27 replies to this topic

[ksin86]

Hi Everyone,

 

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STORY (for technical details skip this)

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A year ago in Japan when staring the car on the way home from work, the engine would turn but not continue run. I later found that there was no power going to the pump.

With the key in the "on" position, there was no 'whir' of the pump priming the fuel system. I thought I was stuck. That day I took the train to work.

When I got home, tried to fire up the car, heard the 'whir' and she started right up. Weird, I thought.

 

Problem went away, then came back a few months later. Same thing. Brought it to the shop, they couldn't find anything.

 

Now just a couple days ago, after driving around town for about an hour, park it, went to dinner, when we came back, it happened again. Left the car there thinking if we waited overnight that it would work (as we have done in the past), came back the next day still nothing.

 

 

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TECHNICAL

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Searching around different forums:

I've realized the 4 main points of failure could be:

• Fuse (glass)
• Inertia Switch
• Relay Box
• Wiring (purple/slate color)

So far:

1. I've checked the fuse (10A), it was blown. I quickly replaced it, still nothing. What blew the fuse? (Fuse holders and fuses were replaced with new ones just a few months ago.)
2. I've checked the inertia switch and it's in, not popped up.
3. I've connected a fused link directly between the battery and the posi+ive terminal on the pump and the pump sounds just as good as usual.

 

After directly running a wire directly from the battery to the pump, drove the car home without any problems. Strange thing to me was that after unplugging the wire while the car was running, the pump still ran under it's own power. I decided to turn off the car and then turn on the car again, and she fired right up without the wire. So to me it seems like it's still getting power. I'm going to try to fire it up again without the wire tomorrow in the morning to see if the problem persists. What I'm worried about is that it'll work fine again and I won't be able to find the point of failure.

Next up will be the relay box however I'm worried because I understand the pinouts are different for the Japanese-spec Minis with A/C compared to the "Pinned" post on this forum. Also will check the wires.

 

What are your suggestions? Any idea what might've blown the fuse?

 

 

I've owned my Mini for 3 years now, and just recently imported to Vancouver, Canada. There are lots of Mini shops in Japan so every time I've had a problem and couldn't figure it out myself, just popped it by the local Mini shop and got it fixed quick. After moving here... I have no idea who to bring it to so I am hoping to find some more specific advice with this post.

 

Thanks so much.

 

 

[xrocketengineer]

Well, first of all, if it is a 1993 it uses the standard SPI relay (YWB10022) which is what my 1994 Japanese Cooper with A/C uses. The 1997 on Japanese models are the ones that use the unique parts.

The wire to the pump fuse is purple brown with a slate tracer. If the fuse is blowing it is because it is getting hot due to local resistance or higher than rated current.

What I would do:

1. Check the fuse holder for evidence of heat damage and make sure the connection is clean. If there is any indication of melted insulation, replace the fuse holder and make sure to solder the wire splices.

2. If everything looks OK, try to use two pins or needles to make contact inside both ends of the fuse holder while it is all connected. Make sure they make good contact inside the fuse holder. Be careful the pins do not create a short to ground outside. Try to run the engine (and pump) and measure the voltage from the pins to ground, it should be 12V.

If there is less than 12V but the same voltage on both pins, the relay contacts might be dirty or worn out. If the voltage is much lower on the output pin the the fuse holder is no good.

3. If the relay contacts are good, the pump could be on its way out, possibly needing more current to run.

 

Cheers,

Ivan

Edited by xrocketengineer, 12 June 2014 - 09:24 PM.

[ksin86]

Ivan, thanks for the advice, good to know that my car has a standard SPi relay box so I don't have to worry about messing it up in the future.

 

Anyhow, this morning, I try to start her up and fires up with no problem.

 

1. I've checked the fuse and holder and it's pretty much squeaky clean since I got all of them replaced a month ago.

2. Voltage across the fuse is 0.06V and the voltage from each pin to ground is 13.5V

 

I guess that rules out those two. So it might be the fuel pump on its way out as you say. Is thee anything else I can check?
I'm wondering if can tell by how much current is passing through to the pump?

