L98 plenum and runner question
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Pro
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L98 plenum and runner question
Hey everybody, is it possible to remove the plenum and runners in one piece?
Or do I have to loosen the runners on one side to get it all out?
That way I only need to get runner to manifold gaskets when I replace the injectors.
Or do I have to loosen the runners on one side to get it all out?
That way I only need to get runner to manifold gaskets when I replace the injectors.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
you won't save more than a few bucks.
the deal is that the runners are a bitch, they have to be rotated out to clear the valve covers. even by themselevs it is time consuming.
joe
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just finished mine this week. supposedly you can remove plenum/rt runner asm, but I couldn't do it. the gasket set included all, plus TB, which I did not remove, also o rings except the two for fuel lines.
you won't save more than a few bucks.
the deal is that the runners are a bitch, they have to be rotated out to clear the valve covers. even by themselevs it is time consuming.
joe
you won't save more than a few bucks.
the deal is that the runners are a bitch, they have to be rotated out to clear the valve covers. even by themselevs it is time consuming.
joe
Le Mans Master
Joined: Aug 2007
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From: WV
Better then that , you can remove just the plenum and replace the injectors without removing the runners..Here is the PDF..This is how I did the injectors on my 89....Easy...
..WW
http://mysite.verizon.net/brianjbalo...torRemoval.pdf
..WWhttp://mysite.verizon.net/brianjbalo...torRemoval.pdf
Last edited by WW7; Jul 3, 2011 at 03:24 PM.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
Better then that , you can remove just the plenum and replace the injectors without removing the runners..Here is the PDF..This is how I did the injectors on my 89....Easy.....WW
http://mysite.verizon.net/brianjbalo...torRemoval.pdf
..WWhttp://mysite.verizon.net/brianjbalo...torRemoval.pdf
have not watched the pdf to which WW7 refers, but the III's are seated in intake, then fuel rail is seated over them, bolted down.
I had heard this, and tried to see if I could make it worthwhile to do that way, decided I had plenty of time. seemed easier to remove runners.
joe
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vette79, gaskets came with the Bosch III's, FIC, but any parts house will have them.
have not watched the pdf to which WW7 refers, but the III's are seated in intake, then fuel rail is seated over them, bolted down.
I had heard this, and tried to see if I could make it worthwhile to do that way, decided I had plenty of time. seemed easier to remove runners.
joe
have not watched the pdf to which WW7 refers, but the III's are seated in intake, then fuel rail is seated over them, bolted down.
I had heard this, and tried to see if I could make it worthwhile to do that way, decided I had plenty of time. seemed easier to remove runners.
joe
Only those on top and bottom of each injector.
Been checking FIC´s new site, he has a set for 30 usd.
I guess I´ll buy that one and see if I only remove the plenum and TB or the runners as well.
I saved the PDF, just in case.
I read somewhere that when you remove the fuel pump fuse prior to dismantling the whole thing, will depressurize the fuel system.
Sounds logical, but is there a downside other than that it might take a long time for the car to start after finishing the surgery.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
Bought mine from FIC (been two or three years) and didn´t come with any gaskets.
Only those on top and bottom of each injector.
Been checking FIC´s new site, he has a set for 30 usd.
I guess I´ll buy that one and see if I only remove the plenum and TB or the runners as well.
I saved the PDF, just in case.
I read somewhere that when you remove the fuel pump fuse prior to dismantling the whole thing, will depressurize the fuel system.
Sounds logical, but is there a downside other than that it might take a long time for the car to start after finishing the surgery.
Only those on top and bottom of each injector.
Been checking FIC´s new site, he has a set for 30 usd.
I guess I´ll buy that one and see if I only remove the plenum and TB or the runners as well.
I saved the PDF, just in case.
I read somewhere that when you remove the fuel pump fuse prior to dismantling the whole thing, will depressurize the fuel system.
Sounds logical, but is there a downside other than that it might take a long time for the car to start after finishing the surgery.
I removed FP fuse, ran engine unitl it ran low on pressure, let sit overnight. you have to pressurize rail to check for lks, so install fuse, turn key on and off a dozen times. don't try to start.
when it is complete and batt cable has been disconnected for 10 mins, it does require about 15-20 secs to run, not sure if ecm resetting, or fuel pressure, but not an issue, just a surprise, because I "checked" schrader valve with a finger and there was fuel.
