Sometimes my Lantra just cranks and cranks but won't start. Eventually it fires after a lot of cranking and with the throttle held wide open. At most other times it starts at first attempt. Usually it was the first start of the day that was problematic but recently it has been playing up when away from home, after being parked for a few hours. When running it is fine.
I've tried the following:
1) New spark plugs
2) Exchanged coil packs and HT leads
3) Exchanged purge valve
4) Exchanged the PCV valve (or whatever it is; the small one on the top of the engine at the back)
5) Run an extra earth cable from battery to the engine.
My wife noticed that when it had this problem yesterday, the clock on the dash went out while cranking. Is that normal or an indication of bad earth of something like that? I'm wondering if the clock is not getting enough power then maybe the ecu isn't either but not sure why.
Could the crank sensor cause intermittent bad starting even though the car runs fine otherwise?
Yes, it can. This can be verified if you have an oscilloscope to check it
Or just replace the crank sensor
But, I hate just throwing parts at a problem
It can get quite expensive ... but sometimes there is no other choice
Thanks. I've read on the Coupe forum that the CPS can get contaminated with rust and metal causing problematic starting and that cleaning it may work. Just hope I can get that little bolt out, it looks pretty rusty after 16 years on the front of the engine! Will give it plenty of WD40 before I try loosening it.
Spoke too soon. Been difficult to start today and hesitating at times; took 10 mins of cranking at one point to get it started! Guess I could try the camshaft sensor next. It is a shame these cars fault codes can't be read with a standard OBD2 reader; at least in the UK they can't; there is no check engine light either to know if the car thinks there is a problem. I suppose after the cam sensor the only things left that I haven't replaced would be the temp sensor, injectors and ecu!
I've never had the chance to work on your particular model, but did have this problem with my old accent. Turned out to be a relay that feeds the ecu. Same symptoms. Might want to give it a look.
More troubleshooting steps: either sparks are not firing, injectors or maybe the fuel pump won't start (check relay!). When it's not starting, get your head under the hood. Crank sensor will cause sparks to not fire. Get an old timing light or a cheap indicator light to check. You can double up by pulling a plug after cranking a few times to see if its wet with fuel.
For injectors just put a finger on one. That could be cam sensor or ecu not getting power.
Fuel pump you should be able to hear it.
That should save you some money on parts. Don't go replacing parts at random. It never works out.
OK thanks I'll look into relays if I can find the right one. The problem is intermittent so hard to investigate; usually causes trouble when my wife drives it.
As for parts; I am fortunate to have an identical donor car sitting on the driveway so no worries about expense. When that one was running it never had a problem but its a saloon and not an estate (station wagon for the yanks) so I kept the estate going.
Any idea where the relay that feeds the ecu is? I found a board under the dash with 3 relays on it next to the ecu. I swapped two of them, these were both small with 4 terminals; is one of those the ecu one you refer to zero_gravity? The other relay was a large three terminal one that looks like the flasher unit.
Other than that I swapped over the camshaft sensor and cleaned the plugs which were a bit fouled and might explain the hesitation. I also set the gap to .03" instead of .04" to help with starting (easier for a spark to jump a smaller gap and less likely not to spark if plugs get fouled). I also reseated the Crank sensor as I think the o-ring was partially caught under it instead of being fully in the recess in the block. Will see how it goes.
So it ran fine for a week. Started up and had two journeys this morning of 18 miles each. This evening it won't fire at all, too dark to investigate and I have no helper to crank the engine while I look for a spark. I did wiggle the CPS wires and although it didn't start it did almost stop cranking like it was firing but too early causing the engine to almost stop cranking. Would dodgy CPS wiring cause that; it has done that before when difficult to start though when eventually started, it runs fine? It smells of fuel so I don't think that is the problem unless it is flooding too much to spark. As I have changed so much, the only things left are the loom and ecu. Previously it has always gone after about 10 mins but not this time. Chances are by Tuesday which is the first chance I'll have to look at it again, it will just start quite alright.
Anyone know how I can test the wiring to the CPS? It has 3 wires.
So to recap it has:
1) New battery; cranks fast.
2) New plugs and leads
3) swapped coil packs for known good ones
4) swapped CPS for known good one
5) swapped Camshaft PS for known good one
6) swapped purge valve for known good one
7) swapped the other small valve on the rocker box for known good one
8) swapped 2 relays adjacent to the ecu on the same board as the flasher for known good ones (don't know what they are used for but they are small, light brown and have 4 legs).
If it is the cam position sensor then check with a DVM whether there is 12V across it.
Then the output should vary between 0 Volts and 5 volts.
Oscilloscope would be better to see the wave form.
If it is the crank position sensor then remove connector and read resistance of the crank sensor
It should be between 486 and 594 @68 degrees F (20 degrees C) between terminals 2 and 3 (middle and end)
Check for power and ground of course.
