My rebuilt engine

[Pete&Matt]

Rob

Sounds like a crank or cam poistion sensor to me! If the ECU doesnt think its turning over then it wont give fuel or a spark....

Vauxhaulls are buggers for it and eventually they go after cranking for ages and ages!

Matt

[stylussprinter]

I've laid the plugs with leads onto the head and spun the engine --- they all spark well . It goes for years competing then the couple of times it's been out of the car it's a pain to start. Last time it was simpler in that the ECU needed it's own direct from battery supply plus bigger battery. This time ------------- well who knows cos I obviously don't

[Werner Van Loock]

Rob, have you tried different (new) plugs already?

I had severe starting problems with the striker in the beginning, bit the same as yours a hell to get the damned thing running but fine once it ran, the plugs did spark nicely in the open, apparently they didn't once compression came into play. New set and it started on the button.

[stylussprinter]

Well , a set of heavy duty plugs are charged for on Dunnell's invoice .

[norma]

i'd try a normal set - heavy duty? put some tried/trusted ones in!!!

[stylussprinter]

No idea where I'd get them as these are nearly 10mm shorter and have no name on them , just a number . Maybe the NKG R 13's would foul the valves/piston on this head? I'm intending phoning Paul on Monday as I can't start it at all since the ecu came back. . I took all the plugs out and peered down the holes and it looked messy but couldn't smell fuel as I said previously so poked a cable tie down to get an idea of what the mess was . Rather indistinct but seemed like oil/water mix and not clean . Just wondering whether the head gasket is leaking but of course it has been on his dyno running . As said above , the exhaust manifold was hot after over 10mins of trying yesterday --- all very strange

[mikeb]

Hi Rob, is the crank sensor lead shielded properly and away from sources of emf? Mike

[norma]

def try some other plugs - cant see how the pistons would hit them?

[Pete&Matt]

Check all of the earths are clean too. If its been sat for a while they may have corroded and the earth dropping out under load, especially when cranking. I would def check out the crank sensors etc and make sure all the connections are clean etc. No position, no start!

[hearbear]

Hi Rob

I will be passing near you on Tuesday evening if you would like a fresh pair of eyes to help look at it PM me a contact number and address and will call you.

George

PS may not be any good at helping but you never know.

[stylussprinter]

This morning I decided to remove the filter off the fuel tank , just to satisfy my mind there was no problem with dirt .I'd already run the pump with the pipe off the fuel rail days ago plus the engine was running for 20mins a week ago. I drained the return pipe into a glass and the same with the exit pipe from the pump ---- all clear . The fuel in the filter looked clean but I flushed it both ways with new fuel while it was out anyway. Back to starting attempts again ---- same thing almost running after loads of tries . Felt the exhaust manifold which was pretty hot . Fuel had to be getting there for that ???????? Tried many more times when it actually ran for 2 to 4 sec's . Jumper battery was getting low but wanted one more go after taking the plugs out to see what it looked like in there --- still wet and messy even though the exhaust was hot. This time it ran . Came to temp' , was cooled then up to temp ' again . I ran it for 30mins then stopped it. Looked in the header for any signs of oil and the dipstick for water ---- all fine . Took plugs out and everything was clean and dry . Left it for five minutes then started it ok again. Then fifteen minutes started it again without any problem . It's really annoying to solve a problem without knowing how you did it but I'll have to assume , even though I couldn't see any dirt , that the filter was my problem . But why did it run last week for 20mins Batteries are on charge again so we'll know tomorrow whether I've sorted it or not when I try again------ just hoping it'll start on the button as it used to. Decided not to phone Dunnell until I'd checked the filter , so will phone tomorrow whatever the result.

[CMA]

So it struggled to start when cold. But when it was warm it started on the button. I guess a start tomorrow morning from cold will confirm or disprove thats its cold starting thats the problem.

Is there some temp sender that might be causing the ECU to confuse things?

[stylussprinter]

Yes there's an air temp ' sender that may be faulty but Dunnell said it automatically reverts to a 20 degrees signal under fault conditions which couldn't prevent cold starts . Having said that I started the engine without an air temp sender when the engine was new because he didn't have one in stock at the time . He sent me a new sensor that I haven't fitted yet because you have to cut all the sikaflex out to remove it and I haven't got any more in the shed . Something I'll have to get. Best thing is the sound when revved --- very sharpe and raspy

[Werner Van Loock]

2 possibilities in my opinion, either plugs are not good for cold starting (eg real race plugs)

Other is that the temp sensor is faulty in such a way that the ecu thinks it's ok, eg -20 or +50 or something


My bet is on the plugs. I know when i put a bosch 7 in that i'm back to horrible cold starts, it's running 6 now. (could be the other way around though)

[stylussprinter]

Well it didn't start on the button , same senario taking about two or three minutes(bit quicker than previously). Restarted easily when turned off after reaching temp . Dunnell had sent me an air temp sensor as the ecu had logged a fault but I fitted it without the flashing on the led/ecu stopping. The only other temp related sensor is the water sensor in the waterail but the ecu didn't log any other fault ????? It just has to be the cold start doesn't it ? What other possible explanation could there be I can see a 260 mile round trip with the trailer looming