Engine Turns Over Slow

Hi all

I have done an ABF conversion on my MK1, and connected it up to a battery, which is brand new but the engine turns really slow.

The starter motor was stuck, so gave it a little tap and it freed up, but the engine still turns slow and it would have no chance to start what so ever.

Everything else looks fine.

Any ideas?

Thanks

Could be as simple as the battery is not fully charged

If battery ok, re-check all connections. Bolts and crimps. When it's turning over, check out the cables to see if any part of the cabling and terminations are warm. Replace if you can't repair.

Check earth return path too, not just the feed cables. It only takes one bad connection to cause this. (if the current finds an alternative route through smaller cables, it will cause serious havoc)

Clean connections with wire brush and apply a little grease prior to making connection. 

Thanks for the replies.

I have taken some photos of my earths, or where they terminate. The cables have been run by me, so I know there are not any broken cables.

Gearbox Strap

Rocker Earth

Battery Earth (Located In The Boot)



Rocker Earth



Unsure if any other specifically earth for firing?

Apologies, wiring isn't my strong point as my other threads suggest.

Thanks

David

Did you check the battery (voltage)?

What length is the +12V lead from the battery to the starter motor, and what thickness is this wire? I don't suppose you checked the voltage AT THE STARTER MOTOR TERMINAL during trying to start the car?

paul_c said

Did you check the battery (voltage)?

What length is the +12V lead from the battery to the starter motor, and what thickness is this wire? I don't suppose you checked the voltage AT THE STARTER MOTOR TERMINAL during trying to start the car?

 

Hi Paul

Haven't checked the battery voltage, but it turns as slow with this new battery as it did an old one (I thought the old battery was knackered, so I bought this one).

The starter motor live goes from the starter to a nipple under the chassis leg, and then uses a thick live to the battery at the rear. The starter motor is the standard one.

Haven't checked voltage at the starter, but to be honest, electrics are my weakness.

Earth leads look of a suitable size, but the fresh paint on the chassis legs may be preventing a good electrical connection. You may need to remove some of the paint around the connection (below the bolt/crimp/washer) and make sure there is clean metal to metal contact at every junction.  All your connections look a little too clean. With this arrangement, you're reliance for electrical contact is in the threads of the rear bumper and captive bolts at the front. Scrape the paint off, then cover with grease to protect from corrosion.

Do also note, if you've moved the battery to the boot, the cables were originally sized for very short runs.  The voltage drop will be pretty big when turning over as the starter does take the largest amount of current in the whole car.

If it's still slow, then its down to the size of feed cable from the battery. Double this up and the problem should go away.

It's all down to that pesky law called ohms law !!

Voltage = Current x Resistance 

Keep your cable and termination resistance as low as possible and ensure that your cable is rated for the current you want to pass over the distance you want to run it and you will be fine.

When I first got my 16v out I, it would turn over slowly when warm. After checking everything out and fitting a new battery, it was the starter, I replaced it with a new one and have had no problems since, as you had to free up your starter it could be it.

Although with the battery moved to the boot wiring is more likely to be causing the problem.

wannabemk1owner said

paul_c said

Did you check the battery (voltage)?

What length is the +12V lead from the battery to the starter motor, and what thickness is this wire? I don't suppose you checked the voltage AT THE STARTER MOTOR TERMINAL during trying to start the car?

 

Hi Paul

Haven't checked the battery voltage, but it turns as slow with this new battery as it did an old one (I thought the old battery was knackered, so I bought this one).

The starter motor live goes from the starter to a nipple under the chassis leg, and then uses a thick live to the battery at the rear. The starter motor is the standard one.

Haven't checked voltage at the starter, but to be honest, electrics are my weakness.

Worth getting up to speed and actually measuring the voltage!!! Without measuring it, you're guessing at problems and with a much longer run of thick wiring from the battery to the starter motor, could end up costing a lot of money to buy/make a thick enough wire to do this without excessive voltage drop.

Pictures of the +12V side would help too. I notice you've not replaced/updated the battery terminal on the -ve side, the original Mk1 Golf item is a little bit weak and there's much better stuff out there, for example: http://www.vehicle-wiring-products.eu/product.php/279/stud-nut-clamp

Also your battery appears not to be held down - is this right?

I relocated my battery to the spare wheel well about 6 years ago, I used 25mm2 welding cable fused through a good qualty 150Amp blade type fuse next to the battery. I ran both Pos an Neg to the front of the car, the Pos onto the starter and the Neg to an earth point next to the fuse box and I've never had any issues.

paul_c said

wannabemk1owner said

paul_c said

Did you check the battery (voltage)?

What length is the +12V lead from the battery to the starter motor, and what thickness is this wire? I don't suppose you checked the voltage AT THE STARTER MOTOR TERMINAL during trying to start the car?

 

Hi Paul

Haven't checked the battery voltage, but it turns as slow with this new battery as it did an old one (I thought the old battery was knackered, so I bought this one).

The starter motor live goes from the starter to a nipple under the chassis leg, and then uses a thick live to the battery at the rear. The starter motor is the standard one.

Haven't checked voltage at the starter, but to be honest, electrics are my weakness.

Worth getting up to speed and actually measuring the voltage!!! Without measuring it, you're guessing at problems and with a much longer run of thick wiring from the battery to the starter motor, could end up costing a lot of money to buy/make a thick enough wire to do this without excessive voltage drop.

Pictures of the +12V side would help too. I notice you've not replaced/updated the battery terminal on the -ve side, the original Mk1 Golf item is a little bit weak and there's much better stuff out there, for example: http://www.vehicle-wiring-products.eu/product.php/279/stud-nut-clamp

I need to spend a little time looking into things I guess, but unfortunately as wiring isn't my strong point at all, I tend to hit my head against a brick wall after no time at all.

Re the -ve side, I was just using what I had to make sure the engine worked, but will look at upgrading bits once it is running.

paul_c said

Also your battery appears not to be held down - is this right?

Correct, it isn't being put here, for testing purposes only.

I messed around with the earths a little earlier, and took the plugs out to make it easier to turn, and it sound like this…

I think you need to decide where the battery is going (as in, its final position), then sort out its clamping arrangements, then sort out the wires. Basically what I think you'll need (can't be sure until actual voltage measurements are done though) is a thick +12V cable directly from battery to starter motor. Because its thick, its not so easy to deal with excess cable length, and its expensive, so you'd want to get it right. Also, you'll (or get someone to) put proper crimp on terminals on it, and protect them with heatshrink. You'll need a hydraulic crimping tool for this.

PS thick means something like 25mm2, 35mm2 or 50mm2 cable. You might even need 70mm2. I'd not go much bigger, it gets awkward to handle etc after that.

Do you not need a bigger battery then the original 063 as you have upgraded the engine, try and find out what battery would be fitted to the car which the engine came out off?
Later Mk1's cabriolets with more electrics (roof, windows) are fitted with the 075.

I'm just guessing…..

http://www.eurocarparts.com/car-battery

 

i would run the earth to the front as well, seen a few guys have trouble trying to earth the engine via the chassis.

use cables off a bmw, they have nice terminal blocks at the engine side for the starter and alt cables

Thanks for all the suggestions so far.

I haven't managed to yet, but I will be ordering a multi meter, however, I was tinkering today and to rule out any earth/positive issues, I used a long set of heavy duty leads from the battery to the starter motor, but there was no difference.

Surely, if the earths and positives were an issue, this would have overruled that?

Thanks again.

David

Hi all

I took the starter off today, and whilst it works, it sounds awfully notchey and screechy.

I think this may be the problem  

yup using jump leads rules out cabling issues, so starter it is then!