Engine Problems

[Alecci]

Posting this in a shortened version in one of my already existing threads (albeit with a non-connected title) gave no response, so here's a thread of its own. There's a good possibilty this will be my last thread on this forum...

My engine isn't running well, symptoms are described below:

With GReddy e-Manage Ultimate:
1: Idle is severly unstable, varying between 500 and about 3,500 rpm. At lower revs the engine dies, and except for at the higher revs it misfires a good deal. Between about 3,000 and 3,500 rpm the engine runs reasonably well. According to the mapping computer, the engine runs somewhat lean.
2: No matter what figures we set in the different mapping sections of the EMU (regarding fuel, ignition and airflow), no change to how the engine runs is noticable.

With Apexi Power FC:
1: Idle is mostly like with the EMU, but it's a tiny bit more stable and not varying as much in rpm's. It misfires less, but when it does, it misfires significantly, to the point of sounding like gunfire. Another thing is new though, the car enters some sort of "launch control mode", revving up to the redline all on its own. When doing this, the engine runs basically as it should, clean and all.
2: Altering the fuel map values makes a good deal of difference to how the car behaves, but doesn't solve the problem.
3: All the in-data signals looks good according to the mapper.
4: When disconnecting the rear AFM a slight change in the engine's running is discernable, when disconnecting the front AFM the engine dies. Switching the connectors between the AFM's make no difference at all.

What's already been checked:
1: The CAS is brand new, bought from Abbey M/S earlier this month. As far as I know, it can only be mounted and connected in one possible way.
2: The spark plugs are basically brand new (less than ½ hour of use). They give spark, and when checking them they are solid black but not wet or moisty.
3: We've changed the AFM's both for other Nismo ones, testing all possible combinations (in case one of mine and in addition one of the borrowed pair was faulty), and for standard ones. Changing the AFM's made no difference whatsoever. My Nismo AFM's are also brand new.
4: The fuel system seems to be the only thing working exactly like it should, and fuelling is also the only parameter we've succeeded in altering with a difference to how the engine runs.
5: I wasn't personally present last time the cambelt/timing belt was installed, but I gave instructions to the workshop doing it and told them to use a clock to determine TDC on the #1 cylinder, checking it against the markings on the crankshaft belt pulley and the oil pump, and to carefully align the markings on the cam pullies to the markings on the bar behind the cambelt cover.
6: The adjustable cam pullies remain at factory settings at 0°, being neither retarded nor advanced.
7: Ignition angle is impossible to set properly, since the engine refuses to hold the same revs for any period of time longer than about 3 seconds. We've tried to set it as close as possible to 20°, and the CAS then sits at about the middle of the adjustment slots.
8: All circuits have been checked and found to be in good order.
9: We still receive error code 21 (primary ignition signal). We had it before but thought that it was due to the mangled CAS mounted at the time.
10: All cylinders are working.

My own conclusions, be they right or wrong:
1: The CAS should not be what causes these problems.
2: ECU should not be the culprit either, as we basically have the same problems when shifting from the EMU to the APFC.
3: The AFM's should not be the ones to blame here, as neither replacing them with other Nismo items or standard items makes any difference.
4: I wouldn't suspect the coilpacks, as all cylinders are running and the engine runs fine on higher revs (when revving up that is, as revs will never stabilize).
5: Injectors or fuel system seems far-fetched since this seems to be only thing working like it should.

My own suggestions to what may be causing these symptoms:
1: The ignition angle, naturally, as we've not been able to adjust this properly due to the engine revving up and down on its own all the time.
2: Position of the camshafts, possibly, but probably not as the workshop installing the cambelt is a one with a good reputation for its competence.
3: The different specifications of the camshafts? My inlet camshaft is 260° with 10.25mm lift while the exhaust camshafts i 252° with 9.15mm lift. I know that the 'lobe center' differs between the camshafts, but I don't know the measurements by heart.

Notes:
1: Replacing the injectors with stanard items is not an option, as the ones in place have different connectors. The standard connectors have since been thrown away, the standard injectors themselves have been sold and the wires are not too short to reverse the operation.
2: I have no loose wire/cable ends in the engine bay or elsewhere, and the same applies to connectors except for one by the oxygen sensors. I've not been able to find a matching cable/wire though.
3: All earth wires has been checked and rechecked. The only ones missing are the ones that originally mounts to the exhaust manifolds or their heatshields, but I have friends running their cars without them, and they don't experience any trouble from it.
4: A complete spec list of the car is available here: Nissan Skyline R34 GT-R (1999) - GARAGET - www.garaget.org Please note that ALL aftermarket parts are brand new.

