Cosworth won't start. HELP PLEASE!
 

Have followed this fault finding procedure and results are:

1) Ensure ignition is OFF...done
2) Remove rear of ecu plug cover and insert plug back into ecu...done
3) Turn ignition back on (do not start engine)...done
4) MAIN POWER CHECK: Check for DC voltage of at least 11.5V between ecu pins 19 and 20...12.28
5) REFERENCE CHECK: Check for DC voltage of around 4.8 to 5.2V between pins 11 and 30...4.94
6) MAP SENSOR CHECK: Check for DC voltage of approx 1.8 to 2.5V between pins 11 and 15...1.55!!!!!
7) THROTTLE CLOSED:
4x4: Check for DC voltage less than 0.5V between pins 11 and 17...0.15
2WD: Check for DC voltage greater than 4.5V between pins 11 and 17.
8) THROTTLE FULLY OPEN:
4x4: Check for DC voltage greater than 4.5V between pins 11 and 17...4.75
2WD: check for DC voltage less than 0.5V between pins 11 and 17.
9) Turn ignition off, unplug ecu, and turn ignition back on (don’t forget immobilizer if fitted) ...done
10) CRANK SENSOR: Check resistance between pins 3 and 4 between 300 and 1200 ohms...633
11) CRANK SENSOR: Check AC voltage on pins 3 and 4 while cranking engine - should be at least 2V. 0!!!!!
11) PHASE SENSOR: Check resistance between pins 5 and 23 between 300 and 1200 ohms...778
12) PHASE SENSOR: Check AC voltage on pins 5 and 23 while cranking engine - should be at least 1.5 - 2V. 0!!!!!
12) INJECTOR: Check resistance from pins 18 to 20 should be 2 to 5 ohms...2.7
13) INJECTOR: Check resistance from pins 35 to 20 should be 2 to 5 ohms...2.7
14) INJECTOR: Check resistance from pins 33 to 20 should be 2 to 5 ohms...2.7
15) INJECTOR: Check resistance from pins 32 to 20 should be 2 to 5 ohms...2.7
NOTE: INJECTOR TESTS MAY NEED MAIN RELAY ENERGISED ON L1 and L6 ecus (link pins 1 and 10 first)
16) IGNITION TRIGGER: Read voltage between pins 24 and 25, should be at least 4.5V. 3.8v so a little low but checked to the negative on the battery aso and the reading is the same...3.5!!!
17) IGNITION TEST: BEWARE DANGEROUS VOLTAGES ON PLUG/COIL LEADS.
Quickly link pins 24 and 25 on and off this will FIRE the ignition coil. Rotate dizzy by moving car in gear to point rotor arm at one plug lead and remove spark plug (earthing it on chassis or engine) to see spark. Try for each plug in turn. Or remove king lead at dizzy and place end within 1 centimetre of earth to see a big spark...didn't do this as have spark on all 4 plugs
18) Place a temporary wire link from pin 1 to pin 10 (energises ecu power relay) - you should hear a click...didn't do this as relays click with ignition so presume ok
19) Quickly link pins 19 to 28 to test fuel pump runs...pump primes on ignition only for a second but runs constant while cranking. Think it's normal.
20) COOLANT TEMP: Check resistance pins 29 and 11 for 800 ohms to 5000 ohms (depends on temp)...6200!!!
21) CHARGE TEMP: Check resistance pins 31 and 11 for 800 ohms to 5000 ohms (depends on temp)...6170!!!

The points out of spec are:

Number 6: map sensor voltage too low
Number 11 and 12: crank and phase sensor AC VOLTAGE is always 0V
Number 16 ignition trigger voltage too low
Number 20 coolant temp sensor resistance high
Number 21 charge temp sensor resistance high

Battery went dead over xmas as the car had been lying idle for a few weeks. Battery voltage is 12.4V but is almost dead from cranking again! Is this too low?

I have fuel to rail, changed fpr to be sure and seems the same.

I have spark.

Checked and cleaned cps and checked dps, all look and ohm out ok.

Any suggestions as it is really testing my patience at this stage :wall:

Cheers,

Philip.

checks
 

have you checked basic cam timing/phase timing is ok?
is it good clean fuel that is getting through?
do you have good compression?
coolant temp sensor-is connection good-have you tried a different sensor
is engine earth ok[try jump lead battery-engine]
are all other earth points good
do all relays work properly[not just click]
are the plugs on phase sensor and around front of engine correct?
is crank pulley key still intact?

cant think of anything else atm-but hope some of the above gives you fresh ideas
good luck

have you got good fuel pressure phil?

I wouldn't worry about the map sensor signal. If you have a 3-bar sensor the signal is perfect.
Can you measure the signal from the temperature sensors in voltage and list the outside temperature when you did it?

have you checked basic cam timing/phase timing is ok?
is it good clean fuel that is getting through? Yes as car was running perfect 2 weeks ago. Took it for a quick spin up and down the road, no issues.
do you have good compression? Don't know but I presume all is good, might have to revisit this one.
coolant temp sensor-is connection good-have you tried a different sensor
is engine earth ok[try jump lead battery-engine] remade cts as part of troubleshooting. Resistance test seems ok. I have a spare but didn't change it yet. Engine earths haven't been checked but haven't been touched either.
are all other earth points good. Other earths should be fine as haven't been touched.
do all relays work properly[not just click] Don't know for sure, guess I'd know of it started.
are the plugs on phase sensor and around front of engine correct? Plugs are correct yes.
is crank pulley key still intact? 4 lugs on crank pulley are spot on. Pump is priming so cps sensor signal is ok, from what I've read on here.

cant think of anything else atm-but hope some of the above gives you fresh ideas
good luck

Thanks very much for the tips Tony. Working today so won't get home til 9pm, will try the ideas later.

