[Mk2] [Turbo] Boost problem - boost seems to start coming on then drops off

[James MR2 Turbo]

Hi All,

Hoping for some help identifying a problem that my mr2 has developed. I will try to detail the problem as best I can.

The car is an MR2 mk2 rev2 turbo, the last few times it has been used when I have put my foot down it has begun to pull and boost starts to rise as normal then as the boost comes on more the power seems to drop off, it is still accelerating but not like it should. This is really the best way I can describe the problem.

Any ideas on what I should check first or what it might be?

I haven't checked for error codes yet as the battery is flat atm.

Thanks in advance for the advice.

James

[simpson_eh]

could be a split hose more you push it the more pressure on the split and you lose boost maybe ?????

[James MR2 Turbo]

Yeah that was my first thought, I visually checked the pipes & connections on the pressurised side of the intake as best I could with out removing anything. I guess a split like that difficult to see by eye.

Anyone know the cheapest place to buy new boost pipes?

[Baker]

Have you got an EBC?

[James MR2 Turbo]

No I don't have an EBC or MBC fitted to the car.

[humdigadi]

Check the AFM, I think their quite a common problem. Mine was sticking and boosted sometimes but not others.

[James MR2 Turbo]

Thanks, an AFM problem kinda stacks up as the car did this once or twice before then went away but seems to be getting gradually worse. Is a sticky AFM fixable or would I need to replace?

[humdigadi]

I had mine cleaned up when the car went in for a service with a Jap specialist. Not sure how to do it. The BGB gives all the details on how to test it with a multimeter though, a very simple job, even I managed it!

[James MR2 Turbo]

Read some stuff online that suggests the internal workings of the AFM are quite delicate. Seems a second hand one should be somewhere in the region of £50 so I might try sourcing one and seeing if that sorts the problem and if it isn't that I can move it on again or keep as a spare.

[humdigadi]

The bits under the lid are delicate and shouldn't be touched. The warning is because people try to take the AFM off by unscrewing the electrical connecter rather than just unclipping it. Once it's off you can play around with the mechanical bits ok. That's when you can also test with multimeter.

Like I mentioned above, even I managed it without breaking it and I'm about as clumsy as you can get with cars!