty it can play havoc with the MPG as it will feed wrong data to the computer.

Unfortunately I can't find a part number but you should be able to buy a suitable replacement without it.

Bill.

Post by **VCA** » 14 Apr 2008, 14:08

Hi Wayne, I agree with Bill-- this sounds very much like a bad coolant temperature sensor, especially the poor tickover coinciding with rich running. I'm showing Volvo part number 1346030 pricing around $35.00. If the part is the culprit I'd expect an immediate improvement in tickover and tailpipe emissions after replacing it.

squealey · Post by **squealey** » 14 Apr 2008, 15:33

Thanks very much for your help. I'll fit a new one in the next few days and report back on my progress.

Wayne

Post by **jonesg** » 14 Apr 2008, 18:42

Pull the vac line from the back of the fuel pressure regulator at the front end of the fuel rail, if you smell or see gas (err..petrol) thats a problem, it will leak right into your intake, flood the throttle body etc and mileage drops, car will run like junk too. $59 I think.

If thats not the problem than I'd definately swap that coolant sensor out, get an intake gasket at the same time and one for the throttle body, you'll be glad you did when you try to get at the temp sensor the hard way.
The easy way is just pull the intake manifold back a few inches.

A coupe of wraps of teflon tape keeps the sensor from leaking coolant.

squealey · Post by **squealey** » 16 Apr 2008, 15:49

Hi All

Well I ordered one of those sensors from PFS on Monday and it was on my doorstep this morning, total cost inc P+P was just shy of

Post by **jonesg** » 16 Apr 2008, 17:55

We like updates like that. Good news.

If you did it again, you might (MIGHT) be able to swap the coolant sensor without pulling the manifold, but I couldn't the first time....I tried.
When I calculate how much money I saved DIY , it just makes sense to get more tools as I need and keep doing my own maintainance.

I paid $500 for my 1990 740GL, thats less than the price of a major tuneup around here for a volvo.
Keep em running and help the next guy.!

Post by **VCA** » 17 Apr 2008, 08:42

squealey wrote: Anyway, got in the car, started her up and............................the difference is incredible. It now ticks over like a new car, there is no lumpyness, there is no engine management light, there is no tutting wife moaning about spending more money on it.

Like I said, expect an immediate improvement. Glad to hear your 940 is back on the road...you should find it to be quite a bit more economical now as well

squealey · Post by **squealey** » 02 May 2008, 16:14

OK, Spoke too flipping soon.

The car drove brilliantly for the first 40 or so miles but it is now back to its horrible, high mpg, lumpy self!!!!

Last night was the first chance i've had to give it a quick look and the OBD is now giving the code 1-1-3. Basically the same explanation as 2-3-2, car is running too rich/lean causing high MPG.

Couldn't find anything wrong. Just went back across some of the other things i've done in the past, still couldn't find anything.

Whilst the car was idling (just) I gave the throttle a few good solid bursts. It poured black smoke out of the exhaust and filled my street.

Im really beginning to reach the end of my tether with this car. If I knew for 100% what the problem was and knew it would cost say

Post by **jonesg** » 02 May 2008, 19:00

Did you forget to check the fuel pressure regulator?
Its at the front end of the fuel rail, pull the vac line and check for fuel.
If its dry then I'd look at the O2 sensor, if that is bad it will send incorrect mixture signals to the compouter.
Its common for sensors to go in bunches, one goes south and ruins the next.

Coolant temp sensor made your engine too rich, that can affect the O2 sensor as it tries to compensate but eventually dies. The O2 sensor can trigger those codes too.

Read the faq,
http://www.brickboard.com/FAQ/700-900/E ... iagnostics