Poor starting 350i
Discussion
Hi Everyone,
I wonder if you could help me with a starting problem I’ve been experiencing with my 350i. It began about 18 months ago when I noticed the car no longer fired up instantly from cold. It used to only take a couple of seconds to fire, but suddenly on occasion it was taking about 10 seconds instead, and at times needed a couple of tries before eventually firing. It only ever seemed to do this from cold, with ambient temperature not seeming to have any affect.
Just lately, the problem got a bit worse. It was now taking ages to start the car from cold every time, perhaps 20 seconds of cranking although hot starting was fine. Yesterday though, the car finally refused to start despite many minutes of cranking.
I had previously carried out lots of diagnostics to try and remedy the problem, but it was difficult since you only got about 10 seconds or so of cranking before the car eventually started, which didn’t give a lot of time for testing things. I did run through the various topics in the “Wedge Epistles” though to try and troubleshoot, including the EFI checking guide where by I checked all the pins on the ECU and tested all the sensors etc. Everything seemed to be fine.
Today, I have checked the following.
Fuel pressure was 2.5 bar on cranking.
Swapped the rotor arm, ignition module and coil with either brand new or known working spares.
Checked for any lose wires in the engine bay and reseated all the push fit electronical connectors.
The ECU tempterature sensor was also swapped last year as part of the troubleshooting.
On cranking, the car would try to fire, but not catch. The engine would shudder like it was about to start and the exhaust would emit a brief rumble, but the cranking would just continue for ages and ages. It probably spent about 15 minutes being cranked during the morning whilst I was checking things one by one, but it just wouldn’t catch.
Eventually, it finally spluttered into life with lots of grey/black smoke, but instantly cut out. I restarted it, and it cut out again instantly. After a few more tries, it ran roughly for about 10 seconds before settling down into a completely normal tickover. It revved freely and whilst I didn’t drive it, I’m sure it would have run faultlessly like it has done over the last 18 months.
So what could be causing the poor starting on a car that otherwise runs perfectly?
I’m certain that tomorrow morning it will have the same fault again, so is there something that happens during cranking that could account for this? I'm handy with a multimetre btw!
Also, most of the service parts are relatively new and of good quality (genuine Lucas arm and cap from RPI, good leads, coil etc etc). Flapper type AFM.
Thanks in advance,
Dan.
I wonder if you could help me with a starting problem I’ve been experiencing with my 350i. It began about 18 months ago when I noticed the car no longer fired up instantly from cold. It used to only take a couple of seconds to fire, but suddenly on occasion it was taking about 10 seconds instead, and at times needed a couple of tries before eventually firing. It only ever seemed to do this from cold, with ambient temperature not seeming to have any affect.
Just lately, the problem got a bit worse. It was now taking ages to start the car from cold every time, perhaps 20 seconds of cranking although hot starting was fine. Yesterday though, the car finally refused to start despite many minutes of cranking.
I had previously carried out lots of diagnostics to try and remedy the problem, but it was difficult since you only got about 10 seconds or so of cranking before the car eventually started, which didn’t give a lot of time for testing things. I did run through the various topics in the “Wedge Epistles” though to try and troubleshoot, including the EFI checking guide where by I checked all the pins on the ECU and tested all the sensors etc. Everything seemed to be fine.
Today, I have checked the following.
Fuel pressure was 2.5 bar on cranking.
Swapped the rotor arm, ignition module and coil with either brand new or known working spares.
Checked for any lose wires in the engine bay and reseated all the push fit electronical connectors.
The ECU tempterature sensor was also swapped last year as part of the troubleshooting.
On cranking, the car would try to fire, but not catch. The engine would shudder like it was about to start and the exhaust would emit a brief rumble, but the cranking would just continue for ages and ages. It probably spent about 15 minutes being cranked during the morning whilst I was checking things one by one, but it just wouldn’t catch.
Eventually, it finally spluttered into life with lots of grey/black smoke, but instantly cut out. I restarted it, and it cut out again instantly. After a few more tries, it ran roughly for about 10 seconds before settling down into a completely normal tickover. It revved freely and whilst I didn’t drive it, I’m sure it would have run faultlessly like it has done over the last 18 months.
So what could be causing the poor starting on a car that otherwise runs perfectly?
