GTV6 Won't start

Fylnn · February 07, 2010, 10:24:12 PM

Hoping someone can cast some wisdom my way.

I have tried today to start my GTV6 after about 3 years. In that time had to remove the engine and wiring loom to weld up rust in firewall. The engine has been sitting out of the car all that time. It is a rally car so it now runs a lift pump and surge tank feeding the original Bosch fuel pump. The fuel injection and ignition are standard apart from that. So it cranks just fine, it has fuel, the cold start injector is working. But it just won't fire. Checked the static timing and it is fine. OK since I have pulled it all apart and put it back together it could be anything but interested in ideas on diagnostics.

I am thinking it is ignition related, it just doesn't even kick, but it could be fuel pressure maybe the reg did not appreciate sitting without fuel. So how do you check for spark? if it was carbies I would pull out the plug and earth it and see, but not sure you can do that with the electronic ignition. it appears that there is no voltage in the low tension lead on the distributor, but there is voltage at the coil.

Any ideas anyone? How do I diagnose the ignition or the fuel pressure without sophisticated tools.

dehne · February 08, 2010, 12:04:19 AM

you can still check spark at plugs

MD · February 08, 2010, 09:01:50 AM

Recently had a 75 /2.5 L that gave me a lot of ignition grief. It turned out to be the combined ignition/ fuel pump relay. Its the one with two million wires to it.

Take it apart very carefully, and using a 600-800 grade sandpaper clean the dual contacts inside. Air blow any residue off the points whilst they are pryed opened a little. Spray some RP7 into the multipin connector and push it on and off the relay pins numerous times to remove and joint resistance.

Be very gentle and careful when cleaning the contacts-no ham fisted stuff.

As Choderboys has said, new fuel please. This may mean a temporary rig up to an external small tank if you dont want to pump out the stuff in your original tank.

If you finally get high tension and fuel and still no fire, the injectors may require a clean just in case they are stuck.

Fylnn · February 08, 2010, 10:24:51 AM

Thanks for the input. The fuel system is all new, the tank has been out and cleaned and I bought the fuel the day I tried to turn it over.

The fuel pumps are working. I have not verified fuel pressure is correct. the cold start solenoid is working as I took off the trunk and there is fuel there. Random thought came to me to actually listen to the injectors and see they are clicking. Is there a better way to test.

My guy feel is that their is fuel, the plugs are wet and the exhaust smells fuely. I will pull the double relay apart and check for actuation. That was the problem last time no fuel pump, there was a break in the computer that I corrected and it ran like a treat.

Dehne says you can still check spark at the plugs, by that do you mean pull one out and earth it to the valve cover and crank?

dehne · February 08, 2010, 11:33:25 AM

yes thats right

MD · February 08, 2010, 09:10:02 PM

If one bank of the relay is faulty :

The engine will crank but not fire
The engine will crank and fuel pump will operate but the engine will not fire
Finally the engine will crank, there is high tension, but no fuel pump operation and the engine will not fire.

My money at the moment is on the relay fault.

BTW; they cost around $280 if you can get one so take care with it as I said earlier.

Fylnn · February 09, 2010, 11:13:15 AM

Yes in the quiet reaches of the night I also came to the conclusion that I might only have half a relay. When I first got the car it would not run unless you manually held both sides of the relay shut. That was due to a break in a circuit board in the computer. So thanks MD that is definitely worth a check. I finally managed to get a decent wiring diagram for the ignition yesterday that suits my actual car and I have one for the injection. I had totally removed the wiring and fuse box to weld the firewall so I am suspecting (hoping) I put a wire back wrong on the fuse box or something.

My plan is to check for spark with a plug out and grounded and check the injectors are operating and the relay is firing on both barrels. Presuming that one of those leads me to a diagnosis then I will trace back the wiring and look for the fault or wrong connection.

Thanks for the ideas so far, hope to report success shortly.

