My B200F-GLi has been suffering from massive overfuelling over the past weeks, fuel comsumption was around 16L/100km - that's about 60% more than usual. Cold starts were fine (at least no worse than an LE/U - jet fuelled 360 usually is) but after a mile or so, the idle speed dropped dramatically. If I turned the lights on, or the rear window demister, it was on the point of stalling.
So I did some searching on V3M - found lots of helpful stuff, and then, armed with a Haynes, went to have a look.
It was solved quicker than I thought - the air mass meter seems to be faulty. Swapped the part over from the GLT (same part no.) and now everything's fine!
So now some questions - can the old part be overhauled? Haynes says you can test it with an ohmmeter, but TBH it just looks like a flappy paddle controlled by some circuitry - can't really see there's much to fix here ...
And a second question - if it hadn't been the AMM I would've started looking at the cold-start injector and its thermal time switch. Embarrassingly, I couldn't find either Are they anywhere near the auxiliary air valve, mounted onto one of the cam cover bolts?
Cold start injector is in the inlet manifold on the underside. Look for the small fuel hose that feeds it coming directly off the fuel rail on the RHS.
The thermal time switch is on the RHS of the cylinder head, it looks like any other temperature sensor. The coolant temperature sensor is beside it and has a proper clipped terminal whereas the thermal time switch just has a push fit connector.
Bad news on the overfuelling and the AMM. If you take the black plastic cover off, you'll see the electronic gubbins. As far as I can see, its just a potentiometer, with multiple carbon tracks, a wiper and a complicated compound spring system that helps the flap overshoot slightly on quick movements to provide acceleration enrichment etc. At least that's what I assume it does, I've never seen any books/articles actually explain how it all works properly. I suspect that one of the carbon tracks is broken or worn out and knackered. I suppose you could find somebody to replace the potentiometer part, but where would you find them from and how would you get the main spring recalibrated again once you take it apart and put it back together again.
Just to add what Andy's said, it's well worth multimetering if you have one Tom, the green book has the values that are required. One thing that works well as a temporary measure is to get a load of Ultrasolve in there, move the flap forwards and backwards a fair few times, and repeat. That should last a good 6 months or so, the tracks get a huge build up on them that increases the resistance massively.
I've never seen any evidence that you shouldn't do this every service period anyway, so that it doesn't build up in the first place.
Thanks for your replies guys. I'll have a go at cleaning the old one, but I'm not sure it will have that much of an effect - it was a very sudden change, not something that got progressively worse or anything.
Looks like I'll need to look out for a new one. The replacement AMM I have knocking around is for the earlier <'87 cars unfortunately ... Anyone want to swap ?
And I'll go back and have another search for the C.S.I. and temp sensor, cheers, Andy!
Hi trabitom, at one moment i disconnected the cold start injector for 2000 km (84 Gle) without observing an fuel consumption improvement. I also swaped the MAS from the Gle to Glt and the result is...s&so.Be careful that the MAF and the butterfly switch must have the same code.
the early bird gets the worm
`87 B200E on LPG grey GLT aka Time Machine
alf wrote:Hi trabitom, at one moment i disconnected the cold start injector for 2000 km (84 Gle) without observing an fuel consumption improvement. I also swaped the MAS from the Gle to Glt and the result is...s&so.Be careful that the MAF and the butterfly switch must have the same code.
Thanks, Alf. I have a spare air mass meter, but it's the wrong code so I won't fit it ...
Since my friend got his 360 with this fuel injected setup I've also been wondering about refurbing the AMM concept ie is it possible?
If the green books give the range of outputs from the AMM that's pretty helpful for checking and also possibly commissioning a replacement of sorts.
If the tracks are worn then that just happens to be the same fault which affected the P2 volvos from 2000 onwards (until the supplier redesigned it) using the Magneto Marelli throttle bodies. In principle, as detailed on one of the investigation sites for the ETM (electronic throttle module), the tracks can be replaced once worn. The other alternative as has been marketed by a US company is a non contacting position sensor which replaces the tracks in the ETM. Something similar could be applied to the 360 AMM as one knows the expected outputs from the AMM under certain conditions from the green books
Thanks for that Shimon. I've been a bit busy lately, so no chance to test the old one yet ...
Found out however that despite what the parts catalogue says, even late UK GLTs seem to be fitted with the "034" AMM. Both Mark and Steve's AMM's had this part no. despite being sourced from 87 on cars ... Maybe they "programmed" the "096" AMMs to work with both "B200E" and "B200F" engines, but while they still had the earlier type in stock just kept fitting them to non-cat cars, I'm not sure ...
Are they anywhere near the auxiliary air valve, mounted onto one of the cam cover bolts?
?
These things run on normal gas!
