Gas guzzling

Started by 2 of the left, June 12, 2022, 00:01

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2 of the left

When E10 arrived on the forecourts I decided to stay with E5 No probs with my Blue but Betsy threw a strop at that time on E5 and her mpg dropped drastically from 40 mpg to 24 mpg - Have tried everything to rectify - MAF checked - Brakes checked and fuel lines and exhaust emission checked filters are top line as are plugs - I'm getting fraught!! Costing me a fortune to find the solution - Could it be chain tension or engine on it's way out- But why so suddenly? A car is but a car but an MR2 is something else !!
SI VIS PACEM PARA BELLUM!!

Ardent

Did you sort out the split in the bellows(?) Pipe.
The rubber bit just after the maf?

Unmetered air getting in.

Joesson

Quote from: 2 of the left on June 12, 2022, 00:01When E10 arrived on the forecourts I decided to stay with E5 No probs with my Blue but Betsy threw a strop at that time on E5 and her mpg dropped drastically from 40 mpg to 24 mpg - Have tried everything to rectify - MAF checked - Brakes checked and fuel lines and exhaust emission checked filters are top line as are plugs - I'm getting fraught!! Costing me a fortune to find the solution - Could it be chain tension or engine on it's way out- But why so suddenly? A car is but a car but an MR2 is something else !!

Sometimes, just sometimes, when you have been chasing your tail without result it can be that you need to stop and start again. In this case that is  to check your MPG again.
The only time I recall having such a dramatic drop in MPG was in my Beetle, the fuel tank started leaking around an outlet pipe!

Carolyn

We found one loose and split vacuum hose.  There could well be another!
Perry Byrnes Memorial Award 2016, 2018.  Love this club. 
https://www.mr2roc.org/forum/index.php?topic=63866.0

2 of the left

Quote from: Carolyn on June 12, 2022, 13:07We found one loose and split vacuum hose.  There could well be another!
Have had all hoses replaced yesterday will now be checking consumption again - could be fuel tank leak getting a random whiff of petrol every now and then!
SI VIS PACEM PARA BELLUM!!

Chilli Girl

Unusual for a petrol tank leak on our cars - not heard of that one.  Hope you get Betsy sorted soon Rob - that's expensive motoring! :'(
Ex owners of Chilli red facelift 52 reg called Chilli, silver 55 reg called Foxy and blue pfl W reg MR-S called Sapphire. Now 2 less!

Call the midlife!

Quote from: Anon on June 12, 2022, 18:36If you look a the fuel trims and lambda values with a scan tool that will speak volumes.

If it's running a massive negative amount of fuel trim e.g. -10% then its trying to reduce its injected fuel quantity beyond it capabilities.

Thus look towards the fuel pressure regulator on the end of the rail, or the vacuum line to it... Vacuum reduces the rail pressure, if the vacuum hose is defective then it will run at the diaphragms relaxed state being like 2 4 bar or something thus over fuelling.

If the fuel trim is like +10%, then it is trying to add fuel to sort itself out (incorrectly), thus look for exhaust leaks before the lambda sensors.
The fuel pressure regulator is built into the fuel pump, in the tank but I know what you're meaning.
60% of the time it works everytime...

Carolyn

Quote from: Anon on June 12, 2022, 18:36If you look a the fuel trims and lambda values with a scan tool that will speak volumes.

If it's running a massive negative amount of fuel trim e.g. -10% then its trying to reduce its injected fuel quantity beyond it capabilities.

Thus look towards the fuel pressure regulator on the end of the rail, or the vacuum line to it... Vacuum reduces the rail pressure, if the vacuum hose is defective then it will run at the diaphragms relaxed state being like 2 4 bar or something thus over fuelling.

If the fuel trim is like +10%, then it is trying to add fuel to sort itself out (incorrectly), thus look for exhaust leaks before the lambda sensors.

There is no regulator on the end of the rail on a 1ZZ.  There  is a damper in the middle of the rail.  The regulator is at the pump.  They are very reliable. Failures must occur, I suppose, but it's way down on the list of likely culprits.  A mis-reading MAF will not throw a code, but could be the cause.  The hose replacement may well have done the job, let's see...
Perry Byrnes Memorial Award 2016, 2018.  Love this club. 
https://www.mr2roc.org/forum/index.php?topic=63866.0

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