Again an oscilloscope would be better to see the signal
From what you are saying about moving the wires, it (could be coincidence or) could be a wire is shorted??
Check the wires that lead to the sensors ... especially near exhaust pipes or anything metal rubbing against it??
The sensors themselves are fine as I swapped them from a car with no starting issues.
I'm wondering if it could be something like capacitors in the ecu as I have had this trouble intermittently for years but it has got much worse lately. Previously it was only the first start of the day that might cause trouble but now it can be any start. A right pain because even if the car runs; I no longer trust it not to leave me stranded somewhere.
I mean it sounds silly but back to basics
Fuel, air, spark, timing, exhaust, compression
What is missing?
Anyway, the hardest thing to do is to check for proper injector function
Seeing if there is a signal to the injectors is relatively easy (noid light)
But, to actually confirm the proper operation of the fuel injectors is a bit tougher.
Sticky fuel injectors can give you all the symptoms you speak of ... just hard to diagnosis
Remember this is still a guess.
Should check for proper fuel pressure.
Well as I suspected it started up this morning though reluctantly. When cranking it kept nearly stopping like it was firing too early or on the wrong cylinder but it did go on second attempt and then ran fine so all the 'basics' must be there it just won't bl**dy start sometimes. I thought it might be a weak spark but I have swapped coil packs and closed the spark plug gap so it can jump the gap more easily; I don't know if the ecu just switches the primary of the coils or discharges a cap into them? Anyway will see if I can get the ecu off and take a look for cracked solder joints and leaking caps; will also inspect the plugs again and maybe get new ones again, and reset the ecu. Really can't think of anything else.
When cranking it kept nearly stopping like it was firing too early or on the wrong cylinder but it did go on second attempt and then ran fine so all the 'basics' must be there it just won't bl**dy start sometimes.
If the basics were all there then it would start and run all the time.
You've got an intermittent problem and you are guessing at what might be the solution.
Well, I wish you luck and hope it works out for you.
Took the ecu off my donor car (awkward job) but once opened there is nothing serviceable because it is all covered in rubberised gunk. I can't just swap it over because of key issues which are electronically mapped to the ecu as I understand it.
So the latest is I swapped the plug leads for some copper-cored ones I made up and reset the ecu. So far it has started much better then it has in a long while although the leads that were on there worked fine in the donor car and I have had these copper ones on my wagon before and I was getting this problem which was why I swapped them.
One thing I did differently this time was after resetting the ecu, I let it idle for 10 mins without touching anything. Read on a Honda forum that that was a good thing to do after an ecu reset. Is it possible the timing was previously too far advanced for starting reliably but fine when running?
The wife reports it starting at first touch of the key which it hasn't turn before; usually needed a few seconds of cranking. So I am thinking the ecu reset followed by 10 mins of idling has changed some setting that so far has improved starting. I would imagine it has retarded the ignition as far as starting goes. Fingers crossed but would be strange if that was all it needed after swapping so many parts.
Still starting well. Seems like all it needed (or needs if it gets difficult again) is to reset the ecu and let it idle for 10 minutes. Would have saved me a lot of work if I'd known that.
Another update as I know a few people are interested:
Still starting alright but sometimes hesitates when under load; usually slightly but occasionally severly; like it fired at the wrong time or momentarily cut out. It never did this before the ecu reset. Seems like it's difficult to get everything working well; both starting and running.
Another update as I know a few people are interested:
Still starting alright but sometimes hesitates when under load; usually slightly but occasionally severly; like it fired at the wrong time or momentarily cut out. It never did this before the ecu reset. Seems like it's difficult to get everything working well; both starting and running.
Have you checked the throughput on the catalytic converters? A clogged converter will make starts difficult and will certainly cause performance under load issues.
As far as "binning" it, too bad you're in another part of the world. I'd take that challenge! But the shipping fees would be a Btch!!
I put new plugs in to see if that would fix the hesitation; it didn't but it has only hesitated once in a week's worth of driving. Also it was difficult to start once over the weekend. Same old symptoms; nearly stopping while cranking like it had fired too early then cranking a bit more. Eventually went with throttle down to the floor. After that its been fine again for the last several starts.
Any other ideas what this can be? I am seriously frustrated with this car and may just bin it.
Primary ?s:
What is the mileage? What is the year?
Can you feel (and hear) ECU relay click when you turn car to On position - every time?
And Start position - each time? Have someone turn key and you lay down and feel it.
Can you hear or confirm if FP is running in On (few seconds then off)? And Start?
What does CPS resistance (ohms) show - at time of cold non-start?
What does Cam PS resistance (ohms) show - at time of cold non-start?
When were the injectors ... and o-rings ... last replaced?
When was FPreg and both o-rings last replaced?
What is the manufacturer name on the side of the TPS?
What is the resistance reading on your CTS at cold non-start time?
Can you hear ISC valve when in car in On position?
