Hard starting?

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bluejay
Joined: Fri 16 Jan, 2004 13:40
Posts: 222

  Z1 roadster

Hard starting?

Post by bluejay »

So over the last year on and off the Z1 decides it doesn't like turning on. Difficult starting with wild statioanry initially, but when it runs it is OK.

This first started when the v-power was changed, added cleaning stuff to the fuel with normal unleaded and it was fine again, but now it started doing it with regular fuel too (unleaded 95).

Discussed this at length and we think it could be due to ethanol content in the fuel, but also possible deteriation of the fuel lines, I read somewhere? Butyl lines don't do very well with ethanol fuels?

So anyone else has observed this?

Robert

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Gazza
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  M roadster S54
Location: Romford Essex

Re: Hard starting?

Post by Gazza »

Mine turns over fine but like it isn’t getting enough fuel and put put puting into life from cold.
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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blue_and_white
Joined: Fri 28 Jul, 2017 23:19
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Re: Hard starting?

Post by blue_and_white »

There was a cold start mod for the M20 engine back in the day which basically consisted of a small loom, a relay and a resistor . As I remember, the switching side of the relay connected to the starter motor so when cranking, it would activate the relay. This then was connected to the engine temp switch and when activated, switched in the additional resistor to alter the total resistance of the coolant temp switch hence tricking the ecu into thinking it’s is colder than it actually is therefore a richer cold start. You got a choice of three resistors which I think were around 1000 ohms but I’m really not sure, it was 25 years ago . Wether anyone still makes this mod or could rig one up I’m not sure. Good luck


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bluejay
Joined: Fri 16 Jan, 2004 13:40
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  Z1 roadster

Re: Hard starting?

Post by bluejay »

After the whole summer starting OK, it is back again... going to try engine cleaner again through the petrol see if that makes a difference...

It costs a lot of extra fuel this, easily takes 20-30miles of my range of a full tank...

Any other suggestions?

felix
Joined: Sat 02 Jul, 2005 16:25
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  Z1 roadster

Re: Hard starting?

Post by felix »

Check the fuel pressure?

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bluejay
Joined: Fri 16 Jan, 2004 13:40
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  Z1 roadster

Re: Hard starting?

Post by bluejay »

Fuel pressure is fine, it started well over the whole summer.... :head:

felix
Joined: Sat 02 Jul, 2005 16:25
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  Z1 roadster

Re: Hard starting?

Post by felix »

Have you actually checked it or do you just believe it to be OK because the car started fine over the summer?

For an engine to start and run it needs fuel, spark and compression. When fault finding it's best to make a minimum number of assumptions but just to start checking things methodically.

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bluejay
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Re: Hard starting?

Post by bluejay »

I had similar problems last year, also after the summer, seems outside temperature related....

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Gazza
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Location: Romford Essex

Re: Hard starting?

Post by Gazza »

Could be an air leak
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

Z3 S54 M roadster Image, BMW Z1, BMW M3 CSL, Z4M Coupe
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bluejay
Joined: Fri 16 Jan, 2004 13:40
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Re: Hard starting?

Post by bluejay »

Maybe a code reader would be usefull...

Any one can suggest which can be used on the Z1?

Thanks
Robert

felix
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  Z1 roadster

Re: Hard starting?

Post by felix »

A code reader won't be of much use - the Z1's ECU predates the OBD era.

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bluejay
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Re: Hard starting?

Post by bluejay »

It has an OBD ECU, not ODBII, the E30 engines still have an ECU that can be connected to a reader, just owndering if that would give any useful information at all...

felix
Joined: Sat 02 Jul, 2005 16:25
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  Z1 roadster

Re: Hard starting?

Post by felix »

To the best of my knowledge you can’t actually get any useful information from that diagnostic connector. You can reset the service indicator in a conventional E30 as was as resetting airbag and ABS lights but in the Z1 the connector is pretty much of no value. Happy to be proven wrong. If you read up on various pieces of aftermarket BMW diagnostic software the E30 is pretty much absent.

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bluejay
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Re: Hard starting?

