[Kaas]

Hi guya, I have had this up before, but I still got alot knock problems. I have soon tryed every things, and I dont know what to do now.
I have replaced the ignitions leads and rotor and distrubitor cab and spark plugs and so on!
I have testet the fuel pressure and thats ok, 3.2 bar on full boost! I have tryed severel timing settings. Betvine 19 - 9.5 degress TDC and 16 - 5.5 degress TDC.

I have a 900 from 1990, lucas full pressure turbo 16. Running with mbc/bleeder valve and 3" down pipe and mats fuel chip and 9000 intercooler and blow off valve and KN air filter. The boost is about 1.1 bar!
I have looked at the timings marks and they are ok! I replaced the chain tensioner because the chain was a bit loose. That did not help! I am running with octane 98 fuel!
I cant hear the knock, but I can see it on the led!

I am planing to try another knock and another AMM. First I will try adjust my AMM for somthing.

Can it be the cat maybe? Or the O2 sensor, have hears that the O2 sensor is not the same as bosch.

What can it else be?

 

[Adrian W]

I don't think anything is "wrong" with your car. If you are detonating, lower your boost pressure. If there is anything "wrong" with your car, it is probably just carbon deposits on the valves and combustion chambers causing hot-spots.

It could also be the fuel chip; it may be too lean.

You could also install water injection.

 

[ShadowWorks]

Is it possible that your knock sensor is fualty? it must happen ever now and then, i think i read they can be over sensitive and detect engine vibration and not knock? how are your engine mounts.

Your car sounds like a powerful moster TBH.

 

[Eric van Spelde]

I have testet the fuel pressure and thats ok, 3.2 bar on full boost!

Shouldn't that be in the region of 4 bar, being 3 bar (or whatever your FPR rating is, assuming it's a fixed rate one) over the 1.1 bar positive manifold pressure on full boost?

What's the fuel pressure at idle?

 

[Kaas]

Hi guys, thanks for the quick responce

I have been thinking on making a water injection system, I just need to find a good an easy way to make a system. I have a spare fuel cut out switch I will use somehow

I am running on octane 98 right now, maybe I shall try shell's fuel "called V-power octane 97 here in Denmark" it cost a bit more, but they have added some cleaning producs in it! Maybe that will clean the carbon deposits on the valves and combustion chambers if there is some!

ShadowWorks: My monster said 225 bhp and 350 nm tourqe on the last rolling road :evil: test , nice !
I think I will try another knock sensor tomorrow, to see if the old chould be over sensitive! My engine mounts are good, or I hope so anyway They look ok, and I have the hydralic ones!

Eric van Spelde: I have a stock 3 bar fpr, but I have given it a bit of pressure on the top, so now its a 3.2 bar The fuel pressure is 2.7 bar at idle

 

[trackside]

So the fuel pressure is 4.3 bar at full boost (3.2 + 1.1)?
O2 sensor will not effect the mixture on boost - this is the AMM signal and the fuel map in the ECU - have you tried adjusting the AMM?
I have encountered Knock when I ran just base boost but took the signal for the actuator from after the IC instead of off the turbo - seems that the turbo can surge for a short time before the pressuer signal can reach it to open the waste gate. Everything sounds right so it could be the APC unit being over sensitive - have you treid swopping this?

 

[Kaas]

Its my turbo boost that is 1.1 bar And my fuel pressure that is 3.2 bar


I have a little update: As I was installing another AMM for half an hour ago, the other AMM did I set to 450 ohm and the old AMM was set to 515 ohm.
When temp. just got in the green zone and I pushed the throttle the boost was VERY nice as it should be, but after I had run the car in normal temp "in the middel" for about 15 kilometers, and then the car startet to knock and there was alot reduce in engine power.
I hope you can understand my half english and Danish

I am starting to think of the temp sensor for the EFI, maybe!

 

[Kaas]

Does any of you have the specs on the NTC sensor when testing it, both for bosch systems and for lucas system. Maybe I can use a NTC sensor from a bosch system!

 

[Jezzadee]

I just replied to the other thread on this in the C900 Workshop here.

Lucas system:

0 deg C: 5700-5900 Ohms
20 deg C: 2400-2600 Ohms
40 deg C: 1100-1300 Ohms
60 deg C: 500-700 Ohms
80 deg C: 300-400 Ohms

Bosch system:

-20 deg C: 14000 Ohms
-10 deg C: 9000 Ohms
0 deg C: 5800 Ohms
10 deg C: 3800 Ohms
15 deg C: 3000 Ohms
20 deg C: 2600 Ohms
25 deg C: 2000 Ohms
30 deg C: 1700 Ohms
80 deg C: 320 Ohms

What I found is that my Lucas plug had a 4 pin connector (or maybe 2, will confirm in daylight). The Lucas sensor they gave me only has one connector - no way would it fit. So I've got a new one coming, and if it fits and has the same connector as yours I'll give you the part number. I don't think the Bosch one will fit.

