popping

Aug 7, 2009
1,395
0
Manchester U.K
Started the car today 1st time and i know its blowing from the cat but also noticed that there was a poping coming from the airfilter any one any idea what this is, also has a slight missfire, im seriously at theh end of my patience w ith it now spend 2800 on it and no better.
 
Aug 7, 2009
1,395
0
Manchester U.K
ALSO it has a black top coolant temp sensor if that makes a diffrence. And it takes a moment to fire but then it revs to 3k and splutters then evens out at 1200k
 
Last edited:
Aug 7, 2009
1,395
0
Manchester U.K
Right narrowed it down, its either running lean, which i dont know il whip a plug out, it smells way to rich or igniton timing, which could be down to faulty coolant temp sensor as its a black top sensor, need to double check everything tomorrow and i have a green top on order, got to pick it up in the morning.
 

CupraMVR

Awesome GTi Technician
Oct 19, 2006
1,371
0
Crewe Cheshire
Could be the old black temp sensors not knowing if the engine is hot or cold. get a new 1 in there and reset all basic setting in vag com.

sounds like the auto choke is running aswell which will make it run rich for a few mins

Dont give up on it mate keep going its nearly there now
 
Aug 7, 2009
1,395
0
Manchester U.K
Whats the popping though, has it pulled the spark timing aswell? its mega rich i can smell it, also going to have to paste the exhaust up till new year when i can get new gaskets, should hold for 2 weeks if i put a nice ammount on. Dont think the blowing exhaust helps lol sounds awful :( Also dont have vag com so cant even do a TBA :(
 

CupraMVR

Awesome GTi Technician
Oct 19, 2006
1,371
0
Crewe Cheshire
has it got a coil pack down on it ? you said its got a small miss fire. maybe this is causing it to pop.

yea should be fine with the cat get it sealed up wont help with the running
 
Aug 7, 2009
1,395
0
Manchester U.K
Just read:

The coolant sensor is often called the master sensor because the computer uses its input to regulate many other functions, including:

^ Activating and deactivating the Early Fuel Evaporation (EFE) system such as the electric heating grid under carburetor or the thermactor air system.

^ Open/closed loop feedback control of the air/fuel mixture. The system won't go into closed loop until the engine is warm.

^ Start up fuel enrichment on fuel-injected engines, which the computer varies according to whether the engine is warm or cold.

^ Spark advance and retard. Spark advance is often limited until the engine reaches normal operating temperature.

^ EGR flow, which is blocked while the engine is cold to improve driveability.

^ Canister purge, which does not occur until the engine is warm.

^ Throttle kicker or idle speed.

^ Transmission torque converter clutch lockup.

So basically i hope its just running rich with spark timing out due to sensor, one EML is on due to decat but nothing else atm, dont even want to run it tbh its not even been started properly, run in total for about 25 seconds, not taking the risk.
 
Aug 7, 2009
1,395
0
Manchester U.K
Cant be coil packs i dont think, they look like new, its been a missfire on origional engine, afte rebuild and now this, cant be cam or crank sensor as it was a runnning engine when it come out the S3 it was in, Only origional sensor really is coolant temp sensor, 2nd lambda and MAF and MAP rest are what was on the engine, ive checked where ive put a new loom on and wires are fine, cant be coil packs and on 2 engines so im thinking coolant sensor.
 

adam cupra 20vt

Built Not Bought.
Mar 31, 2005
6,162
2
Mud Hut
I'm not sure excatly what you've done to motor but I noticed decat? you havent just fitted it and damaged a lamda probe have you?
 
Aug 7, 2009
1,395
0
Manchester U.K
Deecat was done ages ago as cats wer like concrete had them cut and 2 pipes welded in till i got this sorted, post cat wont really cause missfire. Precat is the one that came with the engine and was guarenteed working, so that is Lambda sensor (pre) coil packs, CA and CS sensor, oil pressure switch, knock sensors. Ones off the old engine are my throttle body, my map pipe, MAF, and coolant temp sensor. MAF would more than likely cause a dead spot in rev range and lack of power, unsure about throttle body as i cant get vag com to work but dbout its that, and all im left with really is a black top coolant temp sensor. Its not miss'ing bad as rev counter is seady, it just has a shake which could be made worse by the powerflex DBM, so a tiny missfire could make it look worse.

Its had new stat, timing belt, tensioners etc, spark plugs, oil cooler, oil filter, oil, dual mass fly wheel, clutch, CSC, water pump. Timing was bang on or i wouldent have put the motor in,

Ive built it standard so ECU can calibrate its self, so thats standard air filter, standard Diverter valve. I cant see it being the ecu as it doesnt seem to be a cylinder down. I also used the injectors and inlet that came with new engine so cant see them being the problem.

Ive cut and put the coil loom on my engine and basically its 13 wires colour coded and im not stupid so its not that. Only other thing is a decat which i cant see making much diffrence in causing a missfire or popping.
 

Trev_m

Guest
I got mine started yesterday it had a bit of a missfire no managment light on I plugged a snap on ethos in had a load of fault codes some off old engine knocking others caused by spinning it over to get oil up with injectors unplugged cleared all codes now running spot on.
 
Aug 7, 2009
1,395
0
Manchester U.K
Yeh i had injectors off and no fault codes for them. All im getting is 02 sensor #2 as its de-catted. Im going to try sensor tomorrow, boung it up with paste as the noise goes through me and let it run a little see if it clears up. Think the blowing exhaust makes it sound worse than it actually is lol.
 
Aug 7, 2009
1,395
0
Manchester U.K
Ive been monitoring live data etc hence why i found coil 1 plug had popped off so just wrapped a bit of tape round coil and its stuck on like a goodun now :) For some reason i just want to go out and work on it today LOL but decided to have a rest, il be on it tomorrow though :)
 

OFI

Active Member
Sep 5, 2007
350
0
Salisbury
Could be the old black temp sensors not knowing if the engine is hot or cold. get a new 1 in there and reset all basic setting in vag com.

sounds like the auto choke is running aswell which will make it run rich for a few mins

Dont give up on it mate keep going its nearly there now

Is there a list somewhere of all the basic settings and what they do etc? (like the module thread)
 
Genuine SEAT Parts and Accessories.