Well that's likely my problem. Needle lift showing zero as well until revs go over 1500. Seems a bit intermittent. No fault light.
I'm a bit puzzled by there being no response from the needle lift sensor below 1500rpm. Does it appear that the engine is misfiring? Have you checked the connector for the lift sensor is not corroded and that the wire is not trapped by the manifold?
 
I'm a bit puzzled by there being no response from the needle lift sensor below 1500rpm. Does it appear that the engine is misfiring? Have you checked the connector for the lift sensor is not corroded and that the wire is not trapped by the manifold?
Me too. I redid the static timing today just to make sure everything is spot on. 0.90 as the book says. The new injector is a Bosch 0 432 217 279 which seems to be the correct one. I have checked the injector for correct impedance and it seems to within normal range. I also traced the wires from the connector back to the ecu and checked for continuity and and it’s good.

Perhaps the ECU has gone loco? Is that common with these?

Will check fueling again tonight or tomorrow. We have a national holiday today. Got to take the kids and watch a big bonfire - Valborgsmässoafton.
 
Me too. I redid the static timing today just to make sure everything is spot on. 0.90 as the book says. The new injector is a Bosch 0 432 217 279 which seems to be the correct one. I have checked the injector for correct impedance and it seems to within normal range. I also traced the wires from the connector back to the ecu and checked for continuity and and it’s good.

Perhaps the ECU has gone loco? Is that common with these?

Will check fueling again tonight or tomorrow. We have a national holiday today. Got to take the kids and watch a big bonfire - Valborgsmässoafton.
This is the resistance reading I got on a brand new no4 injector.
Screenshot_20250430_190826_Chrome.jpg
 
Me too. I redid the static timing today just to make sure everything is spot on. 0.90 as the book says. The new injector is a Bosch 0 432 217 279 which seems to be the correct one. I have checked the injector for correct impedance and it seems to within normal range. I also traced the wires from the connector back to the ecu and checked for continuity and and it’s good.

Perhaps the ECU has gone loco? Is that common with these?

Will check fueling again tonight or tomorrow. We have a national holiday today. Got to take the kids and watch a big bonfire - Valborgsmässoafton.
ECU failure is not common. Enjoy the bonfire.
 
Just a thought, why did you replace the original #4 injector?
It was actually the previous owner who did that. He claimed he was getting errors for needle lift sensor and bought a new injector. U have the receipt and it looks new compared to the others.

Today I started the car and was having readings on injection actual close to Injection set point. Needle lift was spot on crank rpm as well. But it seems to go to zero on idle when car is getting warm. Modulation at hot idle is at 55% - no fluctuations.

I drove it a bit and computer says that boost is about 1.5bar over atmospheric on full load. That’s seems like a lot! It’s still very slow. I pulled the hose from the map and drove again. No difference in power delivery although computer says atmospheric pressure and nothing more ( resonable since hose from manifold was disconnected.

I checked the wastegate arm and it opens and closes mechanically and there is good tension on it when trying to open the wastegate.

Throttle pot is at 0.4mv at idle att tops out at 3.4mv at full throttle. Smoth in between.
 
I can also add for the curious one that if I adjust the top pump with the gentle rubber mallet technique I can it make it idle at 750. But the throttle input is almost non existent. Current fuel number will be around 25.
That will also give me needle lift sensor error och timing deviation error.

I’f I move it the other way with mallet, idle increases immediately and settles to about 820-830rpm. That will work between 3-12 on the current fuel. Lower than 2.5-3 ish will make the idle hunt very much. I’ve settled around 4-5. Very good throttle response although if I rev it fast and let go it will drop fast to about 1000rpm and then go down to 830ish little slower. The fault codes will not reappear.

I wonder if it’s possible to adjust the potentiometer in the pump and if that would actually make any benefits? Or to freshen up the contact surface. I’m not sure how or if that’s possible.
 
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Well. Spent the evening yesterday tinkering and thinking. Tried various qa positions and tried to retard and advance the timing in small increments.

