another rb20 problem. stutter,miss on cyl 4

[stprasinz]

Ok,my buddy got a new ecu, it worked great. for about? 3 weeks now it (only after running a minute or 2. we looked at a lot of clips. only bad ones looked like the injectors... the subharness of 3, we replaced them (inj 1,2,3....). after replaceing them it seemed to have been fixed, went for about 50 feet down the road, stutter stutter.... so coil packs... took them all apart cleaned the tips.... still there same thing, seemed gone till test drive. so, what cyl. is it, we start pulling clips from coils, easier than the inj. clips. its cyl 4... bad pack on cyl 4?, we'll switch it with another and make sure(as his buddy about 45 minutes has a set he'll trade for my turbo.... switched the pack with a different cyl, its still on cyl. 4... ugh, so we pull plugs from 2 cyl, switch them... same thing. but when we did this the cyl. 4 plug was wet..... So????? tommorrow were tearing into it again, thinking its a injector..... but not sure yet.... anyone have some things that we can check? seems to be cyl 4? wiring, ecu, or inj.... but its also not there at initial start... and once it startsdoing it its there, like doesn't go away unless you shut it off.. if you rev the heck out of it!!! I mean scream!!! it starts at the rev down almost everytime. if you baby it under no load, it seems to take longer........ so any input would be great!!!!

 

 

and how about inexpensive plugs? he claims the only ones he can get are 16$ a pop!! the plugs in it do look pretty trick, little pin tip, and the electode has a nub for spark "concentration?"

[Lozer]

Always use normal copper sparkplugs with turbocharged engines, overpriced iridium/platinum plugs fail and crack at high temps and can cause alot of damage. Cost me 8 valves and one piston to find it out for myself, one valve was completely destroyed/cut off from a blown iridium spark plug.

 

NGK SPARK PLUGS for your RB

gap to .025" to .031"

COPPER #BKR5E-11

 

I would start with the plugs they are like 2.50 each if that dosent fix it then swap around the injectors.

 

And the injectors are not that hard to swap. Just pull the rail (carefully) (3 or 4 bolts i think) and juggle 2 injectors (relube the rubber grommets with vasaline).

 

and if it is failed RB20 injectors are the same as KA24E injectors. You can grab a grommet kit from autozone.

 

 

For good info from lots of people that have been down the rb road go here nicolub rb forums

[stprasinz]

yeah, thats the plan.... but are the ka injectors the same as the rb20det? if so, I'll buy him a set if we find that to be the culprit lol

[stprasinz]

boy, harness it is suspected? things weve tried, and the problem is still always cyl 4!!

 

1, switched coil packs

2, switched injectors to different ones

3, switched spark plugs

4, switched coil ignitor? pack

 

 

we have also tested to ensure there is =,- to the coil(3 wire 2 of them are constants, other sinal)

 

also I had tried to test for power to the injector, when I noticed with the key on both sides are constant hot? this is on all the injectors? is this normal?

 

I'm taking the week off from his car, but if anyone thinks of something, please let me know.....

[Lozer]

boy, harness it is suspected? things weve tried, and the problem is still always cyl 4!!

 

1, switched coil packs

2, switched injectors to different ones

3, switched spark plugs

4, switched coil ignitor? pack

 

 

we have also tested to ensure there is =,- to the coil(3 wire 2 of them are constants, other sinal)

 

also I had tried to test for power to the injector, when I noticed with the key on both sides are constant hot? this is on all the injectors? is this normal?

 

I'm taking the week off from his car, but if anyone thinks of something, please let me know.....

 

 

try swaping ecu's.

[stprasinz]

have a spare one? lol... I'm gonna have him test at clips, and at the ecu clip for pulse etc. See if I can find a noid light... maybe have him pull the coil, and test the coil for spark(since the cyl seems to do nothin starting at spark sounds better than fuel). then try installing an inj in the clip, and apply fuel press. to it..... to see if it sprays.... if the coil sparks, and the inj. sprays...... ah um lol... oh car doesn't smoe, only when the bov goes off, or from high rev drops, both are VERY suttle, and only noticable when in a well lit garage, while staring at the exhaust and its black..... so for general puposes it doesn't smoke...