Strange SR idle resurfaces

[180fan]

It's all gravy guys. I think I'm gonna keep testing parts. For all I know it could be my fuel pump going to crap. But I've basically got spare parts all for the entire fuel system, and for the ignition system I've got more sets of plugs and coil packs. Ha ha ha. I'm eventually gonna find the cause of the problem, it's just a matter of time. I think when I get back from heading over to my buddy's house, I'm gonna switch my FPR and coil packs and see where that takes me. For all I know, it could be something as stupid as a ground not properly grounded or a bolt not totally tightened down. On the other swap I've done, his car wouldn't start, but when the multimeter was whipped out, we saw a spark jump from the grounding lead and suddenly the clock came on and everything else was good. lol

Oh yeah, I'm still wondering about that o2 sensor thing, if it were dead, would it behave similarly to the way it's behaving now?

On a side note: Could leftover metal shavings and other crap from the port and polish entering the cylinders cause something like this?

[NISTECH]

No and no.

Did you try the carb clean thing around the intake?

[s13sr20chris]

nope the SR20det in a 240 is not CARB approved. And it was my understanding it was not federally approved either. Nismo-freak I believe was who said it. but he could have just been reffering to his state. Quiksilvia had come by my shop wanting me to smog his and unfortunitly I had to tell him no. I hate doing that but If I got caught doin it it could mean fines and jail time if I put info in that wasent truthful. like say I told the machine it had a 2.4l since it wont accept 2.0L If the BAR found out they would come down and hall my a double s to jail.

federal? yeah, that may be true. i am not sure. i do know that there are no state laws in virginia that i am breaking. i just dont know about the feds though. i should find out. what if you were working on the side? like at home?

[NISTECH]

thats kinda ify but I would do it. My license says I cant do any emissions repair which covers just about any engine components. I dont do much side work though either.

[s13sr20chris]

aha, i used to do a lot of side work. i have slowed down a lot. interesting.

[180fan]

No and no.

Did you try the carb clean thing around the intake?

Yeah I tried it when I was finding the leak around the intercooler at the same time, basically hosed everything down with carb cleaner. But I haven't gotten around to hosing the bugger down since this last issue. However, I will when I get back into SF to work on my car again. Right now I'm taking a break from the car thing since I've been working on the car for a couple weeks installing and trying to trouble shoot for a while now and just need a break from it. I will probably be taking off the throttle again just to replace the gasket again to be sure. Hopefully the gasket wasn't an issue since I did replace it with a new one but might be worth looking into to see what's up and besides it's not much work.

[180fan]

Well here's an update on my situation. So far I've switched my FPR with the one from the KA and the idle's gotten a bit smoother but still has the oscillating idle and after I give it some gas, it will rev and then die out when the rpms drop. I've still got yet to find the cause of that one. The injecters were checked for physical damage and no luck there. I'm going to check over the injectors with a multimeter later today. But first, I'm going to have a look over the FSM for the injectors and their resistances and then check over the gasket on the intake. I used the one from the sentra SE-R and that one seemed to match but I'll double check that to be sure.

[NISTECH]

I dont think its your injectors That would show it self as a misfire. Your resistance should be around 14 or 15 ohms. but what you are really looking for is for all of them to be basically the same resistance. I am still thinking this has to do with air intake and what the A/F meter is sending to the ecm. Either a bad signal or the meter it self is not seeing what is going in the engine.[vac leak]

[180fan]

Yep you're right on the money from what I can see. I started up the car again today, it runs very smoothly. I checked over the MAFS again, this time jiggling the plug. It caused the idle to fluctuate even more. But the strange thing is that it did the same with the SR's MAFS (I had changed the SR MAFS to the SOHC KA MAFS with the same problem). So I figured it had something to do with the wiring of the MAFS and the connectors. Well the SR MAFS had no corrosion while the KA one did. The common link in this case was the wire used to extend the MAFS wire. I used regular wire instead of shielded wire. I'm currently in the process of lengthening using shielded wire and cleaning the MAFS connectors. Hopefully everything will be gravy after.

thanks again guys.

[s13sr20chris]

you may want to tighten the connector terminals up a little. those terminals will spread over time. a small straight awl or pick tool works well.

[s13sr20chris]

also, try to find a beck-arnley dealer. they sell nissan connectors that are identical to oem(they even say jecs on the ones i got). they may be able to sell you a brand new connector with pigtail wires.

[180fan]

whoa that's a good thing to know. These connectors are pretty effin corroded. Strange that they worked fine on my old KA without a hitch but run like a toilet that just had an office building go poop in it without flushing.

[NISTECH]

Strange that they worked fine on my old KA without a hitch but run like a toilet that just had an office building go poop in it without flushing.

LMAO

you disturbed them thats why they are now giving you problems. clean them up tighten them as Chris said and you should see drastic improvements.

[180fan]

Alrighty, got the MAFS corrected. However, I've still got the idle problem. The MAFS was part of the problem I think but not the total picture. I've noticed something though, when the motor is cold, the car idles like crap. When it's warm, the motor idles like a champ with a + - 30 rpm range from 800 rpm. Could it be my coolant temp sensor? My temp gauge on my cluster works fine but it's strange that when the car's warm that the idle should go to crap. Me thinks I'll change that tomorrow...come to think of it...I think you mentioned that earlier too...Crap.

[180fan]

Alrighty, changed the coolant temp sensor without any luck. Still does the effed idle bit on me. Now I'm totally stumped.

One thing though, when I pinch the vac hose that runs to the pcv at the top of the valve cover, it still idles like poop. Isn't that supposed to bump up the idle a little?

The car still runs rough when cold, but when warm, the motor runs like it should.

