RB20 DET Engine Swap problems

[mrbrightside]

Hey guys and girls

I have just done an engine swap on my R32 GTST Skyline( both engines RB 20 Det - completely stock)...Reason being the old head was cracked and it worked out cheaper buying a complete second hand engine... anyway the second hand engine was slightly different, the wiring harness clips were of a different size and shape. This was no big issue as i ended up swapping the tophalf of the inlet manifold and the injector rail...with the original engine. Everything was going good, i started her up, started first time but idled a little bit rough (barely noticible). Took her for a drive and every time i opened the throttle a bit the car would surge and almost die. Now it drives fine with minimal amount of throttle applied but as soon as you give it a bit it coughs and splutters...wat the??

Everything is plugged in properly all hoses are on etc... I have taken the carbon cannister out and blocked off the two hoses from the inlet manifold, wat do i do with the 2 fuel lines going 2 the cannister at the moment they arent connected to anything...

Also in installation of the new engine I have ripped two wires out of a plug. The plug runs off the main harness that goes 2 the starter motor, alternator etc... the loom is plugged into some oil lines (possibly for power steer or transmission) near the crossmember below the inlet manifold. wat is this plug for? Is it important? could that be my problem?

And one last question when doing the valve timing (cam belt) there are marks on the harmonic balancer and a mark on the bottom cover, when on TDC the mark on the cover lines up just before the 1st mark on the harmonic balancer, is this correct? Thanks for your help guys

[Yellow4g63]

sounds like a vacume leak did you put pressure on the system to see if there are any leaks? what about the TPS? did you check the ecu for any codes?

[king723]

yeah my harness came with the missing plug and it sounds like the same place you are talking about. Its has two wires a light blue and black wire.

[mrbrightside]

Well i replaced the sparkplugs and it runs a whole lot better. it isnt as powerful as it should be and it runs like a dog, but it is driveable under full throttle. i did a head gasket test on it and the results were negative, thank god for that, i alsodid a compression test and each cylinder had roughly 135 psi of comp (i think thats good) I had a mechanic look at it quickly, that plug was just a plug for hicas (has no effect on 4ws, just controls the hicas light in the cluster) anyway the mechanic told me my car was only running on 5 cylinders and that it was boosting fine. He also said it was most likely a coil. Now I disconnected each individual coil one at a time and every coil when i disconnected it seemed to make a difference (ie the car seemed to drop a cylinder)! I am completely lost to wat the problem might be??? I am a mechanic myself ( 2nd year apprentice) Does anyone know wat the problem might be, all suggestions welcome... Could be ignition timing? The engine i purchased second hand came with the module on the front of the engine (the circular thing on the top cover) however i had to use the module that came with the original engine as the second hand engine had a different shape plug in it. Could this be the problem? Both modules look exactly the same except for the shape of the plug (one is rectangular, the other is rectangular but with rounded corners). It is turning into a s**t fight and i am now starting to regret buying the car I have put many many hours into this beast but nothing seems to be working for me. Maybe its about time i see an expert and let them fix it. PLEASE HELP

[Yellow4g63]

Well i replaced the sparkplugs and it runs a whole lot better. it isnt as powerful as it should be and it runs like a dog, but it is driveable under full throttle. i did a head gasket test on it and the results were negative, thank god for that, i alsodid a compression test and each cylinder had roughly 135 psi of comp (i think thats good) I had a mechanic look at it quickly, that plug was just a plug for hicas (has no effect on 4ws, just controls the hicas light in the cluster) anyway the mechanic told me my car was only running on 5 cylinders and that it was boosting fine. He also said it was most likely a coil. Now I disconnected each individual coil one at a time and every coil when i disconnected it seemed to make a difference (ie the car seemed to drop a cylinder)! I am completely lost to wat the problem might be??? I am a mechanic myself ( 2nd year apprentice) Does anyone know wat the problem might be, all suggestions welcome... Could be ignition timing? The engine i purchased second hand came with the module on the front of the engine (the circular thing on the top cover) however i had to use the module that came with the original engine as the second hand engine had a different shape plug in it. Could this be the problem? Both modules look exactly the same except for the shape of the plug (one is rectangular, the other is rectangular but with rounded corners). It is turning into a s**t fight and i am now starting to regret buying the car I have put many many hours into this beast but nothing seems to be working for me. Maybe its about time i see an expert and let them fix it. PLEASE HELP

Did you check the codes from the ECU yet to see if it's throwing any?