*** the Haynes manual is good for this, and I followed it pretty much. was replacing hoses to TB coolant so I removed most of the "front" but no need to rem TB.
Last edited by joe paco; Jul 3, 2011 at 04:13 PM. Reason: add ***
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Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
it is mostly wrench work, and thinking of next steps while doing so. I used a simple checklist that saved me from having to remove rail to clear out the Intake manifold temp switch.
joe
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
the wire connector plugs in as plenum is reassembled to runners. I had captured it beneath the rail somewhere, so when I pulled it to see that it was clear, I caught it before I went too far.
also, one hard plastic vac line goes OUTSIDE the plenum, on passenger side, it and all lines under plenum need to be dressed before plenum is assembled. if so, you can plug in in a few seconds.
even if you know, take some close ups of lines and hoses routing esp in the front of engine. I forgot your year but mine was 91. of course, you can put paint dots on inj plugs, 1-6 dots, to ID those.
j
also, one hard plastic vac line goes OUTSIDE the plenum, on passenger side, it and all lines under plenum need to be dressed before plenum is assembled. if so, you can plug in in a few seconds.
even if you know, take some close ups of lines and hoses routing esp in the front of engine. I forgot your year but mine was 91. of course, you can put paint dots on inj plugs, 1-6 dots, to ID those.
j
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From: Overland Park Kansas
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You could probably remove all runner bolts and pry the plenum/runner assm off the intake. The problem would be aligning/slipping the runners over the new gaskets. I'd think that would be VERY difficult (if not impossible).
Removing the plenum (only) is the proven way to short-cutting the process.
If you turn the key to "on" and listen, you'll hear the fuel pump (line) pressurizing. Not sure why depressurization would be an issue. It doesn't hurt the motor to rotate a few extra times before firing. In fact, the ECM programming diliberately delays firing for about 10 cycles. I coded my for 5 to make it start more like a "normal" car.
Not a bad feature though...at least it insures the oil pump has time to pressurize before ignition. (That's why I didn't change mine to no delay).
Removing the plenum (only) is the proven way to short-cutting the process.
If you turn the key to "on" and listen, you'll hear the fuel pump (line) pressurizing. Not sure why depressurization would be an issue. It doesn't hurt the motor to rotate a few extra times before firing. In fact, the ECM programming diliberately delays firing for about 10 cycles. I coded my for 5 to make it start more like a "normal" car.
Not a bad feature though...at least it insures the oil pump has time to pressurize before ignition. (That's why I didn't change mine to no delay).
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 78
From: Monroe OH
NCM Sinkhole Donor
I have rmoved the complete manifold on both of my cars combined a total of 5 times. I use the factory manual if I have any questions. I think it would be very difficult to remove the injectors without removing the runners. Not saying it isn't possible, but it would be difficult to remove and replace the injectors without using some force. I don't understand why one would want to cut corners to save time and take a chance on damaging new injectors. As well, doing a complete dissasembly would allow to inspect the system. As far as where to get the gaskets, you could get them from TPIS or Chevy parts dealer. Good luck.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
You could probably remove all runner bolts and pry the plenum/runner assm off the intake. The problem would be aligning/slipping the runners over the new gaskets. I'd think that would be VERY difficult (if not impossible).
Removing the plenum (only) is the proven way to short-cutting the process.
If you turn the key to "on" and listen, you'll hear the fuel pump (line) pressurizing. Not sure why depressurization would be an issue. It doesn't hurt the motor to rotate a few extra times before firing. In fact, the ECM programming diliberately delays firing for about 10 cycles. I coded my for 5 to make it start more like a "normal" car.
Not a bad feature though...at least it insures the oil pump has time to pressurize before ignition. (That's why I didn't change mine to no delay).
Removing the plenum (only) is the proven way to short-cutting the process.
If you turn the key to "on" and listen, you'll hear the fuel pump (line) pressurizing. Not sure why depressurization would be an issue. It doesn't hurt the motor to rotate a few extra times before firing. In fact, the ECM programming diliberately delays firing for about 10 cycles. I coded my for 5 to make it start more like a "normal" car.