 

Thanks,

Keishin

[xrocketengineer]

Well, that seems good. Last thing to check would be the voltage at the pump while it is running. If that is good too, then the pump or pump area is suspect. I had 91 Chevy S-10 truck with a similar setup as the Mini. Two things were giving me trouble and probably the pump was fine even though I replaced it.

The first one and main problem was the short hose connecting the pump to the metal piping had rotted and split allowing all the fuel to return to the tank. The second one was the strainer that was also rotten and coming apart and about to be ingested by the pump. That could potentially have caused the pump to jam and blow a fuse. So maybe your strainer is coming apart.

The Chevy pump:

 

Also, if you need to replace the pump you might want to investigate a substitute available on this side of the pond. Somebody posted this and I saved it:

 

"SPI Fuel Pump

I just posted on the minimania.com forum my experience this past weekend replacing a 1993 mini SPi fuel pump with a US substitute. It worked perfectly for about 82USD. It took only about an hour to do and saved me 450 dollars. (A rover pump here in the US is about $550. USD and a month wait to get it. It cross reverenced to a 1990 3.0L FI Dodge Caravan."

 

Bosch 69305

Airtex E7012

Bestfuel BE7012

Carter P74036

 

Good Luck,

Ivan

Edited by xrocketengineer, 12 June 2014 - 01:47 AM.

[Guess-Works.com]

I'd put my money on the MFU, the black box which sits on top of the servo, this has the main relay in for the engine and fuel pump...

 

The are notorious for getting wet and failing, and also being the source of intermittent faults.

 

Also does your car have a rover immobiliser, this will also stop the pump from running.. as your history describes, when the ignition is turned on, you'd hear the pump 'charge' the fuel rail, but when started you'd get a short run before the engine cut out. this generally means the immobiliser is not sending the 'you may start the car' message to the ECU which is then turning the pump off.

[xrocketengineer]

Being a Japanese Mini, it should not have the immobiliser. The MFU is a different story. You would need to catch it when it fails. However, can that blow the fuse or was it a mere coincidence?

[FlyingScot]

^^^ what he said. No immobiliser on Japanese spec. You probably have moisture ingress or cracked solder joints on your Relay Pack (MFU). If it's a standard relay pack have a look in the thread about this in this section, there is a description of how it works and a picture showing the wiring.

FS

http://www.theminifo...-functionality/

Edited by FlyingScot, 12 June 2014 - 08:51 PM.

[xrocketengineer]

Oops, I screwed up, the fuse for the pump is on a brown with slate tracer wire and not purple as I said. Are you sure you checked the right fuse?

[ksin86]

See post below, sorry, I just found out how to use the MultiQuote button to reply.

Edited by ksin86, 19 June 2014 - 04:05 AM.

[ksin86]

I'd put my money on the MFU, the black box which sits on top of the servo, this has the main relay in for the engine and fuel pump...

 

The are notorious for getting wet and failing, and also being the source of intermittent faults.

 

Also does your car have a rover immobiliser, this will also stop the pump from running.. as your history describes, when the ignition is turned on, you'd hear the pump 'charge' the fuel rail, but when started you'd get a short run before the engine cut out. this generally means the immobiliser is not sending the 'you may start the car' message to the ECU which is then turning the pump off.

 

Guesworks, just to confirm, no immobilizer. I'm going to head to a local Mini meet this Thursday and hopefully someone will have a box that I can test with however it's really intermittent and only fails once in a while so I'm having a hard time diagnosing it. Also, if it is actually failing, why only when priming? I've never had it fail while driving, only when trying to start.

 

 

Being a Japanese Mini, it should not have the immobiliser. The MFU is a different story. You would need to catch it when it fails. However, can that blow the fuse or was it a mere coincidence?

 

How would I "catch" it when it fails? For example it stared consistently for a few days now but this morning it didn't again. Am I looking for some voltage going to the fuel pump relay from the ECU on FlyingScot's pictures here: http://www.theminifo...-functionality/? 

I'm still wondering what blew the fuse as well. So far it's still intact.
 

 

^^^ what he said. No immobiliser on Japanese spec. You probably have moisture ingress or cracked solder joints on your Relay Pack (MFU). If it's a standard relay pack have a look in the thread about this in this section, there is a description of how it works and a picture showing the wiring.

