intermittent missfiriing

[love_boost]

im having problems with cylinders 5 and 6. i start it up and it purrs like a kitten. let it run for awhile maybe 5 mins and it starts missing. not like a coilpack but just when i try going it kinda stutters. i checked my gap on my plugs and they are 32 thou.

the first 4 are a tan colour but the 2 back ones are different. they dont smell like gas but they are a little wet. i did a compression test and got 145-150 across all 6.

when i take the CAS off and spin it manually i cant really hear the last 2 injectors click. i swapped them to the front to see if it was the injectors or not and thats not the problem.

if i mixed the injector number 5 and 6 up could this be my problem? i dont even know what to do at this point.

[skaG]

looks like you got fuel going but no sparks that's way 5 and 6 spark plugs are wet so may be swap coilpacks with 1~4 cylinders and check on power transistor as well.
good luck

[Terrh]

I'd start moving coils around. easy way to check to see what cyl is missing/making noise with RB's is to disconnect the ITB linkage and then you can put only a pair of cylinders under load alone, tells you right away which pair is missing. So move the #1 and #2 coils to #5 and #6 and try again, if it moved you know it's coils, and if it didn't that eliminates them. I'd do a compression test too just for peace of mind.

[bobbo]

I'll bet you'll find the same cylinders will continue to misfire after changing coils. See if you can borrow a friends ignitor. Mine did the same thing except it was 4 that failed after a short period of time.

[love_boost]

alright ill double check spark on 5th and 6th. i moved coils and injectors around.
ill try that with the ITBs, never thought of that haha.
i got a spare ignitor so i will try that also

but when i pull the CAS off and manually spin it, i can hear a definate click from the first 4 but 5th and 6th dont seem to click. like they are not getting power?

[caliber676]

Check your coilpack harness too. Could definitely be a problem with the wiring. Look it up in the manual, its a quick test.

[mitch32]

Your injectors may be finished. They can get stuck sometimes too, or the wiring is bad.

Do you have node lights? Find node lights or even a test light and plug it into the injector clip, turn the motor, and see if there is voltage going to the injector clip. That way you can eliminate a wiring/electrical issue.

Also take the last two coil packs out, put a spark plug in them, ground it somewhere, and turn the motor to see if the coil packs are working.

Test the resistance of the coil pack.

[love_boost]

the coilpacks are def firing, ill test the power to the injectors tonight, thanks!

[jdms13rhd]

you can diagnose the transistor if you suspect fuel problems. Remember that the injectors always have 12V. The ecu gives the injector a ground pulse to close the loop. It may just be your ears messing with you.

Way I always check and what I always do when working on a RB is to do a tune up. If I suspect problems before I do a tune up i always start off by removing the coil pack cover and then starting the engine and letting it warm up to operating temp. Then, one by one i un plug the coil's, listen for consistent result of the engine dropping a cyl. 9 times out of ten I find the problem cylinder right there. If I find a suspect hole I just replace all the plugs with new ones. You can run copper number 6's at a 1.1 gap for oem RB's. Then onto the coils. Again, one by one I take my feeler gauge and clean out all the built up electrical erosion/carbon whatever it is. clean it all out. Then I use a razor blade and pack sensor safe black permetex into the gap. I've done a hundred tune ups on rbs this same way and i 100% of the time get a better result and usually fix the problem.

I can usually hear what the engine is doing prior to working on them. If your not too familiar with these engines always start off by checking codes on the ecu. That can let you know if your having any sensor issues. Common ones being maf, temp sensor and TPS from my experience. Tho, sometimes you wont get a code and one of those sensors may be giving you an intermittent grief, then you can pull out the FSm and run a diagnostic and go from there.

Easy as pie, just dont jump to conclusions unless you know, and be patient. There is a problem to any solution.

In the FSM there is a diagnostic for the injector resistor box and the power transistor "ignitor". 5 min job on each to test minus finding the page on the FSM. It can take a little bit if you haven't read it several times

Only place I know how to find it quickly is on gtrpwr.com in the file section. Im glad its there too