Author Topic: New to 75 ts  (Read 28607 times)

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Divano Veloce

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New to 75 ts
« on: June 20, 2014, 05:53:17 PM »
Hello,

i have recently purchased a 91 75 twin spark for what seems like not much money..... However, it has a couple of minor (i hope) issues. They are:

its down on power but really sings above 5000k (i suspect VVT isnt working)
engine/prop shaft vibration at and just above idle (950-2000 rpm)
gearbox oil leak
rusty drivers side headlight
power steering belt idler pulley noisy
one coil leaking spark
some creaks in the front suspension when braking to a standstill


Having gone through a similar process recently with a TS powered berlina (thanks Julian) I am not too concerned about the motor. My plan is to check the ecu fault codes then work through things methodically - valve clearance, timing, plugs, leads, caps and rotors, and to pull apart, test and clean the Motronic bits on the intake.

My main concern is the prop shaft vibration.... I will have a chance to inspect things properly this weekend and would appreciate tips on what to inspect or do to isolate the source of the vibration. Also, as the car has done 270,000kms (with a full service history), what should i replace for piece of mind?
« Last Edit: June 20, 2014, 07:09:52 PM by Divano Veloce »
1968 Berlina TS
1989 75 TS
1990 75 TS
2007 147 JTD

Neil Choi

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Re: New to 75 ts
« Reply #1 on: June 20, 2014, 06:17:08 PM »

At idle, if you push the clutch in, it should be smooth.  Clutch out, you are spinning the entire length of shaft plus the clutch and it is usually not so smooth.Check all 3 donuts and centre mount bearing in the prop shaft, for cracks and wear.  I bet they will be wore and cracked unless changed recently.  If in doubt, change them all.  When taking the shaft out, mark and align everything so it does back in the same orientation.


You can get the donuts and bearing from the usual local suppliers but make sure you get ones for the 75.


Check all the nuts connecting the donuts are tight.


This could be a starter.

shiny_car

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Re: New to 75 ts
« Reply #2 on: June 20, 2014, 09:20:26 PM »
It will depend, as Neil said, what's been changed before. But in general, there'a many parts that are subject to wear and may benefit from replacement:

front suspension: lower control arm bushes, upper control arm bush, steering knuckle balljoints, tie rod ends

rear suspension: De Dion bush, Watt's linkage bushes

mounts: engine mounts x3, transaxle mounts x3

prop shaft: donuts x3, centre support + bearing

I would personally change the donuts and centre support, and all the engine mounts and transaxle mounts at a minimum, unless you can be sure they are in top condition.

Also change all fluids and if necessary the brake pads and discs of course.

:)
Giulietta QV TCT . 1.75 TBi . Magnesio Grey - Black
GT . 3.2 V6 . Q2 . Kyalami Black - Red
75 . 3.0 V6 . Alfa Red - Grey

shiny_car

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Re: New to 75 ts
« Reply #3 on: June 21, 2014, 09:12:35 PM »
I'm not familiar with the 2.0 engine, sorry, so can't advise there.

The donuts look ok. Can't really tell about the centre mount. I found my centre mount to be perished, and replacement will hopefully remove the small vibrations I noticed.
http://pic20.picturetrail.com/VOL166/13567593/24504607/408631939.jpg

You may still need to remove the prop shaft to be certain.

I guess you have to decide if you're wanting to do things as quickly and cheaply as possible (ie: replace only what is required), or have the time to have the car off the road for a period, and replace everything regardless, to make the car fresh, particularly if you plan to keep it for a long time.

Enjoy. :)
Giulietta QV TCT . 1.75 TBi . Magnesio Grey - Black
GT . 3.2 V6 . Q2 . Kyalami Black - Red
75 . 3.0 V6 . Alfa Red - Grey

Divano Veloce

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Re: New to 75 ts
« Reply #4 on: June 21, 2014, 09:35:36 PM »
Thanks SC, that center support does look bad! Nice build thread too!

I think that the minimum will be done immediately for rwc and then a major teardown in the next 12 months. The car has a full service history with benincas and everywhere I am finding evidence of of a well maintained car. The exception would be some of the oil leaks...

I haven't been able to check the ecu fault codes yet as the loom has a different diagnostics port to the Berlina. It's located under the dash but doesn't have all of the wire colours as described in a post by festy in this thread
http://www.alfabb.com/bb/forums/milano-75-1985-1993/206535-ts-engine-issues.html

Specifically I can't find the blue and yellow wire.

I will need to replace the drive shaft seals at the differential. Is this a big job?
1968 Berlina TS
1989 75 TS
1990 75 TS
2007 147 JTD

Divano Veloce

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Re: New to 75 ts
« Reply #5 on: June 23, 2014, 07:41:45 PM »
Ive had a thought.... the fuel quality plug (blue) would enable closed loop control of the mixture. With a missfire would the lamda sensor become fouled? I can test by removing the fuel quality plug to enable open loop control.
« Last Edit: June 23, 2014, 08:48:01 PM by Divano Veloce »
1968 Berlina TS
1989 75 TS
1990 75 TS
2007 147 JTD

colcol

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Re: New to 75 ts
« Reply #6 on: June 23, 2014, 09:10:14 PM »
If the plugs are wet and fouling, they may be too cold and you need a warmer plug to run hotter and burn off all the crap, is your thermostat working properly?, if the engine is running too cold, then the engine temperature will be too cold, as will the spark plugs, and they won't get hot enough, Colin.
1974 VW Passat [ist car] 1984 Alfa 33TI [daily driver] 2002 Alfa 156 JTS [daily driver]

Divano Veloce

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Re: New to 75 ts
« Reply #7 on: June 24, 2014, 06:44:37 AM »
Thanks col, I have my doubts about the thermostat. Indicated coolant temp sits at around 70 but as ambient temp goes down so does coolant temp, as low as 60... It's on the list of things to check. I put ngk 6s in it to replace champion 9s.

