1987 3.2 Carrera Backdate project - Sladeys hotrod

[sladey]

Just throwing ideas out there…

What actually makes the spark on your car? I know you have the CANEM ecu for the fuel but where does the spark come from?

Pixies.

Or

It’s the Canems DIS ignition conversion kit - does away with the dizzy. I fitted a spark detector inline with the plug on number 4 cylinder and set it videoing - I have spark


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[sladey]

OK so plan (c?) is this

I’ve now fitted the anti-roll bar and the rear wheels and lowered it off the lift.

I’m going to put the engine stand and engine hoist away and then phone the AA to say it’s not starting (I do pay for homestart) - I’m tied up tomorrow but aim to do it on Wednesday

I’ll let them analyse it for me. Whatever the problem is I don’t mind fixing it but I’m not great at problem analysis (though I am getting better)

If someone comes up with stuff I can test in the meantime I’m happy to give it a go


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[Gary71]

What does the immobiliser immobilise?

[rhd racer]

Does your system use the original crank position sensor or an aftermarket one on a toothed wheel? Any chance either bracket could be damaged and the distance incorrect so not giving a signal to the ECU?


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[Nine One One]

There are these posts here which may help with someone in the same situation, particularly ‘hot wiring the fuel pump via the fuse.

I take it that putting the Loctite on the cylinder head temperature sensor does not impede it earthing?

https://www.impactbumpers.com/forum/ind ... rt/page/2/

https://www.impactbumpers.com/forum/ind ... ent-438669


https://forums.pelicanparts.com/porsche ... start.html

[RobFrost]

You say you have fuel pressure and no smell of fuel, so the injectors aren't receiving a signal. I'd focus on confirming that fact.

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[sladey]

Thanks for all those comments and links guys

I dont know what the immobiliser immobilises.

My system uses the original crank sensors and neither have been touched throughout the recent work.

Those posts are interesting. The cylinder head sensor one was surprising. I’ve read up on using loctite on earthing bolts and what I’ve read says it won’t affect it but will fill in the gaps between the metal to metal contact. There are some tests i can do on the ch sensor so I’ll try those when I get a chance

I’ll also look a bit deeper into the fuel delivery - I’d assumed because the fuel was pressurised that I had fuel, but with all the cranking I’ve done i think I’d expect to smell a bit of fuel, so that avenue seems worth investigating


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[Gary71]

…but with all the cranking I’ve done i think I’d expect to smell a bit of fuel, so that avenue seems worth investigating

100%. You’ve proven spark.
Only one other ingredient needed! (Except air!)

I’d imagine if the temp sensor wasn’t working you get the wrong mixture, i.e leaner than you’d ideally want for a cold start, but it would at least fart and cough into life.

[jb]

Are you able to take out an injector and put it in a container while you crank it to check you are getting fuel past the injectors?

[DustyM]

Did you pull a spark plug to confirm it’s dry?

If it is and you have fuel pressure at
The rail then as has been mentioned the injectors aren’t firing.

A quick way to prove if it is fuel related and not ignition is to spray some easy start into the air box, it should cough or splutter if the ignition system is good.

The head temp sensor won’t stop it starting as it defaults to rich mode


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[sladey]

Thanks guys - will hopefully be having another go on Wednesday.


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[RobFrost]

A quick way to prove if it is fuel related and not ignition is to spray some easy start into the air box, it should cough or splutter if the ignition system is good.

I'm not so sure easy start is the way to go because I've a hunch it will spontaneously combust under compression, thereby not ruling out a lack of ignition. So some other volatile combustible is better such as petrol or carb cleaner.

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[Gary71]

I’ve resisted for a while but I think we are at this point:

[Bootsy]

Good idea Gary, this book may assist too


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[Nige]

Marky Mark. Must be something simples.

Dunno if it's any help but I'm free from tomorrow/Wednesday onwards. Happy to pop over and bring an extra head for thinking, can also bring my car if needed to cross reference wiring locations, etc. I've had my engine in and out a couple of times so familiar with things.

I may have spare sensor somewhere too.

There are 3 sensors on the crank, speed and position which are located next to each other and are the bottom two of the 3 in the engine comp, top one being the temp sensor. The third sensor, which is positioned on top of the flywheel is for TDC positioning and is the the loose connector flapping about in your engine bay. It's usually secured near the air flow meter and isn't connected to anything, a factory gizmo can be connected to that to TDC electronically.

Are you sure you haven't disturbed the gap between the speed sensors and the flywheel?