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Valve and TBI questions


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I just go through have headers put on my 89. $200 labor, $230 pacesetter headers, $60 @ dealer for replacement bolts, nuts & washers. They guy worked from 8:30am to 4pm, awesome job for the money.

 

However, in the process I noticed a couple of things that concern me. Only one stud was broken, passenger side, upper rear. The wierd thing is, and the guy noted this to me, the manifold for the most part was rust red in color, but right outside the middle it was grey, like brand new kinda grey. He said it was running lean and that is why it was that color at that cylinder. The opposite side was not that way but when he shined his light up there we could both see that the valve itself was coated in white rather than black like all the rest. Another clue? He said that it was a sign of the truck running lean.

 

Now, I have to deal with the smog Nazis and have been having trouble getting through inspection. It was said on a topic I posted a while back that if it is failing the carbons that it is running rich, and if all the codes have been checked, fixed etc... then maybe the injectors are warn and need to be replaced.

 

Any advice here would be great, there is deffinatly somthing wrong but putting my finger on it is a problem.

 

Next question, the drivers side manifold had two pipes coming from it, the front side was going to the emmisons thing(for lack of what it really called) behind the driver side headlight, and one coming from the rear going to the EGR valve. Pacesetter put one tap in the headers and it only EGR tube fit it. However, since it was on the front side we cut the EGR pipe nipple off and welded it to the other pipe and it fit fine, we welded the end of the EGR pipe shut and put it back on so that in the future we can put a T in the other pipe and perhaps it.

 

Any thoughts on this as far as will it hurt emmisions not to have a functional EGR?

 

Sorry for the book guys just want to be detailed.

 

Your response is appreciated in advance. I would offer Jack Daniels to ye gods of the Pathfinder but alas no one is local so :beer:

 

Thanks,

 

Joe

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You won't pass any visual inspection if the EGR isn't hooked up, for one. The "emissions thing" is the carbon canister, which recycles fuel vapor from the tank back into the intake.

 

You can compression test it... If any cylinder reads too low or differs from an adjacent cylinder more than 5-10 psi or so, it may have a bad head gasket or ring problem.

 

Try replacing the PCV valve. If it quits working it'll allow all the crankcase pressure to shoot into the intake PAST the MAF, which makes it run funny. It causes the O2 sensor to read lean, but the MAF isn't seeing that much airflow so the ECU won't know which way to go on fueling.

 

Also, I bet if you remove the TBI and the EGR valve, the valve passage will be completely plugged up anyway. Here's what mine looked like after about 140k miles...the passage is on the top of the pic, see the black crust crap where there should be an open hole? I had to dig that stuff out with picks and carb cleaner for a half hour before it was clean.

intakecrust1.jpg

 

Bottom line is, you have to MAKE SURE EVERYTHING WORKS before trying to smog it, cause one thing will screw up another thing and cause a cascading crap-effect on emissions.

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Wow, I'm feelin you guys... How the hell, or did it even run?

 

Hate to pop you theory though 88, I had the PCV and the Heater plate replaced last fall and no such blockage, a little dirty yes but a clear visual into the manifold. I do agree however that somthing is wrong and am determined to find out what.

 

Anybody know a way to test the injectors? I am interested and will test the compression in the cylinders, thanks 88...

 

 

The search continues...

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Although not quite as bad, I also had to clean the passage out on my truck.

It builds up over time... perhaps local environment, difference in fuel quality and driving style could all make a difference on how quickly it builds up. But no matter what it does and there will come a time that it needs to be cleaned ;)

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I wish I didnt have to deal with emmision here, but for now its cheaper to try and fix it than move so...

 

 

Any thoughts on the injectors needing to be replaced?

 

Thanks for your thoughts guys...

 

Joe

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They're expensive and it takes a special tool to remove them from the TBI. I had to make a tool to get mine out. Honestly, if injectors are malfunctioning it'll usually throw an error code and run funny. I doubt that's your problem.

 

When I took apart my little bro's 85 Blazer engine, the exhaust valves were all multicolored...I wouldn't worry about it unless they have some real thick nasty deposits on them.

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Special tool? I used a pair of diagonal cutters and pried on one and it poped right out. Read the manual and it said to push it out from the bottom though. Meh, I didn't do any damage to it my way ;) .

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Nope, no special tool here either... I did it much like you did GG

 

As for the cost, they are typically expensive but a local parts guy found me a killer deal on my replacement pair. :aok:

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2 questions 88: do you have any sort of backfireing or any wierd popping noises around 1500 Rpm on decelleration? and are you auto or manual? I have a manual and it has been doing that for years just wondering if it could be your clogged spot before I take it all apart...

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I'm a different 88 but I have an auto and I also experiance the same exhaust popping noise when I rev the engine a little and let it go back to idle. Not quite a backfire just kind of a light popping noise. I have had problems with my EGR valves clogging, but whether that is the cause of the noise :shrug:

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2 questions 88: do you have any sort of backfireing or any wierd popping noises around 1500 Rpm on decelleration? and are you auto or manual? I have a manual and it has been doing that for years just wondering if it could be your clogged spot before I take it all apart...

No, but it does do a wierd little "bump" thing where RPM's fluctuate between 1500 and 1700 a few times before it settles down to below 1500. Only on deceleration.

 

I have an auto, and it never gave me any problems with the clogged EGR port. It simply didn't work. *shrug*

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After haveing the headers installed mine EGR plugged runs better than ever. I did go back to the muffler shop beacause it was making sort of a poping sound on decel, I thought maybe cause I had a resonator tip on it but turns out it was an exhaust leak in the doughnut, the guys fixed me right up with a thicker gasket than the one that came with the pacesetters.

 

Moral of the story, a slight leak may make some noise on decel due to sucking in cold air. I seem to remember also that poping on the decle may have somthing to do with timing and inefficient burning of fuel but I wont swear it.

 

Good luck...

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Well I'm glad its not only me anyway...Still I wish I could figure ot out. Its really loud on my truck with the headers and exhaust. Maybe if I could figure out a way to increase the backpressure it might lessen it. What do you guys think?

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I was in search of more info on the emmisions system so I can satisfy the smog nazis and ran across this.

 

Anti-Backfire (AB) Valve

To check the AB valve, Open the engine hood, and remove the air cleaner cover. With the filter out, and the engine running at idle, place your finger over the opening in the base of the cleaner. If the valve function correctly, there should be a sucking action under all conditions, except under throttle.

 

There is an illustration and much more info at this web site:

 

http://search.epnet.com/login.aspx?authtyp...site=autorefctr

 

username=fl2823 password=horn

 

cut and paste the following link after you login:

 

http://arrc.epnet.com/autoasp/framerq.asp

 

Hope it helps...

 

:beer:

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