Need some help.......engine won't start.
Discussion
Hi Guys,
Last time I ran the car (about 3 weeks ago) it was running perfectly. Friday night I went to start it for a warmup and checkover before heading out for the races this weekend.
The car won't start. It will kick over but will not fire up and run. I have checked the plugs and they are all getting spark. 1 and 4 look dry and 2 and 3 look wet. I swapped the wet plugs with the dry plugs and tried it again. Same result.
Swapped the Coil, wires, TPS, ECU, pulled the stator cover and everything looks fine inside.
I feel like it is firing on 2 cylinders being 1 and 4 or 2 and 3. Since the plugs on 2 and 3 are wet I think these are the problem cylinders. I can confirm that all the cylinders are getting spark. Although 2 and 3 seem weak.
I did a test on the Crank position sensor (although I am not sure I did it properly) and according to the internet it is fine also.
I'm lost. and pissed I missed the weekend.
Any help would be greatly appreciated.
Ron
Last time I ran the car (about 3 weeks ago) it was running perfectly. Friday night I went to start it for a warmup and checkover before heading out for the races this weekend.
The car won't start. It will kick over but will not fire up and run. I have checked the plugs and they are all getting spark. 1 and 4 look dry and 2 and 3 look wet. I swapped the wet plugs with the dry plugs and tried it again. Same result.
Swapped the Coil, wires, TPS, ECU, pulled the stator cover and everything looks fine inside.
I feel like it is firing on 2 cylinders being 1 and 4 or 2 and 3. Since the plugs on 2 and 3 are wet I think these are the problem cylinders. I can confirm that all the cylinders are getting spark. Although 2 and 3 seem weak.
I did a test on the Crank position sensor (although I am not sure I did it properly) and according to the internet it is fine also.
I'm lost. and pissed I missed the weekend.
Any help would be greatly appreciated.
Ron
Edited by Ron V on Sunday 27th July 04:07
If you're getting fuel and spark the TDC sensor will be fine.
I don't know that engine, but:
If the plugs to the same cylinders get wet when swapped over, suspect the cylinders. Otherwise suspect the plugs. Sometimes fuel soaked plugs will not recover.
If cylinders, do a compression test. I'd suspect a HG failure between 2 and 3.
I don't know that engine, but:
If the plugs to the same cylinders get wet when swapped over, suspect the cylinders. Otherwise suspect the plugs. Sometimes fuel soaked plugs will not recover.
If cylinders, do a compression test. I'd suspect a HG failure between 2 and 3.
In case you haven't realized, then engine is wasted spark so there are only two coils. The coils fire plugs 1 and 4 together and 2 and 3 together. If one pair of plugs is wet and the other isn't then it sounds like an ignition problem to me.
You said you have a spark on all four - by what means did you verify this. A weak spark is still a spark but it can be hard to tell whether it's enough to make the engine fire.
How's the battery?
Measure the voltage at the coil for the pair that aren't firing while cranking. You can do this through the back of the plug (you may have to cut off the heat shrink on the grey plug). Correct pins are on the wiring diagram. The loom puts constant 12v on two pins when the ignition is on, and the other two pins are controlled by the ECU to collapse the field in the coil when spark needed.
You said you have a spark on all four - by what means did you verify this. A weak spark is still a spark but it can be hard to tell whether it's enough to make the engine fire.
How's the battery?
Measure the voltage at the coil for the pair that aren't firing while cranking. You can do this through the back of the plug (you may have to cut off the heat shrink on the grey plug). Correct pins are on the wiring diagram. The loom puts constant 12v on two pins when the ignition is on, and the other two pins are controlled by the ECU to collapse the field in the coil when spark needed.
I checked the spark with the plug out and holding it to a ground point. There was definitely spark on all the cylinders albeit 2 and 3 seemed weaker than 4 and 1. I did know about the wasted spark system.
Simon, I am going to try that today.
If that fails then I will do a compression test.
Thanks Guys.
Ron
Simon, I am going to try that today.
If that fails then I will do a compression test.
Thanks Guys.
Ron
TheRealFingers99 said:
As wasted spark, worth seeing if the wet plugs change with coil packs swapped round.
Good luck with it.
I was going to suggest this, but when I thought it through I felt it might not help. As the coil pack is a single unit you can only swap the two pairs of plug leads (so 1 and 4 go into 2 and 3 and vice-versa). But if you do this then whenever the ECU thinks it is firing 1 and 4 it'll actually be firing cylinders 2 and 3. But it'll still be injecting fuel into 1 and 4. Hence you'll end up with 4 wet plugs instead of two. I think ?!!!Good luck with it.
