3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.
Sponsored by:

Boost and stalling issues

Thread Tools
 
Search this Thread
 
Old Aug 12, 2009 | 10:17 PM
  #1  
BenjiRX-7's Avatar
Thread Starter
Senior Member
Tenured Member 05 Years
iTrader: (3)
 
Joined: Aug 2007
Posts: 383
Likes: 0
From: Monteral, QC
Boost and stalling issues

I recently installed a used engine in my FD after I cooked a coolant seal. Everything was doing great for about a week untill now. I got these 2 problems that are most likely not related.

First, I get poor boost. I only get about 3-4 PSI max, on the primary or secondary turbo. I don't hear anything like a big wooshing sound that a boost leak would do, so I was thinking of a wastegate jammed open. could it be something else? my rats nest hoses have all been checked before putting the engine in. Last owner says the turbos were rebuilt a year ago.

Also, my engine stalls randomly. When I get into neutral at a red light or a stop, the engine just dies sometimes. It doesnt get flooded or anything, and it starts perfectly after. I can litteraly shut the engine down by getting into neutral reving a little. When I take my foot off the pedal, The revs will simply go down to zero.

It only happens when the engine is hot, but it doesn't happen all the time.


mods: downpipe, intakes, lightweight flywheel, running premix.
Reply
Old Aug 12, 2009 | 10:22 PM
  #2  
RotorDream's Avatar
Rotary Ninja
 
Joined: Oct 2007
Posts: 683
Likes: 0
From: Wichita Falls, TX
I'm assuming you have a stock ECU since a PFC/Haltech/etc. isnt listed in your Sig, but correct me if im wrong. have you noticed if the engine is stalling while you have lights on, AC running, fans running? anything like a heavy electrical load, etc?
Reply
Old Aug 12, 2009 | 10:28 PM
  #3  
BenjiRX-7's Avatar
Thread Starter
Senior Member
Tenured Member 05 Years
iTrader: (3)
 
Joined: Aug 2007
Posts: 383
Likes: 0
From: Monteral, QC
Yes, I have the stock ECU

I assume the rad fans were working when the stalling problem occured since it's pretty hot outside and I was not on the highway, and I was listening to music on the stock bose system.. no real huge electrical load, no A/C.
Reply
Old Aug 12, 2009 | 10:41 PM
  #4  
Speeder165's Avatar
T/Y Jesus! Re-employed!
Tenured Member: 15 Years
iTrader: (7)
 
Joined: May 2009
Posts: 372
Likes: 4
From: TN
It could be something else but have you had the compression checked on that engine?
Reply
Old Aug 12, 2009 | 10:48 PM
  #5  
RotorDream's Avatar
Rotary Ninja
 
Joined: Oct 2007
Posts: 683
Likes: 0
From: Wichita Falls, TX
IIRC bad compression shows most when the engine is cold, but the OP said this only happens when the engine is hot, but I could be wrong.
Reply
Old Aug 12, 2009 | 11:04 PM
  #6  
Speeder165's Avatar
T/Y Jesus! Re-employed!
Tenured Member: 15 Years
iTrader: (7)
 
Joined: May 2009
Posts: 372
Likes: 4
From: TN
It`s the "dying when hot at idle" thing that is making me wonder about it. Mine did it before I dumped the engine & put in a new one recently. Low compression & a coolant seal leak was its demise.

On the low boost issue, have you checked to see if you have the pills in the hoses on the turbocharger actuators?

Are the vacuum hoses on the engine new or are they the stock ones that were always on the motor before you bought it?
Reply
Old Aug 13, 2009 | 02:29 AM
  #7  
BenjiRX-7's Avatar
Thread Starter
Senior Member
Tenured Member 05 Years
iTrader: (3)
 
Joined: Aug 2007
Posts: 383
Likes: 0
From: Monteral, QC
I gotta correct what i said, I drove the car tonigh,. and the "die at idle" thing happens when I use A/C. Actually I use the automatic climate control but it's so hot outside, it just blows A/C like crazy.