Hi James,

I've no fuel pressure gauge. Initially we thought this was the issue as removed return pipe from bottom of regulator and fuel was pissing out. Got another fpr but not sure if this one is working either!! Clamped the pipe by hand for a couple of secs to try and build pressure but the bugger still won't start. Initially we had no fuel to plugs and now I do. Albeit it doesn't se likeucj so we thought the signal to open the injectirs wasn't getting through. Think it's from the dps. Anyway have fuel now and spark but still won't fire. Thanks for the help James.

I can do that yes but will either be tonight after 9pm or tomorrow evening. Thanks for the tips.

Will keep this updated. Thanks a million lads. What a bloody nightmare :(

As said, MAP is fine if you have a 3bar MAP sensor
crank and phase are obviously working if you have spark on all 4 when cranking and the fuel pump runs.
If you are getting a good spark on all 4 then i wouldn't worry about the trigger voltage.
Seems strange why both Charge and coolant temp senders would both be off. I'd start here. Can you check the resistance direct from the sensor?

Still won't start. PLEASE HELP.
 

Update --> Going nowhere fast.

Put a LOW power bulb in each injector and they're all pulsing like they should. Plugs are all wet. Spark on all 4 plugs. Changed back to old plugs which were gapped by MSD.

Changed CTS, DPS and ACT sensors. Car still won't start.

Resistance of CTS in car with loom disconnected was 7.8k Ohms.
Changed CTS, disconnected resistance is 6.3k, connected now it's 8k.

ACT resistance disconnected was 7.6k.
Changed ACT, disconnected resistance is 7.4k, connected now it's 8.5k.

It's freezing, well almost. It's 5 degrees outside temperature here in the southwest of Ireland and getting colder.

All engine earths removed, checked, cleaned and reinstalled.

All sensor plugs are connected correctly and seem ok.

All timing marks checked and all check out ok.

A q in an earlier post:

do all relays work properly[not just click]? --> How do I know if the ECU and fuel pump relay are working correctly like you ask? I presume they both are though as injectors are pulsing and fuel is being fed to rail and when cranking, fuel pump is on constantly.

Doing a continuity check now. ECU diagram from big turbo.co.uk just to see if everything from engine is connected to ECU hairbrush plug like it should be.

Really can't think of anything else.

Anyone got any ideas?

Maybe time to rip off the rocker cover and check all valves are opening, cam isn't split etc?!! A cam has broken on me before on the rolling road just after a new build ffs!!! :cry:

Please help, cheers :top:

Philip.

How much fuel is in your tank and how old is it? Iv had it a couple if times if the car is low on fuel and a few weeks old mine wont start

1/4 tank or less. It's been there since Xmas....

It surely should still fire as the petrol isn't that old.

http://i1308.photobucket.com/albums/...psv3rigxe0.jpg

Pins 13 and 14 go to OCTANE. What is this?

Also my amal valve, with loom disconnected, the 2 amal valve pins are shorted together when testing for resistance with the multimeter, is this normal?

Everything else checks out ok.

:tiff:

You seemed to have dived into it mate, could I suggest a step back.old school style.
Is there a spark, is there fuel in chamber, is there compression ,is there air drawn in.?
I'd have thought if nothing's been touched since last ran, if u put capful o petrol down spark hole it would cough at least?
Do u have cosworth friend that would swap out ecu for two mins?
I'd suspect a duff sensor/ crank gap,lead.
But tbh if you're already at pin testing then I'm talking Boloks and your way past me mechanically :-( so this thread is only helping by bumping up

Pin 13 and 14 (Octane) are for a ignition retard when using fuel with a too low octane number. Well, at least with the standard software.
Mapped software may assign other functions to these pins, like water injection and ALS.

Resistance of the temperature sensors seems to be o.k.
According to this http://bigturbo.co.uk/main4.htm the resistance at 0 degrees is 9750 ohm.

Thanks for bumping up the thread haha. I don't have a spare ECU or friend with ECU that is close by unfortunately.

Thanks for the octane answer. I have ALS and LC. It's mapped to 380/400. I thought the sensors were ok but changed them anyway.

I'm all out of options.

Going to take it to my mechanic who built the engine and see what he can do.

What a ball breaker.

Cheers for the replies.

Philip.

Have you had any luck with your car?

Solved!!!
 

Hey mate,

It was a dodgy GRP A coil. I had spark with the plugs out in the open but under compression, no spark.

Took my mechanic a good while to find it! He had a load of spare parts which was handy. I didn't unfortunately!

Sold my spare coil about 2 months back, always the bloody way isn't it?!

All sorted now.

Philip.

nice one phil

Thanks James.

coil
 

good that you have it sorted now without much cost/outlay

Cheers Tony, yes indeed it didn't cost too much but still, what a ball breaker!!! :wall:

Heated windscreen is next, never stops.

Philip.