I have figured out the wiring of the late style diagnostics port. The thing that threw me was the wiring colour for the diagnostics switch.... Instead of blue and yellow it's blue with white stripes (page 38 to 40 of section E of the workshop manual)
1968 Berlina TS
1989 75 TS
1990 75 TS
2007 147 JTD

GTVeloce

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Re: New to 75 ts
« Reply #8 on: June 24, 2014, 10:07:11 AM »
Remember you have a fully working TS to steal parts from! If you are suspect of a part, swap it with a known working one (i.e from the Berlina), but do it one at a time to make sure you isolate.

I am running NGK FR5 spark plugs in both TS motors and have only fouled plugs once and there were many issues leading up to that.

As I understand the O2 sensor; if the ECU detects an issue it just starts to ignore it. It is also not used at idle or WOT. Idle because the gasses are not hot enough to give a consistent reading and WOT because the program is set to a different ratio (12.5 as compared to lambda - 14.7).

Pulling the fuel quality plug often exacerbates an idle issue in my experience. Also, when you do pull it out, the engines seems to have to relearn a bit so take it for a good drive on open road (shouldn't be too hard for you!). Sometimes when I switch between the two settings (91 and 98) it will stall and run poorly for a little while till it learns the new program.

The thermostat shouldn't be an issue. My GTV had a partially open Tstat all summer and ran fine. I finally replaced it because the heater was taking too long on the cold morning/nights! I sourced one from www.alfa-service.com
They are a little short on notifications but both times I have ordered through them the part has just arrived a week later.

GTVeloce

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Re: New to 75 ts
« Reply #9 on: June 24, 2014, 10:11:40 AM »
Sorry, I was working off memory (and google) with my plug choice. They are actually Bosch FR5DC.

Divano Veloce

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Re: New to 75 ts
« Reply #10 on: June 24, 2014, 12:41:12 PM »
I've swapped where possible leads and dizzy caps but until the 75 is sorted i need the Berlina to get around. This limits how far i can go with part swaps. I could swap coils.... or the motors

Circumstantially i have wet something and its malfunctioned or its wrecked. Unfortunately i cant investigate the prop shaft with the motor like this.
1968 Berlina TS
1989 75 TS
1990 75 TS
2007 147 JTD

colcol

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Re: New to 75 ts
« Reply #11 on: June 24, 2014, 09:45:31 PM »
My thermostat was removed for a full coolant flush, and it took me a while to remember to put the thermostat back, but after a plug kept fouling and being wet with petrol and not firing, i put back the stat and the engine ran hotter and the plug started firing again, Colin.
1974 VW Passat [ist car] 1984 Alfa 33TI [daily driver] 2002 Alfa 156 JTS [daily driver]

Divano Veloce

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Re: New to 75 ts
« Reply #12 on: June 25, 2014, 07:07:37 AM »
I'm not near the 75 until this evening, can someone tell me what diameter the original ht leads are? I'm thinking of making a new set to match the originals in length/diameter but to suit ngk plugs.
1968 Berlina TS
1989 75 TS
1990 75 TS
2007 147 JTD

Henry Goodman

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Re: New to 75 ts
« Reply #13 on: June 25, 2014, 10:56:34 AM »
I'd suggest you may wish to consider Denso Iridium plugs as they come with removable threaded caps, to suit the original Twin Spark lead connector ends. As you've probably discovered the NGK recommended spark plug has fixed caps so you would need to change the leads as well. I run IK22 (part # 5310) which is one range cooler than normal as my car spends most its time on track. They definitely fixed my rough idle problem but then again I changed from the original and very worn Golden Lodge 25 HLDs.
Hope this helps and save you a few bucks along the way.
Henry.

Divano Veloce

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Re: New to 75 ts
« Reply #14 on: June 25, 2014, 09:42:54 PM »


i have measured the resistance the HT leads. The primary leads (coil to distributor) were both ~1kohm. The spark plug leads were all over the place, none lower than 11kohm but most were open circuit. I couldnt resist (ha!) the urge to pull one of the leads apart. It seems there is a resistor in the plug end of the lead (inside a red/brown bakelite sleeve, which is inside the rubber boot). Most of these seemed to have failed (ie open circuit). With this removed the leads measured the same as the primaries (~1kohm).

I'd really like to retain 7mm leads so they fit under the cover plate. any suggestions on repairing these leads (is the resistor necessary if resistor plugs are used?) or sourcing others for under 95 pounds plus postage?

as i have ruined my stuffed leads i cant troubleshoot the TS without pinching the HT leads off the berlina... a job for the weekend as the berlina needs to start at 5:30am
1968 Berlina TS
1989 75 TS
1990 75 TS
2007 147 JTD