Starting problems Part II

R

reisertracing

New member
Did all the suggestions, new plugs, dried out car, ATF trick, new plugs, wires, coils, sprayed gas into carb, new battery, exhausted my limited wealth of knowledge.
Car turns over, doesn't catch...........
BTW new rotor, I am losing my patience, the car ran fine, then ran 2 minutes stopped and won't refire, then this as above.

I am ready to throw in the towel, anyone want to buy a 1985 Mazda RX-7 ITA car?

Many spares..........Anxiously waiting replies with valium and vodka in hand, Looks like I won't be racing this weekend
Thanks in advance Johhny
 
Is it possible that the timing got messed up for some reason? Engines need 3 things to run, gas, spark and timing.

I think there's a nut that holds the distributor in place to set the timing. Maybe it came off and the distributor moved?
 
Thanks for the quick reply,UPDATE
just got the car fired up, ran about 1 minute not missing, then died.
had to pump the gas pedal alot to start it..........have a fuel regulator set on 4, maybe the fuel is clogged or carb dirty, I cleaned carb with carb cleaner.......any thoughts now?
Ran at about 1500rpm up to 2000RPM, then quit after about 1 minute, hard to start and pulls on new battery. Fuel is in the carb window BTW.
Thanks
 
Another wild suggestion:

Look at your exhaust system--any chance it is plugged?

Don't laugh. Had this happen to a freind's RX-3 rally car years ago. She had a supertrapp and the end plates were oil carboned and "plugged". Anything else that would collapse in the header, pipes, mufflers, etc. could do the same thing.

Good luck!

Took them off and it fired right up and ran fine...
 
Originally posted by reisertracing:
.......any thoughts now?
Ran at about 1500rpm up to 2000RPM, then quit after about 1 minute, hard to start and pulls on new battery. Fuel is in the carb window BTW.
Thanks
Click to expand...

Is the fuel in the window "before", "during", and/or "after" it stalls?

Just wondering out loud if maybe you have a dirty fuel filter. This happened years ago on an old piston car, but it had similar symptoms. The fuel requirements of the car are slightly higher than what the filter is able to supply. Therefore, the car runs for a short period of time (i.e. until it literally runs out of gas).

An easy way to test this (assuming the filter is accessable) is to remove the filter long enough to try to run the engine more than a couple of minutes. If it works, definitely get a new filter. But running it for a few minutes w/o a filter shouldn't hurt.

I hope you get it going! My "7" is my first racecar, and although I get passed by lots of 2nd gens it's a hoot!!!!!!!

------------------
Mike Spencer
NC Region
ITA/7 RX-7 #60
1990 RX-7 Convertible (street car)
 
Ok..it's a carb car, right?
If so, am I correct in assuming the choke has been eliminated? It's the flat plate at the very top of the carb. When it is cold, the plate will be closed, or nearly so. I bet your choke has been removed.

Has your engine been rebuild very recently?

Rotories can be a pain to start after a long rest without a choke. And will often refuse to run for long.

So....first, dbl check the fuel level..is it centered on the front and esp the back window?

Second, confirm that the PLUGs are firing when you crank the motor...ground the lower front one and observe a spark, then do the same for the back lower. Don't bother with the uppers. Double check to be sure the wires go where they are supposed to. ON the rotor cap it says "T1", etc. 1 is the front rotor, "T" is trailing or top. "L" is leading, or lower. Easy to remember.

Now, you have fuel and spark....but is the fuel getting to the chambers?? Look down the primaries..the smaller holes, and observe to see if you see two streams of fuel when you open the throttle. Use the cable or the linkage on the carb and a flashlight. If you don't see two streams shoot down the throat when you open the throttle, it is doubtful that it will ever start.

(If you don't, reply, and we will go from there on that possibility)

Now put it all back together, except the aircleaner, and make sure the battery is charged. If you have confirmed your car has no choke, give the gas pedal 5 firm full pushes all the way to the floor, then start cranking. As it cranks, pumping the pedal is often a good idea.

It SHOULD start. I am surprised how much pumping it takes sometimes, esp. in spring!

if it does start, keep running it up and down the tach, say 2K to 4K rmp, for a few minutes, then see if it will idle.

If it starts, runs, then dies after a couple minutes, shut the ignition right away and check the fuel level in the float bowls. If it's low, remove the fuel line feed right as it enters the carb, and get a glass bottle. Turn on the ignition, and you should see a flow. If it isn't strong, you need to find out why.
If the float bowls were half full, (as they should be), double check for spark...perhaps there is an ignition issue.

Is your gas new and fresh?

And, if this motor has just been rebuilt, make sure you keep it running for more then just a minute when you first start it, or you will have severe compression issues when you go to restart. Run it until it warms fully. If you can let it idle without overheating, do that for a while.

Let us know...if it gets desperate, email me for my phone #..



------------------
Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]
 
Both primaries fill with throttle, feul windows half full.
Tried and checked lower plug spark, here is my arrangement, the rotor has T to 1 ignition in the front left wheel well, T Right to the upper right spark plug, t to the left of big t to the left upper plug, I have a MSD Ignition that goes to a right blaster 2 for the right lower and a left blaster 2 coil to the left lower, the lower spark plugs do not fire very often and mainly when first cranking over the ignition,
The upper plugs spark continuosly when cranking over.
Here is diagram:
 
Distributor
T-to igniton 1
T-LU Plug T-RU Plug


Ign 1 Blaster 2(1)Left lower Blaster2 (2) Right lower plug

MSD To Points

What is wrong?

