24 replies to this topic

[ryomini]

Hello good Spi people

I have enjoyed trying to be helpful and point other Spi users to solutions to their problems

I have read a fair few threads and try to make a habit of keeping up to date with the Spi question section on the forum

 

now it's my turn once again to be stuck

I have a '93 Spi with an SW05 cam and a slightly lightened flywheel and a mildly ported head

The car starts and runs but it insists on idling at 900 and until it establishes a fairly stable idle it is prone to stumble

 

My thoughts are maybe the fuel filter at the rear of the car. 

 

Also when I try to take the car for a spin it bogs down and kangaroos unless you sort of feather the throttle.  I keep trying to find the answer but am stuck

 

If I unplug the air sensor in the air filter housing this makes no difference to the running

If I unplug the CO2 sensor idem this makes no difference to the running

 

the throttle cable is free, adjusted and not stiff or sticking.  The throttle pedal itself moves well and there is nothing obstructing it.  If I can't sort it I will have to call my mini garagist to take care of it as I am getting fed up of trying to find the solution

 

cheers if you can help or you want more information or a precise description of certain symptoms

 

[edkirk30]

Does the stepper motor routine at ignition on/off run smoothly? Does the idle fluctuate at all?

[FlyingScot]

Check the TPS a worn throttle position sensor can give misleading data to MEMS. Using a multimeter either back probe the connector and read volts or unplug and measure resistance. In either case check for smooth changes as the track wears you can get spiking.
As yours is an early one does it have the idle switch on the throttle pedal - is it working consistently?

Fuel filter is a service item - change it as a matter of course and make sure the vacuum pipes are in good order.... I think you have the silicon tubing - check it's not being sucked flat when the manifold depression rises - it's why I recommend the original rigid type.

Flywheel and reluctor ring in the right position relative to the old one (ie is the timing okay)

Few things to try but as always check the basics including tappets and chaffed wiring. Ideally you would want a code reader on her to check out some of the component readings.

FS

[ryomini]

FS

thanks for your input, I will try to get through those items mentioned.

It may be the TPS but I have had the car running and idling no problems so it seems that there are multiple issues and that some new ones are surfacing. 

Yes you are right about the vacuum tubes, but I am using the 7mm OD tubing which doesn't seem to suffer from the collapsing issue.

I just wondering as I am beginning to run through gas and the tank has probably still got a fair bit of gunk in it, could that clog things up to cause such erratic running ?

 

I have not seen any kind of idle switch on the throttle pedal, what is this ?  What does it look like and where is it located.  The pedal just has a single cable input and that is it - very simple

 

@edkirk thanks - yes the stepper motor does it's little dance at pre ignition so that is ok, but yes until the car is a little warmed up the idle fluctuates and should not.  I am going to try and check the fueling today - I have a feeling the petrol is not arriving smoothly.

 

FS I am trying to check all the relevant wiring too,

 

Oh yes and I doubled checked the tappets all set at 0.4mm so good there

Edited by ryomini, 16 August 2016 - 08:22 PM.

[FlyingScot]

Throttle idle switch is in the cabin side at the throttle pedal, simple push switch. Does your ECU have two plugs or one - that would tell me too.
TPS can cause the kangaroo ing behaviour.
Fuel filter is cheap and a service item should why take a chance? I would be changing it they are usually full of thick goo rather than bright liquid petrol.

You have discovered one of the "problems" with MEMS, it's programmed to keep the car running even with multiple faults; this wasn't an issue when cars went to the dealer and were plugged into testbook as the service department read, took action and cleared them.
It's why without a code reader most spi owners are working blind - it's also why I keep one and go interested in them years ago.

FS

[edkirk30]

Throttle idle switch is in the cabin side at the throttle pedal, simple push switch. Does your ECU have two plugs or one - that would tell me too.
TPS can cause the kangaroo ing behaviour.
Fuel filter is cheap and a service item should why take a chance? I would be changing it they are usually full of thick goo rather than bright liquid petrol.

You have discovered one of the "problems" with MEMS, it's programmed to keep the car running even with multiple faults; this wasn't an issue when cars went to the dealer and were plugged into testbook as the service department read, took action and cleared them.
It's why without a code reader most spi owners are working blind - it's also why I keep one and go interested in them years ago.