I’m certain that tomorrow morning it will have the same fault again, so is there something that happens during cranking that could account for this? I'm handy with a multimetre btw!
Also, most of the service parts are relatively new and of good quality (genuine Lucas arm and cap from RPI, good leads, coil etc etc). Flapper type AFM.
Thanks in advance,
Dan.
Hi,
Is the connector fitted to your cold start injector? If so I'd suggest removing it and leave it removed.
Are your plugs wet with fuel before it starts? I'd guess they are from your description.
Do you know what type of coil you have? If it should have a ballast resistor is the ballast resistor ok? Also is the feed from the starter motor connected and does the starter supply voltage to it whilst you're cranking?
Have you changed your spark plugs?
Have you tried holding the throttle open a touch whilst cranking?
Danny
Is the connector fitted to your cold start injector? If so I'd suggest removing it and leave it removed.
Are your plugs wet with fuel before it starts? I'd guess they are from your description.
Do you know what type of coil you have? If it should have a ballast resistor is the ballast resistor ok? Also is the feed from the starter motor connected and does the starter supply voltage to it whilst you're cranking?
Have you changed your spark plugs?
Have you tried holding the throttle open a touch whilst cranking?
Danny
Hi
I have had a problem over the weekend with my 420 not starting.
Had some really useful posts back on the forum topic, check back and have a look might be of interest.
In the end i was told that it was down to a flooded engine and that if i put my foot to the floor on the accelerator and kept cranking her over she would start. And she did...
Im looking into other areas now to see why she is flooding, could be the cold start injector etc but if you look at the last post i had there is a link to some very interesting documents explaining the ignition system etc. Thinking along the lines of a leak in a vacuum pipe or something similar, maybe around the plenum chamber.
Hope this helps.
Keep in touch and good luck
I have had a problem over the weekend with my 420 not starting.
Had some really useful posts back on the forum topic, check back and have a look might be of interest.
In the end i was told that it was down to a flooded engine and that if i put my foot to the floor on the accelerator and kept cranking her over she would start. And she did...
Im looking into other areas now to see why she is flooding, could be the cold start injector etc but if you look at the last post i had there is a link to some very interesting documents explaining the ignition system etc. Thinking along the lines of a leak in a vacuum pipe or something similar, maybe around the plenum chamber.
Hope this helps.
Keep in touch and good luck
Hi Dan, i've been chasing the exact same starting symptoms as you've described for last month, although these last couple of days as the outside temp has increased its ability to start. have you found that if you give the engine a quick flick of the key to start it almost starts but if you continue cranking nothing? mine actually started after i let go of the key once, i turned it over for a few seconds, let go of the key and the engine shook and spluttered and then started!
i've disconnected the plug to the cold start injector as i found this was flooding the plenum chamber with fuel. i've found that i can start the car 2 ways:
1. undo the 2 bolts securing the extra injector and pull it out slightly but not fully, just enough to allow a little extra air in (this way only works sometimes)
2. Turn the dizzy anti clockwise about 20 degrees retarding the ignition, once fired can turn it back almost immediately (this works all the time)
my car also runs perfectly when warm and is pretty good starting hot. I've checked and swapped many parts extra air valve, thermotine sensor, temp sensor, AFM has been checked, ECU was a newly refurbed item, coil, leads, amp. I've just got a second hand dizzy but needs a little modifying to fit as its a later hot wire type but is a lucas (can't find a lucas flapper one!!). I'm figuring that its either a lack of air or the dizzy but after reading Danny's post i realised the one obvious thing i haven't checked is the plugs, can't believe i never thought of the obvious, got to be worth a try considering it would be a cheap fix. if it does i think i'll cry
would be interested to know if you have any luck starting yours
i've disconnected the plug to the cold start injector as i found this was flooding the plenum chamber with fuel. i've found that i can start the car 2 ways:
1. undo the 2 bolts securing the extra injector and pull it out slightly but not fully, just enough to allow a little extra air in (this way only works sometimes)
2. Turn the dizzy anti clockwise about 20 degrees retarding the ignition, once fired can turn it back almost immediately (this works all the time)
my car also runs perfectly when warm and is pretty good starting hot. I've checked and swapped many parts extra air valve, thermotine sensor, temp sensor, AFM has been checked, ECU was a newly refurbed item, coil, leads, amp. I've just got a second hand dizzy but needs a little modifying to fit as its a later hot wire type but is a lucas (can't find a lucas flapper one!!). I'm figuring that its either a lack of air or the dizzy but after reading Danny's post i realised the one obvious thing i haven't checked is the plugs, can't believe i never thought of the obvious, got to be worth a try considering it would be a cheap fix. if it does i think i'll cry
would be interested to know if you have any luck starting yours
digga951 said:
I’m certain that tomorrow morning it will have the same fault again, so is there something that happens during cranking that could account for this?
