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+T 1990 245 dies after boost

H

hackster

Active member
Joined
Jun 17, 2011
Location
Portland Or.
So I have been battling this since I first did the +t on my 90 wagon. Current setup on car is as follows

1990 manual 245
90+ manifold
15G turbo in great shape
Stock CBV, no tears but it is cracking and looks bad, just checked it
Stock intercooler
stock tubing
AMM is an 020 with the meter moved to pre turbo location about 6" in front of inlet to turbo. I am feeding the vent from the breather box back in between the amm and the inlet of the turbo.
850turbo injectors
TLAO chips in both computers
Idle on the car is right around 800 RPM
T5 trans
3.31 rear gears

Ok so what I have going on is that if I get into boost and then lift off the throttle and let it go down to idle, the car dies. Every time.

If I am running down the freeway and the car is at a descent rpm but not in boost push in the clutch and let the car go back down to idle, it dies then as well.

As I have been working on the car sorting out the little things I have been driving it a little harder and harder seems as though this happens more and more. I can now make it do it on command.

I installed a new AMM a week or so ago and upon installation the idle came up a little bit at first and no more stalling....however, once LH figured out whats up, idle returned and the exact same problem came back.

Jerd said to check the CBV as that could cause this problem so I pulled it out today to check it out, it doesnt have any holes or anything in it so I put it back together.

Tried the stock chips, same thing.

So, what do you guys think?

Thanks in advance.

Sean
 
I have adjusted base idle and TPS is working properly from what I can tell. Brake Booster valve could be a culprit.

Ill check it when I get home.

It idles fine, its just when coming off boost....

Keep the ideas coming, I appreciate the input.

Sean
 
Onetrillionrpm said:
How sure are you the cbv isn't leaking? Also is your oil breather ok?
Click to expand...

Not 100% but it doesnt do anything weird and holds vacuum on the diaphragm.

So, came home, checked the check valve for the booster, it was still good.

Adjusted up the base idle and readjusted the throttle position switch. All seems good now.

I have base idle up around 900 rpm now, not a lot of lope to the cam at that RPM and I am wondering if that 800 or maybe below that was just too low for it to recover after boost.

Ill see how it does tomorrow and report back.

Thanks for the input guys,

Sean
 
I know when I swapped lh2.2 and b230ft into my 242, I had a bad check valve for the vac supply to climate control. So every time under load and off load, there was the whole volume of vac reservoir that was filling and emptying. That threw everything off. Good place to start is check valves. All that metered air going bye bye.
 
My 244 did this and I was never able to figure it out.

The ECU and ezk you are using are not the same as the ones I had in the 240+T I had a few years ago mind you.

Maybe it has something to do with being a manual car?
 
Any tears in the cbv cause a massive vac leak.

Also the AMM is supposed to be a 016 that might be an issue.
 
DAMN! This is all good stuff.. Im having same issues with my 82 242 b21ft, swapped to lh2.2 90+ intake -- Runs good till warm then idle is a bit jumpy, very intermittent drops in power and driveablity.. Change the temp sensor. 3 AMM tested OK and all the same issue with each one. Now Ive got the fuel pump out and a used one from a 740.. but!! Can I drop this accumulator next to pump? or to I need it? Has anyone swapped a 740 pump and how it done? Im going to try the throttle adjust & stop screw next.
 
CJs 142E said:
DAMN! This is all good stuff.. Im having same issues with my 82 242 b21ft, swapped to lh2.2 90+ intake -- Runs good till warm then idle is a bit jumpy, very intermittent drops in power and driveablity.. Change the temp sensor. 3 AMM tested OK and all the same issue with each one. Now Ive got the fuel pump out and a used one from a 740.. but!! Can I drop this accumulator next to pump? or to I need it? Has anyone swapped a 740 pump and how it done? Im going to try the throttle adjust & stop screw next.
Click to expand...

You can drop the accumulator. Its not needed.
 
OK Cool... Sorry hackster didn't mien to highjack this thread.. But I was having this same trouble with warming up and stalling and no power,, so I got the 740 pump in with the check valve and chucked the accumulator, plugged up that return line and she is running like Swedish sweetness again, but for how long?? we'll see.. It did this to me last week for 2 days than back to crap..
But much more smoother rev and acceleration, no boost lag.. :volvo:
 
Bad idle air valve. Same issue on my +T. You can replace it with a PVC ball valve with 3/4" barbs for like $10 from HD or Lowes to test.
 
OK! So, No Go.. :grrr: Started fine this morning and ran beautify. about 2 miles to work.. I was so hopeful.. :-P
I think it has Gremlins or Swedish Leprechauns..:wtf: On the way home did a loop out the highway back home 2 to 3 miles and I was about to pat my self on the back and poof she sputters and I have to limp her home again. I tried the air valve and nothing with or with out. I actually got the car without one and it ran fine.. I think it's VooDoo!! :twisted:
 
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