17 replies to this topic

[Korczuch]

Hi everyone,

 

Couldn't find the answer to my question online and on the forum (Maybe I'm bad at searching) so I decided to ask.

 

I have a 1.3 SPi engine in my Mini, everything seems great except for the fact that the car will not rev. 

 

Let me go into more detail though.

 

The car was running fine, however the brake master cylinder (I think that's what you call it) needed to replaced. We did that, and suddenly the car refuses to rev, it just stutters and won't rev. We made sure we have fuel, made sure the fuel pump works and has a good flow, checked and replaced a bunch of cables we weren't confident about, and even tried getting rid of newly installed brake master cylinder to see if it was some weird electric issue, nothing helped. The car starts without an issue, idles fine, but the moment you rev it, it stutters. I suspect some electric fault but would love it if someone was able to point me in the right direction. My mechanic is by no means a Mini expert but he's been able to figure out most things on the car, until now. Any help is greatly appreciated.

 

Michał

[genpop]

Hi,

what year is it and how do you want to rev it up. Are you doing that from inside or on the carburator.Or in other words do you have the problem when you step on the gas pedal or when you accelerate manualy on the carburator? Have your mecanic look if it has a switch at the pedal linkage. If yes take of the plug and shorten it with a bridge,then try again.

[hunterg30]

Check the vacuum pipe elbows especially the two at the back of the manifold

[Korczuch]

Hi,

what year is it and how do you want to rev it up. Are you doing that from inside or on the carburator.Or in other words do you have the problem when you step on the gas pedal or when you accelerate manualy on the carburator? Have your mecanic look if it has a switch at the pedal linkage. If yes take of the plug and shorten it with a bridge,then try again.

Hey,

 

So in the papers the car is a 1981, and has a 1.0.... The engine was swapped by the previous owner, so not sure the year will help here. Issue occurs both from the carb and when pressing the pedal, so that's not the issue, I don't think. I might be totally off but I'm putting my money on some electrics, I know that's my mechanics weakest point, and I think they checked everything mechanical, I'm just not sure where to even look at the electricals, and honestly not sure that's gonna be the issue 100%

[Korczuch]

Check the vacuum pipe elbows especially the two at the back of the manifold

Thanks for the tip, I'll ask my mechanic to have a look and see what's up, I'll keep the thread updated.

[RooBoonix]

 

Hi,

what year is it and how do you want to rev it up. Are you doing that from inside or on the carburator.Or in other words do you have the problem when you step on the gas pedal or when you accelerate manualy on the carburator? Have your mecanic look if it has a switch at the pedal linkage. If yes take of the plug and shorten it with a bridge,then try again.

Hey,

 

So in the papers the car is a 1981, and has a 1.0.... The engine was swapped by the previous owner, so not sure the year will help here. Issue occurs both from the carb and when pressing the pedal, so that's not the issue, I don't think. I might be totally off but I'm putting my money on some electrics, I know that's my mechanics weakest point, and I think they checked everything mechanical, I'm just not sure where to even look at the electricals, and honestly not sure that's gonna be the issue 100%

 

 

so is it a carb engine or SPi engine? You say SPi in first post but carb in the quoted post

[Korczuch]

 

 

Hi,

what year is it and how do you want to rev it up. Are you doing that from inside or on the carburator.Or in other words do you have the problem when you step on the gas pedal or when you accelerate manualy on the carburator? Have your mecanic look if it has a switch at the pedal linkage. If yes take of the plug and shorten it with a bridge,then try again.

Hey,

 

So in the papers the car is a 1981, and has a 1.0.... The engine was swapped by the previous owner, so not sure the year will help here. Issue occurs both from the carb and when pressing the pedal, so that's not the issue, I don't think. I might be totally off but I'm putting my money on some electrics, I know that's my mechanics weakest point, and I think they checked everything mechanical, I'm just not sure where to even look at the electricals, and honestly not sure that's gonna be the issue 100%

 

 

so is it a carb engine or SPi engine? You say SPi in first post but carb in the quoted post

 

Might have gotten confused with the words, I generally write all of this in Polish not English. Here is an old (but relevant) pic, might help

https://ibb.co/iwmK3A

 

Edit: The right picture https://ibb.co/dhoMGV

 

Edit 2: Also I've basically got no clue what I'm actually talking about for the most part, just trying to communicate what the person that actually knows how to deal with an engine tells me and you guys.

