bad idle issues

Post by **NeedCAforS13** » Wed Mar 10, 2004 1:42 pm

i'm sure this is somewhere in the old posts, but I'm working on the car now, and don't have time to sift through tons of threads... could someone list things for me to check with regard to bad idle?

the motor is running but it idles high (around 1500rpm) and if I bring the idle down (with the idle air screw) it stalls... its kind of sluggish down low (between 1000rpm and 2000rpm it shakes alot), but as soon as it gets moving (say 3000 rpm) it gets alot smoother. I'm not really boosting it either...

also the vaccum is around 15-18psi at idle. Is that right?

I hit it once and got about 7psi of boost, but other than that I've stayed off the throttle...

another thing is it doesn't like to start again once it stalls. Or when its been running for awhile and is hot. I took it up the road to get some gas because its running rich as hell (you can smell it) and I couldn't get it to start again once I filled up. I waited for like 10 minutes and it started up fine. I really need someone local to come help out, but everyone's too busy:(

if anyone has suggestions they want me to check, it would be appreciated:) I've tightened down the intercooler piping alot, so I don't think its a leak there, but I'll go out and check more now.

Thanks,Sean

Post by **USDM_OneVia** » Wed Mar 10, 2004 1:42 pm

timing!!!!!

Check your timing. Sounds WE-TODD-DID to me.

I have about 20mmHG at idle, so you might have a slight leak some where too.

Joe

Post by **float_6969** » Wed Mar 10, 2004 1:42 pm

:withstup I run about 20mmHG at idle too. That would account for your high idle. Remember, !!!YOU CAN'T USE THE LOOP AT THE BACK OF THE COILPACK HARNESS!!! Sometimes it's right, and sometimes it's way off. I had it right on one time that I tested it that way, and then another time it ws 7* off!!! Break down, pull a coil, and do it the right way. Other than that, pull the codes from the ECU and see if you get anything. Let us know how it goes.

Post by **Nismo1182** » Wed Mar 10, 2004 1:42 pm

The only code his ecu is throwing is a TPS sensor (43).

I adjusted his idle somewhat but it still stalls when you rev it and let go. Then it doesnt want to start back up again.

How do you check the timing?

Post by **Trigger** » Wed Mar 10, 2004 1:42 pm

timings off i think. that would be the reason its idling rough and not wanting to start back up. hit that bad boy with a timing light and see what you get. the vacuum you got is fine. i have a big leak and i get 13 when i am at idle and it still works fine. yours is good enough for it not to be the problem. If i was you I would check the timing.

Tim

Post by **NeedCAforS13** » Wed Mar 10, 2004 1:42 pm

yeah so replaced the TPS with another CA one, and it went away. But now its throwing the coolant temp sensor code. I guess I can try that too now. At least I have extra stuff!

gonna head to work with it now (its 6 am

) and play with timing there. we might even have the special tool;)

Sean

Post by **r34 gtr** » Wed Mar 10, 2004 1:42 pm

hm...mine used to do the idle-dip-when-let-off-gas thing but for the life of me i can't remember how i fixed it. check for leaks, definately re-time the car and uuum, make sure all the sensors and stuff are getting the right voltage. shoddy wiring is NOT your friend (believe me, i know)

not to hijack the thread, but is that loop at the back of the engine ok to use for the tach/rpm signal when you run the car on a dyno?

- tim

Post by **Trigger** » Wed Mar 10, 2004 1:42 pm

i wish you could remember how to fix that problem tim...my car does that

Post by **Dori Dori** » Wed Mar 10, 2004 1:42 pm

Totally off topic, but NeedCAforS13, are you going to the Miami drift event (practice) this weekend? Curious...

Post by **NeedCAforS13** » Wed Mar 10, 2004 1:42 pm

nah, I'm heading home to visit the parents in Tampa... I was thinking of driving, but there seems to be alot of walls on that course, and walls are not my friend;) It'll be fun to watch though! I can almost guarentee someone will hit the wall:)

Sean

Post by **Dori Dori** » Wed Mar 10, 2004 1:42 pm

They won't be driving on the track for the practice run...this will be on a paddock similar to your Tampa event.

Post by **NeedCAforS13** » Wed Mar 10, 2004 1:42 pm

ok, current car situation:

not throwing any codes any more:) yea!!!

I disconnected and re-connected my intercooler piping, replaced my fuel injector o-rings and seals (they were spraying gas again, first I tried toyota seals, then the old seals that came with the motor, finally I got new ones from Discount Auto Parts) and messed with the TPS setting. I also took off the timing cover to verify that the belt was on correctly (and it was;)). After that I played with the CAS some (but I don't have a timing light yet) so I got the timing roughly on I think.

Its idling at about 1000rpm. It seems alot more responsive and it doesn't die nearly as much any more. The fuel injector seals were the kicker I think... Oh well, hopefully I can set timing tomorrow, and have it running even better!:D of course suggestions are welcomed as usual...

Sean

Post by **USDM_OneVia** » Wed Mar 10, 2004 1:42 pm

I made a whole timing write up a few months back. I'm sure if you look hard enough you can find it.

DON'T USE THE FREAKIN LOOP!!! IT IS NO WHERE NEAR ACCURATE!

Joe

Post by **NeedCAforS13** » Wed Mar 10, 2004 1:42 pm

I already found it joe;) i just need to find someone with a timing light!

Anyone in Orlando have one?

Sean

Post by **biosehnsucht** » Wed Mar 10, 2004 1:42 pm

timing lights are cheap! like $40 or $50 for a craftsman OR an off brand autozone one.. unless you want fancy-*** ones that you can adjust an offset to the timing blink, which is really unnecessary..

