rdw72777

So i finished the MAF/IACV/TB/EGR tube cleaning today. Put everything back together and went to start her up today.

Car starts and revs to about 4,000 rpm (which could be me screwing up the Idle Screw I know) and then dies. When it dies it idles real rough and I can see the engine shaking, and when it dies it sound slike its gasping for air and I hear vacuum suction but can't tell from where. Unfortunately from start to die is about 10 seconds so its difficult to diagnose much..I wish roommates were home.

I had most of the hoses labeled so they are all hooked up the way they should be...any thoughts? Is it possible a hose could cause this

beansrmajikle

This happened to me after putting a salvage motor in the car. It is most likely a vacuum leak dude. I only put on my airbox without any of the piping and couldn't figure out why it was dieing. Check that all the hoses on and around the airbox are connected, including those on vacuum gallery A and B.

rdw72777

I mean the more times I try and start it and it dies I hear the vacuum leak more pronounced. problem is I've removed the Air box et al numerous times and I know those hoses are on there correctly. Ugh.

I think it may just make sense to try and tkae it all apart (next weekend) and try and find the leak. I just can't find anything near the air box. Quite honestly it sounds like its down near the EGR tube. But I know the EGR tube is mounted back on and I didn't unhookl any hoses dowwn by the EGR tube so I'm sort of at a loss. Every hose I did remove during this entire process was in good shape (surprisingly good actually) so I don't think the process if disassembly/reassembly damaged any hoses.

Oh well. Disassembling everything the second time won't be near as hard as the first time :-)

beansrmajikle

There are so many vacuum lines right there around the intake though, and you can't really see most of them because the throttle body is in the way, but moving that stuff around could have pulled one of them off. Errr wait did you take off the UIM when you did all this? If so that could be leaking, or the line that runs from the UIM to the valve cover on the back side that is impossible to put on unless you have the UIM completely disconnected.

rdw72777

Removing the UIM is WAY beyond what I'm comfortable doing. I just wish I could find the leak. The damn thing stalls so quickly I can't really find it.

Maybe you're right, maybe I did unhook something without realizing, but my fear of this made me take a good hard look around for unhooked hoses before I put the TB/IACV and Air box. Thought everything was where it was supposed to do. These hoses are really clamped on so I don't think I could have accidentally unhooked one.

Yeah I put an ad out on Craigslist to see if one of these mobile mechanices wnats to find the leak for me. Unfortunately I'm starting to work 2 jobs this week so finding time to do it myself will bu difficult. If I cant find this, then it will become a weekend only project.


Thank god for public transportation.

95maxse3000

there is a big vacuum hose that is on the uim on the passenger side. if it has a leak somewhere it could cause the vacuum noise your hearing and the stalling problem

95maxse3000

check it with a scanner and see if you can pull any codes out.

rdw72777

I probably should have stated the only codes I pulled currently are P0325 (KS) and P0443 (ECPVCV), which were there at the start of the process. On an odd note the P0400 (EGR) that started this all is now gone; I guess that's technically a positive. No new codes have appeared with this potential vacuum leak issue.

The only problem I really have is that the engine doesn't run long enough to truly find the leak. So I think, like I said, I need to take "humpty dumpty" apart yet again and re-trace mysteps but checking not just what I worked on but anything that I might have bumped. I'm sure if it ran for 60 seconds before stalling it'd be easier, but that's life.

And if that doesn't work, I have no problem taking it to a mechanic to find a vacuum leak. That's something that I will be very unlikely to get destroyed financially with.

One thing though, does the high revving at startup also sound like a symptom of a vacuum leak. It goes up to like 4,000 RPM's at startup and drops down after about 5-10 seconds. I've done some searches and I've yet to see where a vacuum leak causes high revving like this (the rough idle and stalling I think we all agree could very much be vacuum leaks).

95maxse3000

a vacuum leak can cause high idle(1000-1500 rpm) but never that high. check your fuel pressure. it should be between 34-36 with engine idling and 43 psi with engine off key on if its over 43 you will need a new fuel pressure regulator. codes p0443 is evap canister purge volume control solenoid valve.
check the wiring harness on the bend spot on top of the engine on the right side(as sitting in the driver seat) make sure theres no wire showing or and breaks in the harness.

rdw72777

I kind of thought that the issue seemed to be different from the vacuum leak. Checking the FPR is the same dilemma as vacuum leaks; I only get 15 seconds or so before it stalls each time I startup. So testing it is "complicated" lol.

It may just be time to go to a mechanic and get a bunch of stuff done and suck it up for the $1,000+ I know I'll get taken for.

95maxse3000

the car doesent have to be running to get a pressure test with engine off and key on it should read 43 psi. with engine running it will be 34-36 psi

rdw72777

Didn't feel like reading the FSm tonight, but I'll read the testing procedured and see what I get.

HandsonMaxima.

iTrader: (2)

dude can you please either resize your stupid sig or only have it post once a thread. ****s annoying.

did you TOUCH your tps, if so, thats it. Did you use gasket maker on all the parts you changed? if you didnt buy a new TB gasket then theres one leak. another could be with your IACV. its not your MAF or else you couldnt get above 2.5krpm so dont worry about that.

long story short i think you messed up near the egr somewhere, your going to need to take apart and put back together everything sadly to figure out all whats wrong.

when you go to bed tonight unplug the battery. let the ecu reset itself

rdw72777

I didn't intentionally do anythign with the TPS but who knows. I unplugged it to take out the TB, but I didnt do anything with the TPS itself

Taking it apart won't be too hard, all of the bolts are anti-seized. Plus the EGR tube doesn't need to come off for the inspection in my opinion. Even if it does, its still going to be quick.