Edited by Korczuch, 23 October 2018 - 05:29 PM.

[Korczuch]

To maybe try and explain it better, it's an SPi engine, and maybe I'm calling it a carb incorrectly because it technically no longer acts as a carb, I'm basing it off of a "parts map" I was given where it's referred to as a carb. I'm not sure what to call it as I guess it's still the remains of a carb, just has been converted? If someone can actually try and explain that aswell I'd be grateful.

[RooBoonix]

The SPi uses an injector to inject fuel in measurable amounts, the actual amount injected is controlled by the ECU sending a "pulse" which controls how long the injector open/spraying for. The ECU works out engine load and therefore fuel requirements through the throttles position and the manifold vacuum. The mixture is determined through the lambda sensor in the exhaust and the ECU tweaks the fuel slightly to get the correct mixture at all times.

 

In your case I would be checking all vacuum hoses from the air cleaner to the throttle body, fuel trap and ECU and also the large vacuum hose to the brake servo. I'd also want to check fuel pressure, as it may be a clogged fuel filter or faulty fuel pump.

 

Hope that helps

Cam.

[Korczuch]

The SPi uses an injector to inject fuel in measurable amounts, the actual amount injected is controlled by the ECU sending a "pulse" which controls how long the injector open/spraying for. The ECU works out engine load and therefore fuel requirements through the throttles position and the manifold vacuum. The mixture is determined through the lambda sensor in the exhaust and the ECU tweaks the fuel slightly to get the correct mixture at all times.

 

In your case I would be checking all vacuum hoses from the air cleaner to the throttle body, fuel trap and ECU and also the large vacuum hose to the brake servo. I'd also want to check fuel pressure, as it may be a clogged fuel filter or faulty fuel pump.

 

Hope that helps

Cam.

Thanks Cam,

 

Vacuum hoses have been checked about 3 times now, doesn't seem to be an issue. The fuel pump was also checked quite thoroughly as we thought that's the issue, but it seems to be working fine and delivering sufficient pressure, I really do believe it's fine considering that this morning the car started up normally, and drove normally, after 3 weeks it just fixed itself. However I can imagine the problem will come back and would REALLY love to find out the issue so if anyone has any other idea I'd appreciate it.

[genpop]

When it is a 91 then it has the switch at the gaspedal.Have a look to find it. Flood the switch with Mo or wd40. If it is coroded inside it sometimes does not work and engine will only idle.

[Bat]

Hi,

Does it have a brake servo?

Did you fit a new seal on the master cylinder before fitting it back onto the servo?

Cheers 

[genpop]

@ Bat

This was his problem:

The car was running fine, however the brake master cylinder (I think that's what you call it) needed to replaced. We did that, and suddenly the car refuses to rev, it just stutters and won't rev.

[viz139]

The papers for the car may be 1981 998cc but the pictures clearly show a '92 -'94 SPi that appears to have been lying under a tree for a long time. How long is it since it last ran fine?

[Korczuch]

The papers for the car may be 1981 998cc but the pictures clearly show a '92 -'94 SPi that appears to have been lying under a tree for a long time. How long is it since it last ran fine?

Ran fine about 2-3 weeks ago, was fine, some things were fixed and now I'm having this issue. We've narrowed down the issue to a (or some) faulty cable(s) in the loom. We finally found an electrician that is willing to spend some time on the car and try and help us out so, fingers crossed, we'll find the fault and get rid of it. The picture of the engine is really old, car has been clean and running fine for a year.

 

 

Hi,

Does it have a brake servo?

Did you fit a new seal on the master cylinder before fitting it back onto the servo?

Cheers 

Not sure the actual brake master cylinder has much to do with it, we even tried putting the old one on and the issues persisted, I'm guessing that it's another old part that has reached the end of it's life time (like so many parts have). As I said above, we think it's some wiring that's faulty and causing this issue, car is dropped off at an electrician who will have a good look, and hopefully find the issue finally.

 

To add more, the car seems to work find when the loom was loose, so when they were testing it around the garage it was fine, as soon as they attached the loom properly to go out on a longer drive the car worked on and off, would run fine for a bit, stutter, go back to working fine again.