Engine stuttering problem

[winthattt]

@jonnyfox

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.

You will do very well to find a loose distributor cap on a VHPD, it does not have one!

[jonnyfox]

I know nothing lol, HT leads! I miss my 2zz

Edit, remember now it was actually a lead that was almost off. I remember being quite relived as I’d thought I’d broken it already

[lautll421]

@winthattt

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.

I took the plugs out and it black and wet and i think thats the reason for the cause of my problems. I have changed the new plugs and now it runs fine. However i took the plug out after running engine a bit, the plug starting to go a little wet and black again. Is this normal or I am running too rich?

[winthattt]

It could be running rich, they usually do. The Emerald mapping on a vhpd is VERY simple. It runs open loop just setting the fuel and spark using engine speed and throttle pos. There is compensation for cold coolant when starting and nothing else. No air pressure, maf or even lambda, the emerald can do them, i have never seen them mapped in.

If your car used to run ok, it will probably be fine now. Just make sure it gets some runs where it can clean the plugs.

[lautll421]

Yes, it seems to run fine now and planning to get the stack lambda to run on closed loop! Cheers.

[winthattt]

You can have a go at getting the narrow band lambda running closed loop. It is just a few tables on the fueling maps where you set the target afr, you then have to set which parts of the table you want to run, open loop, closed loop or adaptive. Its all in the manual. Most mappers leave it all blank. I would run it open loop at full throttle and higher rpm, they are not good times to go lean. You will need those tables set up if you install a wide band sensor, so it s not wasted effort.

[lautll421]

I may have to leave it to someone knows emerald to fiddle with it as i don’t want to blow my own engine up

[Evoman]

@lautll421

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:

1. 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!

Hey, wondered did you resolve this engine stuttering problem that you had? I am interested to learn what the problem was as I have had a similar issue recently with a hesitation / stuttering just on very light throttle at around 2500rpm. Trying a replacement coil to see if that sorts it.

Cheers !