My '91 Eunos is returing about 23MPG, I’ve had a good search through the forum but I’m still looking for some advice. Its had an 02 sensor in the not too distant past so I’m ruling that out for the time being. I’ve changed the plugs and leads. I’ve checked the ecu for codes and got a code 2. I’m pretty sure that with a CAS problem it wouldn’t run at all and yet it runs fine, although noticably better since I reset the ecu which cleared the code and hasn’t returned. I dont drive particulary hard so I reckon I should be getting about 30MPG. There are three further things I’m thinkin: 1. Air filter, 2. Fuel filter, 3. Water temp sensor. Which of these is likely to be the culprit?
-halli- is probably more likely to be on the money - easiest way is to feel the centre of the each wheel after a run for heat - one will be noticeably hotter.
Alternatively, you could get it up on axle stands, and have a more detailed look
I’ve checked for binding brakes several times after a run, nothing getting too hot, and matching equally from side to side. With regard to the running, it sometimes cuts out after starting when its very cold outside and the engine’s cold. I thought I’d fixed it by setting the base idle but it happened again today so I guess not. It reaches operating temp quickly, over a similar distance to other cars. Anything else its likely to be?
My rear brakes didn’t get hoteither, but my MPG went down to 23 - 24mpg and after repalcing the rear discs and pads and freeing off the pistons I am back to 27 - 29mpg (driving like I stole it most of the time too)
That’s a pair of pads from the same disc!
OK, so I took the rear calipers off today, no strange pad wear but neither caliper was that free on the slider, the passenger side was particulary bad and took some persusion to get it it to budge. I’ve wound the pistons in and out and they’re nice and free and cleaned and regreased the sliders. Would the sticking sliders be enough to drop the MPG significantly?
I get 28/29MPG out of my mk1 1.8 which seems to be about standard.
What I do not understand is that back in Oz I had an 1990 Astina SP which uses same motor (certainly exact same 1840cc capacity and same looks). The SP was a bigger, heavier car yet returned 35 to 40MPG. Only mech difference I can think of is FWD vs RWD - didn’t think latter would have such a detrimental effect on fuel consumption.
Thoughts anyone?
rgds
bob
Temperature , I get about 28-30 out of mine but would expect better when the weather improves.
Final drive and gear ratios. I don’t know what the SP was like but the 5 is certainly screaming a bit in top gear pulling towards 4000rpm at sensible motorway speeds.
Took the car to see my friend who’s a mechanic yesterday so that we could put it on a gas analyser. Its running rich but he doesnt suspect the lambda sensor, rather the coolant temp sensor. I’ve ordered one so we’ll see what happens…
yeah, I guess it is running rich still. It does do quite a few short journeys, but the last tank was 50% round town 50% motorway and managed 26mpg which just doesn’t seem right.
Are there any components other than the o2 sensor which could cause low mpg? Things like the AFM for example?
