Rebuild Refuses to Hold Idle (PICS)
Thread Starter
Joined: May 2006
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From: Jacksonville, Tampa & Tallahassee
Rebuild Refuses to Hold Idle (PICS)
After hours and hours of trouble shooting I finally got my rebuilt 87' Turbo II to start!!!
Problem is, it won't hold idle. In neutral it will bounce from 800 (where it sounds like it's about to die) up to 1200 then drop down again. once in a while it will hold at 1000-1100 for about 2-3 minutes, then it's back to bouncing again.
If it's in gear you can forget about it, the second you take your foot off the gas, the RPM's start dropping, and don't stop until it dies. This is with the clutch fully depressed mind you.
for a more in-depth explaination of what I've done so far please check out:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/t2-rebuild-turns-over-but-wont-start-576866/
Any ideas or suggestions would be greatly appreciated.
Problem is, it won't hold idle. In neutral it will bounce from 800 (where it sounds like it's about to die) up to 1200 then drop down again. once in a while it will hold at 1000-1100 for about 2-3 minutes, then it's back to bouncing again.
If it's in gear you can forget about it, the second you take your foot off the gas, the RPM's start dropping, and don't stop until it dies. This is with the clutch fully depressed mind you.
for a more in-depth explaination of what I've done so far please check out:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/t2-rebuild-turns-over-but-wont-start-576866/
Any ideas or suggestions would be greatly appreciated.
Thread Starter
Joined: May 2006
Posts: 3,881
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From: Jacksonville, Tampa & Tallahassee
Originally Posted by Karack
for how many hours this engine has been idling i would say it should start holding an idle on it's own by now, as i said i haven't had any issues with my rebuilds idling even a few minutes after starting the first time unless the rotor housings were severely thrashed it should run fairly strong right off.
the idle screw should be doing something or you have a leak somewhere or the BAC is completely blocked off internally somehow. if you have a camera try taking some pics of the intake piping, BAC and engine in general to help us see what is going on in there. my bet is the BAC line to the turbo-intercooler elbow is either missing, cracked or not hooked up completely causing the leak.
the idle screw should be doing something or you have a leak somewhere or the BAC is completely blocked off internally somehow. if you have a camera try taking some pics of the intake piping, BAC and engine in general to help us see what is going on in there. my bet is the BAC line to the turbo-intercooler elbow is either missing, cracked or not hooked up completely causing the leak.
As requested, here are some pictures to aid in the diagnosis:
ACV with proper block off plate. Split air hose was MIA so there was a hole where it should connect. I rigged up a lil something to plug it.
The BAC, doesn't appear to be anyting wrong on the outside...
The EGR. When I got it, there was nothing attached to that nipple, so I capped it.
That hose w/ the blue dotted line comes from somewhere between the UIM and LIM right behind the EGR, it was capped w/ a screw (not by me)
The FPR if I'm not mistaken. Also had nothing attached to that downward pointing nipple, not sure if I should cap it or not though
the FPR should be attached to the port on the LIM and could be part of the issue, without vacuum on the FPR it will be pushing 38PSI vs the idling spec of 29 PSI which can be causing flooding issues. another thing to check is the turbo intake duct, they love to crack where they meet the turbo and cause stalling issues.
Thread Starter
Joined: May 2006
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From: Jacksonville, Tampa & Tallahassee
Originally Posted by Karack
the FPR should be attached to the port on the LIM and could be part of the issue, without vacuum on the FPR it will be pushing 38PSI vs the idling spec of 29 PSI which can be causing flooding issues. another thing to check is the turbo intake duct, they love to crack where they meet the turbo and cause stalling issues.
I will spray the hell out of the TID w/ some carb cleaner once I get it to idle again (hopefully right now
)
this thread should give you a better idea of how things should be hooked up, that spider web of vacuum lines looks scary...
https://www.rx7club.com/showthread.p...ight=fresh+air
the FPR should lead to a nipple towards the middle inside of the lower intake manifold.
https://www.rx7club.com/showthread.p...ight=fresh+air
the FPR should lead to a nipple towards the middle inside of the lower intake manifold.
Thread Starter
Joined: May 2006
Posts: 3,881
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From: Jacksonville, Tampa & Tallahassee
I'll take a look at that thread
In that case, I think either the blue dotted line, or the other one that comes from between the manifolds may just bey the FPR line. I guess I'll have to try each one on and see what kind of results I get.
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the FPR should lead to a nipple towards the middle inside of the lower intake manifold.
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Thread Starter
Joined: May 2006
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From: Jacksonville, Tampa & Tallahassee
Update:
I called the shop back and the guy reccomended that I take out the NGK plugs and replace them with some cheap normal plugs for a 94 Nissan Sentra. I was skeptical to say the least, since they didn't look like they would fit properly but I was out of options and ideas.
Surprise surprise, it actually started (after about 4-7 seconds of cranking) and it's started every time since.
I just drove 270 miles on them and they seem to be holding up just fine. The drive also seemed to help w/ compression and startup. Although it still won't idle while in gear, or even in nuetral if the car is moving
I've sprayed all over the place for vaccum leaks and none seem to be present.
I called the shop back and the guy reccomended that I take out the NGK plugs and replace them with some cheap normal plugs for a 94 Nissan Sentra. I was skeptical to say the least, since they didn't look like they would fit properly but I was out of options and ideas.
Surprise surprise, it actually started (after about 4-7 seconds of cranking) and it's started every time since.
