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2003 156 JTS 2.0 selespeed cold starting problem

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Hi
I’d welcome a few ideas on troubleshooting a morning starting problem with my old car that I need for work (done >250k klm)

Symptoms:
Used to always start first time, then took a while to fire up on first crank. It would stop cranking by itself even though the key was in the crank position (I thought this was weird). Now struggles to start first time, but cranks strongly until I release the key. Usually starts second go but sometimes not convincingly. Problem only occurs in the morning (20 Celsius), never any issues rest of the day.
Generally driving OK, no performance issues that I have detected, perhaps a the odd splutter
Battery tests ok with carbon pile load tester. Voltage drops from 12.6 to 12.3 over night. Having to keep on charger. Alternator is charging OK. Starting issues do not appear to relate to battery voltage
I know I have a main bearing seal leak and there might be oil in the bell housing… not sure if that can interfere with the crank sensor operation
No fault codes stored
Recent repairs:
Fuel rail pressure sensor replaced. Crank position sensor replaced after stalling/starting problems (last repair). New battery July 2020. Starter replaced Feb 2021. Alt replaced Sept 2017. Plugs not due to be replaced.
Cam belt due for replacement at the moment
Troubleshooting so far:
I thought maybe the fuel pump relay might be dicky and swapped the fan and fuel pump relay - no change
Ecuscan tells me the actuators and relays work, fuel pressure is regulated at ~50 bar, lambda signals from each bank are the same, battery voltage 13.7v at idle. Don’t really know what else to check.
I carefully sprayed some gas around the engine bay looking for keaks, no change in RPMs
Spark plugs were dry sooty black but that was after idling for 10 mins, electrodes OK
Sprayed the MAF with some dedicated cleaner
Thanks
Duncan
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Discussion Starter · #81 ·
Addo, sorry but I think I am missing something here …..
The pump does run with ignition on, and stop after several seconds
There is good flow of fuel when disconnected from the system and the fuel pump stops
With the pressure gauge installed, the system is pressurised and the pressure was holding, so the check valve is OK (although I am not sure of the actual pressure as the gauge is probably inaccurate, but MES reports 5 bar)
If I believe MES reported pressure then it is in spec.
 

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I can’t comment on your gauge other than to say it looks like it possibly tries to cover too many bases, to give a dependable result for all.

It‘s unlikely there is a pressure sender in the low pressure line, MES will be conjecturing. So you’re stuck with relying on gauge readings. The few seconds of pump run when keying on, is only to top up the standing pressure in the lines. I note the nominal pressure in eLearn is 4.5 Bar, just over 65PSI. Off the top of my head, free (zero head) fuel delivery with a pump of this nature should be over 4 litres/minute, post-filter.

So, if you’ve got a dependable gauge plumbed in, jump the lift pump and run it (ignition off) until the pressure stabilises and is within spec - then leave for 8+ hours and review gauge thereafter. I can’t offer a number but it should absolutely not be near zero.

Not sure if you’ve seen this flowchart: B13 ENGINE STARTS WITH DIFFICULTY' - Alfa - 156 - eLearn - 4CarData

The last step is blackly humorous.
 

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Discussion Starter · #84 · (Edited)
Somene else had said that the MES reported LP values that were somewhat bogus but surely without the engine running, the pressure in the HP fuel rail would be the same as that on the low side of the HP pump unless there was complete isolation between the two sides the pump.

Just ordered a new gauge. Then i can hopefully get some reliable data.

I have eLearn on a disc didn’t know it was online, still missing lots of info though!
 

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Discussion Starter · #85 ·
Pressure on the LP line did not drop overnight.
Car started OK this morning but air temp was still 28 (hot night)
Should be cooler days coming so will see how cold starting is behaving.
If there is now improved starting, could a poor HP modulation valve electrical connection have contributed?
 

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Discussion Starter · #86 · (Edited)
Quick update:
Took three goes to start this morning so no change to original problem (gauge removed yesterday and back to original)
Runs very well and starts first go after a run to the shops and back
New pressure gauge won’t be here for a week or so

Here is some fun and games: I was looking to turn on the fuel pump by shorting at the relay socket - not working…..three if the relays were in the wrong ocations according to the map on the box…. tidied up now, but this kind of thing doesn’t make this easy! Pump draws about 4A.

I just read that the fuel pump with inbuilt pressure reg (4.5 bar) pressurises both the low and high pressure circuits so MES values are probably from the fuel pressure sensor.
 

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Discussion Starter · #87 · (Edited)
I just checked manifold vac at the brake vac port near the PCV valve (not leaking and I replaced the o-ring a couple of years ago, plugging it made no difference)
Warm engine
It starts off at 12 in-Hg but drops to only 7 after 5-10 seconds, and remains stable at idle. I was expecting 15-20.