Not a bad feature though...at least it insures the oil pump has time to pressurize before ignition. (That's why I didn't change mine to no delay).
was surprised that starting took longer than it ever had, but figured the ecm was doing that.
joe
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From: Overland Park Kansas
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Le Mans Master
Joined: Aug 2007
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From: WV
The plenum is wedge shaped for a reason, the reason being so it can be lifted straight up and removed without removing the runners.I have removed my plenum many times without ever loosening the runners, when the plenum bolts are removed the runners flare out a small amount.. Once the plenum is removed the fuel rails are unbolted and seperated before lifting them from the base ( this way they clear the runners). Using the PFD that I supplied I can replace injectors in half the time it takes if removing the runners and do just as clean a job. At least give it a try, if it doesn't work for you all you have to do then is remove the runners.....Also before bolting everything back together don't forget to pressurize the fuel system to make sure nothing leaks..Im just letting you know this procedure works, its up to you if you use it or not.....
...Good Luck...WW
..Also before bolting everything back together don't forget to pressurize the fuel system to make sure nothing leaks..Im just letting you know this procedure works, its up to you if you use it or not........Good Luck...WW
Last edited by WW7; Jul 3, 2011 at 08:43 PM.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
not being argumentative, just clarifying. removing plenum, then disassembling fuel rail can be accomplished, maybe, but my first time, didn't want to cause myself grief.
saludos,
joe
Burning Brakes
Joined: Feb 2010
Posts: 1,013
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From: California City Ca
I had a leaking O ring one #1 Injector I pulled that Injector and out it back in with out removing the plenum and runners It was not fun but it can be done.
10 mm wrench lossen up the fuel rail and pry it up.
I just wanted ot see if it could be done.
I would not do it again.
If I was going to replace all the injectors I would pull the Plenum and runners.
The 9th injector can be a pain sometimes.
I found out when putting runners back on leave the base runners bolts LOOSE so they can move around so when you put the Plenum back on it easyer to put the plenum gaskets back on with out tearing them.
After all the Runners bolts and Plenum bolts are put in loose then tighten them.
You can get gaskets from Summit Racing either OEM Felpro sell a kit for cheep I have SLP cost a little more but the runners are larger bores.
10 mm wrench lossen up the fuel rail and pry it up.
I just wanted ot see if it could be done.
I would not do it again.
If I was going to replace all the injectors I would pull the Plenum and runners.
The 9th injector can be a pain sometimes.
I found out when putting runners back on leave the base runners bolts LOOSE so they can move around so when you put the Plenum back on it easyer to put the plenum gaskets back on with out tearing them.
After all the Runners bolts and Plenum bolts are put in loose then tighten them.
You can get gaskets from Summit Racing either OEM Felpro sell a kit for cheep I have SLP cost a little more but the runners are larger bores.
Thread Starter
Pro
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Funny, I didn´t recieve an email about new replies.
Well, I´ve read them all sofar, and I ordered a set from FIC for 30 USD and I will try it the PDF way first.
If I see that the runners aren´t going to be a problem I might as well take them out also, but it seems they can be a pain to get out.
I do know that I have been tightening one of the runner to base bolts once, three years ago, that was somewhere around the 6-8 cylinder.
Well, I´ve read them all sofar, and I ordered a set from FIC for 30 USD and I will try it the PDF way first.
If I see that the runners aren´t going to be a problem I might as well take them out also, but it seems they can be a pain to get out.
I do know that I have been tightening one of the runner to base bolts once, three years ago, that was somewhere around the 6-8 cylinder.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
Funny, I didn´t recieve an email about new replies.
Well, I´ve read them all sofar, and I ordered a set from FIC for 30 USD and I will try it the PDF way first.
If I see that the runners aren´t going to be a problem I might as well take them out also, but it seems they can be a pain to get out.
I do know that I have been tightening one of the runner to base bolts once, three years ago, that was somewhere around the 6-8 cylinder.
Well, I´ve read them all sofar, and I ordered a set from FIC for 30 USD and I will try it the PDF way first.
If I see that the runners aren´t going to be a problem I might as well take them out also, but it seems they can be a pain to get out.
I do know that I have been tightening one of the runner to base bolts once, three years ago, that was somewhere around the 6-8 cylinder.
the WORST part is the btm bolts on the runners, because you can't get the #40 Trx on them, UNLESS you asemble the right tool for it.
one tip: I used invisible tape to tape all gaskets at their top, close to bolt holes -even over one hole- to keep them in location during the wiggling part of reassembly. no way the tape would cause a vac leak, since it's only. 0015" thick. of course, keep the gaskets lying flat.
' it's as easy as you let it be,' so my dad used to say.
saludos, joe
** if you get any questions, sent a PM or post.