harley71105

Occaisionally my Rx won't ignite due to no fuel getting past the injectors on start up...(never mind diagnosis about that cause I been fighting that for three years) ....I just need to know where I could inroduce some fuel into the intake side somewhere to get her primed....on these episodes she starts with Ether...just wanna rig some extra fuel injection....
Thanks !

iceblue

Whatever you use you will have to cap it off. But you can pore a lil fule like 3oz anywehre in the intake befor the throttle plates but high enugh up that it will not flow down the intake pipe towrds the AFM. give it throttle wile cranking to allow it to pull fule keep it runing with gas peddle untill she kicks over or runs out of fule in the intake system.

SonicRaT

iTrader: (6)

Wow... an RX7 that doesn't start due to NOT flooding?

Seriously, if the thing isn't injecting gas during cranking (I've NEVER found an rx7 that did this, but would eventually start and run!), you've got a rather major issue with either A) fuel pump B) injectors or C) ECU. It shouldn't take three years to figure that out, but I'd guess it's the opposite and just floods out like every other rx7 in existance (have you checked the plugs when it doesn't do this? Any time specifically?) It's either that or some massive vac leaks and your idle is set rather high once it starts?

harley71105

Well,,,I've been all through this, no one else has ever seen one do this either. If the plugs were not firing the Ether would not make her crank...if she were flooding the plugs would be wet, which they are not....I have two spare ECU's (I have two 88;s and lots of spare parts) and she continues to do it SOMETIMES....usually after running and driving then when you shut her off and a half an hour or more later she will not start....I've replaced or exchanged everything in the system including replacing all the vacuum lines....if it were a vacuum leak she would not run or idle well...runs great when running but never shuts off once running...
Now I've noticed the idle is faster than usual when she does start and is cold, but not when it starts (after the Ether) but that is normal I think...I have replaced fuel pump, harness, fuel pump relay, filter....I have 40 PSI on the fuel line during these episodes....there are at least 50 threads on my deal with "intermittent no start"....we all just collectively seem to not be able to find out what is causing this....I have even offered a reward to the person that can solve this from the forum, as all other help here is free....

harley71105

PS....she almost always cranks up while cold.....except for once in a great while

Icemark

Have you done a compression check when this happens???

It sure sounds like flooding, and if the spark is hot enough, you would not foul the plug for more than carnking, they would look dry if pulled out 5 minutes later.

WAYNE88N/A

Harley and I have been PM'ing each other back and forth for a year of that 3 years, and we've checked everything imaginable, and then some. So don't think that it's an easy fix and should have been solved by now.

I've been on airplanes that took round-the-clock electrical troubleshooting for like two weeks from all of the "sparkies" to finally nail it, so these things happen. Stuff like an airframe guy drilled into a wiring bundle in an inaccessible location, and it only shorts when the plane is in the air and in a left bank with a crosswind, goofy **** like that...

My theory for the past couple of months is that there's a microscopic electrical open somewhere, probably at a wire terminal or solder joint. Heat sink opens it up, and vibration or cooling her off closes it. He's just gotta find it...

He's replaced just about everything that could possibly cause this, lol...

harley71105

Thanks Icemark for your reply, but if it was flooding it would smoke when it starts. Also, if it were flooding there would be times that I would have to do the unflood procedure....also, if it were flooding, Rx"s will sort of stumble trying to fire....when this thing don't want to start...you can hear the compression fluctuation as opposed to that smooth turning sound when it is flooding...I'm convinced she is not flooding during those episodes as I have cranked off and on for five minutes with no flooding, then when she starts there is no smoke of excess fuel....
No sir I have not done a compression check, perhaps I should and if she was flooding I definately would.
Yesterday morning I almost flooded her on crank up ....she was stumbling really bad then would not start, so I flipped my injector cutoff swith (which I have bypassed at times so it is not in the switch or connections) , cranked then turned on and she started...stumbled somewhat, but started and of course there was a lot of smoke from the extra fuel....
so we have two entirely different symptoms and the one that reoccurs does not appear to be a flooding problem....perhaps that will lead you to some other theories....hopefully....I'm getting tired of this thing...lol.....but its a really nice RX.....selective extra fuel "ingestion" is at this point the easiest rigging....

Icemark

well, what might be a simple band aid is then to just drill and tap into the dynamic chamber a single small injector (like a 120 or something) and a relay and resistor tapped off the starter circuit, so it dumps fuel while cranking.

But it is really a band aid, and really just a solution to your first post rather than a fix for the car. I cringe giving it, but it is simular to what some people do for nitrous setups, just on start instead of WOT. I'd probably do up a bypass switch as well, so that you can avoid dumping the extra fuel when you need too.

harley71105

Thats really a pretty cool idea, Ice, and technically sound. I will consider that. I'm just wondering if there is an intake line or something that would serve the purpose, but you would probably know about that. I'm just trying to avoid removing the Dynamic Chamber and the machine work....but your idea is solid.

Icemark

dynamic chamber is easy to remove and work on out of the car.

The problem with most of the vac or other lines in, is that they are either before the throttle plates (something you don't want because of the fire hazard) or only feeding one rotor.

iceblue

Perhaps you can give some more imput into this icemark. I sugested befor TB but make something or make sure that the fule wont run down to the AFM and stays in a little pudle at or just befor TB. This to ensure it is pulled from VAC equaly into the chamber asure that it is spred to both rotors being flow veriable buy amount of throttle applied. You posted fire hazard and I see this is a concern not as much if it is watch controlled and not done evry time car is started but a sound argument. Is there a solution to that or a bettor way to acomplish this?

This may be a bad idea leaving fule lingering but what about a wind shield washer resivor with a pump using spray nozles. Push button and it sprays let go of button no more fule going to chamber. I see accsident as a bad posability but dunno.

68Sniper

iTrader: (1)

Leaky injectors (mabye) i didnt see that their ^^^^^???

SonicRaT

iTrader: (6)

It's still hard to believe the problem is unique, it sounds exactly like everybody elses hot-start issues, which is almost always a combo of flooding, poor compression, and so forth. I've found a lot of times the car won't fire at all (just constant spinning until plugs removed, cranked for like 3 minutes, put back in and attempted aagin).

Compression check!

Icemark

See the problem with the before the throttle body is that the throttle body plates are closed when starting if you don't touch the gas pedal...

so the last thing you want is fuel being sprayed into a closed intake, and pooling down by the AFM and filter (can you say BOOM if there is a spark near the air filter).

Icemark

I agree, but you can lead a horse to water, but you can't make him drink.

And remember most hot start, starting issues are related to leaking or bad condition injectors and/or poor compression.

A compression check should have been the first thing tried.

SonicRaT

iTrader: (6)

Yeah, I find hotstarts to be the following: Poor injectors, poor compression, faulty water thermo sensor. Those three have yet to fail me.

harley71105

Yep...one big firecracker for sure....Ok Ice...if I do this I will use your idea...it is the best one on the extra injection (I have done a couple of UIM removals trying to chase this problem so I can have it off in less than 45 minutes)....by the way....since I can start her with the ether....there are fewer no starts taking place...