60 replies to this topic

[AgentHubcap]

I took two videos today to try and capture the hesitation.  You can hear it more than the video shows.  The engine sound changes dramatically when it is hesitating.  I'm not sure how to describe it, but it feels like the car is stuttering.

 

https://goo.gl/photo...WVc6y7BXDwVwZB9

 

Over the Christmas break I plan to do new plugs, coolant temp sensor, intake temp sensor and o2 sensor.   Any other suggestions?

[firstforward]

Check the operation of the manifold heater, try removing the wire to see if there is any difference in driveability. Make sure the relay is feeding it power.

 

All the items you have mentioned are serviceable items anyway, I change them every 60K anyway.

[FlyingScot]

Good shout above, the PTC comes on when cold to help atomise the fuel.
Also check the power feed to the lambda sensor, it's heated too and if not the reading going back to the ECU could be out.
Time to break out the multimeter in the absence of a diagnostic code reader.

FS

[Alpenflitzer]

I recommend to carefully do one replacement and check engine.

No change= go to the second change and check engine

and so on.

It is hard to hear from the video but to me the injection unit and/or the controle is out of line.

 

On the other hand it sounds like the CTS is informing the ECU " cooling water temperature is going up and down". But then the car would idle 1200 (when cold) or 850 Rpm (when warm). So the Rpms would move between these values. Did you check if the cables of the CTS are ok?

 

That is why I assume that the mistake is with the injection unit. .

 

checklist:

 

- False air caused by vac pipes.
- False air caused by not correctly fixed vac hoses 
- Accelerator cable wrongly adjusted
- Stepper is not correctly controlled by ECU
- Stepper defect

- CTS and/or cable defect

 

I added a paper with some remarks from other SPI drivers which have had similar problems

 

 Idling up and down.doc   27K   11 downloads

 

 

Found another hint in an English Magazine:

 

RESETTING THE ECU

you reset the ECU every time you turn it on - it's why you cant reprogram the MEMS ECU

pressing the accelerator 10 times, with ignition at position 2 , recalibrates the TPS for the ECU, as they wear over time, and can give false information to the ECU - the usual "boost" in power that most people discover, is because their injection system is now actually working properly :wink:

TPS = throttle position sensor; a variable resistor that's fitted to the butterfly so the ECU can know how far your foot is to the floor

 

Edited by Alpenflitzer, 18 December 2015 - 07:09 PM.

[Alpenflitzer]

uote>

Starts perfectly, idles fine at about 1500 (cold) then about 850 hot.
It's just if you want to jump in and take off straight away when its cold. It actually feels like its too lean, no back fire or hessitation, just gets slower and slower till you are actually at about 900-1000 rpm. If you just use about 1/4 throttle it'll limp along for about 1/2 kilometer then cruise away fine. I've tried nearly everything, plugs, cap,rotor,leads, pump,filter, temp sender, throttle body o/h. All the tiny hoses are brand new and on right, even a new wiring harness. Only thing else could be is ECU but I have just got used to it.
Gunna spend some money on it in about six months, do the motor and a 5 speed box, might ping the injection off and fit carbs.

By the way 1500 Rpm is too high when cold. Should be about 1200 RPm. Can only be corrected with Microcheck.

[FlyingScot]

I recommend to carefully do one replacement and check engine.
No change= go to the second change and check engine
and so on.
It is hard to hear from the video but to me the injection unit and/or the controle is out of line.
 
On the other hand it sounds like the CTS is informing the ECU " cooling water temperature is going up and down". But then the car would idle 1200 (when cold) or 850 Rpm (when warm). So the Rpms would move between these values. Did you check if the cables of the CTS are ok?
 
That is why I assume that the mistake is with the injection unit. .
 
checklist:
 
- False air caused by vac pipes.
- False air caused by not correctly fixed vac hoses 
- Accelerator cable wrongly adjusted
- Stepper is not correctly controlled by ECU
- Stepper defect
- CTS and/or cable defect
 
I added a paper with some remarks from other SPI drivers which have had similar problems
 
Idling up and down.doc
 
 
Found another hint in an English Magazine:
 
RESETTING THE ECU
you reset the ECU every time you turn it on - it's why you cant reprogram the MEMS ECU
pressing the accelerator 10 times, with ignition at position 2 , recalibrates the TPS for the ECU, as they wear over time, and can give false information to the ECU - the usual "boost" in power that most people discover, is because their injection system is now actually working properly :wink:
TPS = throttle position sensor; a variable resistor that's fitted to the butterfly so the ECU can know how far your foot is to the floor

This is an urban myth, you can only reset the ECU by using testbook, microcheck or the Crypton ACT system. You won't find what you have quoted documented anywhere officially; why because Rover dealers had the factory tools and it's not true......

The MEMS ECU isn't programmable because the electronics don't allow it in car it can be programmed at the bench frame level.

The long and short is as Bill says without diagnostics you must go step by step remembering that the main issues are wiring (like all minis) vacuum pipes then the sensors.

FS

[Alpenflitzer]

Here some pictures in annex which may help to better understand. As this is out of my collections please forget about "nice style":

 

 

and here some explanations and sketches of the sensor system :     SENSORs SPI 93.doc   657K   20 downloads

Foto stepper motor                                                                            stepper motor.doc   522.59K   12 downloads

ECU control the pins if they are corroded and the cables                  Rover MEMS-Stecker.doc   210.5K   14 downloads

Edited by Alpenflitzer, 19 December 2015 - 10:33 AM.

[AgentHubcap]

I'm confused now.  I was under the impression that the CTS was on the intake manifold, but the sensor diagram shows it is under the airbox.

[Steve220]

On the SPI it's under the intake manifold. Pain in the rear to get to as well.

Edited by Steve220, 21 December 2015 - 08:07 AM.

[AgentHubcap]

I pulled the intake manifold last night to replace the oxygen sensor and coolant temp sensor.  You guys weren't kidding about that being a pain!  

 

I had to disconnect the fuel lines to get the manifold out, and after reassembly the car is not starting.  I shouldn't need to do anything to prime, should I?

[FlyingScot]

No priming needed, it should prime on position 2 of the ignition. I would turn to II wait until buzzing stops, turn off wait a few seconds and turn onto II again. Then try it.

Make sure you haven't snagged the fuel cutoff switch (press centre to reset) or the wiring to the injector.

FS

[AgentHubcap]

Took everything apart again, and put it back together.  Turns out I'd swapped the wires going to the coolant temp sensor with the one on the injector.  Good news is that it runs, bad news is that it runs like crap.  It is missing and backfiring pretty badly now.

 

Here's a video.  I just blip the throttle and it stayed up for a while.

https://goo.gl/photo...oR7UAfPm1k5PfX7

Edited by AgentHubcap, 24 December 2015 - 01:41 AM.

[AgentHubcap]

could a kinked fuel return line cause this?  Somehow I managed to kink it, but not to the point of cutting off flow completely.

[Blatherskite]

Check the operation of the manifold heater, try removing the wire to see if there is any difference in driveability. Make sure the relay is feeding it power.
 
All the items you have mentioned are serviceable items anyway, I change them every 60K anyway.

Our PTC never worked due to melted wires, and even at -20 in Norwegian winter, we never noticed any hesitation or lack of enthusiasm.

[Alpenflitzer]

SENDING ENCLOSED A PAPER WHICH YOU COULD CHECK AND WHICH MAYBE HELPS.

Are you sure that the vac. pipes are correctly sitting on the back of the intake manifold?  Fehlzündungen.doc   1.27MB   7 downloads