I just drove 270 miles on them and they seem to be holding up just fine. The drive also seemed to help w/ compression and startup. Although it still won't idle while in gear, or even in nuetral if the car is moving
I've sprayed all over the place for vaccum leaks and none seem to be present.
Originally Posted by sharingan 19
Update:
I called the shop back and the guy reccomended that I take out the NGK plugs and replace them with some cheap normal plugs for a 94 Nissan Sentra. I was skeptical to say the least, since they didn't look like they would fit properly but I was out of options and ideas.
Surprise surprise, it actually started (after about 4-7 seconds of cranking) and it's started every time since.
I just drove 270 miles on them and they seem to be holding up just fine. The drive also seemed to help w/ compression and startup. Although it still won't idle while in gear, or even in nuetral if the car is moving
I've sprayed all over the place for vaccum leaks and none seem to be present.
I called the shop back and the guy reccomended that I take out the NGK plugs and replace them with some cheap normal plugs for a 94 Nissan Sentra. I was skeptical to say the least, since they didn't look like they would fit properly but I was out of options and ideas.
Surprise surprise, it actually started (after about 4-7 seconds of cranking) and it's started every time since.
I just drove 270 miles on them and they seem to be holding up just fine. The drive also seemed to help w/ compression and startup. Although it still won't idle while in gear, or even in nuetral if the car is moving
I've sprayed all over the place for vaccum leaks and none seem to be present.
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Joined: Jan 2005
Posts: 2,181
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From: USA
Originally Posted by Karack
this thread should give you a better idea of how things should be hooked up, that spider web of vacuum lines looks scary...
https://www.rx7club.com/showthread.p...ight=fresh+air
the FPR should lead to a nipple towards the middle inside of the lower intake manifold.
https://www.rx7club.com/showthread.p...ight=fresh+air
the FPR should lead to a nipple towards the middle inside of the lower intake manifold.
also to the original poster, misrouted vacuum lines can be as bad or worse than completely unhooked/leaking ones. i suggest you restore them all to stock or completely remove emissions and follow the diagam in the thread karack linked. the FPR definitely needs to be connected to a 'fresh air' source, along with the primary and secondary injectors.
another thing, the only reason those plugs worked is because your old ones were probably shot.
Thread Starter
Joined: May 2006
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From: Jacksonville, Tampa & Tallahassee
Originally Posted by Mx6-Rx7 Addict
Those plugs are not the right plug for the rotary motor. get those things out of the car right now. get some new NGK's.
-Justin
-Justin
I will put NGK's back in, just doesn't look like it'll be immediately
Originally Posted by eriksseven
Have you set your timing and TPS since rebuilding?
Originally Posted by NOPR
...also to the original poster, misrouted vacuum lines can be as bad or worse than completely unhooked/leaking ones. i suggest you restore them all to stock or completely remove emissions and follow the diagam in the thread karack linked. the FPR definitely needs to be connected to a 'fresh air' source, along with the primary and secondary injectors.
another thing, the only reason those plugs worked is because your old ones were probably shot.
another thing, the only reason those plugs worked is because your old ones were probably shot.
I plan on following the diagram to reroute the vac lines. Do I need a new gasket if I remove the UIM?
Perhaps my old plugs did crap out, but even when they were new, they would have to be cleaned every couple of cranks. It just seems like the design is very prone to failure. My question is, if normal plugs will work why would mazda go w/ this strange plug instead?
Last edited by sharingan 19; Sep 13, 2006 at 11:45 AM. Reason: add info
Originally Posted by NOPR
NZconvertible is gonna love that you highlighted 'fresh air' haha.
also to the original poster, misrouted vacuum lines can be as bad or worse than completely unhooked/leaking ones. i suggest you restore them all to stock or completely remove emissions and follow the diagam in the thread karack linked. the FPR definitely needs to be connected to a 'fresh air' source, along with the primary and secondary injectors.
another thing, the only reason those plugs worked is because your old ones were probably shot.
also to the original poster, misrouted vacuum lines can be as bad or worse than completely unhooked/leaking ones. i suggest you restore them all to stock or completely remove emissions and follow the diagam in the thread karack linked. the FPR definitely needs to be connected to a 'fresh air' source, along with the primary and secondary injectors.
another thing, the only reason those plugs worked is because your old ones were probably shot.
lol, i couldn't think of any keywords that were bringing that thread up.
the FPR actually needs to be hooked up to a vacuum/pressure source, which is what the middle nipple on the LIM is, if it still isn't hooked up i would start there, as i said it is pushing too much fuel if it isn't hooked up.
Rotary Apprentice
Joined: Jan 2005
Posts: 2,181
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From: USA
Originally Posted by Karack
the FPR actually needs to be hooked up to a vacuum/pressure source, which is what the middle nipple on the LIM is, if it still isn't hooked up i would start there, as i said it is pushing too much fuel if it isn't hooked up.
Thread Starter
Joined: May 2006
Posts: 3,881
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From: Jacksonville, Tampa & Tallahassee
You bring up a good point, fortunately my fuel cut switch seems like it should do the job long enough for me to get a chance to take off the UIM and fix that vaccum mess.
Also, the engine now idles at 700-800 once warm . I know I haven't fixed the vaccum line problem yet so is this new idle be due to the engine gaining compression? or what?
Also, the engine now idles at 700-800 once warm
. I know I haven't fixed the vaccum line problem yet so is this new idle be due to the engine gaining compression? or what?
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