Go Back   Rotary Car Club > Tech Discussion > RX-7 2nd Gen Specific (1986-92)

RX-7 2nd Gen Specific (1986-92) RX-7 1986-92 Discussion including performance modifications and technical support sections.

Reply
 
Thread Tools Display Modes
Old 01-28-2009, 12:15 PM   #16
Hello Roto
El Mas Tiguere..DR
 
Hello Roto's Avatar
 
Join Date: Jan 2009
Location: Big Red Country
iTrader: (0)
Posts: 21
Rep Power: 0
Hello Roto is on a distinguished road
Default

Have you checked your injectors yet? They may be old and leaking...






__________________
DD: 91' Slow EF'in Hatchback
Project: 87' TII *Rebuild* (Build Thread Pending)
Hello Roto is offline   Reply With Quote
Old 01-28-2009, 12:24 PM   #17
djmtsu
My minds tellin' me no...
 
djmtsu's Avatar
 
Join Date: Feb 2008
Location: Murfreesboro, TN
iTrader: (10)
Posts: 4,043
Rep Power: 21
djmtsu will become famous soon enough
Default

Quote:
Originally Posted by classicauto View Post

Are you running all leadings? or all trailings? Never tried all 7's in a boosted (even stock boosted) 13B before....interesting.
Wait, I can't remember now. Been a while since I changed them!
__________________
1976 Mazda Cosmo RX-5
1976 Mazda Cosmo RX-5
2003 Toyota Tundra TRD
2015 Toyota 4Runner SR5
djmtsu is offline   Reply With Quote
Old 01-28-2009, 12:34 PM   #18
vex
RCC Loves Me Not You
 
vex's Avatar
 
Join Date: Jul 2008
Location: Influx.
iTrader: (6)
Posts: 2,113
Rep Power: 19
vex will become famous soon enough
Default

Quote:
Originally Posted by Hello Roto View Post
Have you checked your injectors yet? They may be old and leaking...
They were cleaned awhile ago. I don't think an old and leaky set of injectors would only misbehave when operating temps were reached. could be mistaken though.
vex is offline   Reply With Quote
Old 01-28-2009, 07:43 PM   #19
WE3RX7
RCC Addict
 
Join Date: Feb 2008
Location: VA
iTrader: (1)
Posts: 1,812
Rep Power: 18
WE3RX7 is on a distinguished road
Default

Are you sure its the engine and not electrical issues? Weak alt, etc?

If the idel is not lopy (like 1500 to 3000, back to 3000, etc) its probably not a vac leak. Pull the new plugs out now and see what they're like just after running for a while. Also, check the fuel filter...
WE3RX7 is offline   Reply With Quote
Old 01-29-2009, 11:16 AM   #20
vex
RCC Loves Me Not You
 
vex's Avatar
 
Join Date: Jul 2008
Location: Influx.
iTrader: (6)
Posts: 2,113
Rep Power: 19
vex will become famous soon enough
Default

Quote:
Originally Posted by WE3RX7 View Post
Are you sure its the engine and not electrical issues? Weak alt, etc?

If the idel is not lopy (like 1500 to 3000, back to 3000, etc) its probably not a vac leak. Pull the new plugs out now and see what they're like just after running for a while. Also, check the fuel filter...
I'm pretty sure I found a vac leak. I checked the vac too on the RTek and it was only pulling in 5inHG. Normally I pull in 11+inhg at idle. The rear securing bolt on the LIM had sheared, and while running it condensation had developed on the engine. The condensation got sucked into it, and that opened up the passage way. Forcing me to cool the engine back off which developed more condensaiton in the vac leak which froze again blocking off the vac leak. Repeat until vac leak was found.

At least that's my theory. I really won't know until I replace the UIM and test out the idle again.
vex is offline   Reply With Quote
Old 01-29-2009, 01:05 PM   #21
classicauto
crash auto?fix auto
 
classicauto's Avatar
 
Join Date: Feb 2008
iTrader: (0)
Posts: 816
Rep Power: 17
classicauto is on a distinguished road
Default

Don't take this the wrong way, but 11 inches of mercury is LOW for an N/A engine especially.

My 1/2 bridge with monster exhaust ports would pull 13in/hg idling!!
__________________
Quote:
Originally Posted by djmtsu View Post
Wars are started over beliefs. Ideas are safer.
classicauto is offline   Reply With Quote
Old 01-29-2009, 04:52 PM   #22
vex
RCC Loves Me Not You
 
vex's Avatar
 
Join Date: Jul 2008
Location: Influx.
iTrader: (6)
Posts: 2,113
Rep Power: 19
vex will become famous soon enough
Default

Quote:
Originally Posted by classicauto View Post
Don't take this the wrong way, but 11 inches of mercury is LOW for an N/A engine especially.

My 1/2 bridge with monster exhaust ports would pull 13in/hg idling!!
(I don't know if the ports have been ported on this engine or not. So they might, they might not) I'm of the thought that I have alot of little vacuum leaks going on. When I rid myself of the emissions crap I imagine that I'll eliminate alot of the vac leaks. I'll have to double check the actual numbers when I idle again.
vex is offline   Reply With Quote
Old 01-30-2009, 05:22 PM   #23
vex
RCC Loves Me Not You
 
vex's Avatar
 
Join Date: Jul 2008
Location: Influx.
iTrader: (6)
Posts: 2,113
Rep Power: 19
vex will become famous soon enough
Default

alright, i put it all back together and it idled fine until it warmed up to operating temperature.

