Stupid car. It has been running very well the past few months, but the last couple of days, it went to crap.

My idle is all screwed up. It used to just hunt around for a few minutes when it was cold, but now it is surging between 1500-2000 rpm continually.

After it gets warmed up, now it stays idling high and hunting.

When I shut the car off, it won't restart. Turns over, but smells like unburned fuel in the exhaust (flooded, I am pretty sure). If I let it sit a while, it starts up, but continues with the same problem.

In an effort to try and fix this, I first swapped the TPS. Then I swapped a totally different throttle body with its original TPS attached. Still the same problem. I also tried cleaning out the IACV (with it still attached) and that didn't help, either.

When I drive it, it pulls strong and seems to run OK at speed, but anytime I push in the clutch or come to a stop sign, the idle will stay high and hunt around.

Totally strange to me. I have never encountered a problem like this.

Any suggestions?

 

check all vacuum hoses and run an ECU diagnostic.. see if that comes up with anything.

 

Got your pm on nwmaximas Chris. I used your old IACV as Shawn never mentioned having problems with that one until I replaced it. The JDM unit had a cracked connector but I was probably ok. I would have used that one if I had known you original was having problems. I don't know why you are having starting problems but yet the car runs fine. Very odd. I did use your original coolant temp sensor though. Maybe it's going bad?

Also make sure your cruise control cable isn't holding the throttle open. Happend to me.

 

I can bet it's the water temp sensor. Change that first($10).

 

I will try the coolant temp sensor. Hopefully, if MrGone is feeling really nice he will send me his spare IACV.

I am also going to check for codes. The CEL never came on, but I should check them, anyway. I also had the battery disconnected when I was doing a lot of the work, so I don't know if it stored them or not.

I will take a look at the hoses, too. Some of the ones from the JDM engine have paint on them and that may have caused them to crack. Most of the painted ones seem to be the small coolant hoses that go through the bottom of the TB and IACV, though.

I am not sure what is causing the car to flood. The flooding is causing the starting problems. If I let the car sit for a while, it will start, but kind of coughs up some gas first. Once I get it started, it will not idle correctly, but seems to run fine, otherwise.

Thanks, guys.

 

How does it start when cold?

 

It coughs and acts like it has too much fuel. It usually jumps immediately to about 2k rpm. The last few times if I didn't get it to start on the first try, it would not start.

I haven't had a chance to look at it. I am at lunch right now. I have to watch my son at night and I have been working until 5:30 p.m. and my wife works from 6-10 p.m.

When I get some free time (probably Thursday night) I am going to check everything out really good and also swap in my spare o2 sensor. That could possibly be related to the flooding part. Not sure, but I have a spare and it's not hard to replace.

Just for good measure, I am going to put in a new coolant temp sensor, o2 sensor and when Shawn sends me the IACV, that plus new gaskets for the IACV and the TB. After that, I will start replacing vacuum hoses.

 

If it starts like it's too rich when it's totally cold also, then you might have a fuel leak past the injector 0-rings. I didn't touch them (other than the insulators) when I did the swap.

But for the amount of pain endured to fix a leaky o-ring, you might try the coolant sensor swap first (red connector). You could probably use the jdm IACV if you need to.

Off hand, I don't think it's the 02 as the ecu ingores it during cold starts.

How are the plugs? Any of them wetter than the others? One really wet one would indicate a fuel leak in that cylinder

 

I will check the plugs, too.

I wasn't thinking about the injectors, since everything was fine up until a few days ago. I had a bit of a high idle, but nothing serious. I assumed you hadn't messed with them and if anything, one would go bad and it would run on 5 cylinders. When I get it on the road, it seems to run just fine.

o2 will be the last thing I replace. I am leaning more toward the IACV or the coolant temp sensor. I have a brand new coolant temp sensor in my hand right now, but I have to wait until tomorrow before basketball or Thurdsday night to get out to the garage. Luckily, I have the old green POS Dodge to drive to work.

 

Just trying to suggest some very low cost ideas on how to pinpoint the problem. It would suck to replace all this stuff and still have the problem.

 

I know. Thanks for your help, BTW.

Really, it's not too much $$ to replace the things I am trying, except if it's an injector (please don't be that!)

I have the o2 sensor already, Shawn is sending the IACV and I paid $20 for the coolant temp sensor. If I need vacuum hoses, I imagine they aren't that much.

 

I have like a billion injectors so don't worry. But it's most likely an 0-ring if it's injector related. I suppose you can just ohm them to confirm though.

 

I will post again probably later this week. Car is just sitting for now. I just have a lot of crap to get done.

Thanks, jeff

 

I didn't read the whole thing, but it sounds like MAFS, try swapping it out.

 

Jeff --

I uploaded a video to my host site (actually, it's Keelan's -- I'll pull it down soon, Keelan) of my car's serious problems. I just shot this at lunch. Still haven't had time to get out there.

