1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Car bogs down when i first hit the gas

Thread Tools
 
Search this Thread
 
Old 03-29-08, 04:07 PM
  #1  
RX-7 NUT

Thread Starter
 
DarkDrakeX's Avatar
 
Join Date: Aug 2007
Location: California
Posts: 444
Likes: 0
Received 1 Like on 1 Post
Car bogs down when i first hit the gas

Okay so i just got my car running less than a week ago. I got plates and insurance on it on Friday and today has been my 1st day off work and school so i worked on my car all day (1983 gsl 12a)
It wouldn't start before i rebuilt the carb (it flooded hard) after the carb had been rebuilt its been okay starting and it runs but this hesitation is getting to me. My parents want me to get it fixed before they let me drive it all the time soo can anyone help =)).

When i hit the gas its rpm's go down and seems like its gonna die then it picks up and runs normal.

What ive done to it so far
rebuilt carb
put a new inline fuel filter in
new air filter
changed oil
new spark plugs (densos yeh i kno i wanted ngk's but they were out)
new wire set
new battery terminals
i have seafoam for once i start driving it to clean it also.

What do i need to do.. my dad thinks its either timing or the air fuel mixture is off.

I have searched and searched and couldent find anything please anyone.
Old 03-29-08, 04:17 PM
  #2  
Moderator

iTrader: (2)
 
rxtasy3's Avatar
 
Join Date: Jun 2002
Location: Spartanburg, SC
Posts: 9,310
Likes: 0
Received 256 Likes on 237 Posts
sounds like the accelerator pump isn't working right. work the throttle by hand while looking down the carb. there should be gas squirting out into each primary barrel.
Old 03-29-08, 05:54 PM
  #3  
RX-7 NUT

Thread Starter
 
DarkDrakeX's Avatar
 
Join Date: Aug 2007
Location: California
Posts: 444
Likes: 0
Received 1 Like on 1 Post
Yeah its squirting gas into the 2 smaler barrels.

so if thats not the problem what else could it be.
Old 03-29-08, 09:02 PM
  #4  
No distributor? No thanks

iTrader: (6)
 
Crit's Avatar
 
Join Date: Oct 2003
Location: Outskirts of Road Atlanta
Posts: 3,438
Likes: 0
Received 6 Likes on 4 Posts
Just to be clear, the carb will draw fuel in when it's running, and you could be seeing that. I'd recommend pulling the plugs, turning the car to 'run', and pulling the throttle cable while looking down the primary barrels. Without the engine running, you should see the Accelerator Pump shooting fuel into the carb. Once you're done, turn the engine over a few times, put your plugs back in along with the wires, and crank her back up.

The only reason to pull the plugs is to avoid flooding. There's a good chance you'll flood it while playing with the AP, and it's a lot easier to restart if you'd already removed your plugs and they're still dry.

The AP is the likely culprit. Another possibility is that the car has mechanical secondaries (not stock, but a common mod) which you're not used to, and it'll make the car bog if you drop the throttle too quick. While you're checking the Accelerator Pump again, also pay attention to the two larger bores. If you slowly turn the primary throttle linkage (or pull the cable) and the secondaries (larger bores) open smoothly with the primaries, then you have manual secondaries. Let us know what you find.
Old 03-30-08, 03:15 PM
  #5  
Rotary Enthusiast

iTrader: (8)
 
Rotospeed's Avatar
 
Join Date: Feb 2007
Location: Southwest
Posts: 817
Likes: 0
Received 0 Likes on 0 Posts
sounds like your AP is out of adjustment. your getting to much or not enuff fuel when it squerts
Old 03-30-08, 04:48 PM
  #6  
RX-7 NUT

Thread Starter
 
DarkDrakeX's Avatar
 
Join Date: Aug 2007
Location: California
Posts: 444
Likes: 0
Received 1 Like on 1 Post
okay so i just checked it. I had the car off but they key to run when wee p[ushed the gas it shot a little bit in then nothing more. so is it the ap?? and if it is how do i fix it?? do i have to replace it or what?
thanks for the feedback guys
Old 03-30-08, 10:00 PM
  #7  
RX-7 NUT

Thread Starter
 
DarkDrakeX's Avatar
 
Join Date: Aug 2007
Location: California
Posts: 444
Likes: 0
Received 1 Like on 1 Post
Okay soo i have a bit of a update to see if u guys can help me. We checked the accel pump and i still dont know if its working correctly or not (we tightened the screw down under it a bit to see and it didnt change much.. idk if i did somethign wrong please tell me). Me and my dad changed the idle screw and the air fuel mixture screw. Right now the car idles between 12-1400 wich is about double what i wanted it but it wont go down much more.. we had it at 1000 at ont point. After messing with the afm and the idle the hesitation isnt as bad.. still bad tho.
starting at 1500rpm's is almost fine... with little hesitation. if i start it at 1700-2000 rpms it almost dies... its like a complete dead spot. and when ur driving and shifting it ont he road it bucks the car every time u shut cuz of the hesitation around that rpm. we can drive it at higher rpms fine and just shift at 2500+ but i still want to get this fixed..

soo any ideas?
Old 03-31-08, 12:38 AM
  #8  
Lives on the Forum

 
2cute's Avatar
 
Join Date: Apr 2005
Location: san diego
Posts: 23,563
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Rotospeed
sounds like your AP is out of adjustment. your getting to much or not enuff fuel when it squerts
exactly what i was thinking
Old 03-31-08, 12:51 AM
  #9  
RX-7 NUT

