• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

run w.o. BOV on 2.4

90volvo

Active member
Joined
May 27, 2017
Location
Eldorado Springs Mo.
Ive read and searched and seems like the more I read the more confused I get on this subject. I just add a T to my 1990 Volvo 240. The turbo is a TD04HL-15g with 940 ECU and EZK, 3 inch ex., V cam,. Have boost set at 6-8 lbs. The car dies alot after acc. Starts right back up and runs fine. The idle does seem a little low and little rough at time. Ive checked for vacuum leaks nothing there. Its been all turned up with plugs and wires etc. The plugs are BPR7ES, the injectors are bosch 0280155830. The intercooler is a stock 740.

The ECU is 937 and EZK is a 148 I believe. The car is a 2.4 system. Im thinking about taking the internal CBV off and putting a cover over it and see how it does? But like to know if this is ok to do? Thanks.
 
What is 3 inch? Your AMM size? What size injectors? Did you take the CBV apart and check make sure it isn't ripped in the diaphragm part? You should be able to hear it blow off the excess boost when you let off the gas in boost. If you don't have it the turbo will do a shuttering thing when you let off boost.
 
The AMM is the stock NA meter which I believe is 2.5 inches. The injectors Flow rates @ 43.5 psi / 3 bar
34.6 lb per hour
261.2 G per min. (N-Heptane)
363.3 cc per min

My fpr is a 3 bar (factory 940T)
Fuel pump is a single in tank upgraded. Don’t have the specks at this time.
Yes. I had the CBV apart and all looks good.
I do hear it working.
Can I crack the throttle open a hair raise idle rpm and maybe help?

12,00 Ohm resistance
 
does it have speedometer signal from the axle. my 740 turbo does similar and doesnt have speedometer signal and from what ive read, thats the cause.
 
does it have speedometer signal from the axle. my 740 turbo does similar and doesnt have speedometer signal and from what ive read, thats the cause.

Yes speedo works great. I did out of curiousity pulled a vacuum line off and it did idle better. Tomorrow I will mess with the idle motor (whatever its called). Not unless someone else chimes in. Thnks
 
maybe this will help someone. I had a bad vacuum leak; the vacuum lines going to the canister under front drivers sided fender. I pulled lines and plugged them going to the intake and everything smoothed out. I believe this canister has something to do with fuel tank vent? I also found a small intake leak. Any way thanks
 
Ive read and searched and seems like the more I read the more confused I get on this subject. I just add a T to my 1990 Volvo 240. The turbo is a TD04HL-15g with 940 ECU and EZK, 3 inch ex., V cam,. Have boost set at 6-8 lbs. The car dies alot after acc. Starts right back up and runs fine. The idle does seem a little low and little rough at time. Ive checked for vacuum leaks nothing there. Its been all turned up with plugs and wires etc. The plugs are BPR7ES, the injectors are bosch 0280155830. The intercooler is a stock 740.

The ECU is 937 and EZK is a 148 I believe. The car is a 2.4 system. Im thinking about taking the internal CBV off and putting a cover over it and see how it does? But like to know if this is ok to do? Thanks.

So 2.4 is relying on the air metered at the air mass meter to determine how much fuel to add. A blow off valve after the air mass meter is going to reduce the amount of air in the system to less than what the air mass meter measured. But the computer is still counting on all the air it measured to be there when it adds fuel so you?ll end up with a super rich. Now, is that rich spot enough to choke out your engine? Maybe. Maybe not.

With the air mass meter after the turbo Volvo?s 2.4 computer would really rather have a cbv. Less wooshy noises but the engine will run better.
 
maybe this will help someone. I had a bad vacuum leak; the vacuum lines going to the canister under front drivers sided fender. I pulled lines and plugged them going to the intake and everything smoothed out. I believe this canister has something to do with fuel tank vent? I also found a small intake leak. Any way thanks

Yes, the canister allows gas vapors to vent into the intake. Not really a common failure point but if the lines were cracked you can replace them or just cap them off.
 
When using a BOV with an AMM the BOV should not dump to atmosphere, it should recirculate the air.

The BOV must dump into the turbo inlet after the AMM or the AMM will measure dumped air and the ECU will add fuel causing a temporary over-rich condition.
 
So 2.4 is relying on the air metered at the air mass meter to determine how much fuel to add. A blow off valve after the air mass meter is going to reduce the amount of air in the system to less than what the air mass meter measured. But the computer is still counting on all the air it measured to be there when it adds fuel so you?ll end up with a super rich. Now, is that rich spot enough to choke out your engine? Maybe. Maybe not.

With the air mass meter after the turbo Volvo?s 2.4 computer would really rather have a cbv. Less wooshy noises but the engine will run better.

would AMM be better after the turbo. and want to apologize I have 15g which has CBV. This morning the car started surging. Long story short I have an intake gasket leak. Gonna fix tonght. I really appreciate your help, I would be lost or probably would not have done the +T if it wasnt for the help I get from you guys. Hope one day I can return help to the Volvo kingdom
 
Did you relocate the Amm to the passenger side already? The amm will be happier before the turbo.

An idle that surges or “hunts” is indicative of a vacuum leak. I’d get your vac leak sorted first and then see where you’re at.
 
Did you relocate the Amm to the passenger side already? The amm will be happier before the turbo.

An idle that surges or ?hunts? is indicative of a vacuum leak. I?d get your vac leak sorted first and then see where you?re at.

yes, its on the passenger side now. Yelp puting new intake gasket on tonight will let you know how it does following. I would imagine that will solve the car dying after quick boost and the surger problem too.
 
update: I had a intake gasket leak. Long story short I fixed it last night. It fixed the dying problem and the car is not pinging either. Thanks for the help.
 
Back
Top