*edit -- link deleted

I didn't touch the gas until after it dipped back down to super low idle.

It did all of that **** on it's own.

I still haven't received the IACV from Shawn. The JDM one is filthy inside and that connector doesn't really look too safe. The plastic is broken all the way around and just the wires inside are holding it together. I would imagine any kind of water in there or anything would short it out.

 

When did Shawn send the stuff?

Okay your car is possessed! Still hard to tell what is causing that.

 

about 2 hours ago lol

 

It's a POS. It was running fine. I drove it to Shawn's house just a couple of weeks ago. Ran like a dream and got almost 30 mpg going around 75-80 the whole time. Crap, right before Woodburn this happens, too.

Thanks, Shawn. Did you get the package I sent you today?

 

na, probably tommarrow though

 

stupid slow azz Post Office

 

:runlol:

 

Speaking of the coolant temp sensor, does anyone know what the Nissan part number for it is?

 

why would you need that ?

 

Just go to NAPA and save yourself some money. I think it was $20.

The NAPA part # is ts5520sb

 

OK, I have the problem 1/2 way fixed.

I was stupid and disconnected the battery before starting any work. What I should have done was check for codes, then disconnected the battery. I guess the stored codes were gone the first time I got a 55.

Anyway. The only other time I started the car was when I did that video. Just a few minutes ago, I went out and tried to start it and the car was "possessed" again. I checked the codes and got a 13 (coolant temp sensor). I replaced the coolant temp sensor and it does run better, the fans do not come on at all and the car will start up like normal. I reconnected the battery and I also rechecked the ECU and got 55 again. There is no code for IACV problems that I could find in the FSM, so maybe it is bad, since I still have some problems.

However, the idle is still surging a bit (not nearly as bad) and is idling somewhat rough, sounds like I have a mild cam. It also still smells like it is burning too much fuel (running rich) which it wasn't doing before. This is possibly the IACV or maybe an injector. When I give it throttle, the engine seems to climb normally and quickly. It didn't throw a 45 code (injector leak).

I think the IACV has been clogged or screwed up since I got it back from Jeff. It hasn't idled right. Hopefully, when I put that on, things will be back to normal. Right now I think it is driveable, where I have been afraid to drive it because it wouldn't start.


Cliff Notes: CHECK YOUR CODES FIRST!

I think the problem is twofold = IACV and coolant temp sensor.

Replaced temp sensor and it's better, but not totally fixed.

Will do the IACV when it gets here and I have some free time.

 

Luckily, my 1500 RPM idle is was the fact my idle adjustment screw had backed off... ALOT. I think it just vibrated back, it seemed loose when I adjusted it back. I put a small piece of solder to hold it.

 

thats good to hear chris. I still haven't pin-pointed my problem. Imight go down and get a coolant sensor(saw they were only $20?) also, unfortunatly, i dont have a code reader because the cheapest ones around for a nissan are 200+(they have cheaper ones but they only work for ford and chevy)

 

You don't need a code reader, you can just turn the key on and then turn the screw on the side of the ECU all the way to the right, then all the way to the left and it will flash the red light for the codes. First group of long flashes = first number, second group of short flashes = second number. The codes are:

11 = camshaft position sensor circuit
12 = MAF circuit
13 = coolant temp sensor circuit
14 = speed sensor circuit
31 = ECM
32 = EGR function
33 = o2 sensor circuit
35 = EGR temp sensor circuit
43 = throttle position sensor circuit
45 = injector leak
51 = injector circuit
54 = AT control unit (auto tranny only)
55 = No malfunction in the above circuits

 

done yet?...............

 

Jeff92se has exceeded their stored private messages quota and can not accept further messages until they clear some space.

 

looking at your video i had a very similar problem but mine would hesitate and when driving. i fixed the problem by replacing the air flow sensor and o2 sensor, your problem seems to be the air flow sensor swap it out and it should fix your problem

 

I hope you get it figured out,mine has a similar problem,can anyone tell me where the ECU is on a 91 so I can check for codes?Sorry I'm a newby at working on these.

 

ecu is behind the radio

 

OK, my problem is totally fixed. Car purrs like a kitten and idles strong.

A HUGE thanks to MrGone for sending the IACV in a timely fashion. I owe you Shawn, but you know that.

Anyway, the problem was twofold. The coolant temp sensor was bad and the IACV was not working correctly. I also replaced both the IACV and TB gaskets with brand new ones from my Nissan dealer.

When I replaced the coolant temp sensor, it behaved somewhat better. When I replaced the IACV, the idle smoothed out and stopped "hunting" and surging.

When I checked the codes, it showed faulty coolant temp sensor. When I replaced that, the code for all systems OK (55) popped up. That just shows me that IACV problems likely aren't going to show up and need to be diagnosed through trial and error.

 

coolbeans.

I was going to ask earlier today but figured you'd probably update tonight



I haven't done much to my car since you left I'm bad

 

Cool!!!!... Glad you finally got her fixed.