Post by **Inshan** » Wed Mar 10, 2004 1:42 pm

Sean,You can use my timing light if you want, just stop by and pick it up.I'll email you my #.

Post by **NeedCAforS13** » Wed Mar 10, 2004 1:42 pm

I got one from work, but thanks Inshan! I went into Nissan earlier today and set the timing to 15 degrees BTDC

update on the engine progress: runs like a scalded cat... but only after a week of crap :pface

so today I played around with the maf (with Dee's help on the phone) and was able to determine it was causing my problems... If I unplugged it, it idled perfect, but obviously wouldn't rev past 2k. we had it directly mounted on the front of the turbo. Dee mentioned that if its too close to the turbo it can't get accurate readings, so I got some pipe, and moved it about a foot away.

Still idled like crap. Drove it around the neighborhood, and it runs decent above idle, but still the same bad throttle response and poor idle that has plagued it from the start. I then remember a friend of mine down the street with a CA18DET just upgraded to a z32 maf, and has an extra CA18DET maf laying around (his name is Mike, and he use to post here alot, CA18_RS13 or something like that)

so I drove down the street and got his maf...HOLY CRAP IT RUNS GREAT! Idles rock solid at 800rpm, no hesitation, and woooo does it go!:D I still have a massive exhaust leak where the downpipe meets the cat, but I'll be making my exhaust next week sometime, along with my fmic piping, so I'm not too worried about it.

I'm hitting about 7psi max boost right now, BUT its still idling at 16 or 17 psi of vaccum. When I let off the throttle and cruise, it goes to 20 psi, but at idle it bounces between 15 and 18. I think I have a leak somewhere, but I've been looking for hours and just don't see it! I even pulled all my intercooler piping off and re-did it, with no change. Any other suggestions?

I need to upload these pictures. I have so many its not even funny:)

Sean

Post by **Inshan** » Wed Mar 10, 2004 1:42 pm

Did you lap the valves in?

Post by **NeedCAforS13** » Wed Mar 10, 2004 1:42 pm

yep:) had the other mechanics help me do it. I put new valve seals too. why do you ask?

Sean

Post by **Inshan** » Wed Mar 10, 2004 1:42 pm

An improperly sealing intake valve will give you a flutter on the vacuum gauge.

Post by **NeedCAforS13** » Wed Mar 10, 2004 1:42 pm

ooh i hope not:( its not really fluttering, its just roughly 20 when coasting off throttle, but when actually idling it goes to 16 psi. It stays pretty constant 16 or 17 when idling, its not hopping around.

Sean

Post by **Inshan** » Wed Mar 10, 2004 1:42 pm

Maybe you can try spraying something over the piping or wherever you think it might be leaking, and look for a rise in RPM? On a carb engine, I just spray some WD40 or brake cleaner around the manifold or carb-base gasket. I don't think the sensors would like it on an EFI engine though. Maybe somebody has a better idea?

Post by **NeedCAforS13** » Wed Mar 10, 2004 1:42 pm

I'm re-doing the piping on Sunday for my fmic. We'll see if that fixes it then!

What are you doing Sunday? Do you have a compression tester? I'd kind of like to see what kind of compression I'm getting:) just for grins...

Sean

Post by **biosehnsucht** » Wed Mar 10, 2004 1:42 pm

technically don'tyou mean in. Hg or something for vacuum ?

anyways.. BRAVO !!!

Now keep from blowing up long enough for me to do a "high CR" CA18DET without fearing for the life of my motor

I should think it should run like a scared cat, that extra CR should make a difference in spool and power (not huge in total power, but definately help spool)

Post by **Inshan** » Wed Mar 10, 2004 1:42 pm

NeedCAforS13 wrote:I'm re-doing the piping on Sunday for my fmic. We'll see if that fixes it then!

What are you doing Sunday? Do you have a compression tester? I'd kind of like to see what kind of compression I'm getting:) just for grins...

Sean

Yeah I have one, you can come by on Sunday if you want. I'll probably be busy working on another car, but you can stop by and use the gauge. I would also like to see the car, and see how it runs.

Post by **Trigger** » Wed Mar 10, 2004 1:42 pm

hey check to see if your charcol can has a crack....that is my leak but i havent had the time to replace it. thats the only thing i can think of

Tim

Post by **NeedCAforS13** » Wed Mar 10, 2004 1:42 pm

its like insta-spool... I think its alot quicker spooling than Kevin's car, but I'm not sure about total power... I'm not running over 3500-4000rpm really yet, although I've been told that after about 20 minutes at 2000rpm the rings are set, and the bearings are good from the get-go, so I should be fine beating on it:)

I'll still wait afew hundred miles or so... I'm at 93 miles on the motor right now! damn this is fun:D

Sean

Post by **biosehnsucht** » Wed Mar 10, 2004 1:42 pm

so which pistons are you using again? FWD Pulsar CA18DE pistons or ?

Post by **float_6969** » Wed Mar 10, 2004 1:42 pm

r34 gtr wrote:hm...mine used to do the idle-dip-when-let-off-gas thing but for the life of me i can't remember how i fixed it. check for leaks, definately re-time the car and uuum, make sure all the sensors and stuff are getting the right voltage. shoddy wiring is NOT your friend (believe me, i know)

not to hijack the thread, but is that loop at the back of the engine ok to use for the tach/rpm signal when you run the car on a dyno?

- tim

Yes, it is actually there for RPM measurments. Just not for timing...

Post by **Nismo1182** » Wed Mar 10, 2004 1:42 pm

Once the motor is broken in, I really would love to drive it for comparison. And vice versa of course.

Bio, the motor is a JDM non turbo CA.

bad idle issues

bad idle issues

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