Skyline Running Badly/timing Problems

[sky20det]

hi..

as said in the topic the car runs very badly. the crank angle sensor has to be turned ALL THE WAY to the RIGHT to get the timing to almost 10, but not even 10 degrees. the idle speed has to be turned up a bit to keep it from reving too low and almost stalling (sometimes). it also struggles to rev up in gears sometimes seems like there is not enough fuel..

it was on the dyno, and running very advanced timing, and the dyno showed that it was very lean.. like 0.9 all the way through. at first the guy thought it may have a non turbo ECU in it, but after checking the fuel pressure he told me the pump was very weak and that it needed to be changed.

i since have upgraded to a walbro in-tank fuel pump, new ryco fuel filter and even bought a 2nd hand crank angle sensor off a working rb20det, but still every problem is the same.

i now think that it may be that the timing belt is worn or mis-aligned.. would a timing belt that is misaligned or worn too much cause all these problems i am having?

the car is an r32 gts-t. full 3" exhaust and pod filter. everything else stock.

[BH_SLO32]

Can you please clarify a couple of things, namely:

1. The Crank Angle Sensor (CAS) is currently rotated fully CLOCKWISE? This would imply that the timing should be fully RETARDED. You mentioned that it is set at almost 10 degs. Does this mean it has been difficult to reduce it from 20degs, say, to 10 degs? How did you check the timing? Incorrectly inspected and you will see greater advance than what is actually present eg. 25 degs measured incorrectly can actually be 15degs. This would explain why the CAS is fully retarded and why you think you are seeing very advanced timing. For a manual Rb20det it should be about 15 degs BTDC. Easiest way to check the timing correctly is to place the induction light pickup over the 3 plug wires on number 1 cylinder coil.

2. What is meant by "the dyno showed that it was very lean.. like 0.9 all the way through". Excuse my ignorance but are you saying the O2 sensor voltage was 0.9?

3. Since upgrading the fuel system have you rechecked the fuel pressure?

Cheers,

[sky20det]

Can you please clarify a couple of things, namely:

1. The Crank Angle Sensor (CAS) is currently rotated fully CLOCKWISE? This would imply that the timing should be fully RETARDED. You mentioned that it is set at almost 10 degs. Does this mean it has been difficult to reduce it from 20degs, say, to 10 degs? How did you check the timing? Incorrectly inspected and you will see greater advance than what is actually present eg. 25 degs measured incorrectly can actually be 15degs. This would explain why the CAS is fully retarded and why you think you are seeing very advanced timing. For a manual Rb20det it should be about 15 degs BTDC. Easiest way to check the timing correctly is to place the induction light pickup over the 3 plug wires on number 1 cylinder coil.

2. What is meant by "the dyno showed that it was very lean.. like 0.9 all the way through". Excuse my ignorance but are you saying the O2 sensor voltage was 0.9?

3. Since upgrading the fuel system have you rechecked the fuel pressure?

Cheers,

sorry that my explanation is a bit misleading.

1. the CAS is definately rotated FULLY CLOCKWISE. yes it should indicate that the timing is fully retarded. if i return the CAS to around the middle (which i understand it should be for 15 degs BTDC) it becomes very advanced (no lines on the RHS of the mark on the block which we use to read the timing). i think from looking at the manual its 20 or 25 degs?

2. after it went on the dyno, the fuel mixtures showed that it was lean. very constant 0.9 all the way through the graph. turbo cars are meant to be running at 0.8 arent they? i dunno what units the fuel mixtures are in.

3. since upgrading the fuel mixtures, i have yet to re-check the fuel pressure or put it back on the dyno.

im just wondering if all the information supplied above would cause the problems i am having with my timing/idle/drivability of the car.

i am under the impression (from the seller) that my car has a tuned ECU. but it has a standard ECU in it. which leads me to the conclusion that it may be re-mapped.

another thing that i havn't meantioned is that when i adjust the idle speed without the "AAC electrical connection (brown)" connected, i set it to about 850rpm, and when the AAC electrical connection (brown)" is reconnected, it idles up to about 1200rpm. i use the idle adjustment screw on the AAC and also the one on the ECU. the one on the ECU is now fully turned to the left, but it wont idle down. infact, the idle doesnt change at all when turning the adjustment screw to the right on the ecu. could the incorrent idle be affecting my timing also? should i consider trying another rb20det ECU?

[wrxhoon]

Check the valve timming .

