Gti eng wont start

[beaver700]

Hi,

I realise this was to be expected, but the gti eng which I finished putting in my sierra wont start..

But...

It seems to run for 1 revolution of the engine, then die. I could keep cranking all afternoon and it wouldnt start again, but when I turn the ignition off, then back on (when I turn the key back on I can hear the fuel pumps running, then stopping after a few seconds), she will start momentarily, run for a revolution, then die.

I checked if all the leads were sparking, and all were ( 1-3-4-2), it is all working (I am using a mazda cap).

I have noticed the O2 sensor on the exhaust has a crack down it, is it something as simple as this causing it not to start?

Did anyone have any suggestions on what I could check first?

Thanks for all your help in the past and future with this conversion,

Cheers,
Martin

[joshnz1]

does it have a good spark all the time?
does it have continous fuel pressue?
what cond the fuel filter?is it on the right way?
whats the coil like?
has it been wired up correctly?
blown fuses?

[mr green]

the o2 sensor wil not stop it from running. i ran mine for about 2 weeks without one. you havn't mentioned backfiring so i will assume the whole mazda cap thing is right and if it fires for a second i would think it is injecting, so i am thinking fuel pressure. what is your pump setup?

[beaver700]

Thanks for the replies guys,

I was thinking along the lines of fuel pressure as well...

At the moment (temporarily) I only have one vl pump which is bolted near where the stock fuel filter. I have a HP fuel filter for a vn (I was told by a repco man that the vn one would work fine, plus it was cheaper...) just before the fuel rail...

I noticed the fuel pump only works when the key is turned. I wired it up with a relay with a pink wire from the ECU. How does this ECU control the fuel pump. Does trigger the fuel pump when the pressure gets low?

I will take some photos and send them...



Cheers,
Martin

[beaver700]

Forgot to mention,


I think the coil is working well, the spark is consistent from all the time. So what could be wrong with the fuel pump?



cheers



martin

[small talk]

Does it jsut cut straight out, or like die, making the brrrrrr sound?

[beaver700]

Thanks Smalltalk:

I tried to start it just now, it seems to jump to life then 1/2 a second later it dies (makes the brrr noise). After it stopped I could hear the pump working away again trying to maintain fuel pressure...

Cheers

Martin

[joshnz1]

just wire the fuel pump up so it works all the time see if the car runs if it does u have fixed and found the prob,if not leave it how it was and move on and check something else

[beaver700]

yeah, sounds like a good idea, will do,


Thanks for the input,

Martin

[beaver700]

I just wired the pump right up to the ignition...

The pump constantly pumped, and the same thing happened...

I may have to check the cap setup and coil again,




I cant think of any other things.... if anyone has any suggestions, could you please let me know?


Thanks,
Martin

[mr green]

is yourair flow meter hooked up with no unmetered air coming in after the meter. eg vac hoses off?
and if you have a noid light plug it in to see if you have pulse at the injectors after the engine dies. if you don;t have one $10 at ripco or bursons will get you one.

[Santos]

which year engine is it?

[beaver700]

Hey guys, thanks for the suggestions,

From the plate on the firewall I know the year model of the car is 1989, (mk2 ??). And the engine should be the same unless the old owners put in another engine ?


Sorry another thing... I made a mistake yesterday saying that the engine rumbled to a stop (brrrr). It acually fires to life then suddenly gets cut off immediately....What stumps me is why it wont start again until I turn the ignition off, then back on? I am starting to think this is ECU related....

But I will check airflow and vacuum systems MR green,


Thanks heaps,

Martin


PS: Would the oil pressure have anything to do with the engine not running....

[Cruzer!]

did you connect the diagnostics termianls correctly from the gti harness? If you did, you can jump the wires, connect it to a bulb (i use an LED) and see if theres any codes... might give you an idea of any ECU related codes

[beaver700]

it should start without an exhaust right?

[Cruzer!]

yes... did u get pm?

[beaver700]

Gday,

Could anyone help me wire up the check engine light in the gti?

Thanks

[Rotazuk]

I am pretty sure the system does not have a balast resistor , ie when cranking the starter full volts goes to the coil , when not cranking power to the coil is vai a resistor . You then run a lower voltage coil . Old cars had this and I had the resistor fail , gave your problems . I would say you are missing an input to the ecu . turning ign off reseting the ecu , not sure what one tho , should run without most of them ( if not very well ) .

Chris

[beaver700]

Gday again
Once again I am stuck with some problems with my gti sierra
Heres the story (I apologise for its length)..

A few weeks back the sierra gearbox I had running behind the gti broke, so I went to find another gearbox. I therefore decided it would be easy and worthwhile to lift the whole engine and gearbox out in out hit (because I found it hard to just drop the box out...), and I thought it would pay off if I make a neat fusebox/relay box to put all the relays in to keep it neat... Now, so I done that, I put all the relays and wires into a fusebox neatly etc. When I put the engine and gearbox back in the car, connected everything up etc, I found it would start (of course) so the first thing I checked was the spark (by removing the HT lead from the dizzy to the coil and earthing it on the block to check for sparks... I done so, cranked the engine and the strangest thing happened. The spark jumped the gap consistently, and when I stopped cranking the engine, the spark kept jumping across, but at a faster rate. Funny thing is that the spark stops jumping as soon as the fuel relay clicks off, so does the spark.
Immediately I got out a multimeter and checked for continuity etc. Everything seemed fine except for when I receieved negative resistance??? for a few wires..
ANother thing that happened was that the main relay stopped working all of a sudden... When reading the manual, it said on the main relay one of the trigger terminals (86) connects to the ignition while the other trigger terminal connects to terminal b8 on the computer. I checked my wiring, it was all good. Everything to do with the ECM was dead, even the 'check engine light'! Until I grounded the wire from the 85 terminal of the relay, then everything started working??? When I took the ground away, the relay kept clicking endlessly (on off on off...) until I turned the ignition off...

Right I know its a mouthful, but its had me and a few mechanic friends couldnt figure it out either... if anyone has any lead at all to what the problem could be, or experienced anything slightly similar, it would be fantastic if you could post back with a start...

At this stage I dont know if the ECM is blown, but I was going to start by buying another gti computer loom and replacing the one thats in the car at the moment... because its a bit of a mess...

Ive been told to check the grounding points... which I have checked... The erratic sparking which keeps sparking until the fuel pump relay clicks off?!! what could be going on?



Thanks guys,

Martin

[SLOGQ]

If you have a wiring digram check EVERY ECU earth point.
The ECU switches the relays by earthing them out, if the ECU earths are dodgy then the relays wont switch on. It would also explain why there is no check engine light.

Is the fuel pump relay working correctly?

Also, be carefull checking for earths with a test light, make sure its a LED, not a bulb type test light........

[beaver700]

gday SLOGQ,
I will check all grounds later on this week, thanks heaps for your help! Its good to know I acually have a lead to the problem now!

Cheers,
Martin