In order to answer that question one needs to fully understand the cold start process. I mean fully understand - not just skip through - so please study this:
Introduction
• When the Rover SD1 Efi engine is started from cold the initial requirement is to provide a rich mixture to make the engine snap into life. The colder the engine the more time may be needed to allow the engine to fire and run.
• As soon as the engine fires this extra rich mixture must cease immediately or over-fuelling will flood and stall the engine.
Location and Operation
• The method for cold starting the Rover Efi System has two separate functions.
• The first is under the control of the ECU whereby an electrical supply from the starter circuit signals pin 4 of the ECU for an increased “open time” for all eight injectors during cranking.
• The second employs the thermotime switch (TT) fitted to time the operation of the cold start injector (CSI).
• Located in the coolant gallery at the left front of the inlet manifold, alongside but slightly in front of the coolant temperature sensor, the thermotime switch determines cold start injector “open time”.
• The colder the engine at start-up, the longer the injection time, but only during the cranking sequence.
• To achieve a satisfactory start in adverse conditions the cold start injector, mounted on the R/H side of the plenum chamber, is positioned to spray directly against incoming air to give the best atomization of the additional fuel it supplies.
• The thermotime switch contains a heater coil (HC) around bimetal operated contact points (BMC), and works as follows.
• During cranking in cold conditions current can pass through the closed contact points of the thermotime switch and cause the injector to operate. Simultaneously, current is passing through the heater coil to warm the bimetal. After a maximum of 12 seconds the expansion of the bimetal will open the contact points. The injector then ceases to operate to avoid an over-fuelling condition.
• In any case the injector will cease to operate as soon as the engine fires because it is only connected to the ignition system during cranking. When correctly tuned, the engine will fire and run long before the maximum 12 second limit is reached.
• At higher coolant temperatures the operating time progressively lessens, until at 35°C approximately, the thermotime switch contact points remain open and the cold start injector will not operate.
You will have seen from the above description (second bullet) that the risk of flooding the engine is negated by the CSI cutting out after a specific time as determined by the coolant temperature. It is also mentioned later in the description.
HOWEVER
It is a paradoxical condition of the system that if the engine is repeatedly restarted, EVEN A COUPLE OF TIMES, the propensity of flooding due to repeating the described sequence is increased after every retry of the starting sequence.
Just two or three times is sufficient to kill all hope of starting.
You'll also see in the description the following underlined observation:
When correctly tuned, the engine will fire and run long before the maximum 12 second limit is reached
Clearly then, if the engine is off-tune, the described cold start sequence may easily fail.
OK! Now one understands the cold start process and the probable adverse situations related to repeated starting and trying to start an off-tune engine, all of the above are magnified, the colder the engine is when starting.
Thats why they fitted a Cold Start System. Never-the-less some owners completely disable the Cold Start System and rely upon a perceptive starting technique.
That is, feathering (or even booting) the throttle during cranking to induce a richer mixture from the ECU, just enough to make the engine catch.
So how does all this pan out for "digga951". If you go to this page:
http://www.vintagemodelairplane.com/pages/Rover_Te...
you will find the rest of the article and the full testing process for your flapper Cold Start System.
Further, in the same archive are all the components of the Efi system clearly described and accompanied by their associated test processes, awaiting your multimeter skills.
Even more interesting is the opportunity to review the Efi Ops Manual.
By dint of following the opportunities mentioned to correct any off-tune situation then so the effectiveness of the CS system will be perfect.
Even then, the Efi system is not the only variable in play regarding an off-tune engine. So be prepared to review the health of your ignition system:
http://www.vintagemodelairplane.com/pages/Download...
http://www.vintagemodelairplane.com/pages/Download...
The health of your electrical system especially the earthing of battery and the Efi earth at the rear of the engine block.
