My rebuilt engine

[PeteC]

Can you try push starting as this eliminates the cranking mode in the ecu and also doesn't heavily load your battery, failing this try jump starting to give the battery a better chance.
I guess you have already checked for a spark at the plugs? if so did you smell unburnt fuel while the engine was turning with no plugs fitted? This would tell you if your injectors are opening.
Pete C

[stylussprinter]

Still waiting for the ECU in the post . Can't get another vehicle near to jump start and it's not roadgoing so wouldn't risk plod catching me push starting . Spark is good , fuel is there plus it eventually runs so injectors are firing ok . That's the problem -------- all ideas that come to mind why it may not start would mean the engine wouldn't run and it does BUT it takes 5 minutes buggering about .

[CMA]

Another idea thats prob wrong but I'll throw it into the pot anyway:

If the starter is sucking most of the juice and the coil pack/ignition side cant get a nice clean powerful feed this might cause a weak or no spark meaning it might or might not fire but once it does start running it gets a clean full power feed as the starter is disengaged...

So you could connect it up jump style to another full size, fully charged battery and see if more power makes it start easier?

[stylussprinter]

The ECU came lunchtime so popped it in . Tried plugging in the laptop to monitor starting and running . Couldn't even find a screen showing the software to pop the password in . I really do get bloody cross at not being PC wise , it leaves me totally frustrated when the engine plays up and I can't sort it as I used to be able to ----- before going to TB's Anyway , it wouldn't start today but did try firing here and there. As was suggested , I removed the plugs and whizzed it round to sniff for unused fuel -------- nothing Dunnell said that nothing was logged on the ecu regarding failures of any sort so I'm baffled . Surely injecters not firing would show up even if it's my loom at fault How the he'll does it run without injectors firing ----- I give up . When I first installed this engine in 2007 , I had to trailer the bloody thing the 260mile round trip to Dunnell because I couldn't sus out why it wouldn't start . UGH

[Werner Van Loock]

Rob, how old is the petrol?

Are there any vacuum tubes used? Does your fuel pressure regulator use vacuum?

Used brake cleaner trick around the manifiold when cold to find out if you have any air leaks?

[stylussprinter]

Petrol's in the can from October and the engine's run on the dyno plus at home on two occasions in two weeks .

[kevp]

Rob. if you can get the laptop running, their will be a test button to operate the injectors, even when the engine is not running.

Some points for your consideration. The ECU may not allow the pressure pump to operate until the engine is spinning. Is the crank sensor picking up? (If the plugs are firing I assume it is). Is there a leak or evaporation on the pressurized fuel line, requiring a build up of pressure before the engine fires. (have you got the fuel lines the right way round? If not the pump is pressurising the tank before the fuel rail.)
ECU not programed for cold start.

[stylussprinter]

The ecu is a race version and logs everything which is why I sent it back to Dunnell . My ecu and indution parts were all used on the engine for the dyno run in. It should have logged any fault in my loom so this is why I'm so puzzled because it found no problem. Don't forget , as I've said in this thread before , that this engine runs perfectly once started. This negates all the normal lines of investigation. Dunnell has said he is baffled too . Yesterday when I spun the engine without plugs in there was no smell of fuel YET it will run on occasions ----------- everything's so contradictory

[CMA]

When it starts does it rev freely and normal?

Give it a try with another big battery hooked up, maybe from you normal car, just to discount the poor power feed idea

[stylussprinter]

Yes , when it starts it ticks over around 1000 rpm then at 1200rpm within 3 mins . Once up to temp in 10/12mins it will rev perfectly normally without any misfiring . I'll have to remove the big battery off my bobcat skidsteer and charge that up , to jump it . The ecu logged no power shortage though.

[CMA]

As the ecu is not logging any fault what so ever I'd be inclined to ignore it and try the basics, having had many an issue with computers in my life (as a trade) I've learnt not to trust them to work perfectly.

I think you've already said you have a spark so that leaves fuel and electrics.

As it runs perfectly eventually the pump is working, but does it take some time to work up a pressure? Does it start fine when hot and only suffers problems when cold or is it every start up?
Is there a way to test the injectors are working on the attempted startups?
Are all sensors connected soundly and correctly?

I'm probably not much help but just trying to logically work though things to see if it makes any sense as there is a fault somewhere it's just finding it.

[stylussprinter]

Haven't been able to hot start check yet. I just switched it off after 20mins running and the battery was low by then , after the continual struggle to start it. I tested all the battery positives to the injectors and the firing wires with a small bulb/battery. Also the main positive to the ecu multi plug . All were ok . Attempted another start but no go --- felt the exhaust manifold afterwards and number one and two weren't stone cold but three and four were. I'll wait till the bobcat battery is fully charged before another try . I've had the fuel line off at the rail with the pump on and it seems fine. My pump has continuous flow and it's loud . Perhaps take the filter off for a look next Dunnell had no flashing light on the ecu but it was on today when connected again .

[stylussprinter]

Big 680 amp jumped onto the redtop 25 made it possible to try for longer but still no start . It tried on all four for 2 or 3 sec's several times but wouldn't run . Strange seeing as I've had it running for 20 mins last week. I could hold the exhaust manifold without burning , just , so it had been firing over the 10 mins trying. Put both batteries on charge again for now -- off out tomorrow . Before trying again I'll take the filter off for a look but fuel is getting to the fuel rail. I can't actually here the injectors clicking because the starter makes too much noise but they have worked to run the engine here and on the dyno ----- clutching at straws really

[norma]

This is insane! I can't wait for you to get to the bottom of it - its going to be something really silly I bet!

[PeteC]

Well look on the bright side, you've elliminated the low voltage on cranking possibility and you know that mechanically the engine is correct. (could be worth checking the cam sprockets and belt are tight and haven't slipped!) So that only leaves ignition and fuel !!
Starting from scratch have you had all 4 plugs out of the head but connected and firing? If you are using a wasted spark/coil pack try switching the plug leads about! If these are wrong and your getting plenty of fuel you still get poor burning of carried over fuel in the exhaust. Even if you are sure you have put them back the way they came of the dyno man may have altered the ecu setting to suit his equipment! While doing this you should be able to smell fuel coming out of the plug holes, if not you got fuel probs! Also worth noting, on some ecu's if you have the throttle wide open while cranking it stops all fuel in an attempt to clear flooding, can you check your throttle potentiometer? if the ecu thinks your trying to clear a flood, it won't go.
From what I've heard/read it is rarely the ecu at fault and usually a wiring/sensor problem
When trying to start the air flow meter does nothing, because there is not enough airflow to be acurate (it fuels based on ecu settings, throttle pot and temp). Good luck and keep going!! Carry on posting here cos somebody will eventually figure it out
Pete C