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lahondal

Megasquirt On Xu10J4Rs

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lahondal

Hi!

 

I´m in the procces of adding megasquirt on a 205GTi with a GTi6 engine.

 

I have all the wiring done using the standard loom and trying to setup the sequential ignition/injection.

 

The problems I have are with the wheel decoding setup, at the moment I have 114 degrees first tooth angle and i´m experiencing very bad backfires, and the car wont start.

 

I have spark on all 4 coils and seems to fire in the correct order.

 

I set the wiring like

 

first MS spark output-->first cylinder pin acording to autodata

second with second

and so on...

 

Can the PSA weird naming of the first cylinder the one that sits gearbox side causing problems?

 

This night i´m going to check the timing with a strobo light....

 

Thanks!

 

 

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welshpug

got the cam sensor wired up?

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Stu

If its anything like Megajolt, you need to ensure the timing ring is orientated such that the missing tooth is 90degrees from TDC so this would be my first port of call.

 

Shouldnt matter what you call number one so long as the plug megasquirt fires is called number one, and this is number one on the engine.

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lahondal

Welshpug yes, the cam sensor is wired with shielded cable, but the shield dont have ground at the moment. Anyway seems to work ok.

 

This night i have done some investigation. I found tdc on cylinder 1 on power stroke, and made a mark on the damper pulley for check the timing with a strobo light.

 

I set the ms on fixed timing at 0 degrees, and checked with the strobo while cranking with plugs removed.

 

114 first tooth angle fires soooooo advanced, like 100 degrees or so, and trying with diferent angles let me found a number that leave me in the ballpark of tdc, aprox 235-245 degrees.

 

Fitted the plugs, give it a try and it fired up in 2 cylinders, but no backfires. So the ignition its almost set.

 

But now im trying to know why i have to put 240 degress in that window while all other people set it at 114-117-120 degrees with no problems.

 

And im suspecting too that the other 2 cylinder fail cames from the same problem....

 

Anyone knows? Thanks in advance!

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lahondal

I think i have the firing order wrong. The first cylinder y first, but the second is the second cylinder on firing, not phisycally the second cylinder!!!

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welshpug

yeah, its 1342....

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lahondal

Tonight i set the correct firing order an althought i tried all tooth angle combinations the car dont want to start...

 

Inverted the firing order and nothing....

 

Tried 114-120 degrees, tried 240 degrees and nothing, backfires and "frontfires" is all i can get....

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lahondal

My setting are as follows:

 

5an7zc.jpg

 

Thanks!

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unariciflocos

My Vems is set up at 114.5 and it's on the spot. Sounds like you're gettin spark on either intake or exhaust strokes so you'd need to offset your spark + or - in 90 degree increments. To lazy not to vizualize the strokes and how and when each should fire, but write them down and you'll figure it out. At any point in time you'll have one cylinder in each of these states intake, compression, burn and exhaust and you'll need to sync them with the 1342 firing order.

 

Attached two setups, both from Mi16s on bodies and wasted spark ( wasted spark is different because I'll get two sparks per cycle, with an additional one on the exhaust stroke, yours will be different for COP)

 

Do not try other trigger wheel combinations or anything other than 114.5 deg for the first tooth if you're using the standard flywheel trigger. For starters try and get it running without the secondary trigger, sequential is useless anyway. I think you either have some settings wrong or the coils are wired in the wrong order.

post-13076-0-60368900-1417023043_thumb.jpg

post-13076-0-98382500-1417023066_thumb.jpg

Edited by unariciflocos
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lahondal

Well....i have done some improvements in the last hour with the car.

 

I did the wiring seeing an autodata sheet that shows the ecu pins, and apparently there is an error on it because with the firing order set using the pin names on the sheet, the real firing order was an absolutely mess.

 

So I rechecked all the wiring using a multimeter, and checking what pin goes to what coil, and found an error in wiring.

 

Now the estrobo shows a near perfect sync between spark and tdc setting the ms in fixed timing "0", using the 114 degrees angle.

 

 

But the car wont start yet. Backfires are gone and cranking sounds much more good now (tiny backfires but only 2 times of 10 start attemps, at 0 advance)

 

So now....the next step is know which cylinder is in exhaust cycle and which in compression when the coil fires, as i cant know it by seeing the damper pulley.

 

I can rewire all, but is a method of know this without trial and error?

 

Many many thanks, you are very helpful! Its my first ms, only fitted 2 megajolt systems in the past and are far more easy than this...

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unariciflocos

I think mine uses 10 degrees for cranking, 0 is definitely too low.

 

You can also try to use the cam sensor by choosing dual wheel for the trigger, or setting un the coils to fire like wasted spark, twice a revolution, but I wouldn't recommend this as a permanent solution.