And a smart non invasive method of testing for a worn cam using a good multimeter with accurate rev counter facilty:
http://www.vintagemodelairplane.com/pages/Snippety...
Whichever god you prey to - Good Luck!
Edited by honestjohntoo on Monday 18th February 23:26
Thank you sooo much for the responses - so much to think about. As a result, I've had a theory but I'll answer the questions first :-)
Danny:-
I've had the cold start connected disconnected for a number of years now and found it made no difference to starting up until I encounted this hopefully unrelated problem. I forgot to mention that I tried refitting it this morning to see if it made any difference, but it didn't. Whilst cranking, the car didn't seem to smell as if it was flooded, but I can't be sure.
I tried it with various degrees of throttle, but it really didn't seem to make any difference whether it was depressed, pumped, poked or left alone... In the past, the car would always start on the button with no throttle pressing, as it does when it is warm in fact.
I haven't checked the plugs yet, so couldn't tell you if they are wet or not. As I had normal fuel pressure, I would guess they are. They are quite new, probably fitted about 10,000 miles ago and I would have given them a wire brush and set the gap at some point last year.
The coil has probably done about 10,000 miles too and was the recommened one for a Rover SDI. I must admit, I have no idea if it has a ballast resister or not. Is this an external attachment? The coil fitted is the same one that was used when the car had no starting issues, and the spare I tried today is the one that came with the car when I bought it direct from TVR Eng in 1997. I have white wires connected to the - and + terminals, so should one of these supply extra voltage when cranking? Can I measure this with a multimetre?
Ben420:-
Strangely enough, one of the things I am going to do in the next week or so is rebuild the whole plenum assembly as I’ve always been worried about air leaks around this area since I rebuilt it about 6 years ago. I once took the plenum off and found one of the trumpets laying lose, with another only holding on by a thread. When I reassembled, I don’t think I used enough sealing stuff so have always worried about it. I did start to suspect an air leak was the cause of the starting issues, although the car runs just great when warm.
I’ll report back when I’ve taken it all apart!
Al 350i:-
Very interesting that you mention about the car almost starting when you let go of the key, because mine does the same thing. I tried short sharp bursts of cranking and it seemed that it was going to catch every time. I could crank the engine for ages with that “almost catching” sound, but as soon as I let go of the key it seemed to want to start!
My current theory is that I may have a grounding issue somewhere. For about the same amount of time that I’ve had these starting issues, I’ve also had my wipers gradually losing power to the point you can only use them on full speed, and the driver’s window won’t close without a helping hand. I put this down to mechanical wear and it may be completely unrelated of course. The other thing I have noticed lately is that when indicating the volt meter bounces around in time to the “ticks”. I just figured it was a bad connection etc.
Sooo, could a slowly corroding grounding point lead to bad starting? My theory is that whilst the starter is being operated and using lots of current, the rest of the electronics are being supplied a reduced voltage. I noticed that my volt meter was only reading about 9 or 10 volts by the end of my nightmare today, which I just put down to a drained battery.
Sooooo, when the starter is operating, is it likely that if there is a weak ground in the engine bay, the rest of the electronical parts could be deprived of voltage to the point that they no longer operate, or am I being daft now? I assume a warm engine would be easier to start so the problem would be masked somewhat?
If I get chance I'll have a look tomorrow. Assume the main earthing point is the one just underneath the air filter, on the suspension strut? Does anyone know of any good tests I can do whilst trying to start the car from cold which would prove or disprove the theory? Maybe check the voltage of the + terminal of the coil?
Thank you in advance,
Dan.
Danny:-
I've had the cold start connected disconnected for a number of years now and found it made no difference to starting up until I encounted this hopefully unrelated problem. I forgot to mention that I tried refitting it this morning to see if it made any difference, but it didn't. Whilst cranking, the car didn't seem to smell as if it was flooded, but I can't be sure.
I tried it with various degrees of throttle, but it really didn't seem to make any difference whether it was depressed, pumped, poked or left alone... In the past, the car would always start on the button with no throttle pressing, as it does when it is warm in fact.
I haven't checked the plugs yet, so couldn't tell you if they are wet or not. As I had normal fuel pressure, I would guess they are. They are quite new, probably fitted about 10,000 miles ago and I would have given them a wire brush and set the gap at some point last year.
