[ryan.f]

I've been having warm-start issues ever since I've owned my car and thought I'd see if anyone had any similar experiences and fixes. I found some threads on the 164 and Spider boards, but there didn't seem to be a conclusion. It also seems this is a somewhat common problem.

My car starts up instantly when cold. Same thing if the engine is hot and I turn it off and on, no problem. It's when the engine is warm; it has been sitting for an hour, two hours, four hours... Then it will take a few seconds of cranking (and pressing the accelerator) to get it to fire up.

I disconnected the cold start injector (CSI) to see if that would have any effect on warm-start -- no change. I guess the next items to look at are the coolant temp sensor (CTS) and the thermo time switch (TTS)?

Appreciate any help. It's not terrible to start it up warm like this, but would be nice to figure out how to have it start better.

Thanks,

-ryan

 

[alfaparticle]

If you disconnected the CSI and got no improvement then you can also rule out the TTS as it only affects the CSI.

Did you just disconnect the electrical connector to the CSI? If so it might be leaking. Try pinching off the hose to it.

Leaking injectors? Are all of your plugs the same color or are some darker or wet?

 

[Gubi]

Never hurts to go through the whole L-jet troubleshooting guide.

L-jetronic Fuel Injection Technical Troubleshooting Article

One thing that can cause warm start problems on the Milano is a variant of vapor lock. When the car sits for a while after being run hot, the residual heat can vaporize some of the fuel in the lines. When this happens the car will be hard to start until the pump pushes enough fresh fuel through the system to get the pressure back up.

You can tell if this is happening because you'll hear a hollow rumbling from the rear of the car for a few seconds after startup. This is the fuel/vapor mixture kind of burbling back into the tank via the return line.

 

[ronpaci]

my 3.0 makes the same rumble and rattle noise from the trunk on hot restart. especially after the sun heats up the back of the car. runs rough, makes embarrassing noises, clears in a minute or so, then runs perfectly. no cold start problems.

sure sounds like vapor lock. did you (or anybody reading this) ever solve the problem?

my tts reads a low 70 ohms, with 190 degrees at the radiator. tts reading should be 100-160 ohms with a hot radiator

csi, aav, cts checked out.

new silicone vac lines. evap system seems ok. swapped out charcoal canister, no improvement.
new fuel pump, and new filter from difatta in balt.

any advice???

 

[ToonRboy]

I find your description between Hot and Warm hard to follow. The motor should never be "hot" The thermostat and fans keep it where it needs to be unless you have a deficiency. After fully warm, it would read fully cold after an hour of cooling-off. So I'm going to dismiss all that. Hard starting in a particular heat range is usually attributable to the AAV. Which will either be optimized for cold starting or warm starting. Rarely both unless brand-new and sometimes not even then. TTS or CTS can also be a cause if they are telling the ECU that the engine is cold (<86° F) which will engage the Aux Injector when it shouldn't. Book says less than 86 should be 0 Ohms and >86° F 100-160 Ohm. So you may have located your problem.

 

[Gubi]

I find your description between Hot and Warm hard to follow.

Hot = just turned it off a few minutes ago
Warm = it's been sitting for ~20 mins after being run at full temp.

So I'm going to dismiss all that.

Well then you're not going to fully understand the problem

 

[Gubi]

my 3.0 makes the same rumble and rattle noise from the trunk on hot restart. especially after the sun heats up the back of the car. runs rough, makes embarrassing noises, clears in a minute or so, then runs perfectly. no cold start problems.

sure sounds like vapor lock. did you (or anybody reading this) ever solve the problem?

Yeah, pretty sure that's the same warm start issue I described. I don't know that anyone's fixed it, no. I just crank a bit longer and eventually it catches. Runs rough for a few seconds until when the rumbling stops and all the vapor is out of the rail.

My suspicion is that the problem is heat soak of the fuel hoses and rails in the engine compartment. A potentially straightforward fix would be to add some heat shielding (like ThermoTec cloth wrap).

Alternatively one could jury-rig the fuel pump to operate with the car not running so you could flush the lines and build pressure, but there are obvious safety issues depending on how one were to do that.

my tts reads a low 70 ohms, with 190 degrees at the radiator. tts reading should be 100-160 ohms with a hot radiator

70 ohms should still be plenty high enough to keep the CSI from firing. When mine failed it was like 4 ohms cold and the CSI wasn't firing. If you really want to make sure, you can unplug the CSI and see if it fixes the problem of hard starting when warm. But from your description I doubt that's it.

 

[Milanoguy]

To Ryan F.

Assuming this the issue is fuel pressure; then you're going to have to hook a fuel pressure gauge into the fuel line and watch the pressure levels from a total cold start (engine off for 12 hours) a hot restart (less than 5 minutes after turn off) and a warm restart (1 hour).

The cheapie fuel pressure gauge that Harbor freight sells is actually pretty good. Buy some 5/16 fuel line (make sure it says for FI use) and plumb the gauge into the fuel in line before the rail.

Search the AlfaBB for more guidance and images of this, and always have a fire extinguisher in hand when working on the fuel system.

