350i running as if choke stuck on, can anyone help tvr virgi
Discussion
hi, just bought my first TVR, a 350i on a F reg. all was going well until i started it from cold ran it for about 30 seconds then turned it off (needed keys to lock garage), started it back up again and drove off. it seemed to run rough at first, but i just put this down to not liking the cold, once the she had warmed up though and i tried to accelerate it coughed and splutted and became very jerky at low speeds, my friend was following me and said that when ever i tried giving it any throttle it spat out black soot and smoke, it felt almost as if the choke was stuck on and when i accelerated it felt like it was not getting the right mixture. this went on for about 15-20 miles, i stopped a few times checking for anything lose or obvious and tried stopping and starting the engine a few times but no joy. i took it on to the motorway and it seemed to plod along at about 75 but then start to lose power, when ever i tried to accelerate it just made it worse, i decided to pull off the motorway and as i came down the slip road and backed off there was a bit of a backfire and the car regained power and drove on fine for another 30 miles with no problems, although it semms to idle at just on or slighty over 1000rpm. if anyone has any ideas or suggestions i would be most grateful for any help. (only happened today and once i got back i took it out for a couple of short runs, stopped and started it a few times and no problems). many thanks alex
Hi - your problem could be linked to a few things. Start off with the basics - check your plugs and see what their condition is. If they are sooted then your mixture is too rich hence the black smoke.
Check your HT Leads and see if they are in good condition one or more leads may be disconnected or in a bad way.
I would also look at your timing. Start the car and run until warm then stamp on the throttle - if the engine cuts out - you may have a timing problem which is easily sorted by advancing or retarding the distributor at small increments.
Check the throttle pot on the side of the plenum make sure its seated tightly.
I would also start the car and turn the idle screw on the plenum inwards until the engine begins to die then out again to a decent idle 800-1000 revs if the timing is ok. Switch off the engine and restart it should idle ok if not check the airflow meter's adjustment.
I would also try disconnecting the cold start injector and restarting - you may have a faulty thermotime sensor causing an overfuelling problem.
However despite my input, don't despair - there are many threads on here that will give more ideas - there are some guys some with better engine knowledge than me who will be able to be a little more precise but hopefully you have somewhere to start...
Hope you get it sussed
Check your HT Leads and see if they are in good condition one or more leads may be disconnected or in a bad way.
I would also look at your timing. Start the car and run until warm then stamp on the throttle - if the engine cuts out - you may have a timing problem which is easily sorted by advancing or retarding the distributor at small increments.
Check the throttle pot on the side of the plenum make sure its seated tightly.
I would also start the car and turn the idle screw on the plenum inwards until the engine begins to die then out again to a decent idle 800-1000 revs if the timing is ok. Switch off the engine and restart it should idle ok if not check the airflow meter's adjustment.
I would also try disconnecting the cold start injector and restarting - you may have a faulty thermotime sensor causing an overfuelling problem.
However despite my input, don't despair - there are many threads on here that will give more ideas - there are some guys some with better engine knowledge than me who will be able to be a little more precise but hopefully you have somewhere to start...
Hope you get it sussed
Edited by GV on Sunday 27th January 21:12
al 350i said:
this went on for about 15-20 miles, i stopped a few times checking for anything lose or obvious and tried stopping and starting the engine a few times but no joy ...... i decided to pull off the motorway and as i came down the slip road and backed off there was a bit of a backfire and the car regained power and drove on fine for another 30 miles
An intermittent faulty electrical connection to the Temp Sensor would have the effect of gross over-fuelling when open circuit returning to normal when it reconnects.when i first opened the bonnet to see what the problem was i remember seeing what looked like a tempreture sender, the rubber sheild was split and the two wires coming out had lost some of there protective sheathing, will repair and may be change sensor while i'm at it, anyone know what the going price for one is?. thanks a lot for all your help guys (something tells me this won't be my last time here)
TVRleigh_BBWR said:
Are these same for a flapper ?There are two temperature sensors at the front of the engine, one is the thermotime switch that governs the opening time of the Extra Air Valve, the other is the main temperature sensor.