The coil has probably done about 10,000 miles too and was the recommened one for a Rover SDI. I must admit, I have no idea if it has a ballast resister or not. Is this an external attachment? The coil fitted is the same one that was used when the car had no starting issues, and the spare I tried today is the one that came with the car when I bought it direct from TVR Eng in 1997. I have white wires connected to the - and + terminals, so should one of these supply extra voltage when cranking? Can I measure this with a multimetre?
Ben420:-
Strangely enough, one of the things I am going to do in the next week or so is rebuild the whole plenum assembly as I’ve always been worried about air leaks around this area since I rebuilt it about 6 years ago. I once took the plenum off and found one of the trumpets laying lose, with another only holding on by a thread. When I reassembled, I don’t think I used enough sealing stuff so have always worried about it. I did start to suspect an air leak was the cause of the starting issues, although the car runs just great when warm.
I’ll report back when I’ve taken it all apart!
Al 350i:-
Very interesting that you mention about the car almost starting when you let go of the key, because mine does the same thing. I tried short sharp bursts of cranking and it seemed that it was going to catch every time. I could crank the engine for ages with that “almost catching” sound, but as soon as I let go of the key it seemed to want to start!
My current theory is that I may have a grounding issue somewhere. For about the same amount of time that I’ve had these starting issues, I’ve also had my wipers gradually losing power to the point you can only use them on full speed, and the driver’s window won’t close without a helping hand. I put this down to mechanical wear and it may be completely unrelated of course. The other thing I have noticed lately is that when indicating the volt meter bounces around in time to the “ticks”. I just figured it was a bad connection etc.
Sooo, could a slowly corroding grounding point lead to bad starting? My theory is that whilst the starter is being operated and using lots of current, the rest of the electronics are being supplied a reduced voltage. I noticed that my volt meter was only reading about 9 or 10 volts by the end of my nightmare today, which I just put down to a drained battery.
Sooooo, when the starter is operating, is it likely that if there is a weak ground in the engine bay, the rest of the electronical parts could be deprived of voltage to the point that they no longer operate, or am I being daft now? I assume a warm engine would be easier to start so the problem would be masked somewhat?
If I get chance I'll have a look tomorrow. Assume the main earthing point is the one just underneath the air filter, on the suspension strut? Does anyone know of any good tests I can do whilst trying to start the car from cold which would prove or disprove the theory? Maybe check the voltage of the + terminal of the coil?
Thank you in advance,
Dan.
Two quick tests you could try:
First plant the throttle to the floor then crank the engine. If it catches immediately it's probably getting too much fuel and not enough air.
Alternatively, persuade the fuel pump to run for a few seconds (remove air filter, ignition on and lift the airflow meter flap is a quick option), then (ignition still on) stab the throttle rapidly three or four times (akin to firing the acceleration pump on a carburettor, for those of us old enough to recall such things!). If it then catches immediately when you crank it, it's not getting enough fuel.
Check the airflow meter flap for free movement through its range. Also make sure the AFM black cap is properly sealed.
First plant the throttle to the floor then crank the engine. If it catches immediately it's probably getting too much fuel and not enough air.
Alternatively, persuade the fuel pump to run for a few seconds (remove air filter, ignition on and lift the airflow meter flap is a quick option), then (ignition still on) stab the throttle rapidly three or four times (akin to firing the acceleration pump on a carburettor, for those of us old enough to recall such things!). If it then catches immediately when you crank it, it's not getting enough fuel.
Check the airflow meter flap for free movement through its range. Also make sure the AFM black cap is properly sealed.
<the car almost starting when you let go of the key>
This could point to a ballast/coil problem?
Not sure how to check which type of coil you have, but it's probably written on it somewhere - or a search on the part number.
When the engine is running what voltage do you get on the coil? If it's around 6 volt then you have a ballast resistor. The voltage should raise when you crank. If it doesn't I'd suspect a problem with the connection to the 4th connector on the starter, or with the solenoid.
You could connect 12v direct to the coil from the battery next time you try a cold start.
This could point to a ballast/coil problem?
Not sure how to check which type of coil you have, but it's probably written on it somewhere - or a search on the part number.