Fylnn · February 21, 2010, 08:19:59 PM

OK All, finally got back to this over the weekend, and still no joy. I have pulled out No. 5 plug and laid it on the cam cover and no spark whatsoever. I also checked the double relay and both halves are working when I try to start it. Fuel pumps are whirring away. I have been trying to borrow a noid light to double check the injectors but I haven't managed to catch up with the guy just yet. But given the absence of spark, obviously where to focus.

My car is an '83. It has run before I dismantled it so at some point it did work. So I have got the wiring diagram and gone through it for the ignition. I did find a wire from the ignition switch left off the back of the fusebox so I thought that was it, but upon trying again, still no spark. I have the system with the Bosch resistor thing and a control module on the LH inner guard. Having traced the wiring diagram and found nothing more, I have checked for power and connections. At the resistor it has 10.5V. At the +ve terminal (15) of the coil it has 7.5V. That is the same connection from the Bosch resistor and it has 7.5V both ends. When I look at the Bosch control module there is 11V at the green-black which is pretty much the same as at the fuse box. Yet the green that goes to the distributor has only about 0.5V. When I crank the engine it is no better. Not sure if that is right or not, but would think it should have something for the distributor to work with. The coil has about 1.5 Ohm resistance across it, which I think from what I have read on AlfaBB is about right.

So there you go, appears that it is not triggering or something, does anyone have any diagnostics they can share? The obvious thing is to swap out modules but don't have any known working ones. so any help gratefully accepted.

dehne · February 21, 2010, 08:46:32 PM

the fact thats its not producing spark i would be looking at the (sorry i cannot think of the correct name) spark maker i have a couple of these so if you post the details of it up ill check to see if mine match

Fylnn · February 21, 2010, 10:07:27 PM

Dehne,

Do you mean the thingy inside the distributor?

dehne · February 21, 2010, 11:41:09 PM

no the unit on the guard if you take the lead from the dizzy and earth that you should find out if its that. if that produces spark it should then be the dizzy cap/rotor but ill most likly say its the unit on the guard

MD · February 22, 2010, 08:15:04 AM

dehne, I think it's called the ignition module.

The thing that concerns me is that if the car was firing ok before the recent work was done, that would suggest that the ignition module and all else was fine at the time. If for some reason, the wiring was not re-installed as original, it's possible that is what has caused the ignition module to not operate or be damaged.

If you replace it with a substitute and the same wiring remains, you could get the dame result ie no spark, or blown module.

You have to prove the circuitry is correct first.

Fylnn · February 22, 2010, 10:25:18 AM

MD that is my concern exactly. I thought I had it cracked yesterday when I found a loose wire on the back of the fuse box whilst tracing the wiring diagram. It was a wire from the ignition switch, but alas when I connected it up and tried again the Alfa gods deemed it not to be. I don't know if that would cause anything to get fried before I reconnected it, but I am very cautios about throwing parts at it without really knowing what caused it.

One avenue I am pusrsuing is a friend of mine talked to Richard Anderson last week. He suggested that quite often they replace the early system with the later setup. Could be a good idea, but just waiting on the cost.

barts · February 22, 2010, 09:31:31 PM

Hi Flynn,

I think you are probably onto this with the spark but just to throw another possibility...

I couldn't get my GTV6 to start for a couple of days. It had a really weak looking spark (mainly due to flat battery from trying to crank it over and over) and after chasing that around to no avail for a couple of days I noticed fuel pooling around the air clearner from trying to start it. I gave up and took it to some specialists who discovered the fuel pressure reg diaphragm at the front of the engine had let go and fuel was literally pourning into the engine through both the vacuum (I think) and fuel system flooding the engine (quite literally).

Luckily it didn't do any major damage and they were able to replace it and I hit the track for the next weekend.

Just food for thought.

Dan

Fylnn · February 23, 2010, 06:34:34 AM

Yes I am concerned about the fuel pressure since the regulator was dry for 3 years. It is something I should check. But at present the total absence of spark is the prime suspect.

Talking to various people they are suggesting that maybe should replace the ignition system with an aftermarket device, which is $. If I do that then my next question is why not fit a Haltech or Motec that does ignition and replace the L-jectronic as well. Kill 2 birds with one stone.

Has anybody got any experience in thiis? what do you have to do and any idea of cost?