£20 paypal'd to anyone that con figure this out...

[Blackcountryboy]

Hey all,

So here goes...

Been trying for months now to get my freshly rebuilt forged 3sgte to run right..

She starts after lots of cranking, misses, low, lean idle, pulls only 14 HG.. Plugs 1/3/4 are black. Plug 2 is like New..

Changed:

plugs
leads
dizzy
coil
battery
injectors and seals ( cleaned and flow tested)
FPR
Furl filter
fuel pump
ecu coolant sensor.

Checked;

Injectors all squirt when cranking. Also checked with noir light.

All plugs spark when cranking. (All gapped at 0.8mm)

Have 160 - 170 compression on all cylinders. Both cans are spot on too at zero.

Have smoke tested the inlet manifold etc for vacuum leaks. Nothing...

Timing checked at 10 Btdc with a timing light.

NUMBER 2 CYLINDERS DEAD AND IT'S DRIVING ME INSANE?!?!?!

Pretty sure its not a leaking head gasket or vac leak. Makes no difference if you switch round plugs/injectors.

Valve clearances are all in spec.

Have spark, fuel and compression. Anybody ever have a similar experience or even better a possible answer to a mystery dead cylinder???

Thanks a lot. .

Chris

[jondee86]

Twenty quid !!!! Gotta give it a go

Only scenario that I can think of that would fit those facts is that the engine is getting way to much fuel. For some reason plug #2 gets wet down as soon as you start cranking and doesn't fire. Air and unburned fuel go into the exhaust and cause the WBO2 to report a lean AFR when it is actually rich.

Have you checked what fuel pressure you are getting in the rail when the fuel pump is running ? Did you fit larger fuel injectors without telling the ECU

Cheers... jondee86

[Thrillseca]

Here's my 2 bob's worth...You said pretty sure it has no vacuum leak! Look harder,you may need to spray aerostart around intake manifold---engine RPM will increase if leak exists..

Good Luck..

[trdee]

have you done a leakdown test or just a compression test?

[ToyTA22]

I'm with Jondee on this. Check rail pressure first.
Is there any other modifications done? Is the ecu stock or piggy backed or aftermarket?
Are the injectors stock or larger due to modifications?
I know there is a lot of questions but more information may give us a better idea.

[Blackcountryboy]

Thanks for all of your replies. It's massively appreciated.

Stock ecu (my hks is fried, saving for a wolf). Stock 550 injectors. Twin fed rail fed from a Bosch 044 from 1l swirlpot. Tried 2.5 bar. 3.0 bar. 3.5 bar. No change. Using 2 car batteries in parrallel to ensure cranking amps arnt robbing the fuel pumps of power.

Gonna get dirty this morning underneath with the smoke machine, a torch and some jn weld/tigerseal vac leak hunting. Will post anythin I find.

Only thing that I can think of is I used thermotech gaskets instead of oe. Even pressurised the system with an electric tyre pump but still nothing...

Cheers guys

Chris

[jondee86]

Vacuum hose for the MAP sensor has not fallen off/split by any chance ?

Cheers... jondee86

[Blackcountryboy]

Changed the hose on the map to a tarty New silicone one. Bin under the car all mornin n the intake manifold gasket looks sweet. Nipped it up a 1/4 turn but nothin apperent. not done a leakdown just a compression test. Gonna try n fire her up tmrw to see if the nipping ups done anythin. Honestly don't think its a vac leak tho...

[madmont]

Problem with crank pulley? No key?

[jondee86]

OK... new hypothesis Cylinder two has spark, fuel and compression, and it makes no difference if you swap plugs or injectors around. This means that the problem must be related to cylinder two alone. And the only component required for combustion that you haven't verified is air.

So is there something stuck in the intake port ? Rag, mouse, missing part of anything that you haven't been able to find for months ? Can you see all the way down to the valve heads ?

Cheers... jondee86

[Blackcountryboy]

Hahaha I like your hypothesis Jon. It's a fresh build an I'm 99.9999% certain there's no restrictions.

Fired her up this mornin after lots of cranking. First ten secs was 15 Afr. She ran for maybe just under a min leaning out to 19 Afr stall.

Plug on my iac fell off yonls ago, so tried swapping the earths over (open is close, close is open). Again fired n ran for ten secs BUT this time pulled 20 HG instead of 14 Then died even quicker...

Only 3 things left unchecked.

MAP
ECU
altenator

Think any of these if sh@gged would cause hard starting, leaning out to stall, suspected one wonky pot?

Your ideas n feedback are the only thing keepin me sane at the minute, so thanks again for all your help!

Thanks

Chris

[jondee86]

The difficulty here is knowing whether the AFR you are seeing is believable or not. If you have black, sooty plugs, that indicates that you have plenty of fuel. But, if one cylinder is not firing, the extra air getting into the exhaust will show up as a lean mixture. So are we chasing a lack of fuel or too much fuel ?

The fact that the engine fires up at all says that the ECU is probably OK. Hose off the FPR gives a rich mixture. Hose off the MAP sensor gives a rich mixture. A blocked filter or lazy pump will give you a lean mixture. Where to start ?