Presumably you'd have to swap the injector plugs over as well. And I bet the loom can't accommodate that in length terms.
Maybe I'm wrong here. Not sure!?
I tried a completely different coil. Exact same result.
and the battery never drops below 11V while cranking. It is a Varley.
I didn't feel like seeing the car today. I went to Mosport to watch the NARRA race I wanted to run in. Spectating Sucks.
The SR8's were fun to watch. I have never seen one run before.
Back on the car when the work week relents......
I'll let you guys know when I figure it out.
Ron
and the battery never drops below 11V while cranking. It is a Varley.
I didn't feel like seeing the car today. I went to Mosport to watch the NARRA race I wanted to run in. Spectating Sucks.
The SR8's were fun to watch. I have never seen one run before.
Back on the car when the work week relents......
I'll let you guys know when I figure it out.
Ron
Ron V said:
and the battery never drops below 11V while cranking. It is a Varley.
Did you measure voltage at the coil while cranking, on both of the coil feeds? Reason is there can be issues in the loom rather than the various components themselves.How old is the car? Mine is a 2005 and the loom is starting to show all sorts of issues. None of my problems have been faulty components - it's all been wiring issues (high resistance).
So to conclude............the car is running.
I tried a new set of plugs with the same result. Kicks over but wont fire up.
I pulled the fuel rail and set it all up to fire into jars so I physically see the injectors firing. Everything looked good so I put it all back together. I then tried to fire it again and it started!!!....... rough at first but then with a little gas applied it cleaned up and ran as normal. Sounds good too!
UNREAL! I have no idea why it wouldn't start. Is it possible to have an air lock in the fuel system??
Ron
I tried a new set of plugs with the same result. Kicks over but wont fire up.
I pulled the fuel rail and set it all up to fire into jars so I physically see the injectors firing. Everything looked good so I put it all back together. I then tried to fire it again and it started!!!....... rough at first but then with a little gas applied it cleaned up and ran as normal. Sounds good too!
UNREAL! I have no idea why it wouldn't start. Is it possible to have an air lock in the fuel system??
Ron
Ron V said:
UNREAL! I have no idea why it wouldn't start. Is it possible to have an air lock in the fuel system??
Ron
I ran my SR3RS dry at Mallory a few months ago and after filling it up, it wouldn't start. I connected the sampler to the fuel rail and switched it on until the fuel came through, removed the sampler and it fired up straight away, so maybe the answer is yes, you can have an air lock!Ron
ric355 said:
As the coil pack is a single unit you can only swap the two pairs of plug leads (so 1 and 4 go into 2 and 3 and vice-versa). But if you do this then whenever the ECU thinks it is firing 1 and 4 it'll actually be firing cylinders 2 and 3. But it'll still be injecting fuel into 1 and 4. Hence you'll end up with 4 wet plugs instead of two. I think ?!!!
Maybe I'm wrong here.
On cars with batch fire injection, the ECU takes all the information on which piston is where from the crank sensor. Individual triggers in the ECU fire the injectors and plugs. Maybe I'm wrong here.
On cars with semi sequential or sequential injection, it takes the information on what stroke the engine is on from the cam sensor (and uses that to inform the injector driver) and the TDC sensor for sparks.
The coil pack(s) are basically dumb devices, about as intelligent as the coil on a 1960s Mini. There's nothing useful they can tell the ECU.
I suspect you've mis-understood what Ric355 was saying.
TheRealFingers99 said:
On cars with batch fire injection, the ECU takes all the information on which piston is where from the crank sensor. Individual triggers in the ECU fire the injectors and plugs.
On cars with semi sequential or sequential injection, it takes the information on what stroke the engine is on from the cam sensor (and uses that to inform the injector driver) and the TDC sensor for sparks.
The coil pack(s) are basically dumb devices, about as intelligent as the coil on a 1960s Mini. There's nothing useful they can tell the ECU.
On cars with semi sequential or sequential injection, it takes the information on what stroke the engine is on from the cam sensor (and uses that to inform the injector driver) and the TDC sensor for sparks.
The coil pack(s) are basically dumb devices, about as intelligent as the coil on a 1960s Mini. There's nothing useful they can tell the ECU.
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