 

[Matthew]

That fuel pressure does sound low...

Check fuel pressure at idle with the regulator's vac hose disconnected and plugged.

Is the engine noisy? The knock sensor is just a microphone and can be fooled by mechanical noise.

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[Kaas]

Hi matt!

I have testet the fpr at idle with the vac hose disconnected and that said 2.7 bar and with the vac hose connected it said 3.2 bar, it that ok?

The engine sounds good, but there is some kind of mechanical sound if I press the throttle by hand, the sounds is about 2000 rpms, it sounds a bit like piston tilt. There is no valve sound or chain sound at all!

 

[trackside]

It should be 3.0 bar (or above if you have modded it) at idle with the vac hose disconnected - change your FPR as you are running lean. Also set your AMM to 360Ohms as I beleive that that higher resistance is leaner ( yet to be100% certain) I get the occasional knock when I push my throttle hard with a 450Ohm setting but It's much more economical and I tend not to push it hard these days.

 

[Kaas]

Hi matt!

I have testet the fpr at idle with the vac hose disconnected and that said 2.7 bar and with the vac hose connected it said 3.2 bar, it that ok?

The engine sounds good, but there is some kind of mechanical sound if I press the throttle by hand, the sounds is about 2000 rpms, it sounds a bit like piston tilt. There is no valve sound or chain sound at all!

I see I got it wrong! Its of couse 2.7 bar with the vac hose connected and with the vac hose disconnected it said 3.2 bar, sorry :lol:

 

[Matthew]

That's more like it

I thought it was odd that fuel pressure rose when the vac hose was reconnected. At idle you should be seeing manidolf vacuum, which would reduce fuel pressure.

Get a hand pump and accurate gauge on the FPR, pressurise it and see what happens to the fuel pressure.

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[Kaas]

I use to use my compressure and set it on 1.5 bar , when I am finding the timing advance, I think I can use the same way to test the fpr, right?

 

[Bennie]

I cant hear the knock, but I can see it on the led!

Test the RPM signal for the APC, pressuresensor and the wires.
Exchanged the wires from the pressuresensor.

If this not the problem then swap the APC for a good on.

Clean the injectors.

With howmust boost is the knockled active?

 

[Matthew]

I use to use my compressure and set it on 1.5 bar , when I am finding the timing advance, I think I can use the same way to test the fpr, right?

Agreed - same method will work with FPR (assuming the engine doesn't stall due to flooding!).

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[Kaas]

Bennie: I am running with a mbc, I only use the APC as a knock led system, I will use the APC again, I am about to test the diffence betvine the new APC mod and a mbc, on the rolling road!
I dont know where the knock starts, as its not the same every time!

I have replace the NTC last night, but to a bosch one. Thats the only one I can get here! But I see on jezz's list that there is a diffence, but not much!

 

[trackside]

Kaas - are you getting a constant and continuous knock or the occasional blink as your boost climbs? If the former yoi have a serious problem with your setup somwhere ( which sounds unlikely from your description)If the later and you are using an MBC it's likely the turbo will be spooling too quickly - as I have said before. If the boost rises very quickly it can overboost for a short time or 'surge' which will lead to knock before the various control systems ( ignition retard, MBC, FPR etc) get a chance to adjust things - this will not bee seen on the stock boost guage which is heavily damped. Is the MBC a bleed type or ball and spring threshhold type? Is your wastegate uprated ( so it can fully release large amounts of boost) or is it a stock one that is cranked up (this can cause surge by not being able to dump enough exhaust gasses)

 

[Kaas]

Kaas - are you getting a constant and continuous knock or the occasional blink as your boost climbs? If the former yoi have a serious problem with your setup somwhere ( which sounds unlikely from your description)If the later and you are using an MBC it's likely the turbo will be spooling too quickly - as I have said before. If the boost rises very quickly it can overboost for a short time or 'surge' which will lead to knock before the various control systems ( ignition retard, MBC, FPR etc) get a chance to adjust things - this will not bee seen on the stock boost guage which is heavily damped. Is the MBC a bleed type or ball and spring threshhold type? Is your wastegate uprated ( so it can fully release large amounts of boost) or is it a stock one that is cranked up (this can cause surge by not being able to dump enough exhaust gasses)

Ok, I have not been thinking of that, but I think you have a point there mate!
The mbc is a bleed type, and my boost is very quick :evil: The knock sometimes comes on boost climbs but most at full boost!
My wastegate is just a stock one that has been cranked up If I shall have another one, whitch one shall I use, or can I mod my old old, with an outer spring or?

Chould my fast boost climb really cause the knock? Maybe thats why I get less knock, if I set my ignition timing lower 16-5.5 degress TDC. If I set it 20-9.5 degress TDC the boost climb is more fast!