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'91 164L 3.0 V6 12V 5-speed
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Discussion Starter #1
'91 3.0 V6 12V is behaving oddly as taking off either ignition lead to spark plug or fuel injector connector doesn't affect. The car is missing power and but idling pretty much normally at 900-1000rpm or so. Revs like normal (gear neutral).
Searched for air leaks but couldn't find one.
With the lambda connector off idle is smoother. I assume this should be changed.

Covered this far:
Spark: yes. Changed the plug and tested for spark against the engine ground.
Fuel: yes. A mist of fuel is coming from the cylinder when engine running w/o spark plug.
Compression: yes (about 140psi).

Going to check for timing but should be okay as the belt has been changed recently. Camshaft and crankshaft marks are (or were) aligned.

Without spark plug the engine idles rough and speeds up if I reconnect the injector connector.
 

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'91 164L 3.0 V6 12V 5-speed
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Discussion Starter #3
That’s what I thought but no. Fuel pressure okay and I ran the injector test. All the front injectors worked the same.
 

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'91 164L 3.0 V6 12V 5-speed
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Discussion Starter #6
Dead cylinder has woken up again. Still I think there's a lack of power, though.

Something else has appeared:
  1. Trip odometer doesn't work. Mileage and other gauges work like a dream. How about fixing this?
  2. Power steering isn't assisting when idling (on standstill) and turning left. It's lighter if I raise RPM but I think it's still too heavy (and heavier) than when turning right. Could it be the pump or those teflon seals inside the rack pinion?
 

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Those trip odos do seem to fail in some 164s. I think Steve has messed with them in his cars and maybe repaired one?

As for the recalcitrant plug firing, have you cleaned out the distributor cap and removed any corrosion deposits on the internal contacts and rotor tip?

Which sparkplugs are you using? The NGK Iridiums seem to stay the cleanest and work the best for the longest time.

One other thing, in that the Bakelitelike terminal socket part of the plug wiring which pushes onto the top of one of the sparkplugs in my 91S sometimes pops up just a little, the end of it then not being secure onto the plug top, and then that plug sometimes misfires. I then have to go through and shim it ever so slightly where it snaps into the large hole in the cam cover every once in a while. Might check to see if the offending plug wiring connector is secure when installed.

Don't know about the steering, sorry. Zero toe front alignment, tire wear same for both front tires, and pressures the same?
 

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Probably the little gear for trip odometer has failed heat and old age.

 

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'91 164L 3.0 V6 12V 5-speed
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Discussion Starter #9 (Edited)
I did change the distributor cap and the rotor has been changed recently. PO had changed plugs to DENSO and those old NGK BP6ES or so are still laying around in the car. But thanks for the tip for those sockets; gonna check them asap.

I noticed the steering issue today and haven't investigated it yet. Wheel alignment is off as front suspension has been overhauled so might be it.

Is that trip odometer gear serviceable? Found it, thanks! I think this isn't the first priority now.
 

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'91 164L 3.0 V6 12V 5-speed
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Discussion Starter #10
And more😳 The ABS light comes on immediately when I pull handbrake when the car is moving. Where to start with this? And the light comes on even before the handbrake starts to slow the car.
 

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Another possibility: Bad spark plug wire(s). A couple of years ago I replaced my wires with a set from Magnecor. Then had symptoms very similar to yours, turned out the Magnecor wires had several intermittents between connectors - crappy wires! Replaced with an OEM set from the now-sadly-defunct Di Fatta Brothers and car runs perfectly.
 

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'91 164L 3.0 V6 12V 5-speed
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Discussion Starter #12
Yeah, I would like to change those but I'm yet to find a set at a reasonable price. Maybe soon…

Another thing, this time about oil pump. If my oil pressure problems are coming from the oil pump, is it possible to fix or overhaul that? My assumption is that when all the crank and bearing metals have circulated the system the oil pump has worn and hence idle output is a bit too low.
 