Let me ask this semi-dumb question. I misunderstood the directions about taking off the accelerator and cruise control cables and actually undid the bolts that help them in place (instead of releasing the cable from the tb asssembly like I was supposed to). Is it possible that I over/under tightened the cables and that could cause the revving issue.

Sorry I forgot to mention that earlier. If it has become apparent yet, I'm not only anoob, but kind of spacy as well. Right now I'm more concerned about the revving cuz that could really damage things in a hurry. The vacuum leak is probably something that will just take time (i.e. re-doing the whole process for EGR tube and checking every hose again).

Oh, and I dont know how to resize my signature...I didn't even know I had one. It doesn't show up on my screen.

95maxse3000

how can i get the pic smaller? i tried cus its annoying me but i couldn't figure it out lol.

95maxse3000

the sig was me man lol. it could be the cables not adjusted right. and if for some reason its holding the throttle wide open the ecu will tell the fuel pump to shut off causing it to stall. just like if the engine floods hold it wot and the fuel pump wont send fuel. so when it primes it just enough to keep it running for a couple sec at wot then shuts off.

rdw72777

So my next process is to take off the air box and check the setting on the TB, which of course I should have done during re-assemply but I totally forget i screwed up the cable removal.

I'm now also wondering if I put the throttle body drum back on correctly. Pretty sure I did, but there are no pictures of what the drum looks like since its pretty much never removed. I wish I hadn't screwed up the cable removal step lol.

Good night man, thanks alot.

HandsonMaxima.

iTrader: (2)

throttle body drum?
just calibrate your tps first

rdw72777

So basically, when I removed the battery cables I thought you had to remove the little thing on the outside towards the front that attaches to the TB. I ook the little screw off and popped it off, which helped remove the first cable (I think the one to the left is the cruise control cable). However that didn't help with removal of the second cable, so I posted on here and figured out the cable can just pop out of the little thing they are hooked into, which I did with the second cable.

I just need to re-trace my steps with that process and make sure everything looks okay. I also need to pull off the airbox and see if the TB is stuck open while the car is off, as the revving says the TB is def stuck open. If its not stuck open while off, I'm sure the TPS thing is correct.

One question though, it seems that in the FSM to test the TPS itself the engine is supposed to be warmed up. Since mine stalls out after a short time, will my cold engine TPS still test in the range prescribed in the FSM?

Page EC-166
http://www.nicoclub.com/FSM/maxima/1995/ec.pdf

HandsonMaxima.

iTrader: (2)

great idea about the tb.

but none of that means the tps is correct, it is its own separate entity, it just meansures.

rdw72777

Oh yeah, just laying out my process of elimination. This message board is not only a sounding board when i screw up but also how I plan my work schedule.

1. Check TB, see if its stuck open when off.
2. Check that TB "drum" was re-attached corretly.
3. Check the TPS vs FSM specs
4. Check Fuel pressure Regulator.

I can't think fo too much else that could cause the crazy revving. Solving that should get me to where my engine will at least run but be normal RPMS and hopefully not stall, which will make the finding of the vacuum leak MUCH easier.

Just in case though, what would be your recommendation about a TPS from a scrapyard should it come to that. I always try to sue the scrapyard first, but curious if its a part I should try and get new. Its not too terribly expensive but I bet its $20 at a scrap yard.

rdw72777

Took off the Airbox tonight, and checked the Throttle body. It didn't look like it was being held open with the engine off. It got dark so I didn't get to do too much else.

Will need to check TPS next, couldn't get to that tonight as I needed to get caught up on Lost from last week so I was in the loop for tonight's episode

Decided to throw some low quality cell phone pics up in case ther eis something obvious that I'm missing. TB looks okay, its fully closed with engine off, and the slack on the cable looks acceptable. For the life of me all the hoses look hooked up correctly.

rdw72777

Put the Airbox, hoses and connectors all back on this morning so I could spray some carb cleaner in to try and find vacuum leak. Lo and behold the high revving is gone...in fact it barely catches at all now lol. Still stalls quickly too so that's comforting :-)

Tested the TPS and couldn't get any voltage on pin 1, so who knows. I've officially given up. Just going to put in a new KS harness so hopefully the KS code will go away. I don't want the shop to waste time investigating any KS issues, since they seem unrelated to these issues.

Then going to push her to the auto shop. Set aside $1,000 to put into a car worth about $1,000; but the frustration/confusion just isn't worth it.

Thanks all for your help..."next time, next time"

eddie982

iTrader: (10)

I know people will just love to chime in on bumping an old thread but it would help others to know if and how this issue was fixed. OP- did you take it to the shop and get it fixed, what was the cause?

maximus_2

I too would like to kno wat was the conclusion to this?

rhonster

I don't know the conclusion but was I was having a minor starting issue and sink in rpm below 600 so was told to clean the IACV or replace it. I then went back to motorcycle 101 and picked up a tin of SeaFoam, ran a full can through a full tank and the problem had gone away in the first 50 miles. ( I did a follow up oil change after the full tank was gone and was surprised with the dirt in 3000 mi old oil )