Rough Running! CURED!!!

[dalecrx]

Hi,

I have had a real problem with my tvr over the last few months. It used to always misfire below 2000rpm and Kangaroo if at 30mph in 4th or fifth gear.

I tried new leads, new spark plugs, checked and tested all sensors refering to the bible.

I was getting no where fast, i spent alot of time reading Steve Heaths Bible and paid partciular attention to the Coolant Temp Sensor, which is a sensor which checks the temperature of the coolant around the engine and sends the info back to the ecu. I checked this sensor using a ohm tester, as described in the bible and it looked as though it was ok, but it is hard to get a true reading comparing it to the temp of the engine. As it states in the bible if there is any problem with the fuelling, this sensor is normally changed straight away, as it normally cures most faults.

I bought this sensor from my local motor factors in farnborough "Whoppe Motor Factors" part no SNB802, this is a Lucas Part. This sensor only cost £13.

After changing this sensor i thought i would take the chimaera out for a spin, thinking that it wouldnt make the slightest bit of difference. Well the change was amazing, no more misfiring, no more kangarooing, nice smooth running and it pulled so much better at low revs.

This sensor did not come up on any test equipment saying it was faulty or out of range when tested at a TVR garage.

I strongly recommend if anyone is having rough running, or idling problems or not being able to drive at 30mph or 40mph in 4th or 5th without kangarooing and shunting the transmission everytime, to change this sensor.

Cause this sensor was not fuctioning correctly it was causing over fuelling and rough running.

I can now enjoy driving my Chimaera every day!!!!

Cheers

Dale

[shpub]

Glad the bible helped. It makes the grief I got for setting up a temp sensor electrical lab up in the kitchen all worth while!

>> Edited by shpub on Monday 29th March 14:58

[M@H]

shpub said:

Glad the bible helped. It makes the grief I got for setting up a temp sensor electrical lab up in the kitchen all worth while! >> Edited by shpub on Monday 29th March 14:58

I wish I could have seen that..

[zzr1200]

I'll have to try the same before I go for a unichip.

Paul

[morgala]

dale, was the sensor easy to replace?

My chim is driving like a right slag, doesn't misfire but it definetly chuggs and feels rough as.

[dalecrx]

It took me at leat 2 minutes..

Use a 19mm spanner, it is located in front of the plenum chamber just under the pipe going to the swirlpot from the engine. it has a white connector or maybe black depending on year of chimaera.

It is well worth changing!!!!

It takes no time at all.

[morgala]

excellent, £11.54 from camberley auto factors.

"what car is it for, sir?"
"TVR"
"hmm, i don't know about that, not sure.."
"Doesn't matter, can I order it?"

[cptsideways]

It would'nt be blue & Bosch would it?

If so it's a common fault on Bosvh K-Jetronic cars too, engine thinks its always cold, so runs rich all the time

[dalecrx]

Its a Lucas part SNB802,

but youre exactly right!! as i used to beable to smell the petrol after starting up mine, it used to run rich very rich!!!

There is also another one of these sensors in the fuel injection rail, im tempted to replace this one too, but i will take it out and test it first.

[kippax]

Hi Dale what year & engine size is your car or is this part universal?
I have a 4.3 Chim that sometimes is a little rough at low revs so need to change down a gear thought it was a trait of the car maybe not?
I'll dig out the bible to see how to change it?

Thanks
Howard

[cosmoschick]

dalecrx said:

I strongly recommend if anyone is having rough running, or idling problems or not being able to drive at 30mph or 40mph in 4th or 5th without kangarooing and shunting the transmission everytime, to change this sensor.

I posted with this problem a few months ago except the 'kangarooing' tends to be more apparent at slightly lower speeds/revs, ie, under 30mph in 3rd and even 2nd (around town etc). IIRC 40mph in 4th is ok altho' I might have to take the Chim out tomorrow to check again especially if the weather is like today's! However, your recommendation is definitely worth a try.

[shpub]

kippax said:

Hi Dale what year & engine size is your car or is this part universal? I have a 4.3 Chim that sometimes is a little rough at low revs so need to change down a gear thought it was a trait of the car maybe not? I'll dig out the bible to see how to change it? Thanks Howard

I always find it surprising that owners expect to be able to drive at 30 mph in fifth when that translates at an engine speed of virtualy idle revs. Some cars are worse than others and in some cases the temp sensor or any one of the other parts in the system is at fault. In most cases the engine just simply does not like idling in fifth gear and actually changing down a gear makes life a lot easier. It also makes keeping below 30 a lot easier. If the car isn't happy in these conditions it may simply be a characteristic of the engine. The 500s are particularly bad at this BTW.

The details of how to remove the sensor is in the bible. Nothing really to it providing you have a deep socket which is a lot easier than trying to get a spanner in.

[dalecrx]

I have a 94 L reg TVR Chimaera 4.0 HC

Im almost 100% sure this part will cover all the chimaeras?

For the matter of £12 - £13 and its so easy to change too!!

Let me know if it cures any of oyur idling or kangarooing??

Dale

[SiH]

Heheheh, just reading shpub's post has made me chuckle 'cos every time I go for a blast and come to a little village with empty roads and a 30 limit I usually just stick it in 5th and let it trundle along at idle speed. It works out at pretty much 30mph exactly. A bit of a TVR cruise control

[MikeGF]

Dale - I think I might need your help doing this to mine....

[DustyC]

shpub said:

Glad the bible helped. It makes the grief I got for setting up a temp sensor electrical lab up in the kitchen all worth while! >> Edited by shpub on Monday 29th March 14:58

I suppose a new kettle was needed afterwards too!

[dalecrx]

I can do Mike, let me know if you need any help at all. I can get the part for you if you want as my friend works at Whoppee Motor Factors.

Dale

[morgala]

dalecrx said:

It took me at leat 2 minutes.. Use a 19mm spanner, it is located in front of the plenum chamber just under the pipe going to the swirlpot from the engine. it has a white connector or maybe black depending on year of chimaera. It is well worth changing!!!! It takes no time at all.

having ordered the part I decided to read the bible last night just to check on the installation process. It says there is no room for a spanner, it's tough to get off and a deep socket thingy should be used. Did you use a magic spanner

[morgala]

shpub said:

The details of how to remove the sensor is in the bible. Nothing really to it providing you have a deep socket which is a lot easier than trying to get a spanner in.

fair enough

[dalecrx]

I didnt have a deep 19mm socket, so i just used a 19mm spanner, which did the job very easily.

My Chimaera does not have PAS, or Air Con, so there is more room to get to the sensor. Now i have smooth !!

Dale