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And more😳 The ABS light comes on immediately when I pull handbrake when the car is moving. Where to start with this? And the light comes on even before the handbrake starts to slow the car.
Are you sure it is ABS light. parking lever has a park red light icon
 

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Yeah, I would like to change those but I'm yet to find a set at a reasonable price. Maybe soon…

Another thing, this time about oil pump. If my oil pressure problems are coming from the oil pump, is it possible to fix or overhaul that? My assumption is that when all the crank and bearing metals have circulated the system the oil pump has worn and hence idle output is a bit too low.
What is issue red light or gauge or both? I suspect it is one or both of time and oil pressure is fine unless engine is trashed from running with low or now oil.
 

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'91 164L 3.0 V6 12V 5-speed
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Discussion Starter #15 (Edited)
Are you sure it is ABS light. parking lever has a park red light icon
Yellow light, says "antilock". But I do think this lights up faster than the "park" light.

What is issue red light or gauge or both?
PO or PPO had ground the crankshaft using bearings so that could cause some issues. The oil pressure has been measured with a mechanical gauge and is reading around 0,4-0,6bar/6-9psi with 10W-60 oils (hot). The light barely stays off. With 10W-40 that I had there first the light was always on when idling hot.

Looking at the oil pump structure I can see how it may have worn when all those particles of metal were flying around.
 

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'91 164L 3.0 V6 12V 5-speed
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Discussion Starter #16
When did Alfa introduce the more efficient (or powerful?) gear for oil pump? My car's gear has those grooves for distributor and I wonder if someone has for some reason changed the gears to older type…?
 

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I wonder how many miles were on the crank when it was ground. Usually, unless a rod bearing spun, or engine run without oil, the crank and oil pump should have still been in good condition. These V6 Alfa cranks just don't seem to wear enough to lower the oil pressure, IMO, unless it was seriously damaged in some way. My 91S with 192k miles, still measures ~55 psi hot at ~3000 rpm (cruise), and ~25 psi hot idle. This using 15W-50 oil. Nothing in the engine has been touched.

Maybe the replacement main/rod bearings were wrong for how much was removed from the crank, or indeed, the oil pump is damaged.

Just a thought.
 

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When did Alfa introduce the more efficient (or powerful?) gear for oil pump? My car's gear has those grooves for distributor and I wonder if someone has for some reason changed the gears to older type…?
The 164Base and 164L early cars did not have oil squirter ball check vales in the block for piston cooling so had that slotted "distributor" gear set. The 164S AR64301 engines
1616484
1616485
and later production got the same oil pump gear set as used on 24v models with no notch. Those gear sets are matched so you have to have both gears.

It is possible you have a bad oil pump but if your oil pressure is that low when measured with direct reading gauge I would suspect excessive main and rod bearing clearances.

oil pump 3​
pump driven GEAR
60523313​
V1​
C9761​
01​
60559665​
V1​
D9761​
01​
60559665​
V2​
Mod D9761 oil jets in later 164B/L AR06412 engines starting with motor serial number 20053

2​
GEAR aux shaft drive gear
60507412​
V1​
C9761​
01​
60559666​
V1 ,V2​
D9761​
01​
 

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'91 164L 3.0 V6 12V 5-speed
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Discussion Starter #19
The 164Base and 164L early cars did not have oil squirter ball check vales in the block for piston cooling so had that slotted "distributor" gear set.
Where is the block’s cooling valves? I remembered in mine there was holes for the jets in con rods, and I have also thought that to be the reason to lower pressure if one valve has jammed open
I would suspect excessive main and rod bearing clearances.
I've thought that too. Main bearing clearances were about 0,05mm so they're a bit off the charts. But is this enough to lose the oil pressure in these engines? Old Nord engine from Spider had a clearance of 0,10-0,13mm and the light wouldn't come on (the pressure was still lower than expected)
I wonder how many miles were on the crank when it was ground.
I baffled by this. Sure, it's difficult to hear when the main bearings are shot but still. Don't know how the rod bearings did but rod journals are intact and still in (great) standard measures.
 

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What is your engine number? AR06412**20053 lower or higher number? Number on block under distributor area.
Lower number no cooling jets. If 20053 or greater oil jets are in block between main bearing caps. They start opening at about 37 psi (2.5 bar).
 
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