Discussion
My 97 Chim 400 engine is free revving and when moving is very smooth. When in neutral and I rev to 4000rpm and then remove the throttle, the rev counter reduces to around 2000rpm, settles there for about 1 second, then falls again to about 700rpm and rises promptly to 1200rpm before settling at 900rpm. Obviously in traffic this produces kangarooing and is a pain to drive smoothly.
It always used to be really smooth in traffic. It might be worth mentioning that on occasion the idle continues to hunt but this isn't very often.
Also driving to work today the coolant temp didn't reach 70degress. At speeds of over 60mph the engine doesn't get a change to warm up. Is this normal?
It always used to be really smooth in traffic. It might be worth mentioning that on occasion the idle continues to hunt but this isn't very often.
Also driving to work today the coolant temp didn't reach 70degress. At speeds of over 60mph the engine doesn't get a change to warm up. Is this normal?
Sounds the same as my 400. It's always done this. Just been service and no problems detected.
Engine is very smooth and drives perfectly. Stepper motor also cleaned frequently. Never thought it was a problem.
Only thing mine does suffer from is it occassionally lets the revs drop too much when coming to a stop a junctions. Not when cold, and not when fully warmed up, just a period of about 10 minutes when the engine is warming up, starting about 2 minutes after the engine is fired up.
Strange.
Engine is very smooth and drives perfectly. Stepper motor also cleaned frequently. Never thought it was a problem.
Only thing mine does suffer from is it occassionally lets the revs drop too much when coming to a stop a junctions. Not when cold, and not when fully warmed up, just a period of about 10 minutes when the engine is warming up, starting about 2 minutes after the engine is fired up.
Strange.
Mine was doing something similar - surging at idle speeds would never settle down to an even idle, nightmare a very low speeds or when in traffic. Turned out the HT leads were breaking down. Replaced with Magnecors and a Bosch Coil and shes smooth as a smooth thing from smooth town.
Problem was worse at op temp, I guess the leads were breaking down when heated ...
>> Edited by bigdods on Monday 14th November 18:27
Problem was worse at op temp, I guess the leads were breaking down when heated ...
>> Edited by bigdods on Monday 14th November 18:27
meeko said:
I might treat the Chim to a new set of leads and coil in hope that it will cure the probs. On a different note, is it possible to test the stepper motor?
In my experience you won't ever cure it. You'll probably make it better for a while.
All mine seemed to drive differently most days! (e.g. not idle at all, idle high revs, surge & mostly just lumpy)
Just adapt your driving style to match!
You'll be asking about how to make the hand brake work next
Thanks for the advice. The annoying thing is I've had the car about 16 months and for the first 14 it drove sooo much better. When it heats right up it starts to hunt and actually stalls now if you don't catch it. Can broken down HT leads/coil cause this? Would've thought it was more on the lines of a stepper motor? Any thoughts before I splash out on something that may be perfectly OK?
Meeko, have you tried cleaning the stepper motor (or even looking at it)
It's a really easy job and well worth the few minutes it takes. the steve heath bible has information but the best source of information is the south wales tvr car club
stepper motor
I did it last month - then had a minor panic as it didn't start straight away but all was fine it just wanted a couple of tries.
if you've got a big adjustable spanner (I had to use a plumber wrentch carefully) ten minutes then it's easy and sorted out my idling problem completly
hope this helps
It's a really easy job and well worth the few minutes it takes. the steve heath bible has information but the best source of information is the south wales tvr car club
stepper motor
I did it last month - then had a minor panic as it didn't start straight away but all was fine it just wanted a couple of tries.
if you've got a big adjustable spanner (I had to use a plumber wrentch carefully) ten minutes then it's easy and sorted out my idling problem completly
hope this helps
Hi Meeko,
It would also be worth checking your throttle pot and Air Flow Meter voltages.
My Griff was behaving similar, I ended up buying a new stepper which cured the problem for a while but then it came back. I checked the throttle pot and the voltage was way out (had to file the hole on the pot to set it correctly) and I checked the AFM which was also out. After setting these it has been fine for the last couple of months and running as sweet as it ever has!!!
Settings and instructions are on RPIs web site:
www.rpiv8.com/carbs-2.htm#setting-up
Select setting Air massflow meter and throttle pot.
Hope you get it sorted!!
Lig.
It would also be worth checking your throttle pot and Air Flow Meter voltages.
My Griff was behaving similar, I ended up buying a new stepper which cured the problem for a while but then it came back. I checked the throttle pot and the voltage was way out (had to file the hole on the pot to set it correctly) and I checked the AFM which was also out. After setting these it has been fine for the last couple of months and running as sweet as it ever has!!!
Settings and instructions are on RPIs web site:
www.rpiv8.com/carbs-2.htm#setting-up
Select setting Air massflow meter and throttle pot.
Hope you get it sorted!!
Lig.
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