No boost

[TonyS9]

Originally Posted by vickyg

It's also had new cap and leads, more tomorrow, if it stops raining...

The main problem causing weak spark in the 940 is oil leaks into the distributor, it normally causes hesitation, the lack of a check valve in the PCV system causes oil to push out of the seals during the pressure dump. If you drive it gently (off boost) its less of an issue.

The ignition amp can go bad too, usually heat related.

[vickyg]

Originally Posted by TonyS9

The main problem causing weak spark in the 940 is oil leaks into the distributor, it normally causes hesitation, the lack of a check valve in the PCV system causes oil to push out of the seals during the pressure dump. If you drive it gently (off boost) its less of an issue.

The ignition amp can go bad too, usually heat related.

The old cap was certainly an oily mess but it's probably not even done 100 miles since the new cap and rotor. I'm hopeful of some better weather today to take a look.

[TonyS9]

Originally Posted by vickyg

The old cap was certainly an oily mess but it's probably not even done 100 miles since the new cap and rotor. I'm hopeful of some better weather today to take a look.

It can deteriorate quite quickly, mine drives very well just after I clean the cap, but it goes back to the normal hesitation within about 30 miles. I have wasted spark distributorless ignition on my 360 B230FT, it so smooth and torquey. I have the bits for the 940, its just not bad enough to spur me into action.

[vickyg]

Should waste gate arm/rod move by hand or only under power? It is solid. Still attached however. No air leaks anywhere we can find but zero boost. Cap, leads etc. fine and runs and revs really smooth so no reason to suspect fuel.

[vickyg]

I also have a hole in my diaphragm (the words that would scare so many men lol)

[TonyS9]

Originally Posted by vickyg

I also have a hole in my diaphragm (the words that would scare so many men lol)

Thats to control the dump valve. If its faulty it will cause stalling after boost, not a lack of boost.

As already mentioned the word boost means turbo boost pressure. If your boost guage is showing boost, you have boost. What you are having is a lack of power.

Reving without load does not indicate perfect fuel delivery. Its more an indication that spark is ok (but not 100%). You need to measure the fuel pressure to check the FPR, and you might need to look at the AMM, or look for post measurement induction leaks. Also check all injectors are working by disconnecting each one at a time while the engine is running. The effect should be equal each time.

Is there any possibility the valve timing belt might have slipped? Has it been off recently?

[vickyg]

Originally Posted by TonyS9

Thats to control the dump valve. If its faulty it will cause stalling after boost, not a lack of boost.

As already mentioned the word boost means turbo boost pressure. If your boost guage is showing boost, you have boost. What you are having is a lack of power.

Reving without load does not indicate perfect fuel delivery. Its more an indication that spark is ok (but not 100%). You need to measure the fuel pressure to check the FPR, and you might need to look at the AMM, or look for post measurement induction leaks. Also check all injectors are working by disconnecting each one at a time while the engine is running. The effect should be equal each time.

Is there any possibility the valve timing belt might have slipped? Has it been off recently?

Due to recent work to rectify the rain that got in the tank all the injectors have been off and checked, new fuel pressure reg also. No codes on LEDs. it would appear I have two problems, the hole in the diaphragm - yes it stalled on my husband AND the stuck waste arm which as I understand will mean no boost. The turbo does not kick in at all. Until this latest issue it once again was running like a dream and sailed through MOT. I'd just got 4 new tyres when this happened. I think the priority has to be getting that actuator arm to move again, if it will.

[Laird Scooby]

Originally Posted by vickyg

Due to recent work to rectify the rain that got in the tank all the injectors have been off and checked, new fuel pressure reg also. No codes on LEDs. it would appear I have two problems, the hole in the diaphragm - yes it stalled on my husband AND the stuck waste arm which as I understand will mean no boost. The turbo does not kick in at all. Until this latest issue it once again was running like a dream and sailed through MOT. I'd just got 4 new tyres when this happened. I think the priority has to be getting that actuator arm to move again, if it will.

If the actuator arm has siezed through rust, mix some synthetic ATF (Carlube ATF-U, NAPA MV or similar) 50/50 with some acetone aka nail varnish remover. Shake well, dribble, paint or spray it on to the wastegate rod/actuator arm fulcrum and any other parts you deem should be capable of movement and leave to soak for a while. Seal the tub/pot you mix the WMP (Weapon of Mass Penetration - oooooooooo-errrrrrrrrrr missus, we're back to diaphragm jokes! ) to prevent evaporation and shake it well before each use as the two liquids have a tendency to separate.

Maybe add a second dose of WMP and wait a few more minutes, try to move the arm etc each way and evenutally it should move. It's also great on rusted fasteners, i haven't found one yet to beat it.

[TonyS9]

Originally Posted by vickyg

Due to recent work to rectify the rain that got in the tank all the injectors have been off and checked, new fuel pressure reg also. No codes on LEDs. it would appear I have two problems, the hole in the diaphragm - yes it stalled on my husband AND the stuck waste arm which as I understand will mean no boost. The turbo does not kick in at all. Until this latest issue it once again was running like a dream and sailed through MOT. I'd just got 4 new tyres when this happened. I think the priority has to be getting that actuator arm to move again, if it will.

I think you said the wastegate arm was stiff, this is normal. Its held closed by a stiff spring in the actuator, which is pushed out and opens the wastegate when it gets whatever pressure it is set to (around 7psi for an FT, 4.5 for a FK). If its held shut you will get too much boost (after around 2500 rpm driving not reving without load), and if its stuck open the boost won't reach the normal pressure until higher rpm.

If you remove the hairclip with needle nose pliars you can lift the arm off the wastegate pin and the wastegate should move freely then. Try not to lose it.

Neither will stop the car accelerating totally, although about 15psi boost the engine will cut out totally at a certain load as there is a air flow limit set in software. Stuck open will just be low on acceleration, but will be driveable at most speeds. In fact stuck closed will make it go like a bat out of hell, but it might cut out, this is why you have a boost gauge). On my gauge the T in Turbo represnts about 11psi, which is a safe level of over boost and many people use for fun. An FT would be around halfway to the T.

[vickyg]

Originally Posted by TonyS9

I think you said the wastegate arm was stiff, this is normal. Its held closed by a stiff spring in the actuator, which is pushed out and opens the wastegate when it gets whatever pressure it is set to (around 7psi for an FT, 4.5 for a FK). If its held shut you will get too much boost (after around 2500 rpm driving not reving without load), and if its stuck open the boost won't reach the normal pressure until higher rpm.

If you remove the hairclip with needle nose pliars you can lift the arm off the wastegate pin and the wastegate should move freely then. Try not to lose it.

Neither will stop the car accelerating totally, although about 15psi boost the engine will cut out totally at a certain load as there is a air flow limit set in software. Stuck open will just be low on acceleration, but will be driveable at most speeds. In fact stuck closed will make it go like a bat out of hell, but it might cut out, this is why you have a boost gauge). On my gauge the T in Turbo represnts about 11psi, which is a safe level of over boost and many people use for fun. An FT would be around halfway to the T.

Driving the boost gauge won't go past say 11 o'clock. We have some steep hills nearby (17%) and it barely crawled up, didn't think I'd make it home at one point. On the flat someone who didn't know better would probably think it was just a really old slow banger. It does accelerate but v.v.slowly (no turbo engaging) and no more than 50-60mph. Can be hard to judge as the speedo often doesn't fire up until you've been on the road a bit!