Thread Starter
 
DarkDrakeX's Avatar
 
Join Date: Aug 2007
Location: California
Posts: 444
Likes: 0
Received 1 Like on 1 Post
okay. so if thats the problem. how do i adjust it?? whats a good advustment for it??
Old 04-10-08, 05:37 PM
  #10  
Rotary Supremacist

iTrader: (1)
 
LizardFC's Avatar
 
Join Date: Jan 2004
Location: Maryville, TN
Posts: 2,909
Received 1 Like on 1 Post
Bump, I'm having the same issue! There's a dead spot right at 1700 RPM. I don't hit it when revving very lightly, but it cuts in the same spot every time I take off below 1700. So how is the accel pump adjusted?
Old 04-10-08, 07:13 PM
  #11  
Senior Member

 
Hec's 79 gs's Avatar
 
Join Date: Mar 2006
Location: Houston, texas, Tomball Texas x
Posts: 389
Likes: 0
Received 0 Likes on 0 Posts
you both soud like you have some intake leak some where.
Old 04-10-08, 08:26 PM
  #12  
No distributor? No thanks

iTrader: (6)
 
Crit's Avatar
 
Join Date: Oct 2003
Location: Outskirts of Road Atlanta
Posts: 3,438
Likes: 0
Received 6 Likes on 4 Posts
If your idle's that high, then you have a vacuum leak. Since the engine now draws in more air than normal, you've also adjusted your idle to be super rich. That way, what little bit of air DOES come in through the carb, it has to mix with an extra-rich mixture in order to get it to run once you add in the air from your leak.

You should be able to spray starting fluid or brake cleaner on your manifold gaskets and ports (including everything that gets a vacuum line), which will temporarily clog any air leaks. If the idle changes for just a moment, before the fluid evaporates, then you've found your leak.

Once you have your idle down to a semi-steady 600, you can bump it up to a rock-solid 800 or so and deal with the AP. You'll also lean your idle mixture back in the meantime, and your throttle response should improve a little.

You can use Mazda gaskets, RTV, or gasket dressing (I swear by hylomar) to resolve the vacuum leak once it's located. Just be patient, and check everything.
Old 04-10-08, 10:20 PM
  #13  
Lives on the Forum

 
Kentetsu's Avatar
 
Join Date: Jun 2004
Location: Grand Rapids Michigan
Posts: 11,359
Received 14 Likes on 11 Posts
Check your timing, and get some NGK plugs in there. How is your vacuum advance hooked up?

It sounds (based on your description) like the AP is fine, or at least working well enough not to be an issue right now. Chase down that vacuum leak before anything else...
Old 04-11-08, 12:23 AM
  #14  
Senior Member

 
Hec's 79 gs's Avatar
 
Join Date: Mar 2006
Location: Houston, texas, Tomball Texas x
Posts: 389
Likes: 0
Received 0 Likes on 0 Posts
If you can have a vacum guage it will help a lot to diagnose your problem.I think for a rotary it should read about 15.These are pretty cheap at the auto parts store.All you have to do its to conect to a vacum source.
Old 10-09-10, 07:08 PM
  #15  
Junior Member
 
Bull_dog_1989's Avatar
 
Join Date: Mar 2010
Location: Pittsburgh Pennsylvania
Posts: 13
Likes: 0
Received 0 Likes on 0 Posts
PA 83 rx7 bogs out going up hills n when throttle is pressed fast.... hesitation

I'm having the same problem. 83 limited edition rx7, k&n airfilter n rb headers only mods. If I hit the gas at all fast, It drops rpm n almost bogs out, and when I'm driving up a long hill, after about half way my car starts bogging out to the point where I have to pull over for a second then its fine when I pull off. I've put new ngk plugs n wires, k&n airfilter, seafoamed it. I do know that there is no intake manifold gasket but I just ordered it n have it and also have a nikki carb rebuild kit I just got. I got mine running at about 750 rpm since I've kinda tuned it. I have no timing light to time it or understand how, n I dnt have a oxygen sensor to see what my exhaust is putting out to tune the gas mixture. Its tuned as good as I can get it. I dnt think my carb is the problem although I am rebuilding that n I'm putting a intake manifold gasket on. But why would my car drive steady up a hill then just start bogging out, I down shift, bogs out, down shift to first bogs...... sit for 15 seconds n I can drive.....?
Old 10-09-10, 08:15 PM
  #16  
It's supposed to do that.
iTrader: (3)
 
84 GSL's Avatar
 
Join Date: Jul 2009
Location: Fayette, AL
Posts: 286
Likes: 0
Received 0 Likes on 0 Posts
Just for clarification, are all of you are running stock Nikki carbs?
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
smikels
2nd Generation Specific (1986-1992)
3
08-18-15 01:26 PM
torky007
3rd Generation Specific (1993-2002)
7
08-17-15 05:14 PM
rx7jocke
Single Turbo RX-7's
1
08-15-15 03:36 PM
Marty RE
New Member RX-7 Technical
0
08-13-15 11:19 AM



Quick Reply: Car bogs down when i first hit the gas



All times are GMT -5. The time now is 10:06 PM.