No workshop here in Sweden has a clue to what these problems may be. I'm close to losing heart over this, having spent thousands of pounds and 1 year and 10 months rebuilding the car since a crash at a track event in September 2006. I am now seriously considering selling the car, as this process has regrettably drained my bank account, my motivation and my stamina.

[paul cawson]

You need to check the intake system for air leaks, then I would carry out a cylinder leakage check.
After that have your injectors cleaned and flow checked.

[Alecci]

A small update:

We once again checked and double-checked the position of the camshafts, and there's nothing wrong there.

We've also done a compression test, and it worked out just fine, all cylinders giving a ratio between 9:1 and 9,5:1.

[n boost]

Originally Posted by paul cawson

You need to check the intake system for air leaks, then I would carry out a cylinder leakage check.
After that have your injectors cleaned and flow checked.

I second that and would also check wires incase u got one trapped and may have a short.
Have u had injectors flow tested? as this could be causing u running problems.
Does sound like an ignition problem related to the cas, so would check all wires/loon/plugs going to it.
Basically u need to go through everything to eliminate possible causes.

[Alecci]

I'm afraid I don't have the tools nor the skills do do a leakdown test, and neither do anyone I know around where I live. Like I've mentioned, I simply don't have the funds to let a garage/workshop do it for me.

The injectors have not been flow tested, I don't even know how to perform the test. Just stressing a previous point, the fuel system seems to work fine, in fact it's basically the only thing that we're sure is right. Please explain the process and I will look up if that is a viable option.

I agree that it sounds like an ignition problem... The CAS itself is brand new (less than ½ hour running time), and wires have been tested, nothing weird going on there.

I know I actually do need to go through everything, but this would take so much time to do alone, that season will have passed before long, and in that case I'd rather sell the car.

I appreciate your help, I really do. But I need a point where to start looking, as I do not have the time to check everything. I've got two jobs and a household to run on my own, so time is scarce I'm afraid.

My next step will be to disassemble the intake plenum, check the throttle bodies and then move on to vacuum lines and idling system.

[Alecci]

Originally Posted by Alecci

2: I have no loose wire/cable ends in the engine bay or elsewhere, and the same applies to connectors except for one by the oxygen sensors. I've not been able to find a matching cable/wire though.

This appears to be the Exhaust Temp Sensor. I didn't think of it earlier as there's no flange for the sensor on my GReddy L-bow... I also thought that only the V-spec was equipped with this sensor.

Could the lack of the temp sensor be causing the trouble? Do I really need it?

Or could it possibly be that one of the O2-sensors doesn't work?

Anyone have the prices on these two types of sensors and where I could get hold of them quickly?

[R34 lover...]

I would get in contact with nicolas Kiesa.. he has a R34 of his own... totally rebuild.. but i guess you know this....

He has done the work himself... also mapping....

[r33gtsman]

Originally Posted by R34 lover...

I would get in contact with nicolas Kiesa.. he has a R34 of his own... totally rebuild.. but i guess you know this....

He has done the work himself... also mapping....

Seconded there, also I know it may be a long shot but have you spoken with skylinemecken over on skyline.se to see what he says ? He has been very helpfull with mine so far here in Sweden so it has to be worth asking ?

[Alecci]

I managed to solve the problem myself, it turned out to be quite simple.

By mounting the GReddy intake plenum the position of the throttle linkage was changed, since the aftermarket item is larger than the OEM part. Since the manual that arrived with the GReddy plenum was in Japanese only, I was never made aware that I had to adjust the throttle arms.

Now we'll only have to adjust idle and iginition angle once again before sending the car off to mapping. Hopefully this will be accomplished next week.

[Hugo]

That's brilliant!! You must be well chuffed!

[Chamber]

recently joined the board and having read your post and dedication to your project i was upset to see you were selling it but the good news you are getting now, well done! good luck to you! great project and car! this is what it should all be about! having to sell your left kidney for your own built dream machine but it's all worth it in the end!

[binjoau]

Imagine if you had sold it and somebody had fixed it that quickly, you would have been pissed!!! Glad you got it sorted, its nice to see such a sad story turn out great in the end!