[Triskillion]

at first it seem like a fuel problem but you change the fuel stuff... so mayb a blockage in the lines...?

i had sortof a similar problem in my nx awhile ago (similar not exactally.)

had to take it 3 times.... to the mechanics. first was screwed engine mount. second was 02 sensor. third was thermostate..... after replacing all these my self and costing around $400 each time for just a diagnostic... i was out of money... so the car sat there for 3 days stright.... started it up... and it was running perfect... so in the end i think it just need ecu reset.

[sky20det]

sorry BH_SLO32, i may have gotten "advanced" and "retarded" mixed up. its just when i got it on the dyno, the mechanic said it was VERY advanced.. so thats y im confused...

ok this is what i see when i look and adjust the timing...

with the CAS in the MIDDLE position, the red marks on the pulley DO NOT go past the referencing mark on the block.

when turned to the LEFT a bit, the red marks (obviously) go to the left of the referencing mark on the block.

now we want to set it to 15 degs, so i try turning the CAS to the RIGHT to get 3 red marks on the RHS of the referencing mark. but even with the CAS turned all the way to the RIGHT, i cant get 15 deg, only close to 10...

[BH_SLO32]

with the CAS in the MIDDLE position, the red marks on the pulley DO NOT go past the referencing mark on the block.

Hmmm.....I suspected this is what you meant although I have never seen this scenario before (ie ignition is presumably taking place AFTER TDC). Assuming you do not have any adjustable cam gears a quick check of the position of the intake and exhaust cams will tell you straight away whether the cam timing is out. To do this remove the top cam gear cover and turn the engine over by hand until you reach TDC on the firing stroke. The bottom pulley TDC mark should obviously align with the mark on the bottom timing belt cover and the dimple on the front of the intake and exhaust cam gears should closely align with the white marks on the backing plate (at approximately 10 oclock and 2 oclock respectively).

If this all checks out ok then at least you know the cam timing is not a problem and it may suggest that the base timing has somehow been adjusted electronically. I'm not sure if it is possible to modify this when the factory ECU is reprogrammed but is certainly possible with aftermarket ECUs.

I would certainly suggest you try to get to the bottom of the timing issue as this is likely to affect the overall running of the motor and may explain the idle issue.

I would also suggest checking the fuel pressure again to at least eliminate it from the equation. If it is a reprogrammed ECU you would hope it is a custom chip and not something 'generic' as you may have a chip suited for a specific setup which is not suited to your engine (eg big turbo, different injectors).

Hope this helps.

Cheers

[sky20det]

so is my timing now (as i described) referred to as ADVANCED or RETARDED?

as in when its set UNDER 15deg is it advanced or retarded? and when it is set ABOVE 15deg is it advanced or retarded?

[blind_elk]

sorry that my explanation is a bit misleading.

1. the CAS is definately rotated FULLY CLOCKWISE. yes it should indicate that the timing is fully retarded. if i return the CAS to around the middle (which i understand it should be for 15 degs BTDC) it becomes very advanced (no lines on the RHS of the mark on the block which we use to read the timing). i think from looking at the manual its 20 or 25 degs?

Max timing indicated on the crank is 30BTDC - each mark is 5 degrees. If you can register "20 or 25 degs", why have you retarded it past 15 down to 10?

The other thing I have found is that if you use the "timing loop" on the ignitor module, some timing lights seem to indicate double the actual timing - so if you are seeing "10BTDC", it may well be that you actually have "5BTDC", which is totally inappropriate for a RB20.

On the crank pulley, the rightmost mark is 30BTDC, the leftmost mark is TDC.

If you want to get an accurate timing figure, you need to lift #1 coil off the spark plug and insert a spark plug lead between the coil and the spark piug - then you can always get an accurate reading.

Advanced timing is simply "more timing", retarded is simply "less timing".

If your mechanic says the timing is fully advanced, why the hell didn't he set it properly????

2. after it went on the dyno, the fuel mixtures showed that it was lean. very constant 0.9 all the way through the graph. turbo cars are meant to be running at 0.8 arent they? i dunno what units the fuel mixtures are in.

Generally when it is on a dyno, it is on a power run - the O2 sensors do not play any part under those circumstances.

another thing that i havn't meantioned is that when i adjust the idle speed without the "AAC electrical connection (brown)" connected, i set it to about 850rpm, and when the AAC electrical connection (brown)" is reconnected, it idles up to about 1200rpm. i use the idle adjustment screw on the AAC and also the one on the ECU. the one on the ECU is now fully turned to the left, but it wont idle down. infact, the idle doesnt change at all when turning the adjustment screw to the right on the ecu. could the incorrent idle be affecting my timing also? should i consider trying another rb20det ECU?

Did you pull it apart and clean the carbon build-up out of it?