When I don't use it, it idles perfectly.

the compression is good on the engine, and no coolant seal toast.

the vacuum lines job was done a year ago.
Reply
Old Aug 13, 2009 | 09:03 AM
  #8  
bridgeportfdjonny's Avatar
Junior Member
 
Joined: Aug 2009
Posts: 12
Likes: 0
From: York/UK
distributer cap may be cracked or broken letting water in and not supplying the correct amount of volts, this has happened on my dads merc 190e and that thing used to cut out when slowing to a stop. i presume rotaries have distributed caps, im not sure though. could be an easily sorted problem.

hope this helps

jonny
Reply
Old Aug 13, 2009 | 09:19 AM
  #9  
baggedoutmazda's Avatar
Greasy bastards..
Tenured Member 05 Years
 
Joined: Mar 2008
Posts: 258
Likes: 0
From: bc canada
could be distributer cap? maybe the camshaft or valves went? oh wait it's a rotary, doesn't have any of this crap. imo ppl should only try to give advise if they actually know what they are talking about.
Reply
Old Aug 13, 2009 | 09:23 AM
  #10  
BenjiRX-7's Avatar
Thread Starter
Senior Member
Tenured Member 05 Years
iTrader: (3)
 
Joined: Aug 2007
Posts: 383
Likes: 0
From: Monteral, QC
Lol. I have an oil leak. I think my valve cover gasket is gone

Well, thank you for trying
Reply
Old Aug 13, 2009 | 09:32 AM
  #11  
Speeder165's Avatar
T/Y Jesus! Re-employed!
Tenured Member: 15 Years
iTrader: (7)
 
Joined: May 2009
Posts: 372
Likes: 4
From: TN
Benji, replace the valve cover gasket & your oil leak should quit. You might also want to have your points adjusted too. The car will run much better.
Reply
Old Aug 13, 2009 | 11:37 AM
  #12  
RotorDream's Avatar
Rotary Ninja
 
Joined: Oct 2007
Posts: 683
Likes: 0
From: Wichita Falls, TX
It sounds like the IACV might not be adjusting for the additional load of the A/C
Reply
Old Aug 13, 2009 | 11:54 AM
  #13  
Speeder165's Avatar
T/Y Jesus! Re-employed!
Tenured Member: 15 Years
iTrader: (7)
 
Joined: May 2009
Posts: 372
Likes: 4
From: TN
Originally Posted by RotorDream
It sounds like the IACV might not be adjusting for the additional load of the A/C
I was pondering that earlier. Think RD may be on to something there.
Might want to verify that the connector to it is still plugged in all the way.
The FSM is stating that the resistance of the unit should be 10.7 ~ 12.3 ohms @ 68 degrees. You could measure the thing & see if it is reading right & also that it hasn`t opened up. Could also measure the voltage to the connector & make sure it is active when the A/C is turned on.

Last edited by Speeder165; Aug 13, 2009 at 12:08 PM.
Reply
Old Aug 13, 2009 | 12:44 PM
  #14  
MR_Rick's Avatar
Planning my come back
Tenured Member 20 Years
iTrader: (7)
 
Joined: Feb 2003
Posts: 3,393
Likes: 0
From: Austin, Tx
I had this problem (engine dying) in one of my FDs. My problem was the lighter flywheel. RPMs slowed down to fast when coming to a stop. I adjusted my driving style and it happened less frequently.
Reply
Old Aug 13, 2009 | 01:17 PM
  #15  
RotorDream's Avatar
Rotary Ninja
 
Joined: Oct 2007
Posts: 683
Likes: 0
From: Wichita Falls, TX
if you had a PFC this would be alot easier to diagnose haha. but im sticking with the IACV. your idle should raise when you

1. the Electric load controller sends a signal (this happens with the A/C fans on 3 or 4, the rear defroster on, or the parking lights on)
2. when the A/C switch is on.

try and see if the idle rises when you turn the rear defroster on, this should let you know if the IACV is working like it should. also what is your idle speed with all electronics and A/C off?
Reply
Old Aug 13, 2009 | 11:38 PM
  #16  
arghx's Avatar
rotorhead
Tenured Member: 20 Years
Liked
Loved
Community Favorite
iTrader: (3)
 
Joined: Aug 2004
Posts: 16,205
Likes: 460
From: cold
First you need to clean the ISC and try the factory idle set procedure. I have covered that in this thread: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/idle-screw-adjust-854571/
Reply
Old Aug 14, 2009 | 11:36 AM
  #17  
bridgeportfdjonny's Avatar
Junior Member
 
