My Rev Counter Is Being Silly.

[twinkle]

i got a problem on my galaxy, its a 2L glx mk1.

 

what happens is, if i rev the car either at a stand still or driving above 3k RPM, the needle will fall to about 500rpm and then pick itself back up to 900rpm this ican live with as it dont stall.

 

but whats more worrying, is when driving and i change down gears etc. the need will drop again to 500rmp, but them just die and drop to 0rpm. but heres the strange thing, the engine doesn`t stall, its almost like the electrics are cut from the rev counter.

 

any ideas???

[Andrew T]

Idle stability valve? Do a search, it comes up from time to time - seems especially commmon on early Petrol models.

[greg_68]

Could be wrong (nothing different there)

 

When I changed my alternator the "expert" in the shop said the little plug that plugs in to the altenator is the rev counter.

 

Maybe worth looking at it's connection for the time it takes.

[Andrew T]

Sorry, I misread your post. If the engine is not misbehaving then Gregs theory seems likely.

[twinkle]

Could be wrong (nothing different there)

 

When I changed my alternator the "expert" in the shop said the little plug that plugs in to the altenator is the rev counter.

 

Maybe worth looking at it's connection for the time it takes.

 

cool. will have a look at that, cheers.

 

Sorry, I misread your post. If the engine is not misbehaving then Gregs theory seems likely.

 

no probs :D

 

the only misbehaving it does, is that the revs drop to 500 rpm between gear changes or when i rev it up. but it doesn`t stall, the ecu picks the revs back up quite quickly.

[Vanbursta]

How long have you had the car, and was it doing it when you got it?

[twinkle]

How long have you had the car, and was it doing it when you got it?

 

i have had the car for 3 weeks now, and yer it was doing it when i got it, but as it didn`t affect they way it drove, i thought nothing of it. but its starting to bug me know :rolleyes:

[Guest HairyPlateEater]

the only misbehaving it does, is that the revs drop to 500 rpm between gear changes or when i rev it up. but it doesn`t stall, the ecu picks the revs back up quite quickly.

 

Could be a MAF problem or possible hole/split in the air intake pipes after the MAF sensor housing. Had the same problem on a Volvo 855 which turned out to be a small split in the air intake pipe (found it after replacing the MAF!!).

[Vanbursta]

Heres your answer:-

 

Tacho_fluctuates.pdf

[greg_68]

Heres your answer:-

 

Tacho_fluctuates.pdf

 

I think that TSB is for only when the engine is not running.

 

OP's issue is when the engine is running.

[Guest 3.5bullet]

Idle stability valve?

 

 

would have to agree :o first place to look is the ISV, remove it and clean it, and while your there check the condition of all the intake hoses :o

[twinkle]

the only misbehaving it does, is that the revs drop to 500 rpm between gear changes or when i rev it up. but it doesn`t stall, the ecu picks the revs back up quite quickly.

 

Could be a MAF problem or possible hole/split in the air intake pipes after the MAF sensor housing. Had the same problem on a Volvo 855 which turned out to be a small split in the air intake pipe (found it after replacing the MAF!!).

[twinkle]

well had a look tonight, and i have a hole in the hose from the maf to throttle body, so hopefully this is giving me my problems

[twinkle]

Well had it all apart at the weekend, took the suspect hose off, and the big chunk that was taken out of it, had not gone right through, so its not leaking.

 

so im back to square one now.

 

i had a look at the alternator, but cant see this plug your on about. And looked at the I.C.V. but how the hell do you get it off??? any tips??

[Guest midwife32]

Hiya,

 

I've been having the exact same problem but as its been doing it for a while (since I bought it) its now started stalling when coming to a stop. It was also chuffing clouds of blue smoke out the back so my brother (a mechanic) stripped it down and did the head gasket, valve stem oil seals etc. However, its still stalling at some junctions :25: :P

 

Any ideas??

 

Lisaxx