Bye

 

[ronpaci]

thanks for your answers. sorry for not distinguishing between warm and hot.

in this context i simply meant restarting the car with the engine still 'warm' after a drive, not starting dead cold.
it happens after the car sits a short while, parking the in sun seems to make it worse. the problem occurs whether the engine temp is 190, or 160. the rough running is usually short-lived, and then it runs great.
it starts cold quick and idles fine.


the aav seems to work. cleaned it, saw it open about half when cold, heated it watched it close.
i have seen many of the online tips about this problem. i have a roll of heat shield material ready for wrapping the fuel rail, and i'm looking around for places the fuel lines may be getting too much heat.
and that's interesting gubi thinks 70 ohms on my tts is enough. i going to hook a test light to the tts-csi wire to check for power. read that somewhere too.

i just put the issue out there looking for some one to say 'yeah, mine did that too, fixed it, here's what i did...."
i just described to a friend that owning these 80's cars as being in alfa purgatory, not in the electronic hell of the present, nor the in the perceived heaven of the past, just stuck in the middle without an obd scan tool.

 

[alfaparticle]

Maybe the gas tank is being pressurized and causing high fuel pressure. Try removing the gas cap the next time that it happens. There is a little relief valve somewhere in the vapor system that has a low flow capacity. It might be partly blocked.

 

[Gubi]

i have seen many of the online tips about this problem. i have a roll of heat shield material ready for wrapping the fuel rail, and i'm looking around for places the fuel lines may be getting too much heat.

I've just taken a look and the only place that looks like an obvious issue is the right side. From where the fuel line enters the engine compartment to where it goes into the pulse damper it's pretty close to the exhaust manifold. That's probably where I'd start...easy enough to add a little heat shielding there, see if it helps.

 

[alfaparticle]

My son's Verde pressurized the gas tank due to an exhaust leak that heated the tank. It made the car run very rich and would not idle until the gas cap was removed.

 

[Gubi]

That's another potential cause, I suppose. But the issue I'm describing clears up after about 10 seconds of running, so it may be something different.

 

[Potenziato]

I've been having the same issue so here is what I found.

The other day I ran the car just long enough to open the thermostat and parked it for 15-20 minutes. When I got back in the car, I cranked it five times and it wouldn't start. So i go ahead and disconnect the coolant temperature sensor and it fires up immediately and then dies because there now is no fuel delivery. Now I reconnect the sensor and it clears up immediately with the wonderful sound of air in the heat soaked fuel lines.

If your car is rich, disconnecting the coolant temp sensor disables the dumb l-jet ecu, but the spark is still active.

So I seem so have a rich mixture but it isn't the thermo time switch. I think it maybe one or all of the fuel injectors are leaking.

 

[Gubi]

I suppose you could test for that by monitoring fuel pressure on the rail after shutting off the car. Mine's definitely never been that bad...it always starts on the first or second go.

In related news, I got some Thermo-Tec Expres Sleeves. These are velcro closure heat reflective sleeves for hoses and wiring. I'm going to try wrapping the fuel line from the firewall to the pulse damper and see if it makes any difference in the air sound or hard-ish starting.

Thermo-Tec : Express Sleeves

 

[ronpaci]

'87 verde
i'm still working on the same problem.
my car (mechanically great) will start warm, but then stumbles and rumbles, clears, then runs fine.
i have not tried to disconnect any of the sensors, though i have checked and rechecked resistance in all of them and they read fine.
leaking injectors (including the csi) are on my list of suspects too. mine are orig. at 88000 miles.
but my current theory is the ethanol is evaporating in the fuel rail and causing a short term vapor lock situation. other cars seem to have the same problem and condemn the ethanol.
i insulated the exposed fuel lines in the engine compartment. no effect.
now i'm trying $28 of bg44 additive. after i give that a chance i'm going to insulate the fuel rail itself.
if that fails, then i'll try bg fuel dryer.
i have spent a lot of time on this glitch; every experiment brings up another question: are the sensor signals reaching the ecu?

 

[ronpaci]

i should mention i have a permanent fuel pressure gauge mounted in the engine compartment.
so far i get the vapor lock (if that's what it is) even when the system is holding 35 pounds of residual pressure.
and the pressure doesn't seem to fluctuate during the rough running period.
that may not make any sense theoretically, just my observations so far. i'll check that again.
new: fuel pump, filter, all soft lines, silicone vac lines......

 

[Potenziato]

I started the car up this morning and than stopped it. I noticed the smell of gas when checking the tire pressure. I have a nice drip coming out of the number 2 injector line.

I guess it time to have all the injectors cleaned and replace all the hoses.

 

[Gubi]

I suppose you could test for that by monitoring fuel pressure on the rail after shutting off the car. Mine's definitely never been that bad...it always starts on the first or second go.

In related news, I got some Thermo-Tec Expres Sleeves. These are velcro closure heat reflective sleeves for hoses and wiring. I'm going to try wrapping the fuel line from the firewall to the pulse damper and see if it makes any difference in the air sound or hard-ish starting.

Thermo-Tec : Express Sleeves

For the record, I tried wrapping the fuel line where it enters the engine bay and the pulse damper. It doesn't appear to have made any difference in the warm-start vapor noise.

 

[Potenziato]

So why does the Milano/75 make the fuel pump noise and not the 164?

I remember having a slight hot start issue in a 164L. I would slowly press the throttle and it would start right up. I never once heard all the weird noise in the 164. The 164 manual even stated to slowly press the accelerator on hot start.

Anybody check voltage at the fuel pump? Usually Alfa undersizes all the wiring in the car just to be mean to us.