Post by bluejay »

thanks Felix!!!

Idle(hahahaha) hope than to get any information out of it.... especailly since the Z1 has no service indicators and airbag.

felix
Joined: Sat 02 Jul, 2005 16:25
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  Z1 roadster

Re: Hard starting?

Post by felix »

Finally you’re catching on. Nor does the Z1 have a check engine light that some E30s have so you can’t do the stomp test either.

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bluejay
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Re: Hard starting?

Post by bluejay »

Anyway, booked the Zet one in with a garage...

probably going to cost 1,000€ to repair (as everything seems to cost that)...

any bets on what the issue is going to be?

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bluejay
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Re: Hard starting?

Post by bluejay »

Combination of old fuel filter and a leaking fuel NRV caused it.

Seems to have been solved now.

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bluejay
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Re: Hard starting?

Post by bluejay »

Spoke too soon,....

Made no difference, thinking towards fuel pump now....

:head: :head: :head: :head: :head: :head: :head: :head: :head:

Pat Slade
Joined: Wed 31 Mar, 2004 17:12
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  Z1 roadster
Location: Barnet

Re: Hard starting?

Post by Pat Slade »

If you have the pump replaced I would be interested to know if the garage will cut a hole in the boot carpet or remove the moulded carpet completely to get to the access panel.
I am asking because I would like to replace the two short rubber pipes that connect the pump to the flow and return fuel lines because of the potential problem caused to the original rubber by ethanol in current fuels.
Not been brave enough to tackle this job yet as I fear the carpet will never go back neatly again.

Cheers

Pat

felix
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Re: Hard starting?

Post by felix »

I'm sure I sound like a broken record to some/most but.... has the fuel pressure been tested? A fuel pressure gauge can identify issues with the pump, the non-return valve and the fuel pressure regulator. I have read of a few fuel pressure regulator internal failures quite possibly caused by ethanol affecting the rubber membrane. It's difficult to test the fuel pressure when the engine is under load but you can at least test the pressure at idle, you can confirm that removing and reattaching the vacuum line at the regulator causes the fuel pressure to rise and fall back, you can confirm that fuel pressure builds rapidly to full pressure when the engine is cranking and you can monitor the rate at which pressure dissipates after the engine is stopped.

For the E30 325i fuel pressure with the pump running but engine off (jumper the fuel pump relay with a piece of wire) the pressure should be 3 bar. WIth the engine running it should be between 2.8 and 3.2 bar.

This is a bit of an old school car and needs old school diagnostic methods; throwing parts at the car can get expensive and frustrating.

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bluejay
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Re: Hard starting?

Post by bluejay »

Felix,...

That will be part of the next step. I don't like the idea of the fuel pump to be replaced as this would mean a stripping of the car to get to the fuel tank.

Robert

felix
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  Z1 roadster

Re: Hard starting?

Post by felix »

Hi Robert, do you have a part number for the non-return valve that was replaced? I would have guessed that it's part of the fuel pump or very near to the pump at the tank end of the car.

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bluejay
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Re: Hard starting?

Post by bluejay »

I don't, but I can easily look it up.

I have been away for a bit, need to check with the garage if they actually replaced it with a new one or that they "repaired" it...

Robert

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bluejay
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Re: Hard starting?

Post by bluejay »

So the garage did not replace the NRV but added another one into the fuel line (by the local Expert).

I am going to replace the pressure regulator this weekend, see if that makes a difference, because if the fuel does not flow back in to the tank via the NRV it could flow back via the regulator.

Fingers crossed!!

felix
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Re: Hard starting?

Post by felix »

Can you post a photo of what they fitted?

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bluejay
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Re: Hard starting?

Post by bluejay »

felix wrote:
Tue 28 Jan, 2020 14:24
Can you post a photo of what they fitted?
I would have to crawl under the Z1, i'll see if I can find it...

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bluejay
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Re: Hard starting?

Post by bluejay »

Seems I have corrected the problem by installing a new pressure regulator (at least since I replaced it, the problem has gone and the engine starts after two or three turnovers!!!

YAY for me! :D :D :dunce:

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