Throttle body to manifold o-ring not leaking. Sprayed some gas around but could not detect any vac leaks by change in RPM. Could not hear anything. Flexible coupling not cracked.
What is going on, leaky brake master cylinder (where is it)? Or is it in spec and there is a vacuum pump somewhere?

UPDATE:
Disconnecting brake vac hose and plugged it: man vac now at 12 in-Hg but not very stable
 

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Master cylinder is in the cabin between pedal box and bulkhead. If it was leaking , you would hear it.

It is only clear to me now how you got fuel pressure readings.

Have a look at the diagnostic fuel pressure. See how quickly the fuel pressure rises and decays.
 

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Discussion Starter · #89 ·
It is only clear to me now how you got fuel pressure readings.
Not quite sure what you mean. I have reported MES values in previous posts and I tried using a gauge but that failed as the pressure was too high. Later this week the new gauge will arrive.

I am not sure you I observe the initial pump activity in MES as the system pressurises only when the key is turned to MAR and MES doesn’t connect until the key is turned to MAR. Similarly, not sure how you can use MES to monitor pressure decay as my free version times out.
 

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If you would like to measure initial pressure and decay, stop the fuel pump working by removing the fuel pump relay.

Sorry, I got a little confused. That's me though. I should have written stuff down.
 

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Discussion Starter · #91 ·
Fruity thanks for the clarification (really appreciate the support on this, hopefully we will get there soon without needing a new ECU!). That method had not occurred to me. I should summarise the checks and outcomes and repost them to help you guys out as the post is long.
 

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I don't think it is ECU. All the functions seem OK and it shows even in this day and age the value of simple spark testers and ether spray as a rather rudimentary diagnostic tool.

Things which can affect the ability to start (compression seems good) are then spark and fuel. Currently I think fuel distribution due to injector spray pattern which hopefully ultrasonic cleaning will rectify.
 

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Discussion Starter · #96 ·
I will do the fuel pressure check again tomorrow morning. What kind or pressure stability is normal?
Taking out the injectors will be a PITA so I would have to be really confident that was the problem. (Wonder it it will be worse that replacing the alternator, that was a major PITA without a hoist)
What is the hypothesis: fuel atomisation during the first cranking is not sufficient to promote ignition, but the initially injected fuel is vaporised sufficiently during the second cranking only seconds later?
Is the effect of ether injection 100% diagnostic for injector spray problems?
Brand new injectors are sometimes available for $AU200 each. How much cheaper will injector overhaul be and what kind of life do they have afterwards.
Could the injectors be OK but the injector tip be fouled with carbon?
Can MES diagnostics measure anything useful regarding injector condition?
I did use a can of BG44K last year and then replaced the fuel filter. That stuff is supposed to be good but I had no issues at the time (AFAICR). I have another can if it is worth trying again.
 

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Discussion Starter · #97 ·
Found time this morning
Car standing O/N
Fuel pump relay removed
MES reported 5.5 bar at MAR
Relay reinstalled
First crank failed to start and for some reason MES stopped logging
Second start and idle and revving charts below. I suspect that the spiking is a latency or sampling issue ??? Be nice to elliminate it for cleaner charts.
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Yes, the less data going to MES (fewer data heavy streams), the better it works without drop out even with latency reduced to 1.

JTS injector removal is never something anyone will do for fun as it's a couple of steps down from medieval torture. People have done it (I had engine apart) and use of some trick tools like 1/4" drives for sockets and bit allied to possibly flexible shaft extensions helps. I think a smooth ratchet and stubby spanners also helps take away the pain. If I was to do it again, I'd drain the PAS first to make removing the reservoir nicer.

If you can do awkward jobs at your leisure, that may help but I often find rediscovering extra joints in my digits that look completely normal means progress is better when in the zone, so to speak.
 

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Discussion Starter · #99 ·
I was able to get ohotos of the cylinder head and injectors 1-4. There is some bulidup of residue at the baee of the valve stems but the ports are not obstructed at all
Not sure if the injector tip oictures ae diagnostic.
The new plugs look very sooty to me. Maybe there is a combustion issue.
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Just thinking about what I'm about to type, I promise I'm not trying to be argumentative.

The plugs don't look that bad. They would clean with open road use rather than idling or town use.
I thought the injectors looked a bit dirty but I absolutely cannot say if any of the carbon affects spray.

At this point, all I can suggest is an emissions test. I think fairly high CO or HC would suggest poor combustion which may be indicative of injector spray patterns. The higher the engine speed, the more turbulent the mixing but things may be a bit off at idle.
 
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