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View Full Version : My C20LET Nova won't start.



krobinson
04-07-08, 11:28 PM
Hey Folks,

Have my C20LET Nova all plumbed in and wired, went to start it tonight but with no success at all.

I cant get any spark at all, and cant get the fuel pump to fire.

I have checked the wireing and it seems to be fine. The live is connected and is working, switched live is working when the ignition is on. The ignition light is coming on the dash. The earths are present on the fuel rail, and I have a large earth on the gearbox. The engine cranks over without any problems. I have also tested the wireing to the fuel pump, and this is fine, there is just no power going to the wire when cranking the engine.

To test the crank sensor, I removed the sensor from my Ecotec SRI cavalier, and tried it, this made no difference. However I also fitted the LET crank sensor into my Cavalier, and it took longer to start and hesitated, and when it eventually fired up, it ran very lumpy. I assumed then that my crank sensor was faulty, however I still feel that because it worked to start my cavalier, then it should at least fire some spark or start my fuel pump.

I have also one more theory, and that is - Maybe my ECU is the imobiliser type? and is preventing the fuel pump and spark to fire, The engine is a Late LET, however the ECU is "PK" which I was told on several occasions it shouldnt be imobilised.

I'm totally baffled folks, I need help, and lots of it!! :doh:

Thanks

Keith

craig green
04-07-08, 11:32 PM
Have you got the ECU light coming on with ign?

Do I recall it was a mint/new loom you bought for the LET?

trackdaynova
04-07-08, 11:37 PM
So when you turn the ignition on, there is 12v at the fuel pump, yet when you crank it over the voltage dies?

If so - you've connected the live to the wrong wire on your ignition barrell.

krobinson
04-07-08, 11:41 PM
Have you got the ECU light coming on with ign?

Do I recall it was a mint/new loom you bought for the LET?

Loom was tidy'd and sorted by Nova-andy on MIG, he works for Delphi.


So when you turn the ignition on, there is 12v at the fuel pump, yet when you crank it over the voltage dies?

If so - you've connected the live to the wrong wire on your ignition barrell.

There is only supposed to be 12v at the pump when the engine is cranking. The c20let loom is sending no power down the wire when the engine is cranking. However, if I send a live down the wire from the battery then the pump works. So the wireing to the pump, and pump are fine.

burgo
04-07-08, 11:46 PM
exactly the same symptoms as an x16xel i wired in and that turned out to be an immobilisor problem

krobinson
04-07-08, 11:50 PM
I've been told my PK ECU doesnt have the imobilizer, but i'm starting to doubt that?!?

djbrowney
05-07-08, 12:29 AM
i know this may sound like a long shot, but were did you get the ecu from, if it was brought second hand what are the chance of the casings being change so it not actually a pk type ecu, just pk type casing :thumb:

Cormac
05-07-08, 12:41 AM
i know this may sound like a long shot, but were did you get the ecu from, if it was brought second hand what are the chance of the casings being change so it not actually a pk type ecu, just pk type casing :thumb:

The Ecu came with his first let he got, We checked the ecu case earlyer and it's never been opened and is genuine enough.. It really is starting to sound more and more like a immobillier related problem... That or the guy whos done the loom has fooked it up!

burgo
05-07-08, 12:47 AM
i dont supose you know anyone with a known working ecu you could try ?

R1CH
05-07-08, 12:50 AM
Theres 3 ECU's for the LET, PJ - PK - HD, its only the HD ECU that was imobilised, so your PK one wont be imobilised so at least it rules that out.
As for the problem i've no idea, thankfully mine fired up 1st time, when things just don't work then i struggle as well !!
It'll turn out to be something blatantly obvious !! lol

ck
05-07-08, 02:30 AM
have you got an engine management light wired in? if so are you getting any fault codes?

joff-turbo-nova
05-07-08, 07:41 AM
Keith,

I had similar problems with my XE I put in my Vectra - have a look at the link here :-

http://www.migweb.co.uk/forums/engines-transmission/332832-no-spark-xe-conversion-2.html

Turned out to be the crank sensor not sitting far enough in the block to pick up the crank trigger wheel.

Worth a look if all else fails bearing in mind I was having exactly the same symptoms as you????

Hope you get it fixed soon - good luck :thumb: :thumb:

Joff

krobinson
05-07-08, 10:06 AM
Thanks Joff, i've checked your thread and my crank sensor looks different, it just has a little rubber O ring on it, and i've had it in and out a few times.

However I cannot remember where I got this crank sensor from, i didnt get it with the engine, I think someone gave it to me, so It could be the wrong one by a mile for all I know. I'm going to try and get a new one today.

Keith

adzgsi
05-07-08, 10:13 AM
your tdc sensor will have a very small gap between the sensor and the target wheel (almost spark plug gap size) your sensor will produce a small amount of voltage whilst cranking due to the electro winding inside,
if you have a test light slide a pin into the connector block place your test light (led type) on to it when you crank led should flash as it is an ac voltage. this will test your sensor and target wheel and gap. does sound like a tdc problem as the fuel pump wont cut in because it cant see no engine rpm.adz:thumb:

joff-turbo-nova
05-07-08, 10:21 AM
Thanks Joff, i've checked your thread and my crank sensor looks different, it just has a little rubber O ring on it, and i've had it in and out a few times.