FS

 

There are of course the PC and android based mems readers now should you be so inclined

[ryomini]

@edkirk for the old Spi mini can you give us more details, web page, photos

 

@FS you are absolutely right, thanks for giving me some encouragement

 

I feel doomed

It's over 36 C sometimes 65 percent humidity, my budget is used up, the missus has had enough and I am out of holiday and very tired now

 

I'll give you the historical run down and details so that you can make your own conclusions.  I am going to contact my mini man to see if he can do something (even he doesn't have a code reader, he does it all 'blind' as you say - seems to be good at it though)

 

Historical so far

Rebuild of Spi and first start up.  Car idled constantly at 1100 rpm puttering away but had not been driven.  (You can see the video in my build section).  So I set off on short little trips of 3 minutes or so and discovered the radiator was shot.  Thinking I was 'there' I put in a new ally radiator and new screw in type water temp plug. 

 

Car started up and idled normally.  I then noticed the fuel guage wasn't working.  Drained the petrol down and cleaned and rewired the fuel guage and it now works, not 100 percent accurate but a start for now.  Then I started to take the car for longer test drives. 5 minutes or so.  Was running well and then started to lose idle (just like when the lambda sensor dies). 

 

As these things take place one day after another, I took it for another test drive and it was running super rough, came back and started to work on getting  a smooth idle again (I am thinking I really should keep detailed notes of what has happened I think it would help alot)

 

Final test went like this - starts and runs perfectly at 1100 rpm for 5 seconds and then dies.  Repeatedly

 

I then swapped the throttle body (and the car I swapped to (not the one we are talking about now) now idles sweetly but the idle has dropped from 1100 rpm to 950rpm but works

 

My car now starts, sounds very rough, some popping sounds from the throttle body area,  and then revs itself bananas to about 5000 rpm and dies.  Repeatedly.  I cannot test anymore as I think my neighbours have all had enough, missus included

 

Now at the throw in the towel stage.  Everything seemed to be looking good and has since the first couple of days then gone totally down hill.  May try to pick up the famous ecu reader but haven't got the funds really. 

Thanks for following. 

[ryomini]

OOOOOOOOOFFFF

 

halfway almost to the end

2 problems at once

the throttle body with the TPS sensor and the stepper motor I believe was not tightened down and was sucking blowing - causing havoc

2nd the clutch pushrod seal is not sealing well in the master cylinder or there is still air in slave cylinder so the clutch was starting to slip

 

I now have steady idle at 900 rpm which seems to be linked to this particular throttle body, the idle is a little weak (maybe linked to the high lift cam too)

can I somehow get the idle up to 1100 manually or does the ECU do all this itself - the thing is with the AC unit the idle needs to be stronger rather than weaker

 

I havent touched the little screw on the throttle mechanism flatting against the stepper motor pushrod - should I try to get some more idle through there

 

anyhow I decided to spend some money on my garagist and just finish things off - it shouldn't be too hard for him to sort that out

cheers for your encouragement

[edkirk30]

For the software based ECU reader the common component is a USB to serial cable (has to be correct voltage, 5V). The SPI uses a very simple 3 wire serial connection (ground, tx and rx). In essence you need to connect these 3 wires to the USB to serial cable, with the best way being sourcing the connector used on the SPIs ECU interface... or you could be lazy/tight/impatient like me and just use crocodile clips or wire in an additional different connector (I did the later).

 

There are lots of serial cables out there but you must get one that operates both data lines at 5v not 3.3v. Just a 5V supply line is not enough. The android app homepage and the PC homepage have some further details on the cable. You can get them for between £10-30. 

 

There's a free PC app which has a nice interface and but doesn't give all the sensor readings (not that I could see anyway). There's also an Android app which has a free version and a paid version (<£10). This seems to have most or all of the sensor readings. The free version closes every 5 mins thats the only difference. Do support the developer. For the android app you'll also need an OTG connector which you can get off ebay/amazon for a few quid. Your android device also needs to support OTG (most bought with the last 3-4 years do).

 

Android homepage

http://memsdiag.blogspot.co.uk/

 

PC Based homepage

https://github.com/c...rassa/memsgauge

 

I have tried both on my SPI with great success (diagnosed faulty lambda).

Edited by edkirk30, 17 August 2016 - 11:56 AM.