[wrxhoon]

Did you just replace the timming belt ? If its out by even one tooth on the crank pulley (2 teeth on the cams ) it may cause this . As you said if the valve timming is correct then 15 deg ingnition timming the cas should be in the middle .Take the top cam cover off and check it out , like slo32 has posted above. Line up the very left ( usualy red) mark on the harmonic balancer with the mark on the cover ( usualy white ) , then the cam gears marks should line up with the marks on the backing plate , if they dont (out by a long way) turn the crank 360 degrees and see if they line up .

[sky20det]

Max timing indicated on the crank is 30BTDC - each mark is 5 degrees. If you can register "20 or 25 degs", why have you retarded it past 15 down to 10?

thats the thing, i cant register 20 or 25 degs. if i start to rotate the CAS (from the middle position) a slight bit anti-clockwise, the red marks move even more far away from the referencing mark on the block (to the left of it).

ok this is what is happening.. i want to set the timing to 15degs. so i have to get 3 red marks to appear on the RHS of the referencing mark. but thats where my problem lies.. i cant get anymore than 2 red marks to go past the referencing point.. when the CAS is fully clockwise, i can only just get 2 red lines to appear on the RHS of the referencing point.. so this tells me that my timing is not even at 10degs..!

Edited April 1, 2006 by sky20det

[sky20det]

Did you just replace the timming belt ? If its out by even one tooth on the crank pulley (2 teeth on the cams ) it may cause this . As you said if the valve timming is correct then 15 deg ingnition timming the cas should be in the middle .Take the top cam cover off and check it out , like slo32 has posted above. Line up the very left ( usualy red) mark on the harmonic balancer with the mark on the cover ( usualy white ) , then the cam gears marks should line up with the marks on the backing plate , if they dont (out by a long way) turn the crank 360 degrees and see if they line up .

timing belt will be changed/looked at to see if its mis-aligned in one more week.. have it booked in already.

to check if the valve timing is correct, i would have to remove the top cam cover.. do i have to remove the radiator to get to it?

[wrxhoon]

timing belt will be changed/looked at to see if its mis-aligned in one more week.. have it booked in already.

to check if the valve timing is correct, i would have to remove the top cam cover.. do i have to remove the radiator to get to it?

No need to remove the radiator , 5 allen key bolts ( if i remember correct ) and 3 little hex ( 8mm heads) to remove the coolant pipe , its that easy .

[blind_elk]

thats the thing, i cant register 20 or 25 degs. if i start to rotate the CAS (from the middle position) a slight bit anti-clockwise, the red marks move even more far away from the referencing mark on the block (to the left of it).

ok this is what is happening.. i want to set the timing to 15degs. so i have to get 3 red marks to appear on the RHS of the referencing mark. but thats where my problem lies.. i cant get anymore than 2 red marks to go past the referencing point.. when the CAS is fully clockwise, i can only just get 2 red lines to appear on the RHS of the referencing point.. so this tells me that my timing is not even at 10degs..!

NO! You need one mark on the reference mark and 3 marks on the pulley to be to the LEFT of the reference mark. The pulley is rotating clockwise as you look at it from the front of the car, ie left to right. The first mark that matches the reference mark is 30BTDC. The next mark is 25, the next 20, and so on - the last (leftmost) mark is TDC.

If you have 2 marks to the right (with one lining up with the reference mark), then you have 20BTDC (with the proviso of my previous post about the timing loop).

Regardless, your mechanic should blooodywell know - find a new / decent one.

[sky20det]

NO! You need one mark on the reference mark and 3 marks on the pulley to be to the LEFT of the reference mark. The pulley is rotating clockwise as you look at it from the front of the car, ie left to right. The first mark that matches the reference mark is 30BTDC. The next mark is 25, the next 20, and so on - the last (leftmost) mark is TDC.

If you have 2 marks to the right (with one lining up with the reference mark), then you have 20BTDC (with the proviso of my previous post about the timing loop).

Regardless, your mechanic should blooodywell know - find a new / decent one.

are you sure u want 3 red marks on the LEFT?

this is what i thought it should look like when set to 15degs

refer to http://www.skylinesaustralia.com/forums/in...showtopic=73824

looking at the above pic, when my CAS is fully CLOCKWISE, i get ONE mark on the reference mark, and TWO to the RIGHT (not 3 like above), thats y i say i cant get 15, but only 10degs... because the CAS wont turn any further clockwise

[RB240Dav]

Did you ever get this figured out? I had to advance my CAS completely in order to just get 15* bTDC, it's supposed to be 20* for the rb26.

I did did the valve timing myself when I replaced the water pump, so I know it's spot on.