Idle is the most difficult part of an engine tune to get right, and it doesn't take much to upset the balance. Engine speeds above idle are easier to tune, and more difficult to upset. If you have only been trying to get the engine to run on closed throttle, you might have to try some experimentation

As soon as the engine fires, start goosing the throttle with small, sharp dabs to see if you can get the engine speed to climb to over 2000rpm. Most engines will do this easily with only three cylinders working. It may be a bit rough, but if it has enough fuel you should be able to hold the engine at higher revs. If you don't want to be pumping fuel into the dead cylinder, pull the injector clip off for the test.

Observe the AFR. If one cylinder is not firing it should show lean, and slowly get a little bit less lean as the engine warms up. If the injector clip is on the dead cylinder and it happens to kick in, then the AFR will drop to normal (richer thah stoich) values. If the engine won't rev/just gets leaner and leaner until dies, then you do have a fuel supply problem.

Having pressure in the rail does not mean that you have adequate flow. Observe the pressure in the rail with your other eye while doing the above

Cheers... jondee86

[Blackcountryboy]

Your totally right Jon. Thanks again for your reply. Started thinkin now maybe an injectors not opening under pressure. I've had them flow tested this month and the where all perfect on the machine (also played with them with a 9v battery myself whilst losing my mind) so maybe it could be a bad injector resistor pack? Enough ooomf to light up a noid light but not enough ooomf (resistance in the wire?) To open no 2 under pressure?

Got my pal to watch the fpr pressure gauge today while cranking... Solid 2.8 bar. Also sprayed shed loads of wd40 around the inlet manifold.

Got 3 black plugs and one lookin like new. All new platinums tapped to 0.7mm.

Btw spec wise its a fully forged 185 block. 205 skimmed head. 1mm hg. Fidanza flywheel. 3sge 252 inlet/hks 256 cams. Jun valve train. 9.4:1 comp ratio. Full ball bearing GT2860RS with external wastegate (bonnet venting hehehe). 3inch straight thro zorst. 700BHP relocated chargecooler, brushless pumps etc etc. 1060kg.

Will be fun on the street if I can ever get the bloody thing to run. Sat on my exes folks drive for 3 yrs after spinning a rod.

Last engine build I did was low comp/big turbo. Ran for key turn but was rubbish on the street. This builds had me in tears since last July just trying to get it to run..

Why would 4 injectors work with a noid light but only 3 when "running" .

Thanks again

Chris

[jondee86]

Injectors are quite simple and reliable things... if they test out OK for flow (opening and closing), and have the correct resistance between pins, they should be good. Resistor packs are also basic... if you put 12V in and you get 12V out on all pins, then they should be capable of opening an injector. The noid light confirms that the ECU is grounding the injectors and that there is a circuit from supply to ECU ground.

So a few random thoughts...
1. When running at less than atmospheric the injectors see no more pressure than when they are on the bench. So if they squirt under test, they should squirt at idle.
2. Spark plugs on the other hand see more difficult conditions when asked to fire a compressed mixture. So check the high tension path from coil to plug for anything that could create high resistance to the spark. Faulty wire termination, damage to dissy cap, damage to lead, plug cap or wire not pushed fully home etc. If possible, swap two leads around (both ends ) to see if the problem follows the lead.
3. Check the ECU grounds are firmly bolted down.
4. Depending on the type of igniter you have, make sure the igniter has a good ground. Some of the Toyota igniters ground thru the outer alloy casing, so they need to be bolted down and grounded to the chassis.

The truth is out there.....

Cheers... jondee86

[Blackcountryboy]

Hiya Jon

Changed over 2 sets of known working ht and king leads. Brand new dizzy. Have double grounded the ignitor to the battery And body directly. Also checked out the injector coil pack, got 0.1 ohm on every pin.

Tried again this morning, swapped plugs around and it started after some cranking and "sounded" like was firing on all 4 pots?!?!

Soooooo I get ready to light a cigar and go get drunk, then look down at my wideband (calibrated) and see 16 Afr 3 seconds after starting. Used to be 10-11.

Runs for a min literally then dies!!!!! Arghhhhhhhh!!!!

Same sh#t diffrent day.

Tried to blip the throttle on restart, dies instantly.

Checked the Bosch 044 is feeding the swirl pot, nipping the return line (in tank 340lph in tank feeding 300lph Bosch). Both pumps running. Loads of fuel circulating.

Also tried cleaning the aternator plugs and grounds.

Manifold, head, block and gearbox all grounded. Battery is double grounded.

So now I'm thinking bad loom/map/ECU.

Starts, 15-16 Afr. Runs like a diesel truck for 60 secs.. leans...leans...LEANS... stalls.

New ECU coolant sensor made no diffrence

in open loop makes no difference how high or low the fuel pressure is.

Could the loom have gone bad? (Too much resistance?).

Jon thanks again for helpin me with your thoughts. Genuinely appreciated.

Btw opened up the ECU. Looks like New inside, no weeping capacitors ext. Could a bad loom, lean out the injectors with too much resistance you think?

Will ground the ECU grounds to the body n see if that helps. Only thing I've not tried yet.

Ridiculous me asking to try n solve a prob without even seeing the individual setup, but if anybody can throw somethin out there I've not thought of n get her rich running, there's PayPal beers in the post.

She's not beating me/us... Keep all this good stuff coming!

Thanks!

Chris.