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2003 156 JTS 2.0 selespeed cold starting problem

4823 Views 107 Replies 4 Participants Last post by  156and33
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 · #3 ·
Obviously you have diagnostic equipment.
Charge voltage through diagnostic equipment is a little low but OK.
Have you looked at live data and selected engine rpm whilst cranking? That checks the crank sensor.

How old are spark plugs?
Look at live data- things like spark advance to check that the system is trying to start it. Ditto check "starting authorisation" in live data for the same reason.

It could be you have an ignition switch issue but be guided by the results to these questions.

Sometimes the spark testers which fit on end of spark plugs are a great way to see if the coils are firing. It can save much checking of other stuff.
Just a quck thanks and short reply as it is bed time here.
Yes I have a few tools but soon run into the knowledge wall 😬
Thanks for the crank sensor check method.
Plugs have probably only done 1/2 of their 100k life (not much driving since COVID)
Do you mean check spark advance during cranking? What should I see?
Not sure what starting authorisation is, I will check this out. What inputs are there for the authorisation - crank signal will be one I am guessing?
I have a COP test probe to see what is happening during cold start. Might be able to quickly check all coil packs if I am quick. If I was to use an old school spark plug tester how are the fuel injectors disabled?
Why would the car start first go during the rest of the day?
I should check to see if morning starting, stopping, and restarting shows different behaviour.
Testing could be tricky, and maybe take a couple of days as the cars will start on second or third go. Will have to use the logging function I guess.

cheers
 

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Discussion Starter · #5 ·
Thanks Fruity
I am still to complete the testing. Will do it tomorrow morning and report back.
Plugs are BKR6EKPA. Used to use single earth iridium ones in in my 33 because they were a bugger to get out.
Is it OK to spray WD40 or electrical contact cleaner down the ignition key lock, if there is a contact problem (although I am not sure it would get through the barrel and onto the contacts)?
I will try turning the ignition on twice before starting to see if there is a petrol pump priming issue and also look at the MCU fuel pressure to see if it sags a lot before starting. I believe it should hold pressure for a while.
 

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Discussion Starter · #7 ·
Fruity, here are the test results. Do they tell you anything?
Did not get any data for ENGINE STARTUP. SPARK ADVANCE no data (software problem maybe), but no pinging

My observations ——
G1:
IGN ON: fuel tank pump is working , 7 bar, stable. I think his is normal.
CRANK 1: crank sensor working, high pressure duel pump working at 50 bar

G2:
IGN ON: Fuel pressure did not sag. Rising fuel pressure (after first crank) - not sure what this indicates? (Fuel filter replaced Feb 2021, pretty sure I also replaced the LP pump at some stage)
CRANK 2: FP and RPM OK

Still not sure about ignition system. Will have to check this tomorrow when it is cold using the COP probe.

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Discussion Starter · #9 · (Edited)
Thanks Fruity

Not sure those spark probes would be visible in the hole with the coil pack inserted? Do you think they work on the 2.0 JTS?
I won’t be able to do anything more for a few days and get back to it after..
I might be able to read ignition advance using an OBD dongle and an app on my phone.
The RPM drop out was me stuffing around 🤭, I think I had to quickly turn it off and on to get the computer working, sorry should have indicated that. Just ignore that for now.

What is the best way to find the cause of a current leak? My battery stays at 12.6v for a long time when not connected to the car. When connected it drop to 12.3v overnight without opening the car doors (selespeed pump). It is also OK under load as mentioned above.

Thanks
Duncan
 

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Discussion Starter · #11 · (Edited)
Fruity

Battery drain issue: Using a sensitive DC clamp meter on the negative cables. While the interior courtesy lights are on there is a draw of 10s mA only. However, when the lights go out (doors closed, no keys in ign.) the current drain jumps to almost 1 A. I don’t understand the test results. What could be the issue .. a relay gone short circuit in the off position ? Are there any ignition circuit relays (I don’t think there is for this car) ?
I am fairly confident that the battery is OK.

First start of the day issue: Battery/cranking OK (voltage remained >10V during start, also using a jump starter to support the battery made no difference either). Coils are firing OK when the car is running.
I need to check the coil firing on the first start - not done that yet. Needs two people, and only one go per day.

duncan
 

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Discussion Starter · #13 · (Edited)
All electrical equipment is unmodified, except for LED bulbs in the boot (pulled them out already but made no difference)
I could try a second key fob with a different immobiliser transponder chip
Going to replace all fuses with those that have the exposed terminals for ease of testing.
 

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Discussion Starter · #17 · (Edited)
NGK plugs are 50K klm since new
I ordered some spark indicators but who knows when they will arrive, COVID is going crazy here in Oz.
MAR: engine light, brake light, oil pressure light, battery light. Engine startup parameter shows not data in MES.
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I only have the free version of MES (ver 3.5 and 4) and can only monitor 4 parameters. I also have a OBD dongle and an app. Neither show any spark advance signal during idle or revving. Engine key position only ever shows MAR.
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Battery voltage was low this morning so did these tests at about 12.3V
I never really fully trust the DC clamp meter at low readings. Zeroing it out means disconnecting the battery cable and then the car goes through its startup routine again
I will latch all the doors and bonnet and then check again. Get back to you with the fuse results.