FS

http://www.theminifo...-functionality/

 

FS, thank you for the link. I've make a color printout of it and have been studying it.

 

 

Oops, I screwed up, the fuse for the pump is on a brown with slate tracer wire and not purple as I said. Are you sure you checked the right fuse?

 

Ivan, awesome cross reference to the Caravan pump! I did check the right fuse thanks, the shop I took it to regularly in Japan made a diagram of it for me so it's easier to see.

Edited by ksin86, 19 June 2014 - 04:23 AM.

[xrocketengineer]

Being a Japanese Mini, it should not have the immobiliser. The MFU is a different story. You would need to catch it when it fails. However, can that blow the fuse or was it a mere coincidence?

 

How would I "catch" it when it fails? For example it stared consistently for a few days now but this morning it didn't again. Am I looking for some voltage going to the fuel pump relay from the ECU on FlyingScot's pictures here: http://www.theminifo...-functionality/? 

I'm still wondering what blew the fuse as well. So far it's still intact.

Keishin,

 

What I meant was to be able to measure the voltage at the pump and at the relay output when the pump fails (not running). One more thing to check, is the condition of the earth (ground) connection for the pump. It should be located between the fuel tank and the left taillight. There should be a bunch of black wires connected to a screw.

 

Cheers,

Ivan

[ksin86]

Thanks Ivan, just waiting for to "fail" again.

[ksin86]

 

 

Keishin,

 

What I meant was to be able to measure the voltage at the pump and at the relay output when the pump fails (not running). One more thing to check, is the condition of the earth (ground) connection for the pump. It should be located between the fuel tank and the left taillight. There should be a bunch of black wires connected to a screw.

 

Cheers,

Ivan

 

 

Okay, so took the car to run a bunch of errands yesterday. Wouldn't start about 5 out of 10 times. When the car would not start, I measured 0v at the pump and relay with the ignition in the "ON" position. Under cranking it was reading about 9.8v.

The grounds are squeaky clean.

 

Each "fail" was resolved by connecting a the pump with a 10A fused link directly to the battery. The car will always start up with this trick.

After it starts, I disconnect the link and the pump works on it's own without it.

Alternator shouldn't be a problem because it runs even when I disconnect the battery.

 

 

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This next one not sure if it's related but I'm gonna post up in another forum post.

 

Another problem came up. On the way back home, the car started sputtering/misfiring just died. Pulled over, fired her back up and on idle seemed to occasionally misfire and the RPM would drop below 5 or 600RPM and the engine would die. If I revved it up and stayed on the pedal it would run but still misfire. All fuses were good. Gas was still at 3/4 tank.

 

I let the car sit for about an hour until I hopped back into it again. It would idle alright however this time, when driving, it would only sputter over 3500RPM. So.. Car was driveable again but only if I stayed under 3500RPM. Seemed like it was in some kind of "limp-mode" or the timing advance wasn't working at high revs? I was able to drive her home.

 

The problem is, now it's morning and I've driven to work and had no problems at all. Started fine and drove normally over 3500RPM, even on the highway.

 

Thanks again,

Keishin

Edited by ksin86, 07 July 2014 - 05:53 PM.

[xrocketengineer]

Ok, it is looking like Guess-works.com was right from the beginning. The MFU is acting up. One of the fat brown wires feeds power to the main relay and the fuel pump relay. The fuel pump relay is activated by the white wire coming from the ignition switch that also activates the ECU pin 11.

The main relay is activated by a thin white/pink wire coming from the ECU pin 4.  The output from that relay, fat brown/pink wire, goes to several locations including the + side of the ignition coil. If any of those related functions are not operating properly, the car would no start. It seems that the only thing not working right is the fuel pump relay.

I think that you need to resolve this problem first before attacking the other. The pump relay might be intermittent causing the other issue.

You might want to open the relay box and inspect it using FlyingScot's info. The contacts could be dirty and cleaning them with a finger nail file might do the trick. 

Edited by xrocketengineer, 07 July 2014 - 09:06 PM.

[FlyingScot]

Individual relays can be sourced. Open frame version of Omron G8P 12V is similar.
I would also be checking the circuit board of the MFU once open for cracks and re soldering the connections.

FS