[FlyingScot]

OOOOOOOOOFFFF
 
halfway almost to the end
2 problems at once
the throttle body with the TPS sensor and the stepper motor I believe was not tightened down and was sucking blowing - causing havoc
2nd the clutch pushrod seal is not sealing well in the master cylinder or there is still air in slave cylinder so the clutch was starting to slip
 
I now have steady idle at 900 rpm which seems to be linked to this particular throttle body, the idle is a little weak (maybe linked to the high lift cam too)
can I somehow get the idle up to 1100 manually or does the ECU do all this itself - the thing is with the AC unit the idle needs to be stronger rather than weaker
 
I havent touched the little screw on the throttle mechanism flatting against the stepper motor pushrod - should I try to get some more idle through there
 
anyhow I decided to spend some money on my garagist and just finish things off - it shouldn't be too hard for him to sort that out
cheers for your encouragement

Idle speed is controlled by MEMS via the stepper motor and the timing. Switching on the AC should only result in a momentary dip in revs as MEMS corrects the idle for load - in fact in this case it's probably adjusting the timing as it's quicker than adjusting the stepper and prevents a stalled motor.
Do not under any circumstances adjust the set screw - it provides the reference for the stepper to count and you need proper diagnostics to adjust.

FS

Edited by FlyingScot, 17 August 2016 - 05:10 PM.

[FlyingScot]

For the software based ECU reader the common component is a USB to serial cable (has to be correct voltage, 5V). The SPI uses a very simple 3 wire serial connection (ground, tx and rx). In essence you need to connect these 3 wires to the USB to serial cable, with the best way being sourcing the connector used on the SPIs ECU interface... or you could be lazy/tight/impatient like me and just use crocodile clips or wire in an additional different connector (I did the later).
 
There are lots of serial cables out there but you must get one that operates both data lines at 5v not 3.3v. Just a 5V supply line is not enough. The android app homepage and the PC homepage have some further details on the cable. You can get them for between £10-30. 
 
There's a free PC app which has a nice interface and but doesn't give all the sensor readings (not that I could see anyway). There's also an Android app which has a free version and a paid version (<£10). This seems to have most or all of the sensor readings. The free version closes every 5 mins thats the only difference. Do support the developer. For the android app you'll also need an OTG connector which you can get off ebay/amazon for a few quid. Your android device also needs to support OTG (most bought with the last 3-4 years do).
 
Android homepage
http://memsdiag.blogspot.co.uk/
 
PC Based homepage
https://github.com/c...rassa/memsgauge
 
I have tried both on my SPI with great success (diagnosed faulty lambda).

Interesting I must look into this, I know Colin has been working a lot on this and there is also a build interface for Laptops available but as far I have seen without all functions. The AMP connector by the way isn't readily available unless you buy it in 70 pieces - ask me how I know....

FS

Edited by FlyingScot, 17 August 2016 - 05:14 PM.

[ryomini]

FS  yes about the little screw I thought so, so thanks again, but the 900 rpm idle is too weak, it'll run 3 or 4 minutes  but then it stumbles, so annoying

 

@edkirk I am a Mac user.  I think I know what you mean about the cable - it plugs into the plastic plug in under the bonnet that has a rubber cover on it isn't that right ?

 

Sure looks interesting - very cool, nothing for Mac users I guess, any chance of a video tutorial from A to Z for your average non computer litterate mini owner ?

Edited by ryomini, 18 August 2016 - 05:03 AM.

[edkirk30]

FS  yes about the little screw I thought so, so thanks again, but the 900 rpm idle is too weak, it'll run 3 or 4 minutes  but then it stumbles, so annoying

 

@edkirk I am a Mac user.  I think I know what you mean about the cable - it plugs into the plastic plug in under the bonnet that has a rubber cover on it isn't that right ?

 

Sure looks interesting - very cool, nothing for Mac users I guess, any chance of a video tutorial from A to Z for your average non computer litterate mini owner ?

 

In theory the PC app should compile on a mac but I couldn't get it to in the time I had. The android version is probably your best bet, you can get some super cheap android tablets, you just need to check they support OTG.

 

There's two connectors, one is for the alarm and one for the ecu. I wana say the ECU is the green one, but you might want to check that. It's the white one as mentioned later.

 

I'll try and do a video this weekend. You can pm me if you don't hear from me.

Edited by edkirk30, 19 August 2016 - 07:29 AM.

[AgentHubcap]

pscan works on macs.  I've been considering one of these since I'm also on a mac.

 

http://www.pscan.eu/index.html

[edkirk30]

Thats pretty expensive though. You can buy an android tablet for £50... but you would hope the commercial product is better.

 

The hardware probably costs pennies and the rest is for the software.