Really appreciate your help 😀
 

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Discussion Starter · #18 ·
I latched the bonnet and drivers side doors. All accessories off. Everything else closed.
Key off: battery 12.7V, with Dc clamp meter zeroed, 30mA stable when battery reconnected
Then this sequence——-
MAR: 12.7V
Key off: 12.7V, 33mA
Passenger door open: 2.2A with int light on
Passenger door closed: 300mA stable
(If the clamp meter does not return to zero after disconnecting the battery at the end of the test I will stop relying on this result)

I replaced all the fuses with probe-able ones. Monitored clamp meter during replacement - clamp meter timed out during process so not sure if anything significant was detected.
With the car sleeping: I measured the voltage drop across each fuse and determined current - nothing much to report, some had a few 100ths millivolts, some started high and stabilised low, all less that 20mA). I have a high quality DMM I used for these measurements.

If I can replicate the high current possibly seen previously on the clamp meter, I will do this again
 

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Discussion Starter · #19 ·
I only properly read your last post after my last 2 posts. Sorry. You can use these posts for information but I'd check spark plugs anyway. For information sake, I prefer the PFR6B plugs to the BKR6EKPA plugs. They are cheaper and the BKR6EKPA were only offered as an alternative anyway. I'll disconnect my coils and see what my battery voltage during cranking is and report back.
I ordered PFR6B, take one variable out of the equation
 

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Discussion Starter · #20 ·
Gave the clamp meter the flick.
With the DMM in series, 10A range, the sleeping current draw is only 16mAdc. I am going to monitor battery SOC while connected today to confirm battery drain again.
I load tested the battery again using a carbon pile: it delivers 270A at >10.2v for 15 sec and it holds voltage for at least several days (tested before).
 

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Discussion Starter · #23 ·
Fruity
I just noticed that MES is showing Too High Latency warning and wonder if this may have something to do with no SPKADV and authorisation to start signals?

Vbatt = 12.78V after being connected to car overnight so no drop. This is unusual and the only thing I have done is replace all the ATO fuses near the steering wheel, and manually locked/unlocked the drivers door and bonnet latches when testing yesterday
Voltage between: (batt + and body -) and (batt + and engine -) = 12.78V
MES voltage at OBD plug about 0.2V down

I made a mistake and did not save the graph from the first failed start attempt but here are the two subsequent starts. I think your parameters are met and I recall that the first start was similar (but maybe the Vbatt dropped a little lower). Once the car started, the Vbatt recovered mostly
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Discussion Starter · #25 · (Edited)
The Owners Manual does not show an ECU relay and the only similar one would be the electronic injection relay in the engine bay. There are two additional relays hidden near the fuse panel but not listed, and I know one is for the low beams.

I have not come across a cam angle sensor yet, where is that located, behind the can sprockets? Might be time to test it. How is that best done (simple resistance check or do I need to dig out the oscilloscope and back probe the connector?).

I have one more scan tool I could use tomorrow to see if SPKADV and authorisation data are picked up. This is the one I keep in the boot to help with replacing coil packs when they fail away from home,

It will be a while for the spark plug testers to get here from the UK. Luckily I will now not be needing the car for work until Feb because of COVID impacts

I forgot to mention that I have not changed petrol stations or fuel type but the car spent most of 2021 sat in the garage on a battery charger with a full tank of fuel.

I just fitted new tyres and windscreen and have the cam belt service parts sitting in a box ready to go, so am committed to getting this fixed. Might get a new camshaft sensor while I am at it. Thanks again for the support but let me know when you think it is time to take it to an auto electrician?
 

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Discussion Starter · #28 · (Edited)
More testing
Vbatt = 12.78V after connected to car overnight. Seems like current drain has ceased
Cranking: SPKADV BTDC starts at 4, goes negative for a second and then stabilizes around 10 at 900rpm
Revving: 1000 rpm, 12 deg, 2000 39 deg, 3000 42 deg

I back probed the camshaft position sensor: earth OK, Vsupp = 5Vdc
MAR: Vsig = 0.11Vdc
Idling: Vsig = 6Vac at 30 hz
2000 rpm 80hz
3000 rpm 130hz

I cannot find any timing data or specs on the cam sensor to check these values against
 

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Discussion Starter · #33 · (Edited)
Generally starts second try but not always straight away, or easily. Sometimes it attempts to fire but does not quite get there, sort of splutters and stops as if the fuel tank is empty (but it isn’t). Yesterday the car cranked strongly for 10s but did not even look like starting. Started second go but that was not very convincing as if the engine was flooded (3-4s). For the rest of the day it usually starts easily (1-2s)

Fuel pressures (low and high) seems OK as tested in post #7. Two primings in MAR makes no difference

I might video it this morning and see if that can be uploaded here.

I will switch out the fuel injector relay and see what happens.

The crank sensor did not fail outright. One day the car failed to start when my wife was by herself, and a fault code logged (the car started eventually). I reset the fault log and it then drove OK for several weeks until I replaced the sensor. Luckily I had a new unit in my spare parts box as I knew this was a critical sensor.
 

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Discussion Starter · #35 ·
Not checked compression on this engine yet, fear of getting the adaptor stuck down the hole. Can I pull the injector relay when doing this ? I was starting to wonder if it was a mechanical issues with valves stuck open.

I guess you mean the long term fuel trim values for each bank?
 

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Discussion Starter · #37 · (Edited)
About 250k klm
Always used 10w60, either Selenia or Castrol Edge
Fuel has been 98 RON

Cannot see any way to upload a video file to show behaviour

Just came back from a 1 hr drive and collected this data when idling in garage A/C on:
Eng temp 93
Air temp 53
STFT B1 0.00
STFT B2 0.00
LTFT B1 -2.34
LTFT B2 -3.12
SPKADV 15
TPS 9%
MAF 10.25
Vbat ecu 13V
 
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