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I'm struggling with a no start condition on a 2JZGTE running a MoTeC M800.
It seems the car only wants to start when I flood it with fuel, but then it's so much, that it starts and backfires through the inlet valves and dies.
Things that I double checked:
-) mechanical timing
-) firing order
-) all injector and ignition Outputs
-) trigger wiring and polarity
-) fuel pressure
-) fuel is deliviered and coils are indeed firing
Anyways, all of this took me Friday afternoon before I finally started looking at the diagnostic page and noticed those errors:
-) Error Ref Runt
-) Error Ref Low Level
-) Error Sync Noise Ar
-) Error Sync Runt
At that point I needed to get a clean head and left the shop ….
Today I went through the MoTec Trigger Webinars again and read through their FSAE ECU Seminar again to check if I missed something.
To be honest, I think that the Runt and Low Level errors are only thrown because of what’s happening at the very beginning of the crank revolution.
Also I readjusted the Ref and Sync Mag Levels today (0.1V up and down from what they were initially), but I don’t think they were the culprit.
I think that there might be two reasons:
-) wrong CRIP settings
When the sync tooth lines up with the sync sensor, compression stroke TDC of cylinder #1 is exactly 360 crank degrees away.
But I might have set it wrong as I didn’t line up the very next tooth on the crank with the ref sensor and calculated from there.
According to my Ref/Sync capture, CRIP settings might be off 30 degrees, which could cause a no start situation (15 degrees ignition timing in the main timing table).
-) looking at the Ref/Sync capture every full engine revolution the Ref and the Sync spike line up pretty much perfectly, although the falling edge crossing to 0V is a bit apart.
Now both edges are falling and maybe that confuses the ECU, so that’s why it doesn’t start…?
I attached the Ref/Sync capture, so that you guys can zoom in and see what I mean.
I’d really appreciate you guys pointing me in the right direction ;)
Thanks a lot,
I don't deal with very many 2JZ engines however my recollection is that they use a 36-2 ref input. I'm not seeing any missing teeth in your ref/sync cap. Is this engine using a stock trigger system? What trigger mode are you running? Is it a VVTi engine or fixed cam timing?
It isn't uncommon to end up with a low level, runt or noise error occasionally during crank and this can often be attributed to low cranking speed and battery voltage. The one I would be looking for is 'Error Sync Signal' which tells you the ECU is not able to achieve synchronisation. Also check out the rpm during crank. If it's erratic as hell then this also points to triggering problems.
I have found occasionally that the Toyota reluctor inputs do require low trigger thresholds during crank as the signal level can be low. the ref/sync cap function here is as good as a scope though and you should be able to use this to set up the mag levels. You want to set these at about 1/3 of the peak signal amplitude.
You can check the CRIP value easily by checking the timing during crank while you are in the Crank Index Position mode. You should see stable timing while cranking and can adjust the CRIP value until the timing aligns with the test advance value. If you are having triggering issues the chances are that your timing will be erratic and impossible to adjust accurately.
Answer the other questions and I'll see what else I can offer.
MoTec did wonder too, that we're using a 12 tooth trigger wheel on the crank, but that is the factory wheel the car was equipped with :)
So yes, the trigger system is completely stock, no VVTi and fixed cam timing (apart from adjustable cam wheels, but cams have been centerlined to the specs of the manufacturer).
I didn't get the error sync signal, only those mentoined above ... that would indicate, that even when the ref/sync spikes in the capture line up, that the M800 is able to sync?
RPM seems to be constant at 240RPM, but that was only watching the MoTeC Software Manager live, not logging.
On the capture, the lowest voltage level of both, ref and sync, is about 1.5V, so I set the ref mag levels to 0.4V at 0RPM and 0.6V at 500RPM.
I agree, that runt and low level errors, seem to be a result of low cranking speed during the first crank revolutions.
I had my mate check the base timing during cranking and it did indeed line up pretty much perfectly, BUT maybe the result is a bit different when you check it at idle Speed?
If you like, I'd gladly send you my start map file.
thanks a lot,
That sounds exactly like my first hundred-series ECU experience -- my problem was not understanding that the injector & ignition outputs are numbered in the sequential order in which they activate, and thus they need to be connected in the firing order of the engine (ie. for a 1-3-4-2 firing order, INJ1/IGN1 - cyl 1, INJ2/IGN2 - cyl3, INJ3/IGN3 - cyl4, INJ4/IGN4 - cyl2).
