Overfuelling? - 30Mpg

[Grim.Badger 15]

I've never been very good at hearing pinking, so I set it up acording to when advancing stops increasing the RPM instead, I don't know what difference that makes but that's why I'm thinking of getting a professional to set it up.

 

I got around to taking the advance unit off the dizzy today to double check it's part number (3091 stamped on the lever, or 12371123091 in full - fitted to a 0237009066 dizzy) Unfortunately the advance has dropped bits into the dizzy itself, I found part of a spring and lots of knackered rubber, so I'm thinking of sending the dizzy off for recon as well.

[Grim.Badger 15]

Long time since I updated this.

 

I got the dizzy and vacuum advance refurbished by H&H and got somewhere around a 10% increase in fuel efficiency. The revs are also more stable at low revs and I get much less kangarooing.

 

I'm still not happy with the way it runs though, especially the cold start when the car stinks of overfuelling (I think - a sickly cloying smell, quite different to burning oil or burning coolant). I decided today that I would try my spare ECU, just in case, and imagine my suprise when I found an aftermarket ECU under the dash!!!!! That will teach me to assume that because the car had passed previous MOTs and still had it's limiter that the ECU must be original.... kudos to whoever suggested the ECU should be checked (GLP?)

 

The ECU is made by "ic" and seems to have the part number RFU 0359 - the peugeot part number is also printed on and matches the standard ECU number. I have had no luck searching for this on Google, anyone any idea if it is a standard aftermarket ECU, or one which may be responsible for some of the overfueling?

[jackherer 543]

Take the cover off and have a look. The superchips for jetronic ECUs were a simple daughterboard with a few pots on so adjustments could be made, I imagine you'll find something similar.

 

 

http://www.205gtidrivers.com/articles/e2-superchips.html

 

 

[Grim.Badger 15]

I've opened it up and there is nothing like that in it, in fact the chipboard doesn't seem to have the same configuration as the one in the photos. Attached are two shots, one of the casing and one of the board - sorry for the terrible quality, I will try to get better next week when I have my camera back.

It would make sense though, as the final straw was getting 24-26MPG on a tank because I was sat in heavy traffic for half an hour every day for a couple of weeks.

 

I'm PO'd at myself for not checking this sooner, like 5 years ago when I bought the damn car!!!

 

It seems to run better with a standard ECU, but that could just be because I cleaned out the mayonaise from the breather system, I won't know until I've got an idea of the MPG.

 

 

[Grim.Badger 15]

Second image, this one is of the casing.

[welshpug 1,627]

Probably worth getting the CO levels checked with the new ecu fitted.

[jackherer 543]

I've seen ECUs with similar looking ATP labels on and it just means they've 'reconditioned' them as opposed to modified. Your guess is as good as mine as to what that involves, just a reasonably thorough test probably.

 

Have a close look at the solder side of the board, if any components have been changed the solder is likely to give the game away.

[Grim.Badger 15]

I've just had the car emission tested and got CO 3.11, HC 0606

 

This much much better than last year when I had 6.88 and 0985, but still a fail. For the next MOT I can re-fit my tweaked AFM, which will make the car run lean but get it through, but I would rather find the source of the problem. Apparently the readings come under control when fast idling. At the moment I expect the following may be at fault:

 

• AFM (even though it is a different one from last year and is still factory sealed) Unfortunately I don't have a spare.
• Wiring corrosion causing the wrong signals to get to the ECU (the wires are bad, I will check with my multi-meter what signals I am getting at the sensors and the ECU end of the wires) I do have a spare loom.
• Dirty/faulty HT leads or connections (but I did check these a couple of months ago)
• One or more injector spraying incorrectly?
• The TPS has broken since I checked it.

Anything else?

[Anthony 1,000]

I've just had the car emission tested and got CO 3.11, HC 0606

 

This much much better than last year when I had 6.88 and 0985, but still a fail.

Is yours a CAT car? Limits for non-CAT are 3.5% CO and 1200ppm HC, so yours should have passed if it's a non-CAT.

 

(even if it is a CAT car, check the VIN as quite a lot of them were manufactured before the cutoff and hence should be tested as non-CAT)

 

That said, the CO in particular is quite a bit higher than it ideally should be - something more like 1.0-1.5% is more like it.

[jackherer 543]

It's definitely worth getting the injectors cleaned and tested. It's usually easiest to buy a spare set and send them off to be done so you don't need to take your car off the road while they are away.

[Tom Fenton 1,526]

If another air flow meter makes it run lean then there is nothing drastically wrong with the injectors .

[Grim.Badger 15]

I'm not sure if it does run lean, but it does starve for fuel higher up in the range (this is on an AFM with a heavily adjusted spring).

 

The car is non-cat, but first used in September 1992 so some garages do think it should pass a Cat type test - I was wondering why they had highlighted the Lamba test score

 

I have some spare injectors, but can't get them out of the manifold using the instructions in Haynes, is there a trick to it? If not I suppose they could have been damaged in the garage and I might be better off getting some more.

[dcc 855]

I'd love to be getting 30mpg from mine. Varies from 12mpg around track, 25-28mpg around the roads round here, 30mpg @80mph, but can get it up to 44mpg @58mph iirc

[Grim.Badger 15]

I'd love to be getting 30mpg from mine. Varies from 12mpg around track, 25-28mpg around the roads round here, 30mpg @80mph, but can get it up to 44mpg @58mph iirc

Hence my question at the start - am I expecting too much? I do a lot of short urban journies. On the other hand, I have a known emissions problem and I'm about 70% certain my old GTis got better MPG on the same journies.

 

On that subject, I managed to get it down to 2.76 CO just by cleaning the plugs and breather system, although HC was higher at 676

[davey205 7 1 Cars]

I always used to get about 30mpg, mainly short journeys mine always stinks of petrol on startup , kangaroos and will easily stall if you don't help it, you also have to be selective over which electrics you have on while cold

[Grim.Badger 15]

It did something new today. After three consecutive short journeys, with the engine confused about whether it was warm or cold, it stalled outside my house and refused to start again for some time - it didn't even try to catch, it was as if there was no fuel and/or spark.

It finally caught after lots of turning over, overwhelming petrol smell and pumping the throttle.

 

I've had simialr to this before, but it's never been so reluctant to start again. It was almost exactly like trying to start an old carb engine that has been flooded.

 

I'm assuming it was a bad mix between short journies and cold weather, but it was worrying