However I cannot remember where I got this crank sensor from, i didnt get it with the engine, I think someone gave it to me, so It could be the wrong one by a mile for all I know. I'm going to try and get a new one today.

Keith

I would get hold of a gen bosch one which are metal if you can as the aftermarket cheaper ones are plastic and seem to be considerably less reliable!!

Joff

krobinson
05-07-08, 10:43 AM
yeah mine is plastic, I'll do the crank sensor first, and test the voltage going to it, and if thats fine then it's loom and ECU time :(

fearless
05-07-08, 11:28 AM
Have you checked you have a decent ignition feed to the ecu - when cranking some ignition supplies drop voltage to less than the ecu's like to see !!!

Dave

trackdaynova
05-07-08, 11:47 AM
I changed my metal crank position sensor for a plastic one, brand new, and it failed to start numerous times.

So I swapped the brand new plastic item back for the second hand, a bit haggered looking metal one :thumb: perfect everytime

krobinson
05-07-08, 05:00 PM
Have you checked you have a decent ignition feed to the ecu - when cranking some ignition supplies drop voltage to less than the ecu's like to see !!!

Dave

I'm using the ignition live from the GSI loom, I'll try it direct to the battery to see if this helps.

I have just checked the switched live using a bulb, its live with ignition, and it stays live when cranking, so thats that ruled out.

I have also unpluged the crank sensor, and used the same bulb (indicator bulb) to test if there is any power going to either of the 3 wires in it. There doesnt seem to be any life in them at all, however I'm not sure if this is normal or not?

I have also put a direct earth from the fuel rail to the battery earth. And I've run an earth from the battery down to the bolt on the knock sensor (inlet)
There is supposed to be a bracket from the inlet to the block, but i've lost this. I assume having the earth back to the battery should suffice?

Still no joy at all folks.

Depressed Keith.

krobinson
05-07-08, 05:03 PM
I changed my metal crank position sensor for a plastic one, brand new, and it failed to start numerous times.

So I swapped the brand new plastic item back for the second hand, a bit haggered looking metal one :thumb: perfect everytime

I must price a new metal one from vaux, cheers :thumb:

Rickyb
05-07-08, 05:26 PM
im sure yuoll sort it mate :thumb:

valvercorsa
05-07-08, 06:40 PM
only had a quick read tho but haven't noticed fuel pump relay been mentioned?

no fuel and no spark its the first thing id check :thumb:

sorry if iv missed something!

matty

Graeme
05-07-08, 06:50 PM
I'd say the crank position sensor but failing hat I've got a Oner here with your name on it if you can't sort it, I'll take it off your hands

krobinson
05-07-08, 09:50 PM
To be honest i'm out of ideas.

I'm going to change the ECU, Crank Sensor and Fuel pump relay, and if none of that works then i'm going to have to change the loom.

Keith

Jeff16v
06-07-08, 07:53 AM
Keith, make sure the tank vent valve is clicking when you try and start it. I had a similar problem and i had a problem with that valve.

joff-turbo-nova
06-07-08, 10:02 AM
I must price a new metal one from vaux, cheers :thumb:

Time for a remortgage on the house or a bank loan !!! They are not cheap new - try & source a reasonable condition one second hand maybe??

The metal ones are very reliable unlike the plastic ones for some reason???

Joff

Sturge
06-07-08, 10:38 AM
Is the fuel pump priming when you switch the ignition on? if not then you can discount the crank sensor as it's most likely the relay or the ecu. If it's not, check to see if there's power getting to the relay. If there's no power to the relay, check to see if the feed from the ecu is live, if not it's the ecu, if there is, it's the loom :)

Adam
06-07-08, 12:03 PM
The pump relay would not stop it sparking

Sturge
06-07-08, 12:14 PM
Pump and ignition usually run off the same relay

krobinson
06-07-08, 01:24 PM
Is the fuel pump priming when you switch the ignition on? if not then you can discount the crank sensor as it's most likely the relay or the ecu. If it's not, check to see if there's power getting to the relay. If there's no power to the relay, check to see if the feed from the ecu is live, if not it's the ecu, if there is, it's the loom :)

- There is power to the relay, If I run a wire direct from the live at the relay to the pump then it fires.

- The pump doesnt prime when the ignition is turned on, i assumed it did nothing until its cranking?

