RX7Club.com - Mazda RX7 Forum

RX7Club.com - Mazda RX7 Forum (https://www.rx7club.com/)
-   2nd Generation Specific (1986-1992) (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/)
-   -   Flooding, check all the normal stuff (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/flooding-check-all-normal-stuff-685589/)

Force Fed 09-04-07 02:18 PM

Flooding, check all the normal stuff
 
I'm still working on this '87 NA for my dad, same one that ran good one day then smoked the next. Was gonna do some more work on that problem, only now, another problem has popped up (surprise surprise lol). When I go to start it, it immediately floods out, sometimes I can get it to run for 2-3 secs before it floods out and dies. Here's what I've checked so far:

Compression, 75-80 psi on all 3 sides of both rotors
TPS checks out good, no dead spots
Injectors ohmed out fine and look clean
AFM checks out
Plug wires ohm out good
Coils ohm out fine
Plugs are good and are proper heat ranges, NGK

So, any ideas? FPR bad and pushing too much fuel pressure? CAS gone bad? It is sparking, I laid the plugs up on the fender and spun it over, they all fire. I tried unplugging the pump and turning it over but it still wouldn't catch.

Force Fed 09-04-07 09:26 PM

Anybody? I need to get this thing going again soon.

Dang, I must have a really weird problem here, I haven't even been told to search :D I guess I'll see if I can borrow a voltmeter again and check the CAS, shoulda done when I had the meter before but totally forgot about it. If it checks out I guess I'll get a FPR from somewhere to try out.

Well, checked the CAS and it seems fine, 165-163 ohms through both loops, FSM says 110-210 is normal. Found the pressure sensor had a terminal bent over into another terminal, how someone did that and still plugged it up I dunno. Bent it back into place and plugged it back up and checked the voltage, 3.5v just as the FSM says.

The FSM says 12-16 ohms for the injectors, but mine are only showing 2.4. What does that mean? They're not gonna open, or open too much?

Okay, did some more checking. Fuel pump is working, I put a jumper wire in the yellow connector and it comes on and pumps fuel fine, I pulled the line off and stuck it in a can to check. Injectors are not leaking. I can hear fuel rushing through the fuel rail pretty good, maybe the FPR is bad? Not holding enough fuel pressure? I don't have a gauge to check with at the moment. Is it normal to hear it going through the rail like that?

This thing really has me stumped, everything is checking out good, yet it still won't run. No way it's the computer gone bad I guess?

SpeedOfLife 09-20-07 09:43 AM

75-80 psi compression is pretty low. it might need help restoring the oil coating in the housings, that's what seals the apex seals to the housings. pour a few ounces (doesn't have to be exact) of motor oil into the front and rear rotor chambers through one of the spark plug holes, replace plugs then try again. you might also turn it over like that with the fuel fuses pulled so you build the seal and then try starting it. it'll smoke a lot if you get it started with the oil in there, that's ok.

younG_Gunner 09-20-07 10:10 AM

With compression that low, its going to get progressively harder to start the car. Remember, 85 psi is the acceptable limit for our cars. Might be time for a rebuild.

Force Fed 09-20-07 06:18 PM

Well my '87 TII starts fine on 60-70 psi, using a fuel pump switch.

one320fc 09-20-07 06:49 PM

thats the whole problem the fuel pump switch is a band-aid for low compression I have a 90 GXL with 70psi on all rotor faces front and rear and it will not start on its own until I put a switch on the fuel pump. its rebuild time!

micah 09-20-07 07:06 PM

Are you sure your timing is right on? Try moving the CAS back and forth, see if it idles better. 75-80psi should atleast be a running/driveable motor... might not be the most reliable, but it should start fine.. expecially with a 2-stroke oil boost. :)

If the 2-stroke and checking the CAS doesn't help, check for vacuum leaks.

Force Fed 09-21-07 08:35 AM


Originally Posted by micaheli (Post 7352284)
Are you sure your timing is right on? Try moving the CAS back and forth, see if it idles better. 75-80psi should atleast be a running/driveable motor... might not be the most reliable, but it should start fine.. expecially with a 2-stroke oil boost. :)

If the 2-stroke and checking the CAS doesn't help, check for vacuum leaks.

I hadn't ever messed w/ the timing, doesn't mean it didn't move/hasn't been moved previously :)

Here's the deal, we got it not running, we got it cranked once, ran but had a lot of smoke. Dad brought it to my house, I pulled the plugs and run ATF through it real good and let it sit overnight, also put a few gallons of good fuel in it.

Next day, I get it cranked up, burned out the atf and ran fine, had good power, would spin when I kicked it through the yard. Shut it off and restarted at least 10 times, no switches or nothing, fired up on it's own. Had a bit of fuel smoke from running rich. I figure it's good, so I park it out back.

Fast-forward 1 week, I go out to start it again, just to keep it in shape. Well, now it's billowing oil smoke, looks like the yards on fire lol. But it still runs, but is missing obviously. So I back it into the shed after taking video of it (which I posted in another thread here) and leave it. Next day it it started doing this problem, starts up then dies away immediately.

I thought it was flooding at first, since there was always some fuel on the trailing plugs. But there was never any black smoke, and no kind of playing w/ the throttle made any difference, even holding it wide open didn't help, so I'm starting to think it's the opposite problem, not enough fuel pressure. I tried pinching the return line off w/ a pair of vice grips, but it didn't seem to help at all.

It's no to the point that it won't even try to start at all. I cleared the chambers and run ATF through them again yesterday, gonna try starting it again today but I think it's gonna be the same thing. Is it possible that the computer is bad and not telling the injectors to open? I was hoping to get it started again so I could try running something in the oil to unstick the oil control rings.

Force Fed 09-21-07 09:08 AM

How about the igniters? I checked all the plugs and wires, they all spark, not real weak but not strong either. Could they not be sparking strong enough or at the wrong times? I just tried it again, and again it spun for a bit, started to fire up but didn't quite, now doesn't even try.

I remember when I first checked the spark, the first plug flashed almost bright enough to blind me, after that none of them were that bright, just small whitish sparks, maybe a hint of orange. Maybe the coils aren't firing hot enough? That would explain the fuel on the plugs every time.

82transam 12-22-07 03:35 PM

I'm curious if you ever got this to work correctly?

turbo10th 12-22-07 03:45 PM

He could look up hailers write up on cutting a certain wire on the harness that controls injectors on cold start up. Worked for me just sucks when it is real cold out you have to pump the gas or put a switch on it.

topbro2 12-22-07 05:21 PM

my car did this alot but i think it was because i have 1600 injectors.

Jeppy 12-22-07 05:33 PM

if you think its low fuel pressure wouldnt it atleast fire with starting fluid???


Originally Posted by Force Fed (Post 7353897)
How about the igniters? I checked all the plugs and wires, they all spark, not real weak but not strong either. Could they not be sparking strong enough or at the wrong times? I just tried it again, and again it spun for a bit, started to fire up but didn't quite, now doesn't even try.

I remember when I first checked the spark, the first plug flashed almost bright enough to blind me, after that none of them were that bright, just small whitish sparks, maybe a hint of orange. Maybe the coils aren't firing hot enough? That would explain the fuel on the plugs every time.

thats a good idea 2 but why all of a sudden would it do that after just sitting for a week?? thats wierd goodluck!


All times are GMT -5. The time now is 11:10 AM.


© 2024 MH Sub I, LLC dba Internet Brands