Hey guys needs your help here, i started the car this morning after not driven it for 6 months. I filled up with full tank of petrol. Then the problem starts, i find the rev stutter/loss of power at low rpm on part throttle, but when i press the throttle 80%/fully down the rev seems ok. But when i slow down again then the rev start stutter and it is intermittent and sometime it is ok and sometimes not, can that be:
TPS?
2)Spark plug and leads- but i only replaced it 1000 miles ago so this may seems unlikely.
3)Other problem that i should be aware
Please share your wisdom and certainly is not a good start after 6 lotusless month!
Could be no1, doubt its number 2 unless there is damp in there. Could be an air leak. Check the small vacuum pipes on the throttle bodies and stuff like that.
Today I have checked all pipes and it seems there are no split. All sensors are connected. Spray wd40 in to all possible contacts. However today when i pressed pedal down in neutral gear, I can feel the rev struggled and doesn’t rev clean to higher rpm and it feels like it is misfiring/congesting. Also when i press the accelerator to the bottom and release/back off then accelerate again immediately, there’s seems to be delay or nothing in engine response for a split sec and then engine fire back on again(if you get what i mean) … it seems as tho the engine is not picking up as it should. Does this sounds like a faulty TPS?
It sounds like a slight case, I had similar until I had a monster version of what you describe, albeit on my S2. Can’t harm to change, can you get one cheap?
Is there not a trick with switching on and pressing accelerator 5. Times or something like that?
But I dont know it it works with Emerald.
Why not ask Dave at Emerald for his wisdom…
If you have an Emerald ecu just connect a pc to the programming port and look at the read outs. It will quickly tell you if the tps is dead as the readings will jump about.
Thanks all, i should receive the cable tomorrow from Emerald so that i can connect to my note book . Is there anything i should look at on the read out? the non linear/jumping voltage i guess?
There is a “live measurements” screen. Just look at tye display and press the throttle, it should be nice and linear from closed to full open. You do not even need to start the engine.
If thats ok you need to look at the other sensors to see if they are reading ok. Tbh, most emeralds have such a simple set up there is little to go wrong. The just use engine speeed, throttle pos and temperature. I suspect you will find nothing wrong.
Vhpds can eat plugs, especially champions, I find NGK make it run better.
This is a quote from Track Group in an email when my TPS went faulty…
The picture below is from when your car was playing up at Brands in December, and is a good example of how we can use the data for diagnosis.
If you look at the pink throttle trace, the minimum value gets very inconsistent, almost creeps up throughout the runs (see how high it is in the middle while it’s just idling in the pits!), this makes it run very rich when at off/ part throttle (its nearly always 12:1 or under, even when off throttle). But then when it’s cold later on, the throttle-closed signal drops right down again and the fuelling is back to normal!
Thanks Guys, i checked the TPS and it seems fine and linear, car is now still doesn’t pull cleaning and is running so rich that i got almost choked to death with the fumes. Please see below video i took with the emerald screen. The lambda seems reacting very slow, is that normal ?? …thanks
Sounds horrid. Tps looks ok. Lambda is wrong because it only has a simple lambda sensor and you are having a miss fire stutter. The emerald does not really do anything with the lambda unless it has a wide band sensor fitted. Yours is actually working quite well.
Crank sensor is probably ok as it starts and runs. If it stinks you have probably got a miss fire. If you take the plugs out are they fouled and covered in fuel? It is worth checking, cleaning and drying them. Next on the suspect list are the leads and coil pack. I have a spare set which you can borrow. Collect from near Derby or i can post them to you. I would try new plugs first.
I am not an expert on this, mine has always worked so there may be other options. Does it idle nicely? It sounds like it does? Does your map allow the use of ignition advance to get a good idle? Its a flag somewhere in the mapping. If it idles, it is probably not an ignition problem.
If it idles and it is just the accel that could point to an air leak.
Take the air filter off and have a quick check inside it. It wouldn’t be the first air filter to make a nice home for a family of mice while its been stood for a while!
I totally forgot, the second or third time I used the car I went over a pot hole and knocked the distributor cap loose, I had exactly the same sort of thing as well.