Fuel pressure regulator has been replaced with the one stock on the SR, ditto with the MAFS. The KA MAFS didn't show any improvement over the SR MAFS after I used 16ga. shielded wire. Also the corrosion on the plug was pretty bad. The FPR was switched back since it didn't seem to do anything for the initial idle either, it still ran rough.

I've also got an S-AFC in the loop, I'm probably going to try cutting that out and seeing if it improves the situation I'm in any. But yeah this situation sucks.

[NISTECH]

when starting it cold do you have a fast idle? or does it run and the warmed up idle?

[180fan]

it's got a fast idle when cold. It starts at high rpms and gradually drops down to the regular rpm range. But when the car's cold, it has faster oscillations and the oscillations slow down as the car warms up and gradually goes away to not really noticable oscillations when warmed up.

[NISTECH]

Hmmmmm?? all I can think here is the idle fluctuation may be related to the IAC valve. Its not running fat or anything now that you got the maf connection fixed right? maybe the connection on the IAC valve is corroded too?

[180fan]

Nah that thing's pretty shiney. I was thinking that the IAC's the problem too. It keeps pointing back to that. I was able to adjust the idle from the screw the other day...but dunno if that says anything about if the part's working or not. Only other thing that I can think of is that the FSM for the SR's says to pinch the vac hose to the PCV and if the idle doesn't bump up 200 or so RPM then I've got a vac leak. Also when the car's given gas when the motor's cold the rpms will drop way fast and the motor will die. Possibly a vac leak behind the throttle plate? That's the only other thing I can think of.

[s13sr20chris]

are you pinching both hoses to the pcv? mine idles rough at the stock idle so i bumped it up to 900-950 base idle. that pretty much takes the iac out of the loop. mine is running on 3 1/2 cyls though

[180fan]

Oops, taking a second look at the FSM said if there's an rpm jump then there's a vac leak, not the way I said it before (so rpm jump = vac leak, no jump = no leak) so I guess I don't have a vac leak in this case.

Oh Chris, it's weird since I've tried bumping the idle up on the IACV but it still has that crazy oscillation during the fast idle portion. When it's warm, I don't really see a large oscillation of the rpms anymore. So I know it's gotta be something going wrong during warm up, but when it's warm it's all gravy.

Another thing I was thinking was maybe the o2 isn't getting any power to heat up and was getting heated up through the exhaust gasses to cause that nutty idle during the fast idle phase.

This problem's a real noodle scratcher and I hope it doesn't come down to replacing my IACV or something since that part's a PITA to get out.

[180fan]

My #1 guess now is that my IACV's gone bye bye and along the way left me a message saying "adios sucker".

Update:Got the car to idle pretty well when hot. It stumbled a little bit still when it was hot but no where near death. Double checked the wiring with no faults at the ecu area where I originally thought there might be a possibility of fault. No luck.

Parts so far replaced:MAFS, coolant temp sensor, FPR

Parts checked:-- tested the injectors both with a screwdriver to listen to the little clicking inside the injector and swapped them over with a friend. Not the injectors.-- shook around the plug on the MAFS, tried it in different positions, this part is good and so is the wiring for it.-- had a doubt I got the right part at Kragens for the water temp sensor, well it works and fit the harness. Can't be that either.-- compression tested the bugger, all cylinders within spec.-- pressurized the entire intake system from the back of the hotpipe all the way to the throttle. Pressure held.-- timing is right at 15 BTDC when the car was warm, and the TPS off. I was checking the timing light though when the car was on the warm up phase, and the timing was switching from 20 and 10 btdc which is strange to me. Is that normal?

** while car was running, had different vac hoses closed off to see if that changed the idle at all...no luck. Although this one stands out a bit to me because when I pulled some of the vac lines during the fast idle phase, I couldn't tell if there was an rpm fluctuation because I was already getting that.

In conclusion:I think I'm gonna get shafted hard. Like San Quentin Prison hard. Checking out phase2, they want like $300 for that part...plus tax...plus shipping...yeah I think I'm quite right to think San Quentin hard eh? But before I decide to take a ride on the bone rollercoaster, what are your thoughts on this Nistech, Chris?

[s13sr20chris]

i hate to say it, but i think you are gonna hafta take it. that or just live with the prob. im really not sure what to tell you. this part kind of sucks about rwd sr20s. just say to yourself, "it would be worse if i had an rb." sorry to be so little help after all.

[NISTECH]

Yea this really sucks,one last idea to try to prove thats your problem. start the car and while its having its coniption fit unplug the IACV and see what happens.

[180fan]

actually that's a pretty damn good idea. lol I haven't actually thought about that. to unplug the bugger. well it looks like i managed to pick one up used, but gonna give it a thorough hosing beforehand with carb cleaner (I'm broke as a joke...and that's no joke). Any tips on how to clean them guys? I'm just assuming find a hole and pump it full of carb cleaner.

[s13sr20chris]

yeah, thats how i do it. depending on what type it is i sometimes take them apart. some of them are a pain to take apart.

[180fan]

right on. yeah $300 for a new IACV doesn't float my empty wallet. People complain bout lint and buttons in theirs, I'd be lucky to have buttons. lol

[180fan]

I've noticed that there are a few more posts about idle issues now. It seems like everyone has the same problems at about the same time...maybe it's just because I'm more aware of the idle issue now. lol

[s13sr20chris]

yeah, idling sucks. too bad we cant just keep moving huh?

[180fan]

yeah seriously. i just spent an hour taking the intake manifold off and the iacv. apparently when i hosed it down with carb cleaner, it wasn't as effective a clean and left alot of carbon deposits still. dunno if it's functional at all, but i figure i'd like to keep a spare of that part considering all the hell it's given me.