Joined: Aug 2009
Posts: 12
Likes: 0
From: York/UK
Originally Posted by baggedoutmazda
could be distributer cap? maybe the camshaft or valves went? oh wait it's a rotary, doesn't have any of this crap. imo ppl should only try to give advise if they actually know what they are talking about.
thats why i said im not sure!! and if on a normal car it could have been the problem!
no need to be a PR**k about it run people down. i am only trying to help.
Reply
Old Aug 14, 2009 | 12:17 PM
  #18  
RotorDream's Avatar
Rotary Ninja
 
Joined: Oct 2007
Posts: 683
Likes: 0
From: Wichita Falls, TX
Originally Posted by BenjiRX-7
Lol. I have an oil leak. I think my valve cover gasket is gone
Oh man thats no good! You should make sure to check your headlight fluid while your replacing it! Its right behind the extending mount bracket!
Reply
Old Aug 14, 2009 | 07:42 PM
  #19  
1QWIK7's Avatar
White chicks > *
Tenured Member: 20 Years
iTrader: (33)
 
Joined: Jul 2003
Posts: 13,147
Likes: 1
From: Secaucus, New Jersey
Im also leaning towards the IAC or the dashpot for your stalling problem.

Maybe when your in gear, then put it to neutral and the rpms start coming down, the dashpot isnt slowing down your throttle plates causing it to die out?
Reply
Old Aug 14, 2009 | 09:51 PM
  #20  
leprachaungold9's Avatar
My 1986 Mazda RX-7
Tenured Member 05 Years
 
Joined: Sep 2006
Posts: 30
Likes: 0
From: Illinois
hey everyone i have a 88 turbo 2 and im having a problem sorta like this i just installed a rebuilt turbo i bought stock turbo and it ran perfect no leaks then i took it on the highway and i was in 5th gear and got on it my boost gauge read about 25 pounds and then i heard a pop when i let off and lost alllll boost when i tryed excelerating it bogged down almost like a fuel cut only pushing like 3 pounds of boost when i take it out of gear the car dies unless i toggle the trottle i can also hold the vane air flow meter open and it will run when i let it go car dies instantly please advise and give me some pointers to look for when i got to diagnose this problem... btw all charge piping and vacume lines are still connected
Reply
Old Aug 14, 2009 | 11:43 PM
  #21  
arghx's Avatar
rotorhead
Tenured Member: 20 Years
Liked
Loved
Community Favorite
iTrader: (3)
 
Joined: Aug 2004
Posts: 16,205
Likes: 460
From: cold
^ you should post in the 2nd gen section. You may have blown a hose off.
Reply
Old Aug 15, 2009 | 08:08 AM
  #22  
1QWIK7's Avatar
White chicks > *
Tenured Member: 20 Years
iTrader: (33)
 
Joined: Jul 2003
Posts: 13,147
Likes: 1
From: Secaucus, New Jersey
@ 25lbs of boost, i think he blew something else lol

Good luck but yeah you'll have better luck in the 2nd gen section.
Reply
Old Aug 15, 2009 | 11:41 AM
  #23  
RotorDream's Avatar
Rotary Ninja
 
Joined: Oct 2007
Posts: 683
Likes: 0
From: Wichita Falls, TX
25lbs of boost + POP! =
Reply
Old Sep 18, 2009 | 10:14 AM
  #24  
leprachaungold9's Avatar
My 1986 Mazda RX-7
Tenured Member 05 Years
 
Joined: Sep 2006
Posts: 30
Likes: 0
From: Illinois
lol the cupler ripped eek all good now i got another problem lol just this past weekend after filling up with gas started ideling bad and the next day i had no power and only pushing 4 psi of boost turned idle screw up to keep running floods engine often and its just really slow on excel advise
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Queppa
New Member RX-7 Technical
11
Nov 18, 2024 03:47 AM
distr0
Megasquirt Forum
48
Mar 18, 2022 06:17 PM
Kyo
2nd Generation Specific (1986-1992)
6
Apr 13, 2019 09:24 AM
Rotospectre
New Member RX-7 Technical
3
Mar 28, 2018 03:33 PM
85TIIDEVIL
2nd Generation Specific (1986-1992)
7
Aug 25, 2015 12:09 AM




All times are GMT -5. The time now is 01:39 AM.