I'm still only pulling 5.8inhg according to the RTek. It's got to be quite a big vac leak as I've checked compression and both rotors are fine. The only thing i've changed would be the egr block off plate though i'm hesitant to mess with it until I remove the emissions (Or it warms up).

Anything else I should check?

I checked the condition of the new spark plugs, still look good. Rear rotor tends to flood when the vac leak presents itself.
vex is offline   Reply With Quote
Old 01-30-2009, 08:20 PM   #24
WE3RX7
RCC Addict
 
Join Date: Feb 2008
Location: VA
iTrader: (1)
Posts: 1,812
Rep Power: 18
WE3RX7 is on a distinguished road
Default

Honestly, vac leaks are either there or they arent, cold or hot. The vac numbers sound low, which isnt good. Its hard to get accurate compression checks with a piston tester, but I'm thinking you may want to do another comprsesion test when the engine is hot and see...
WE3RX7 is offline   Reply With Quote
Old 01-30-2009, 11:05 PM   #25
vex
RCC Loves Me Not You
 
vex's Avatar
 
Join Date: Jul 2008
Location: Influx.
iTrader: (6)
Posts: 2,113
Rep Power: 19
vex will become famous soon enough
Default

Quote:
Originally Posted by WE3RX7 View Post
Honestly, vac leaks are either there or they arent, cold or hot. The vac numbers sound low, which isnt good. Its hard to get accurate compression checks with a piston tester, but I'm thinking you may want to do another comprsesion test when the engine is hot and see...
I did it when the engine was hot. It had just been shut down from operating temp to get the readings.
vex is offline   Reply With Quote
Old 01-31-2009, 02:16 AM   #26
vex
RCC Loves Me Not You
 
vex's Avatar
 
Join Date: Jul 2008
Location: Influx.
iTrader: (6)
Posts: 2,113
Rep Power: 19
vex will become famous soon enough
Default

Just out of curiosity, is there a test I can do to see if I have a coolant seal going? Maybe what I'm seeing in the rear rotor isn't fuel but leaking coolant... Is there any test I could do to see without breaking open the engine?
vex is offline   Reply With Quote
Old 02-01-2009, 01:28 AM   #27
vex
RCC Loves Me Not You
 
vex's Avatar
 
Join Date: Jul 2008
Location: Influx.
iTrader: (6)
Posts: 2,113
Rep Power: 19
vex will become famous soon enough
Default

I"m leaning more and more everyday to my coolant seal letting go. It makes sense as the car dives fine one minute and as soon as it warms up it runs like it's on one rotor. I think the rear coolant seal is letting go, hence why the plugs are continually soaked when I check them when the problem occurs. I also have a rather large plum of smoke when I start the car when it sits and feels like it needs to clear it's throat.

Does that fit the symptoms pretty accurately?
vex is offline   Reply With Quote
Old 02-01-2009, 02:13 PM   #28
Ender
rotors excite me
 
Ender's Avatar
 
Join Date: Mar 2008
Location: Iowa
iTrader: (3)
Posts: 372
Rep Power: 17
Ender is on a distinguished road
Default

Quote:
Originally Posted by vex View Post
I"m leaning more and more everyday to my coolant seal letting go. It makes sense as the car dives fine one minute and as soon as it warms up it runs like it's on one rotor. I think the rear coolant seal is letting go, hence why the plugs are continually soaked when I check them when the problem occurs. I also have a rather large plum of smoke when I start the car when it sits and feels like it needs to clear it's throat.

Does that fit the symptoms pretty accurately?
It's a possibility. You could possibly have an injector that's getting stuck open, too, but I haven't witnessed that before, I'm not exactly sure how it would manifest itself.
__________________
He isn't a killer. He just wins -- thoroughly.


'87 TII
240+ rwhp on my DIY streetport, ~13psi on stock turbo, Racing Beat REVTII exhaust
rTek 2.1 awaits a tune

Quote:
Originally Posted by need RX7
This is why I don't do politics, it's just one stupid thing after another.
360 gamertag: quick Tii
Ender is offline   Reply With Quote
Old 02-01-2009, 02:25 PM   #29
vex
RCC Loves Me Not You
 
vex's Avatar
 
Join Date: Jul 2008
Location: Influx.
iTrader: (6)
Posts: 2,113
Rep Power: 19
vex will become famous soon enough
Default

I think I may just go ahead and pull the engine and order an overhaul kit. I'm fairly certain that the apex seals, oil rings, and other seals are fine on the car, just my rear coolant seal has gone to crap.

I think the only sure way to check to see if I have a seal failure (without taking it to a shop and pressurizing the system) would be to check it with a bore scope through the exhaust ports. I should be able to see a majority of the engine through that. At least from the locations of when the full cycle of the rotor.
vex is offline   Reply With Quote
Old 02-02-2009, 06:57 PM   #30
Whizbang
Respecognize!
 
Whizbang's Avatar
 
Join Date: Jul 2008
Location: Δx = ħ/2Δp
iTrader: (5)
Posts: 3,190
Rep Power: 20
Whizbang will become famous soon enough
Default

what kind of temperature are we talking
__________________
For current updates and event coverage check out
Follow on Twitter! @WhizbangRally
Whizbang Rally's Webpage | Facebook
Whizbang is offline   Reply With Quote
Reply

Bookmarks

Tags
coolant seal failure, egr block off, rtv, vacuum leak

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 09:54 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Hosted by www.GotPlacement.com
Ad Management by RedTyger