So this would mean its either the ECU or crank sensor? Or could the relay still be the culprit? (it came out of a working car)

Adam
06-07-08, 01:29 PM
Still the crank sensor IMO
If not, then possibly ecu

burgo
06-07-08, 01:37 PM
i didnt think they primed? i just thought the pump started when cranking. as ad said crank sensor is still the next thing to try

Ben
06-07-08, 04:17 PM
Earth problem by the sounds of it to me,

fearless
06-07-08, 10:31 PM
If you need a wiring diagram for the C20LET engine loom - send me your Email address keith and I'll send you one that I scanned in from work


Dave

ck
07-07-08, 07:17 AM
if its firing with a live connected to the pump then the crank sensor is fine. the fuel pump relay also powers a few vital engine sensors and will stop it sparking if faulty.

id try a known good fuel pump relay 1st tbh.

coombsey
07-07-08, 05:21 PM
when my fuel pump relay went i had no ecu light and when i rplaced it for my spare one tre ecu light came on and started i was getting no fuel up to rail and no spark

Chaz-Turbo
07-07-08, 06:04 PM
im gonna ask my fella if he has any idea's about ur nova?

S1 RST
07-07-08, 06:49 PM
fuel pump doesn't prime until engine turning over, what voltage have you got at the coil when igntion is on?

double check that some hasn't been inside you ECU and put the chips in wrong way round it happened to me took me a while to realise

have you earthed the engine loom especially the 2 wires on the fuel rail the other just attach this to your engine block or starter motor bolts, does the rev counter go up when cranking engine over?

krobinson
07-07-08, 07:34 PM
fuel pump doesn't prime until engine turning over, what voltage have you got at the coil when igntion is on?

double check that some hasn't been inside you ECU and put the chips in wrong way round it happened to me took me a while to realise

have you earthed the engine loom especially the 2 wires on the fuel rail the other just attach this to your engine block or starter motor bolts, does the rev counter go up when cranking engine over?

I'm going to try the ECU in a friends cavalier turbo tomorrow, and collect a crank sensor and fuel pump relay. If those dont work then I have the wireing diagrams (cheers dave/fearless) and i'm buying a multimeter to check every wire etc.

That will probably be after billing though as i'm busy all week :(

Keith

ck
07-07-08, 10:23 PM
if im being ignored fair enough im only trying to help.

1. as i asked a few pages ago. do you have an enging management light wired up?

2. did you say that if you link a live feed to the fuel pump the engine fires?

in my opinion it is utterly pointless trying other stuff if an EML is not wired in.

be sure to check all earths on the LET's loom. also add a couple new earths from the block/alternator/head to the chassis. the LET will still run with a fair few of the sensors disconnected.

do you have a copy of the C20LET workshop manual? it covers pretty much everything and can be a big help, i can e-mail u a copy as a pdf if u dont have one.

Adam
07-07-08, 10:28 PM
ck

1-Yes, he replied on mig
2-no, the pump goes live when he bridges the relay, still no spark.....

Clean 2.0 nova
08-07-08, 09:31 PM
If you have an engine warning light fitted then wouldn't a paperclip test bring up an immobiliser fault if one is indeed fitted?

I had a problem back in the early running days of mine where I couldn't get the fuel pump to run from the ECU. So I wired in a seperate circuit to energise it when the ignition was turned on. The engine would then start after a few hesitant turns and usually plenty of backfiring when attemting to fire from warm. As all the position sensors were new when the engine was fitted I was reluctant to start replacing them. I took it to a garage where they replaced both cam and crank sensors and this cured the fault. After a few days I undid my earlier bodged fuel pump feed and since then it has been fine (running up the fuel pump in advance of cranking).

In short my ECU wasn't firing up the fuel pump because it knew in advance there was a problem with one of the position sensors (probably crank) - sounds wierd!

Ben
08-07-08, 09:56 PM
if its an immobiliser fault and the em light is wored up correctly then it would constantly flash on turn over.

But as perviously ruled out it cant be that.

krobinson
09-07-08, 06:18 PM
if im being ignored fair enough im only trying to help.

1. as i asked a few pages ago. do you have an enging management light wired up?

2. did you say that if you link a live feed to the fuel pump the engine fires?

in my opinion it is utterly pointless trying other stuff if an EML is not wired in.

be sure to check all earths on the LET's loom. also add a couple new earths from the block/alternator/head to the chassis. the LET will still run with a fair few of the sensors disconnected.

do you have a copy of the C20LET workshop manual? it covers pretty much everything and can be a big help, i can e-mail u a copy as a pdf if u dont have one.

Sorry mate, i'm not ignoring you at all.

There is a live fuel pump wire down at the relay, so there is power down their. Also the EML light is wired in, and it stays on whilst cranking the engine. I assumed this doesnt go out until the engine starts, same as my cavalier SRI.

I've tested my ECU in a friends cavalier turbo and it works, and he has given me another fuel pump relay which we tested first. I'm just waiting on a crank sensor next to try.

Keith

Ben
09-07-08, 07:03 PM
Yeah they all stay on until engines running,

Austin_Nova16
16-07-08, 12:01 PM
Don't know if this would help, but with my car one of the lamba sensor wires which T's into to the Fuel pump wire in the loom, or power to the relay - can't remember, was earthing during cranking, so stopped the pump from working.. So disconnected it, and the pump works

Although this wasn't the main thing stopping the engine running (as I had bridged the relay), it was something that needed sorting..


maybe of use....maybe not...