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620ti - engine dying

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2.6K views 9 replies 7 participants last post by  E_T_V  
#1 ·
Hi,

To start off -- I'm quite happy owner of 620ti (1998) owner from CZ (and since English is not my native language, please excuse the lack of technical terms on my part).

I've got a problem -- couple months ago the engine in my car started dying when in "free wheel" (no gear in place).

I was told it's a Throttle problem ... so I bought MHB101770 from Burlen, replaced the old Throttle ... and hoped for the best.

Unfortunately, the problem is still present. :-/

I finally found someone with testbook compatible enough to talk with my car (bigger problem in CZ than you would imagine). There were two errors:

1) air pressure sensor failure
2) unknown error

(three, actually ... but the one showed just intermittently: air temperature sensor failure)

I was told to get the new air pressure sensor ... and to check all air tubes for possible leaks (air leaking in).

Please, could you advise me where to find part number (and/or location) of that air pressure sensor (to check for part number) and where to buy it?

I could go to some car parts shop in CZ, but they tend to overcharge for "exotic" parts (sometimes in 100s of percents). :-(

Also, if there's another possible explanation for this problem than malfunctioning sensor, I'm all ears ... as I have little experience with car repairs.

Btw, is there some sort of guide/website I can look into to find replacement parts (and their part numbers)? I think I'll need other parts (rear part of exhaustion, ...) in forseeable future.

Kind regards,
-- M.
 
#2 ·
Welcome,

Nice to hear from a European Rover 600ti owner!
Your English is good, don't worry,
So the engine dies when you go into netural to stop?
What RPM does it tick over at, theres a adjuster screw to change the tick over RPM but this may higher your revs too much.

I think the air sensor is on the inlet manifold, im sure they are the same on many Rovers, you could try looking for one on www.eBay.co.uk ?
A sensor is a pretty standard part so they may be the same on other brands on car?
 
#3 ·
Hi MetroMartin,

Well, my English's acceptable ... but when it comes to car parts and the like, I'm lost. :)

Yes, the engine dies when on neutral.

As for the RPM -- when it's falling down from normal range (2000-3000), it stays at about 1200 for a bit, then it sloowly continues down to 800 in a floating fashion, but as soon as it trips down to approx. 800, it starts to shut down - it jumps to approx. 500 and then it dies most of the time. Sometimes it doesn't -- and it goes back up to (approx.) 1200 and the cycle repeats. As if it was unable to stabilise below certain point.

As for the adjuster screw -- the guy with testbook told me that the throttle (based on the readings) is properly setup and there's no point in tinkering with it.

The strange thing is that when the engine approaches lower RPM (800 and under), pressure reading goes from the normal range (30-50, IIRC) up to 90-99 kPa. Last reading when it shuts down is almost always 99.

Btw, could you please tell me under which search term(s) I should search for the sensor? I already looked at ebay without much luck. Will try the part number after I locate the sensor, but still. ;)
 
#4 ·
The air pressure sensor which is being referred to is the MAP sensor (Manifold Air Pressure). This sensor is inside the ECU.

One common fault is that the small air line connecting the two gets blocked/contaminated with oil. Often cleaning this air line out can help. Also try removing the ECU and leaving it with the air pipe downward to drain out oil overnight in a warm place. (you will need to place rags underneath it to mop up the oil!).

If the MAP sensor is broken then it can be replaced if you are good with a soldering iron. It is a bosch item so you may be able to find one local to you from another car, or another type of turbocharged car.

The air temperature sensor is located in the inlet manifold and rarely gives any problems.

Also check that the dump valve is working correctly and that the diaphram isn't split (remove the hose from the underside of the throttle body and suck on the end of it attached to the dump valve. If you can suck air through it then the diaphram needs replacing and this can cause cutting out when approaching a junction etc.

Also check/change the coolant temperature sensor as they are a very common fault on this engine, which causes poor cold starting, cutting out whilst warming up and a high idle speed when warm.

I hope this gives you some ideas of things to check
 
#9 ·
If the MAP sensor is broken then it can be replaced if you are good with a soldering iron. It is a bosch item so you may be able to find one local to you from another car, or another type of turbocharged car.
Any suggestion about the MAP sensor? I mean, from which car can i use the MAP sensor (apart from cut a 620 one from the ecu). Can i use externally a lets say 3 bar MAP?
 
#5 ·
Hi,

I own a Rover 600 ti, and had similar problem, engine was dying on idle. Finally we have find out that the generator was not charcing the car a normal way. After driving the car with lights etc on, battery was running flat and due to irregular charging the engine was stopping...

I would propose to have the charging checked once before changing any parts..
Good luck..
 
#6 ·