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lahondal

I have 10 degrees of cranking advance too, but was set at 0 degrees because we are checking the timing.

 

Tonight im going to rewire it in reverse, and give it a try.

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unariciflocos

I think that with cop you need a cam sensor or to configure it to fire twice a cycle, otherwise your chances of the engine starting are 50/50.

 

Before rewiring do a very simple test, turn the crank one full rotation manually with the ecu off and try to start then.

Edited by unariciflocos

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lahondal

Yeea, i inverted the wiring and it fires right up!!

 

The problem was the autodata sheet has two pins inverted, the cylinders 1 and 2, and this cause all this wiring mess.

 

Now i have only to rewire the injection part (now is in batch), and try to get it running in sequential injection too.

 

Anyone needs something only have to say! Thanks!

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unariciflocos

Happy days.

 

Next time have a checklist and measure all wires and calibrate and test injectors, coils and sensors before attempting to run :).

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lahondal

Well...the car is working and im in the long process of making a good VE/ignition table.

 

I put in a safe basemap, both ignition (safe advance) and fuel, and with the engine warm and a strong idle and AFR, took it for a small ride.

 

Turned acceleration enrichment off (tpsDOT > 1000), and turn on VE analyze live.

 

All was going well, and the VE analyze doing its work, AFR slowly going as it should be (at first AFR was too high), and engine was running better and smoother with each minute was running.

 

Slowly increasing throttle load and RPM, noticed a misfire which came up only with higher RPM, first 1 cylinder, and less often 2 cylinders apears not to work...

 

If I do a hard pull at WOT, the AFR is a bit on the rich side but the car pulls like a train, lift off throttle, and then starts to misfire.

 

The strange fact is that if i turn off the car, and restart, the misfire is gone and the car runs smooth again.

 

I suspect that maybe is a dwell setting problem, but tried different values and seems not to change nothing. Now is set and 6ms cranking and 3ms running, and spark duration 1.4ms.

 

Plugs are not new, but misfiring at idle, then turn off and restart and go well again, makes suspect me this is nor the problem.

 

Anyone know?

 

Thanks!

Edited by lahondal

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unariciflocos

Maybe it's flooding the plugs on overrun and they can't fire. Have you set it up so that it cuts the fuel when engine braking?

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lahondal

Nope, that is set like came on stock with the controller, but i´m going to check it right now.

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Chipboy

About to go down the same path so watching this with interest, best of luck.

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lahondal

Well, the intermitent misfire has gone apparently, before touching the fuel cut setting, i was adjusting the ve table and no more appeared in all the day. Anyway, i turn up the fuel cut on overrun, at least only for economy reasons....

 

Tomorrow im going to check the grounds in the ecu, because logs show a little noise in the tpsdot graph and reviewing the manual seems to have the sensors ground wrong. I have all the sensors to the same ground and then to chassis ground to stock wiring loom, and seems like the sensor ground ONLY should be grounded to the MS.

 

The maps are very conservative at the moment, 27 degress max advance at WOT and very rich afr, around 10:1, because i didnt have any knock sensing system.

 

This week i built a knock sensor amplifier and tomorrow will can hear the knock sensor directly throught earphones. Its funny to hear the whole motor at idle, pistons, cams, rockets...haha.

 

More news tomorrow...

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lahondal

Well, the sensors are grounded to the stock loom AND the ms at the same time, wrong indeed.

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petert

The maps are very conservative at the moment, 27 degress max advance at WOT and very rich afr, around 10:1, because i didnt have any knock sensing system.

 

 

 

It won't need anymore than 27 deg. at full load, most likely less, depending on other mods. Just add 6-9 deg. for cruise conditions. ie at 80km/h in 5fth on a flat road, it should have around 36 deg.

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lahondal

More news, the grounds were wrong and now the tpsdot graph is flat as sea, and the acceleration enrichment is not triggering anymore.

So solved that, i took the car for a good tuning session and i managed to take the afr at wot to around 13:1, but i noticed that the power was decreasing too, or at least from my assdyno.

Should the car run best with 27 degrees of advance and 12.8/13 afr or there is anything more that can affect power?

The misfire problem is back! It appeared again before some hard driving, turn the car off, restart it and the misfire gone...i have to check it too....

I will post a log image soon.

Thanks!

Edited by lahondal

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lahondal

Here is it:

 

ilfwus.jpg

 

Thanks!

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wicked

Is your overrun function properly working now?

With my car (different engine, different ecu), the AFR goes directly high if you close the the throttle @ high rpm. Yours goes rich first and then go up again to a higher value. (no scale so don't know if it goes lean; what it should do, due to fuel cut)

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