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Discussion Starter #1
Case in point: Hot-start problems with 1991 164L coming from Southern Florida, where it apparently worked just fine. I saw it myself. The car starts quite well cold, even in freezing temps, with little to no playing footsie with the throttle. But warm start in cold ambient conditions is another matter. It was turning over for tens of seconds with no sign of starting after just driving a mile to the gas station (where we turned it off, totally unsuspecting, but a few hundred miles to the north of where it had been happy). After 20-30 minutes of looking, poking, prodding, hoping, praying, etc, it started trying to catch, and finally did. I didn't see this behavior in the >50F 'ish temps in Florida. No other environmental change is apparent to me.

Related item?: The car's temp indicator was indicating about 210F when in Florida idling or on slow drives. Highway driving pushed it down to about 175F. In the colder winds of Ga, the Carolinas, and Va, at highway speed the temp indicated only about 130F. A missing thermostat from the P.O. who drove in South Florida temps for 10 years? After idling for a few minutes off-highway, the temp indicator comes up to >175F. I thought the engine temp sensor for the Motronic system might be getting a bogus temp (maybe even a failed sensor?) and over-enriching the car. The first coughs and sputters it gives after starting are very rough and contain a lot of carbon (black smoke, typically fuel from my limited knowledge). I am at the first stages of troubleshooting, and have a Bosch general purpose fuel injection manual. Bought for my son's Ljet Spider system.

Help and diagnostics, anyone? Or maybe a pointer to the exhaustive directions compiled just a week or so farther back than my search through the archives. I am really new here, folks.

Michael
 

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Hard Starting 164

Michael,

Hard starting hot or cold problems usually always centered around something amiss with coolant temp sensor or wiring connector going to it.

There are two sensors/senders on thermostat housing under top radiator hose. Do not confuse the two. The temp sensor for signaling the fuel injection Motronic Control Unit aka ECU is the one set at a 45 degree angle to center line of car. The other one pointing straight ahead is sender for temp gauge and overheat light. It has two seperate slip on wires for these indicators.

The coolant temp sensor has a Bosch type spring locked connector like on fuel injectors. Usually there is a wiring or pin connector problem under rubber boot of connector. Sometimes sensor resistance is off the mark. It should be high resistance cold to enrich start and low resistance hot to lean out start.

Frayed wiring or high resistance will cause hard and rich start hot but OK start cold. Broken wire(s) or low resistance will cause hard or no start cold.

Check wires, connector and sensor.

Problems with coil resistance will cause hard start too. Pull off large rubber boot on top of coil. Pull center coil wire check for corrosion inside coil tower.

Also pull distributor cap and check for corrosion on contacts and rotor button and check condition of center carbon tip inside cap.

Take two glasses of vino with dinner and report your findings.

Temp gauge readings are normal (abnormal) sign of typical thermostat on Alfa V6, which is that is opens to quick. So it runs to hot in warm weather and to cold in cold weather. Both My 164 and Milano work this way now. I change them now and then but within a year or so problem is back again.
 

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Near my neighborhood?

Michael,

Do we know thee? Your neighborhood sounds like my backyard.

Did you get an email about my tech session weekend coming up Jan 17-19?
 

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Boy Steve, you sure are an early riser!!

Michael has now received the invite and the update. We have been communicating by e-mail for a week or so. I added him to our new mailing list, and I'll send you two both a test e-mail so you have each other's addresses.

Cheers,
Alex
 

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Neighbor's car alarm CLOCK

Alex,

Yes I am when the little dog decides it is time to go out and neighbor's car alarm decides to keep me up.

I got email from Michael and your test one so maybe we will see him this weekend too.

Remember how rich your Verde ran when wire to coolant temp sensor had broken strands? Maybe that is his problem.

Wonder if he bought Fred D's white 164L A/T car from his son in S. Fla?
 

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Steve,

That would be a GOOD one to buy, huh?

Yes, I understand the getting up early now!

Looking forward to next weekend. Jim Salerno just bought my Milano Gold, so he's going to be there to learn!

Yeah, it sure sounds the same as some of the trouble I was having on my Verde.

Michael - please come to our tech session with your 164! We'd love to meet you and maybe you'll even get some help.

Cheers,
 

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Discussion Starter #7
The coolant sensor wires were very strongly kinked at the junction to the sensor socket where the jacket was pulled back from the pair of wires (no strain relief). For the thread record, when I repositioned the coolant sensor wire to straighten it as much as possible, the starting problem disappeared. This is a temporary measure (no problem found), and I expect to look over this wiring _very_ carefully when I do a (timing belt - water pump - stuff in general area) changeout sometime Real Soon Now. The belt tensioner, too. At 59000 miles since recorded change of belt w/o other records of what was done when, it seems prudent to be pre-emptive. I just have too many other things going to put it at the top of the queue, the area looks so pristine and without coolant/oil leaks, and the driver is gentle of foot. Long may it stay that way.

Michael
 

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Hard Starting 164

Michael,

Hard starting hot or cold problems usually always centered around something amiss with coolant temp sensor or wiring connector going to it.

There are two sensors/senders on thermostat housing under top radiator hose. Do not confuse the two. The temp sensor for signaling the fuel injection Motronic Control Unit aka ECU is the one set at a 45 degree angle to center line of car. The other one pointing straight ahead is sender for temp gauge and overheat light. It has two seperate slip on wires for these indicators.

The coolant temp sensor has a Bosch type spring locked connector like on fuel injectors. Usually there is a wiring or pin connector problem under rubber boot of connector. Sometimes sensor resistance is off the mark. It should be high resistance cold to enrich start and low resistance hot to lean out start.

Frayed wiring or high resistance will cause hard and rich start hot but OK start cold. Broken wire(s) or low resistance will cause hard or no start cold.

Check wires, connector and sensor.

Problems with coil resistance will cause hard start too. Pull off large rubber boot on top of coil. Pull center coil wire check for corrosion inside coil tower.

Also pull distributor cap and check for corrosion on contacts and rotor button and check condition of center carbon tip inside cap.

Take two glasses of vino with dinner and report your findings.

Temp gauge readings are normal (abnormal) sign of typical thermostat on Alfa V6, which is that is opens to quick. So it runs to hot in warm weather and to cold in cold weather. Both My 164 and Milano work this way now. I change them now and then but within a year or so problem is back again.
Hey,
I was having problems with my 91 164. Cranking too much when starting. It seemed rich. It was the fuel pressure regulator. When the diaphragm developed a small hole in it the fuel was pouring into the plenum. Holding the throttle open allowed it to clean out enough to start. Replaced the diaphragm and now everything is good.
 

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FWIW I've dealt with cold start and hot start issues and both were related to the coolant temp sensor TYPE. My (original) light blue wouldn't start easily in sub zero temps, so I swapped in a black sensor. That fixed the cold start... but when the weather got hot, hot restart was difficult. So I replaced the black with a NEW light blue sensor, that fixed that problem. Won't know if I lost my cold start ability until next winter...

Oddly the 100C readings from both those sensors was the same when I tested them (260 ohms), but resistance varied at other temps.
 
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