Tuned Q4 -93

[Q4-Dave]

I bought this car more than a year ago, and have been rebuilding its engine and gearbox since then.. It had a broken cambelt from the previous owner and he had taken the engine out and disassembled the whole thing (not marking anything up) making it harder for me to put together since it?s my first Alfa, first four-wheel-drive and first car with turbo..

Me and my mechanic-brother have built this car from scratch with all the "good stuff", such as helix auto sinter-clutch (4puck), forged pistons and rods all balanced and weighed together with the crankshaft new precision Turbo (good for 600+) hoermann-exhaust manifold, 3" exhaust from turbo, big frontmounted intercooler and so on...

now to the question, we have finally come to the starting moment, doublechecked everything and it wont start!?
we have checked TDC and measured the resistance in the ignition leads but wont get any spark on cylinder 2 and 3..
here in Sweden on the local forums they say it?s a regular fault with these cars and its becaus of leads and/or plugs but all are new on my machine..

please help or come with tips to try at least!?

best regards from sweden
David

[Q4-Dave]

Here are some pictures of the engine and car...

[AlfaJack]

Hi Dave, Welcome to the forum. Lovely looking car
Looking forward to see it develop.

[Q4-Dave]

Thank you very much, I have dreamt about having one of these for years, not easy to come bye even with the more common engines (twinspark or V6) here in Sweden.

[wrinx]

Welcome

Coil packs...crank sensor?

wrinx

[arjunior45]

Q4 has two ignition modules and two coil packs. One pair is for 1-4 cylinders and the second one for cylinders 2-3. So, if you do not have spark on 2 and 3 only {and you have spark on the other two} start checking the corresponding 'pair' {ignition module - coil pack}.

see attachment

Nick

[Juan AR155Q4]

Nice!!!

[Q4-Dave]

I was in on the fault being one of the coil-packs as well, therefore I tried with other igniton-leads I had lying about (for a Volvo) with those there were a nice and good spark on all cylinders, so I ordered new ones today...

the future will tell if it is something more..

I have had thoughts about the following as well:

which spark plugs do you use, can it be those maybe (aswell), mine have three "taps" on them, never seen that before on a turbo-charged car, but these cars never stop surprise me

I used the injectors from a Volvo (5cyl turbo) as well to start with, since it is being tuned I reasoned it being a good idea to start with the original map and without the progressive fuel pressure regulator and the high-flowing injectors for the tuned-setup to see how everything works without pushing it from the beginning!?
which ohm is it on standard-injectors, and later on (or now maybe) how do I mount the resistance to change betwenn high/low-Ohm injectors (if I need to, that is)?

David

[AlfaJack]

NGK B8EGV are very good plugs for the Q4.

[arjunior45]

I think, but not 100% sure - need to check it, that we use the low impedance injectors.
B8EGV plugs are quite good and I use them in my car.

Nick

[Juan AR155Q4]

High impedance injector (saturated), and if memory don?t fails me, 12ohm

[kepsus]

Correct 12ohm Do not put low Ohm injectors in you car, you ECU Die right away.

[Q4-Dave]

Isn?t it possible to correct the Ohm-difference with resistances like on other tuned cars? thanks for the info on 12Ohm, arjunior45, Juan AR155Q4 and kepsus

I have also checked that the spark-plugs I use are the NGK-variant of the standard plugs for this car (Bosch WR6-DTC) dont?t remember the exact Bxxx number of my sparkplugs, buth shouldn?t be the reason why it wont start anyhow..

better luck tomorrow

[Juan AR155Q4]

Somebody can double check the resistance?
Cause is just in my memory...

[kepsus]

Sure you can put a resistances and the use the low ohm injectors. In fact they are know to be a bit better because they open close faster.

[Juan AR155Q4]

Well, mistery solved:




Ps: sorry, cel photos

[#84]

About the spark plugs: The plugs recommended are Bosch with 3-side electrodes, but my experience and the the experience shared on the Lancia Delta forums is that the engine work much better with the NGK-plugs. BP-6ET for standard map, BP-7ET for up to 1,5 bar and 300-325 hp. B8-EGV was recommended by legendary Evocars, London, but my experience (with Evocars chip) is that it is too hard even a normal swedish summer day. At around 0 degrees C, it makes the engine run very harsh. However, If I should buy new plugs today I would go for the Denso Iridium plus, like IW20 or VW20, maybe 22 for higher boost. I haven't tried but I trust experienced Delta Evo tuners in this matter.

About injectors: I would start with standard injectors and 3,5 bar injection pressure, which gives you 415 ccm/min @ 0 bar boost and 497 ccm/min at 1,5 bar boost.

[SteveNZ]

WR6DTC are NGK BPRR7ET. These are quite cold, there is no need to go to a colder "8" plug IMO. Single electrode plugs are ok, BKR7Es, BPR7Es or iridium etc equivalent

I have also use GL 2HL plugs

EGV plugs are racing gold paladium plugs, high quality but overkill for a road engine.

[jimnielsen]

Steve - I was using iridium plugs when my engine failed (AND I AM NOT BLAMING THEM IN ANY WAY....) However, one of the possible scenarios is that the centre electrode will melt off in a detonation situation - reducing the risk of further damage. This has no change of happening with an iridium plug because the melting point of the electrode is too high. Obviously one should not be relying on the plug to fail and hence lessen the damage.

jimn~

[Q4-Dave]

I got my car running last week, for start it didnt want to start nor run well when cold, but perfect idle and run when hot..

After sorting out leaks and some other issues I got it to start and run well when tonight (hold on now everybody), had in my mind somewhere heard that someone had trouble starting when they had switched 2 of the contacts.. I switched 2 of the contacts, after studying them a bit closer I noticed that one of them looked twisted, the 2 contacts where those between the constant idle speed and/water temp, man I felt stupid..

now running smoothly and waiting for a new wheelhub to safely secure the righthand front wheel for the first test drive, should arrive next week (from italy)

regards

[Q4-Dave]

Old Image of the engine
the white paint helped alot when looking for leaks

[Q4-Dave]

I still have one problem unsolved beside the hub I mentioned, it is the speedometer/tachogauge, there is a connection down by the gearbox underneath the batterytray, there are three cables and all are pulled out of the connector, the other three doesn?t have the colors accordingly!? I can take a photo of it someday, if that will help you helping me

[mindus]

The attached picture should help you

[Q4-Dave]

Oh Mindus you are my Hero of the day
That saves me a whole lot of work.

thx man

David

[Q4-Dave]

Hello again everybody, now the car has gotten the new hub mounted, and a testdrive in the snowy weather, went very well and felt GREAT after all hard work and troubles we?ve come across.
just wanted to know what you have for oilpressure on idle, just in case?
mine were about 2?ish anyhow, too low?

the generator may have to be replaced as well since my (battery)gauge is glowing a bit, I did measure it up, when turned of the battery showed 12.88ohm and on idle 13.30 with lights turned off and 12.94 when turned on!
any tips on where to get a new one?

thanks
David