When the engine is running what voltage do you get on the coil? If it's around 6 volt then you have a ballast resistor. The voltage should raise when you crank. If it doesn't I'd suspect a problem with the connection to the 4th connector on the starter, or with the solenoid.
You could connect 12v direct to the coil from the battery next time you try a cold start.
Edited by Danny Hoffman on Tuesday 19th February 08:27
Danny Hoffman said:
<the car almost starting when you let go of the key>
This could point to a ballast/coil problem?
Not sure how to check which type of coil you have, but it's probably written on it somewhere - or a search on the part number.
When the engine is running what voltage do you get on the coil? If it's around 6 volt then you have a ballast resistor. The voltage should raise when you crank. If it doesn't I'd suspect a problem with the connection to the 4th connector on the starter, or with the solenoid.
You could connect 12v direct to the coil from the battery next time you try a cold start.
hhhmmmm i've tried looking for this mysterious ballast resistor before and never found it????? so came to the conclusion that i don't have one, has anyone got a pic or clue where it might be? my coil connects to the rev counter then across to the ecuThis could point to a ballast/coil problem?
Not sure how to check which type of coil you have, but it's probably written on it somewhere - or a search on the part number.
When the engine is running what voltage do you get on the coil? If it's around 6 volt then you have a ballast resistor. The voltage should raise when you crank. If it doesn't I'd suspect a problem with the connection to the 4th connector on the starter, or with the solenoid.
You could connect 12v direct to the coil from the battery next time you try a cold start.
Edited by Danny Hoffman on Tuesday 19th February 08:27
al 350i said:
hhhmmmm i've tried looking for this mysterious ballast resistor before and never found it????? so came to the conclusion that i don't have one, has anyone got a pic or clue where it might be? my coil connects to the rev counter then across to the ecu
You may not have; inspect the coil to see if it has 12v or 8v on it. If it's a 12v unit it won't need a ballast (you'd never get it started). Some ballasts actually look like a resistor: rectangular ceramic block with a wire out each end, some are made by simply coiling-up several feet of resistance wire (which is often blue-sheathed).Danny is correct though: almost catching then dying as you release the key has all the hallmarks of an intermittent ignition feed.
digga951 said:
Al 350i:-
Very interesting that you mention about the car almost starting when you let go of the key, because mine does the same thing. I tried short sharp bursts of cranking and it seemed that it was going to catch every time. I could crank the engine for ages with that “almost catching” sound, but as soon as I let go of the key it seemed to want to start!
My 280 was doing that and as said it was an ignition feed..Mine was from the ignition switch position 3/crank which was a red and white striped wire to the starter..Via the relays..I had no wipers,Horn or indicators i do believe..well worth further investigation...ZigaVery interesting that you mention about the car almost starting when you let go of the key, because mine does the same thing. I tried short sharp bursts of cranking and it seemed that it was going to catch every time. I could crank the engine for ages with that “almost catching” sound, but as soon as I let go of the key it seemed to want to start!
well new plugs and rotor fitted today which did help a little but still didn't want to start straight away. while trying to start i measured the volts at the +coil and with ignition on was getting 12v but while cranking dropped to 8v, once started and running was up to 12.3v. i've always found that when i start her from cold the battery light is on until i raise the revs, then goes out and stays out.
so some where i'm loosing power to coil when cranking?? was getting cold out so will re try tomorrow, i was thinking is it worth connecting 12v straight from battery to coil with wire when starting to see if this cures the problem or will i break something?
so some where i'm loosing power to coil when cranking?? was getting cold out so will re try tomorrow, i was thinking is it worth connecting 12v straight from battery to coil with wire when starting to see if this cures the problem or will i break something?
Alex, interesting about the ignition light... have a close look at the condition of the cables on the starter and solanoid and the heavy cable from the alternator, heat can increase the resistance in these cables and cause some problems with charging and voltage drops etc. From cold are you getting a good bright spark at the plugs? If you want to borrow it i have a in line indicator for the plug leads which will tell you if this is the case fella?
My ignition light kept flicking on and the volt meter/gauge in mine was indicating a very low charge..Delilah decided to stall and not start right at the toll at dartford when me and chris were off out on a drive..They had to close off five lanes to push me to the side..Chris was on it like a hound on a rabbit and within minutes he had sorted a loose wire on the starter..They then had to close off all the lanes to get me back on route..
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