Other ?s:
Do ANY hoses show any cracks? If so, which ones and where? Check down along firewall in engine bay where cabin air duct vacuum chamber hoses route also.
Can you hear ECU relay click OFF a few seconds after car is turned off (after it does run)?
What does IAT resistance show at cold non-start?
When was fuel filter last replaced?
When were upstream and downstream O2 sensors last replaced?
Has exh man (with integral front cat) been checked for cracks? Replaced?
What is the trans and # of gears?
For EACH part you swapped from the donor, were the parts IDENTICAL? Any NOT identical?
What does each coil pack resistance show?
Have you confirmed power to the coil pack? Injector(s)? IAT? ISC Valve? CTS?
What do each of those show?
On all resistance checks in my above post and below here, disconnect wiring harness connectors and with key out measure on sensors' or actuators' connector pins, on correct scale (adjust scaling up until reading if in doubt).
What are the ohms on each fuel injector?
Ohm the original ECU relay you removed on the secondary side. What's the #?
Supply power to the original ECU relay primary side you had removed ... and listen for click ... and measure ohms on the secondary side simultaneously. Click? What are those ohms?
Have you disconnected purge solenoid and tried to blow through to ensure the valve is closed in its off/de-energized state (which it should be when cold-starting)?
If you can get all the resistance checks for each sensor and actuator, we'll get there.
Also, look carefully at injectors where they mounted into I.M. Do you see any gaps? Are they flush-seated?
BTW, the resetting of your ECU changed the fuel trim, which gradually migrated back as you and your wife drove, as the problems recurred. Failing injectors also would cause the pre-existing intermittent issues that you mentioned at the end of your post. Failing fuel injectors and, all the crankings, would aggravate (impact) the cat. I'm thinking the issue was/is your injectors BUT am asking you to perform all the tests above first. Also, thinking the cat and battery have suffered. What is the battery V cold first thing in the a.m. and then also during cranking and during running (alt V charging)? Are you able to measure the battery's conductance state? Amps? Starting amps? Have any clamp-on current tool?
OK all sensors and purge valve have already been changed.
Mileage is 164K miles.
I don't know where the ecu relay is?? As previously posted, I swapped out two small relays close to it in the footwell; the other relay there appears to be the flasher relay.
Don't think it is a clogged cat as no loss of power when running. Injectors are a possibility; how would they cause an intermittent starting issue when it otherwise runs fine?
It passes emissions test here so cat and lambda sensor (there is only 1) have not been changed and neither have the injectors. There are however cracks in the manifold but I'm not changing that! (a replacement here costs about 4 times the value of the car!)
Ref. binning it - in the UK cars are dirt cheap; it costs me twice the value of the car to tax and insure it each year. I could easily get something with a lot less miles and younger for under £1K (but with a small risk of buying a lemon of course)
OK all sensors and purge valve have already been changed.
Mileage is 164K miles.
I don't know where the ecu relay is?? As previously posted, I swapped out two small relays close to it in the footwell; the other relay there appears to be the flasher relay.
Don't think it is a clogged cat as no loss of power when running. Injectors are a possibility; how would they cause an intermittent starting issue when it otherwise runs fine?
It passes emissions test here so cat and lambda sensor (there is only 1) have not been changed and neither have the injectors. There are however cracks in the manifold but I'm not changing that! (a replacement here costs about 4 times the value of the car!)
Ref. binning it - in the UK cars are dirt cheap; it costs me twice the value of the car to tax and insure it each year. I could easily get something with a lot less miles and younger for under £1K (but with a small risk of buying a lemon of course)
The injectors are commanded to 'richen' at start. Inability or excess = poor or no start.
Failing FI o-rings = lean AFR. Unwanted/unknown/unmonitorable excess air = poor or no start.
FIs and their o-rings are no-start and under load and intermittent culprits.
Cracked manifold = incorrect O2 feedback to ECU. Lean AFR. Intermittent and under load culprits.
Probable/likely ECU has been commanding dumping of fuel. Flooring pedal result consistent with assessment.
Heated upstream O2 sensor on your UK Lantra I presume. ECU goes closed loop right after start. Issues from there.
You should be able to hear and feel the ECU relay at ON ... and 5 secs or so after OFF.
On all the sensors: some were used and some are new. Lots of things have changed, and SP gaps altered. Hence, the request to ohm each with report back. Excepting that, I'd ohm each FI (disconnected) and replace them with NEW and replace their o-rings with NEW and I would replace the FPreg and its o-rings. Excepting that, yeah, bin it.
Where is the ECU relay please? How do I identify it?
Latest problem was that I stalled it at some lights and it then wouldn't start for ages. So the engine was hot but the starter was just cranking it over and it was not firing. Tried with foot to the floor on gas pedal, no go. In the end just kept flicking the starter and it went; almost like there is not enough volts to spark it up with the starter motor running though it is a newish Bosch battery and the starter spins the engine fast. It had previously run for two weeks without any problem.
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