The Adjust->General Setup->Firing Order table is only used in the ECU manager software to label the Individual Cylinder Trims correctly, it does not change the sequence in which the outputs are activated.
I know you said you checked the firing order, but did you actually see which order the plugs were firing in? Pull out all plugs and watch them spark while cranking...
The good news is it's easy to move the pins at the ECU connector if this is indeed the problem.
given that the base adapter loom was bought from John Reed, I've been under the Impression that this is how it has been wired (in the firing order) ;) but I'll check that anyways tomorrow.
Did anyone take a look at the Ref/Sync Capture? What do you guys think of the Ref/Sync "waves" lining up almost perfectly?
I do recall watching a MoTeC webinar were Mark McCoy said, that if that happens with two reluctor sensors, both triggering at falling edge, that this would cause an error. The M800 doesn't show a sync error though?!
Any thoughts on that?
If you are running a 12 tooth wheel then it's critical that the sync trigger input occurs between two of the ref teeth. Your sync input is very close to the ref but as long as it doesn't cross then you shouldn't have trouble. I like to align the sync input where possible to occur as close to the middle of the two ref teeth as possible. You may also find that the relative position drifts with rpm as the cambelt will tend to stretch a little in which case you want to be careful to ensure that at the extreme of the rev range the sync position is still not in danger of crossing a ref tooth.
'Sync Position' on the 'Sensors' tab of the diagnostics window will give you some idea of the relative position of the sync pulse and 50% means that it's exactly in the middle. This is worth having a look at.
All this being said, if the trigger input is factory then you shouldn't have trouble with the location of the inputs. This is how the engine would have run on the stock ECU so you shouldn't have issues.
What is the trigger mode you're using? I'd assume you're using mode 2 - Multitooth? If the ECU is expecting a Toyota 36-2 trigger input this would cause trouble but then you would likely to be cycling a lot of trigger errors and the rpm would be erratic too.
Post up the map so we can take a look.
thanks, I'll take a look at the sync pulse tomorrow.
The sync tooth is directly on the camshaft but the cams aren't factory anymore, so lets hope HKS was doing their job well :)
Correct, mode is set to multi tooth...also I just attached the map.
The trigger mode is correct for that setup then. I had a quick look at the ref/sync capture and based off this your mag levels are probably pretty close to the mark.
Ultimately if the ECU is achieving synchronisation, the rpm is steady and the timing in CRIP mode is stable, there should be no reason for the engine not to start. Your fuel table is currently filled with a single value and this may need a significant tweak to get the engine running cleanly dependent on your IJPU and injector size parameters. Have you adjusted this up and down dramatically to measure the effect? I'd try doubling it to see what the effect is.
When you say that flooding it with fuel will get it running but then it pops back out the intake, this to me sounds like a timing issue. As per my other post, you should be able to get the CRIP pretty close prior to starting the engine. This should get you to a point where the engine will run ok and then you can revisit the CRIP once you have it idling comfortably.
Did you try changing the CRIP by 360 degrees? (i.e. CRIP = 17.0) If you were off by 360 degrees, then the timing light would still show the correct alignment, but coils would be firing at the top of the exhaust stroke.
You can ignore this if the engine really does start running, and doesn't just pop-backfire when cranking.
thanks for all the suggestions, I'll be at the shop in about an hour and will continue trying to get this thing running.
A timing issue was also my first guess, but from what we've checked it _seems_ correct ... we'll see.
By flooding with fuel, I meant that had an IJPU of 12ms, a cranking enrichment of 150 across the map and a value of 40 in the main fuel table. ;)
Alright, first things first ... car fired up and ran.
The problem was coil#2 firing twice while cranking ... basically imagine the firing order as 1 5 3 6 2 2 4
And now for the weird part:
As soon as I used the second cam sensor for sync (MK4 Supra's have two cam sensors, triggering 180° apart from each other on the factory ECU), it didn't fire twice ... hooked up the fuel pump again, adjusted the CRIP and fuel a bit and it fired right up.
Tried the first one again - no start.
Thanks a lot guys for your suggestions.
I'm glad you got to the bottom of it.