[mrbrightside]

I checked the ECU for codes just then. i got 3 long flashes then 4 short flashes (knock sensor i think). Anyhow i didnt swap the original knock sensors from the old engine onto the new one shouldnt make a difference i dont think. Could faulty knock sensors cause the engine to run rough? Im thinking that i mnight have set the cam timing up wrong maybe a tooth out, i havent bent valves because i did a compression test and the results were good (135psi in all cylinders). Can someone tell me where i can find a guide on exactly how the cam timing should be set. Also a how to on setting and checking ignition timing would be good too. cheers

[Yellow4g63]

I checked the ECU for codes just then. i got 3 long flashes then 4 short flashes (knock sensor i think). Anyhow i didnt swap the original knock sensors from the old engine onto the new one shouldnt make a difference i dont think. Could faulty knock sensors cause the engine to run rough? Im thinking that i mnight have set the cam timing up wrong maybe a tooth out, i havent bent valves because i did a compression test and the results were good (135psi in all cylinders). Can someone tell me where i can find a guide on exactly how the cam timing should be set. Also a how to on setting and checking ignition timing would be good too. cheers

135 is really low. Did you warm the motor up 1st the hold the throttle plate open to get the reading? Bad knock sensor will keep the car in limp mode and bad Crank angle sensor will make it run like ***.

[mmatl16]

I had the same 5 cylinder problem.

you need to change your coil packs and your ignitor. ur car will most likely run fine after that.

if its none of those you could have a burnt valve

[crxcess]

I had a bad ecu that was causing one of the coil packs to misfire. the ecu was burning out cylinder 5 inside the ignitor. I ripped the old ignitor apart and found a burnt diode. It pissed me off because i bought an ignitor first thinking it would fix it but the ecu burned that one out too. pos ecu!

[mrbrightside]

wat is the igniter? When i did the compression test the engine was cold and i didnt open the throttle (left it closed) Does anyone know where i can get a coilpack i live in Canberra, Australia. To clear the ECU i just disconnect the battery for about half an hour, correct? If the knock sensor code returns that means my knock sensors are faulty?? I have another set of knock sensors but they look like a bi*ch to replace. Under the inlet manifold! Umm also wat would the car behave like in limp home mode?

[Yellow4g63]

wat is the igniter? When i did the compression test the engine was cold and i didnt open the throttle (left it closed) Does anyone know where i can get a coilpack i live in Canberra, Australia. To clear the ECU i just disconnect the battery for about half an hour, correct? If the knock sensor code returns that means my knock sensors are faulty?? I have another set of knock sensors but they look like a bi*ch to replace. Under the inlet manifold! Umm also wat would the car behave like in limp home mode?

For you to get a Knock Sensor or any other factory RB part is way easier since your in Australia. Did you try the nissan dealer? or an importer for those parts.

[mrbrightside]

Yeah i rang around today, parts are pretty easy to get. I also found out today that the car revs to about 5500 RPM but no further. How can i get a timing light on it, the timing light I have doesn't seem to work as there are no sparkplug leads to run off? I have a set of knock sensors that ill put in it tomorrow do you think that will fix it? As far as i know knock sensors retard the timing when the car revs high and starts to ping. But it still runs rough and high (1100RPM) at idle. I will get the car looked at this week if i cant fix it myself. Any more suggestions to wat my problem might be??? Cheers for your help guys

[crxcess]

Check your fuel too while your at it... you car might be knocking.