No change in result. There is just not enough fuel coming to the cylinders to produce power - I think. 3500 rpm seems to be it. It almost feels like hitting a revlimiter at 3500, kind of just bogs down there. (No smoking).
No air in lines from filter to fip. Lift pump giving 400ml of fuel on 10 second run. Newish filter. Will measure from filter to fip today.

I have not yet seen any black smoke in any setting, only white smoke when timing is too retarded.
I’ll try to make a test of each injector by collecting return fuel in a can of each one and see if they are about equal.

Any other suggestions?
 
Well. Spent the evening yesterday tinkering and thinking. Tried various qa positions and tried to retard and advance the timing in small increments.

No change in result. There is just not enough fuel coming to the cylinders to produce power - I think. 3500 rpm seems to be it. It almost feels like hitting a revlimiter at 3500, kind of just bogs down there. (No smoking).
No air in lines from filter to fip. Lift pump giving 400ml of fuel on 10 second run. Newish filter. Will measure from filter to fip today.

I have not yet seen any black smoke in any setting, only white smoke when timing is too retarded.
I’ll try to make a test of each injector by collecting return fuel in a can of each one and see if they are about equal.

Any other suggestions?
Blocked CAT.
 
Well, the car was cheap and meant to be a project/learning experience. So I tapped on the cat with a steel bar and it was a very muffled sound - maybe it was plugged. So I cut the exhaust right before the cat. Made zero difference other than noise 😂.
 
I can also add for the curious one that if I adjust the top pump with the gentle rubber mallet technique I can it make it idle at 750. But the throttle input is almost non existent. Current fuel number will be around 25.
That will also give me needle lift sensor error och timing deviation error.

I’f I move it the other way with mallet, idle increases immediately and settles to about 820-830rpm. That will work between 3-12 on the current fuel. Lower than 2.5-3 ish will make the idle hunt very much. I’ve settled around 4-5. Very good throttle response although if I rev it fast and let go it will drop fast to about 1000rpm and then go down to 830ish little slower. The fault codes will not reappear.

I wonder if it’s possible to adjust the potentiometer in the pump and if that would actually make any benefits? Or to freshen up the contact surface. I’m not sure how or if that’s possible.

I wouldn't touch that pump too much. Tap it to idle at 750 rpm and leave it. If there is no throttle response then someone may have had the top off and not engaged the pin into the collar.
 
There is a potentiometer in the pump top. I'm trying to remember what it looked like but I recall you can clean it. I think it might have some sort of ribbon cable that solders on one side in order to get it out and clean underneath it but I really wouldn't bother unless it is last resort. Blast it with carb-cleaner or brake cleaner and blow it out.

If I have time I will see if I can find any photos. I took some but I tend to photo the engine at the start and then not take any till the end because I don't want to get my phone screen dirty.
 
You can unplug the lift sensor and it will run on default values using the crank sensor.
Yeah i dit that but it made no difference. I think the pump is shot. It’s provably not delivering enough fuel pressure for needle to get a steady reading. It will start to register when rpm is raised to min 1500 rpm.
I wouldn't touch that pump too much. Tap it to idle at 750 rpm and leave it. If there is no throttle response then someone may have had the top off and not engaged the pin into the collar.
I’ll take the top of and check the collar. I was under the impression that a missed pin in collar would give other symptoms but it’s sure worth a try.
Plausible that the return line ball and spring valve is too tired and releasing pressure back to tank?
There is a potentiometer in the pump top. I'm trying to remember what it looked like but I recall you can clean it. I think it might have some sort of ribbon cable that solders on one side in order to get it out and clean underneath it but I really wouldn't bother unless it is last resort. Blast it with carb-cleaner or brake cleaner and blow it out.

If I have time I will see if I can find any photos. I took some but I tend to photo the engine at the start and then not take any till the end because I don't want to get my phone screen dirty.
 
Possibly. Old lift pumps had a non-return valve built in. Later ones don't so I fitted one just after the fuel filter.
 

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