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 Post subject: Ignition problem?
PostPosted: Mon Aug 08, 2016 9:08 am 
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Hi everyone,
I have a european spec 1.8 GTi Colt with 4G67 in it and I have some troubles, so I hope someone here can help me out. I tried to start another thread but I can't see it here so I'm trying again lol.
So I'm using a self-made datalogger cable and TMOlog and what I see there is that when I step on the gas the ignition timing basically goes in the wrong direction. At ~5deg BTDC at idle it goes to minus degrees which is basically ATDC which is bad... The car has no power and stumbles up to the mid ranges; the knock sum increases and the ECU brings back the ignition timing to normal. I've checked the ECU, I have a good black top CAS from 1g DSM which is working.. According to the logger everything seems to be OK.... Another strange thing is then I take out ignition cables to check them, and the sparks etc. the engine runs kinda good without the 1st and 2nd cable, even when I take them both out. But when I took out only the 3rd or 4th cyl. the engine is gonna stall. I don't know if I explained it correctly, I can show some logs too.
I hope someone have some idea what to do, because I have none anymore..
Thank you!


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 Post subject: Re: Ignition problem?
PostPosted: Tue Aug 09, 2016 8:45 pm 
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Joined: Wed Dec 24, 2003 3:32 pm
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Location: Ottawa, ON, Canada
Hi and welcome.

Firstly, please don't run the engine without the cables being attached to the spark plugs and or a very close path to ground; it is a sure fire way to fry the ignitor/PTU unit located somewhere near the FPR regulator on the back of the cylinder head.

If you have the Euro spec 4g67, you might have the high compression motor setup that comes with that - high compression naturally aspirated pistons! Something like 10.X-:1 compression.

If the ECU has never had new capacitors installed, THEY HAVE TO BE REPLACED with updated capacitors! MUST, must must. Everyone running the original capacitors is running on borrowed time. They may look clean, but the entire batch of those capacitors used in this and ALL Mitsu/Chrysler applictions from this era, created an entire rebuild industry. They cost less than $5-10, plus either your time or a person who can do good solder and solder pull work. Start there and work back out into the engine bay. It may solve nothing, but it has to be done. If not, sometimes repair becomes too costly or you will have to ship your ECU overseas to have it done properly.

That aside, you should have the same effect from pulling any single plug wire with the engine running (remember this is not the way to diagnose with the ignition running but you get the idea for concept) while the other three remain intact. You should drop a considerable amount of RPM or stall outright due to %25 non contribution of power coming in.

Your first thread might not have shown up because the first maybe 5-10 threads/posts, need moderator/admin approval. Nothing personal, we just had a slew of bots posting things at one point. This weeds that out.

When did you get the car?
Was it always running properly or did this just happen?
When were the spark plugs installed and have they been checked for gap and coloration? Are they factory replacement or proper equivalent?
What fuel are you using and is posted on your fuel door/owners manual?


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 Post subject: Re: Ignition problem?
PostPosted: Wed Aug 10, 2016 9:19 pm 
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The Silent Administrator
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Joined: Wed Dec 24, 2003 3:32 pm
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Location: Ottawa, ON, Canada
I saw your other post and you mentioned having removed the CAS and flipped it in either orientation. This requires reinstallation and checking your timing with the timing plug grounded (up on the firewall - single wire leading into a two wire connector). Once you have done that, you can check for base timing being set to factory specification with a timing light aimed just behind the LH headlight and down to the crank. That is the only angle that is pretty much straight on, to view the timing mark cast into the plastic lower timing cover and matching up with the mark on the crank dampener pulley. Should be around 5 BTDC. Without grounding that wire, the ECU compensates for everything you do and you have no idea where the timing actually is. We have seen and heard about (in very very rare cases) where crank pulleys have the outer ring rotate in direct opposite correlation to the crank snout, leaving the timing mark invalid. Possibility later on as we walk through this.


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 Post subject: Re: Ignition problem?
PostPosted: Fri Aug 12, 2016 9:50 am 
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Hi, Flying Eagle, and thank you very much for the approval and the answers. I'm sorry I posted 2 threads but I thought something is wrong lol.
I have a Euro spec 4G67, compression ratio is 10.5:1 and the compression pressure is like 13bar on all cylinders.
My old ECU was bad and I bought another one from Germany, which was never opened. The first thing to do was to change the capacitors and then I put it on the car.
About pulling the cables - I know its not the best method for diagnostics but it's simple and it works. There is something wrong with cylinder 1 and 2. When I turn off the injectors from the logger I have the same issue so I think this might be the problem, not the spark plugs and cables.
I forgot to mention that I have a LPG system mounted on the car. When I disconnect the cables running on LPG its even on all cylinders so I guess I have bad injectors. I bought them from the same DSM I got the CAS and they worked for a couple of weeks, but nevermind I will inspect this later. I think its not related to the ignition problem which is observed both on LPG and gasoline.
Also, everytime I move the CAS I ground the timing plug and the diagnostic plug inside - as its written in the books so I'm aware of this.
I don't have a timing light so I'm doing it "on eye". I know its not a good method either, but... Not quite sure how correctly the logger shows the timing though. Fact is its showing moving in the opposite direction and it feels like it. Lastly I ran at around 10deg BTDC and it's a little bit better, but still is moving at the opposite direction and I can't understand why. It does it with both ECUs so I think its some kind of a sensor problem, maybe? I presume the CAS is good as its from a working car, the cooling temp sensor is new (I read somewhere it affects timing); I'm searching for a 6pin MAF, but no luck for now. Also, a colleague from Russia said I should check the knock sensor, and I should do this in the next couple of days.
All ideas are welcome and thank you very much again.


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 Post subject: Re: Ignition problem?
PostPosted: Tue Aug 16, 2016 9:39 am 
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Also I found another interesting thing. I was plugging off the injector connectors to inspect them and I found out that there is no check engine light on when I plug off the connectors. Is this normal? Or I have a bad MPI relay?


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