There is a drawing on the rimmer bros site <http://www.rimmerbros.co.uk/v8engine/images/ld27a.gif> to help you locate the right one of the pair.
A diagnostic test is to warm the engine up to operating temperature then short out the temperature sensor connector - or do as on the wedgepages and use a 120 ohm resistor.
If the car runs well with that short then the fault is with the sensor, otherwise the fault could be in the wiring or something else.
Russ
Edited to put link to drawing.
There is a drawing on the rimmer bros site <http://www.rimmerbros.co.uk/v8engine/images/ld27a.gif> to help you locate the right one of the pair.
A diagnostic test is to warm the engine up to operating temperature then short out the temperature sensor connector - or do as on the wedgepages and use a 120 ohm resistor.
If the car runs well with that short then the fault is with the sensor, otherwise the fault could be in the wiring or something else.
Russ
Edited to put link to drawing.
Edited by TVR 3X on Tuesday 29th January 13:18
richo_i said:
TVRleigh_BBWR said:
Are these same for a flapper ?The flappers did have an extra thermoide sensor. This is very expensive.
Also the Gauge sender can change but the ECU ones are all the same.
I have had very similar behaviour with my 350i; I found two issues, maybe one of these will be of help, however as noted in other responses there are a number of issues to look at...
First, I tried a different ECU and the problem went away. I read that some times they have poor solder joints (I didn't believe it but I was desperate), I reflowed the solder and it was fine.
The other issue that was similar but not identical was caused by a failing injector resistor pack, it had moisture problem that corroded the traces on the resistive circuit board inside.
Both are easy to test if you can find some one with good parts to temporarily swap in.
It's frustrating, but once you track the issue down it should not be too expensive to fix, if you aren't lucky enough to have a failed component that you can simply swap, then it could be wiring - more painful - but still not too expensive, even if you have to pay to have it done.
First, I tried a different ECU and the problem went away. I read that some times they have poor solder joints (I didn't believe it but I was desperate), I reflowed the solder and it was fine.
The other issue that was similar but not identical was caused by a failing injector resistor pack, it had moisture problem that corroded the traces on the resistive circuit board inside.
Both are easy to test if you can find some one with good parts to temporarily swap in.
It's frustrating, but once you track the issue down it should not be too expensive to fix, if you aren't lucky enough to have a failed component that you can simply swap, then it could be wiring - more painful - but still not too expensive, even if you have to pay to have it done.
had another little look, can't do much until the weekend as it's to dark (roll on summer) have notice what i think is the throttle postion sensor was loose and the small gasket had perished, i have tightened it back up but not sure on its postition as the lugs look like they have been designed to give a certain amount of ajustment? i have order a new temp sensor from rimmer bros and gasket will fit on weekend if i get time (got an audi ur quattro that is in need of a little tlc as well)
adam quantrill said:
You need a voltmeter to set up the TPS, it's about 0.65V at idle I seem to recall.
Adam your numbers seem too high so you haven`t had this problem lately :-)?Think 320mV or 0,320V at idle and then it should go up to like 4 Volt (move the throttle by hand). This can be done without the engine running but ignition switched on. Haven`t done this myself yet (don`t fix what is ok) and seem to remember that getting a multimeter attached is not straight forward. As well as the colours on the wiring to the throttle potentio meter.....
A search on the forum can perhaps help.
Do you have a wedge bible? If not this is a good idea as well.
Rob
Steve Heath (he is shpub on here and has his own website: you can find it via his PH-handle) sells them, as he wrote it! We are all still waiting for part two ;-) Part One is just fine for the moment, just - as it provides all necessary information for maintenance and repair of the wedges. In this series there are some other manuals for TVRs as well, IF you are interested.
Or order via TVR Car Club...
Rob
editted for: Oh, there is only ONE wedge bible. If you know another please enlighten us.
Or order via TVR Car Club...
Rob
editted for: Oh, there is only ONE wedge bible. If you know another please enlighten us.
Edited by 350zwelgje on Friday 1st February 21:11
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