Plugs on lower don't fire much, replaced Blaster coils yesterday and new plugs,

Any suggestions? Distributor bolt is secure.

Thnaks Johhny
 
Are you trying to run a waste spark set up?The waste spark should be on the leading plugs not the trailing. If your waste spark is going to the trailing plugs you will be trying to ignites the A/F mixture while still on an "intake stroke" with no compression.

I see you mentioned points. Are the points adjusted properly?

E

[This message has been edited by wlfpkrcn (edited April 24, 2005).]

[This message has been edited by wlfpkrcn (edited April 24, 2005).]
 
Update,
Changed plugs, emptied out fuel tank/cell and put fresh gas in it, go car to fire briefly, but backfired and never really ran smooth,
may try to adjust points as mentioned and check wiring, yes, I am running a waste spark to burn off gas.
 
85 RX7 with points????

With direct fire you can eliminate the trailing entirely for the ease of diagnosing your problems.

Are you sure the MSD is hooked up correctly? IIRC.. The Green MSD wire DOES NOT hook to the green distributor wire.

What's the timing set at? Are you using the factory pulleys or aftermarket underdrive pulleys?

------------------
Scott Rhea
It's not what you build...
it's how you build it

Izzy's Custom Cages
 
Reading the strings of comments, it seems the 12A hard to start problem is not uncommon.

In this particular case I suspect something is awry with your ignition--it sounds like an odd setup. I've seen MSD ignition boxes have some strange failure modes--I heartily recommend building and carrying an emergency ignition wiring harness that can wire around your MSD. You also need to get yourself an 81 - 85 distributer! Points!?!?! Just say no!
Just for the record, I've experienced similar starting problem 1/2 a dozen times, and here is the sure-fire fix to get mine started:
1) remove the plugs and verify they are wet.
2) Fuel pump off, plugs out, crank engine with throttle wide open until mist stops coming out of the engine (5 sec usually).
3) Install NEW plugs. Dried/ cleaned old plugs for whatever reason don't work for me.
4) Fuel pump on--give it a few seconds to fill the carb. Pump gas 6 full strokes.
5) Crank--it's always started for me.

In the interest of us all moving forward, let's talk about possible causes--I have associated these four culprits with it, but I am far from certain they are responsible! Has anybody else found anything?
Culprit 1) Old, worn plugs (I run stock Denso plugs-two of them consume about 1cc more compression volume than traditional spark plugs. They are worn when the center electrode loses it's sharp edge. Running lean wears them out quickly--like 4 hours)
Culprit 2) This is strange, but for whatever reason, 'soup' builds up in the emissions valve area of my intake manifold. This is the area where the EGR and some other emissions valves used to live. I've removed all of those valves and just have a plate covering the openings. I suspect the 'soup' is a mixture of fuel and oil that condensed on the intake walls and ran into the emissions valve area through the EGR holes. I suspect that under the right conditions, it can work back into the manifold. I used to get ~1 to 2 tablespoons of soup a year, but a rebuilt and properly jetted carburator seems to have eliminated the soup.
Culprit 3) Another weird one, but I also get soup on the vacuum side of the secondary throttle vacuum actuator. I drain it by backing off the 4 screws that hold the vacuum acturator assembly together. If there is fluid in there, it will run out. You don't need to take the housing apart or remove it--just back off the screws ~1/8 inch and crack the housing open.
Culprit 4) Week battery and not enough pumps of gas after the car has been sitting for ~1 month or more.

Tak
#29 ITA SFR SCCA
 
I am baffled by the ignition wiring...sorry. My car has stock ignition, and while my 911 runs MSD, I am unfamiliar with it's application on a rotary.

That said, the lower plugs not firing regularly is a big problem. They must fire strongly and three time(is my math right?) per revolution. Even reversed the engine will run (poorly), but if there isn't a good spark wehn cold, ir's all over.

I am sure your issue rests with the ignition. Resorting to stock might be prudent, and upgrading the dizzy is too.

------------------
Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]
 
Is the MSD new to the car? You shoud have 3 MSD boxes. One for each of the trailing plugs and 1 for the leading plugs. I agree with getting a igniter style distributor. It sounds like the trailing plugs are firing all the time. That sounds like your waste spark wich should be the leading plugs.

Have you pulled the MSD and tried starting it with a conventional set up? That might be the best place to start, becaus eit eliminates a potential problem.

Eric
 
Actually, Direct Fire/Waisted Spark can be run using one MSD on the leading. Very little reason to run direct fire at all on the trailing and you can run a single MSD on it (takes the place of the ignitor).
 
Sounds good to me. I have only seen the 3 MSD set up. I have never used or set up a MSD on a rotary. I still think the problem lies on spark timing to the trailing plugs
 
Sorry for the off topic ...but...is MSD really worth the bother? If I understand correctly, the Multiple Spark Discharge stops being multiple around 3K rpm...and when was the last time we saw that rpm in a racing situation??

It strikes me as more things to go wrong, more weight, more $, and little or no return.

What am I missing?

(I DO have MSD on my street 911 though...)

------------------
Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]
 
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