Jump to content
The mkiv Supra Owners Club

1 problem fixed..now the next one is...


Alex

Recommended Posts

No feckin' boost...well stock boost max on a de-catted, boost controlled j-spec that normally hits 1.3bar with ease.

 

Since I last ran at full power about 2 months ago I have put in a stock bov and removed the HKS SQV and changed the spark plugs.

 

At 10 Best it seemed to misfire on BKR7E's so we gapped them down further and the misfire reduced...but not completely. So first of all I think the BKR7E's are PANTS!! I'm going to clean the old HKS S40's and try them again.

 

But I don't think this is the only problem...the BOV and its pipes are my suspects. The stock bov's I assume can handle more than .85 bar, yes? They won't just dump the boost will they? If they do how can IanC run 1.5 bar on his Hybrids with what appears to be a stock bov?

 

If one of those connecting pipes wasn't on firmly enough could it leak without blowing off?

 

Great the rad is defo the cause of the overheating now I can't get any power.....thanks so fcukin much!!

 

Still even at stock boost I wiped out JB's stock UK spec! :D

 

Cheers

 

Alex H

Link to comment
Share on other sites

Guest Terry S

Alex, I can't see it being the plugs but who knows ( maybe I didn't ned new coil packs:eek: ) These are exactly the same as stock but 1 grade colder.

 

Try some BCP's if you can get hold of them, or Denso IK22's.

Link to comment
Share on other sites

Cheers Guys,

 

What are the Denso equivalent's to the S40i's and the S45i's?? Or are the IK22's the S40i equivalents?

 

I'll give the old ones a quick try this week and nail the bov into place as the stock ring clip things could be tighter...

 

I am also going to check to see if the problem is actually a display problem, the SBC and the Boost gauge both get their pressure readings off the same line....

 

I'll let you know how it goes..

Link to comment
Share on other sites

Originally posted by Alex Holdroyd

Cheers Guys,

 

I'll give the old ones a quick try this week and nail the bov into place as the stock ring clip things could be tighter...

 

 

I know what you mean about the stock clips on the BOV lines. The clips on yours are the ones I use to check it, and it was OK. When I did the swap, they all felt loose. I put my original, back on and it felt loose too. It took a week of motoring before the pipes felt tight on the metal tubes again. Just to check you could small amount of washing up liquid and water on the large pipe union and see if you get bubbles at high boost. I know boost can't be that high on a static test, but it may give you an indication.

Link to comment
Share on other sites

Surely the only pipe that could be causing it to leak boost (assuming the unit is functioning correctly) is the one that goes from the inlet pipe to the BOV? That's the only pipe that's under boost pressure as far as I can see.

 

Does the engine run fairly normally but fail to make boost, or is it not making boost because the engine is running like such a dog that you can't get it to rev that high?

Link to comment
Share on other sites

A faulty bov will cause boost loss. Why not get down to your local DIY store and buy some jubilee clips, they will secure the pipes alot better than the spring clips that hold the pipes on as standard.

 

Are you able to swap the bov with someone else's (anyone local?) to eliminate it?

Link to comment
Share on other sites

I have already bought the Juby clips but the car is not nearby so I can't test yet.

 

the other thought is the line from the intake to the PS pump as this one was reconnected with a new silicon hose I pulled the HKS BOV which tapped into its line...but that look secure and the PS is fine.

 

I'll do some tests tonight might nip round to Ian's...as he has a stock BOV and check the install.

 

Phil tested the BOV before shipping it so I can only assume it works as it was wrapped inside another pipe for protection in the post.

 

I've also got some Emry cloth to clean up the S40's and re-test them...the pain is how long it takes the engine to cool down to allow me to do the swap...I have to get it done in natural light as I don't have a garage I can use. :(

Link to comment
Share on other sites

Just do it while the engines hot! It's no different to doing a compression test for example, the sparkplugs can sometimes be a bugger to get out while they're hot but the worst that will happen is a burnt finger or something. Even that's unlikely!

 

Ya wuss :p

Link to comment
Share on other sites

Right checked the hoses and tested the car....blew the fecking hose off again but I am fairly sure the car is running normal boost levels (with a slight hesitation under load - probably lack of fuel or poor spark)

 

But both the Boost gauge and the SBC are reading .86bar max and at idle the boost only just drops below 0! I thought that was bizarre when i first put the stock BOV in.

 

Can I have put the stock BOV on backwards??? I couldn't check another Sup tonight as the locals with stock BOV's weren't available. If I put it on backwards would it still work to a degree? Could someone tell me if there is something ither than a vacuum hose running from the PS pump to the intake manifold?

 

This must be related to the removal of the HKS BOV and the installation of the stock BOV...there is no other plausible explaination.

Link to comment
Share on other sites

Originally posted by Alex Holdroyd

 

Can I have put the stock BOV on backwards??? I couldn't check another Sup tonight as the locals with stock BOV's weren't available. If I put it on backwards would it still work to a degree? Could someone tell me if there is something ither than a vacuum hose running from the PS pump to the intake manifold?

 

If the stock BOV is mounted correctly, the small vaccum pipe on the black cap faces toward to bulkhead. There are one direction only.

 

There are only two vac connections to the PS pump. One to the throttle body and one to the intake chamber.

 

Have you tried blowing air through the BOV, it should not allow any through unless you apply suction to the vac pipe.

 

 

Which hose is blowing?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.