salex

1991 convertible/ non turbo.

Car has been mostly sitting for about 11 years. Don't know why I stopped driving it, but think it was to save it for grandson - who is now 16. Unfortunately I didn't do a good job of pickling it.

I found rotary mech from closed down mazda dealer in Montgomery about 6 years ago and got it back on the road for a short time. The car ran fine, but I would drive it to work and then it would not crank when I tried to start it. (Think when warm). After a bit it would crank and start. Made a attempt to find the problem but must of lost interest (and faith!) and parked it again.

Last attempt to bring it to life last year ended when found that fuel tank, pump and all was a gooey mess of varnish.

Found tank last week and I'm in the process of bringing it back to life. I have lots of problems from sitting (clutch hydraulics - pedal on floor. Brake rotors rusted, etc, etc).

After installing fuel tank, I had to at least see if it would start. Primed fuel system. Used tip from mech to put a little brake fluid in main vacuum engine inlet and tried to start it. After about 10 cranks it started right up!

Shut it down and went to get wife and phone to take video to send to son. Cranked right up. Shut it down and called neighbor that had helped with tank. Tried to show him it running and it would not crank. There was a buzzer going off, but no lights warning indications. After spending some time looking a listening, it started up!

Going to replace all fluids today, but it looks like I have the same problem from 6 years ago.

What relays, sensors, or whatever will prevent the starter from cranking?

salex

Must have some picky moderators - I'll try a shorter version. Intro post was 3/15/2011. Tried a longer post this morning and ???

1991 convertible - non-turbo.

Just got it running after six years of sitting. While it will crank and start most of the time, sometimes it won't crank. Let it sit for a while and it will again crank (and start).

Is there anything besides the clutch interlock switch that will prevent the ignition switch from cranking the starter?

This is why I gave up on it 6 years ago.

RotaryRocket88

iTrader: (7)

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/ive-solves-2nd-gen-sticky-starter-mystery-896013/

misterstyx69

iTrader: (142)

There is a little rubber "nub" on the clutch pedal that hits the clutch interlock switch...and sometimes it will just fall off.That thing is enough to NOT allow the switch to fully engage,so the car won't be allowed to start.
The next time the car doesn't start,get under the dash,with the car in Neutral,and Push the interlock switch IN(like pushing the clutch pedal in).Turn the key and see if it will start.If is starts you know where to continue.
I had that problem and just disconnected the switch and Jumpered it.Car starts in gear and out of gear now..yay..woops!

salex

There has to be something else other than the switch. My clutch hydraulics is shot right now. Pedal stays on floor. When it won't start, and it is doing that a lot today, messing with the switch does nothing. I have not tried jumping the wires, but will try - but don't think it is the switch. When it starts, I think I hear a extra relay kick in after the warning lights come one.

Got a couple problems that I am sure I can attribute to sitting for the last 6 years. I was getting a warning beep (actually 5) that would repeat. In the FAQ it said those beeps had to do with the power steering computer. Since my clutch fluid is shot, could have some problems with PS. I'll come back to this in a second.

I changed the oil and filter before I played around too much with it. The spec's say it take 6.1 us quarts and I put a 5 quart kit in, figuring I'd be a quart low. But it registers past the full line on the dip stick. Was starting it and checking pressure etc. Confused about the dip stick reading. Then it started running a little rough, even the beeps seemed like they were being cut off in the middle, just like a little attempt to die, but only only lost a couple hundred RPM. Then the beeps stopped???

I don't have total recall, but it seems that when the beeps were around, if I turned on the ignition and it didn't beep, it would not start. Beep = start. After the beeps stopped I having problems getting it to crank.

I remembered that I had removed a little green box (relay) that fell down above the clutch pedal. The mounting bracket broke and removing it didn't cause a problem, but never knew what it was. Looking at I found it is something to do with the Air Bag. Hooked it back up but won't start. When it does start, the air bag warning light will flash though.

I'll try jumping the wires tomorrow, but again I feel like there is something in the computers startup check that is not completing or some relay is sticking.

Still curious about the oil dip stick.

Steve

satch

iTrader: (1)

Your car has the Starter Interlock Switch which has but two wires to it. One is Black/Green while the other wire is Black/Red. Jumper voltage to this Black/Red wire from the battery and each time the jumper wire comes in contact w/the B/R wire the starter should turn over/crank. Do this to help isolate your cranking problem.

And the wipers and turn signals should work w/key to on. If they don't then check the 100 amp Main fuse in the Engine fuse box.

salex

Whatever allowed me to crank the other day intermittently is now not cranking and all.

My switch has two wires, a yellow and green wire that is 12 volts with key on, and a black with white dots and it seems to go to ground. This is the switch that the clutch closes when the pedal is depressed. The wiring diagram that I found agrees with your RB and BG colors. It also shows it going to the starter with black/red. Also shows going to circuit open relay.

I have not tried to put 12v on the RB wire at the starter to see if it will crank for fear of ??? I did jumper the switch connection YG BW wires and it pulled it to ground and no crank.

I have no warning buzzers or anything. Seem to remember that check engine used to delay coming on turning the ignition switch on, but now comes on immediately. Blinker and wiper work along with everything else. Turn radio on and go to start and radio goes off and comes back a few seconds after releasing key from start position.

Been a long time since I've played with wires, circuits, relays except for digital. Might have to look for better wiring diagram.

Steve

satch

iTrader: (1)

There are two switches connected to your clutch. One is the Clutch Switch that is for Cruise Control while the other is the Starter Interlock Switch, so you jumpered the wrong switch. So you need to remove the jumper from the Clutch Switch as that is of no help and jumper the"Interlock Switch" and see what happens. If this does no help then jumper a wire from the positive battery terminal to the R/B wire.

salex

Just found it:-( How I get to it is another thing. Can't fit in there, going to have to take seat out or something.

Thank you. I'll try for a while and if too rough, I'll try the hot wire to see if that is at least the problem.

salex

I had ordered a new clutch master cylinder so I took it out (along with the seat that was a little scary with some bolts with a little rust). That gave me access to the real switch, which I jumped, but did not work. Switch continuity was fine since it has worked.

There is no voltage coming in on the black/green wire. That comes from the Start Cut Relay, which I think I found (black relay in engine bay by clutch master cylinder). Looking at the wiring diagram, I should have voltage coming in on the black/blue wire and it should go out the black/green, unless there is a theft going on (or antenna fuse blown?).

I may have to double check, but I saw no voltage on any of the 4 wires.

I have to get some knife connecter to do the direct battery jumper.

All warning lights, wipers etc have power, not sure why there is not power to the starter cut relay.

This is a convertible and my theft system does not seem to be working. Remember a flashing theft light on when all doors locked. There is no flashing or any kind or warning light on the idiot lights.

Why it stopped woking intermittently is still a mystery - I did nothing except try to turn key on an off and start. Did find a long thread on http://www.justanswer.com/car/3l8wv-...h-working.html but ended up with looking at wrong switch and had nipple fall off. They did go thru a bunch of test though.

satch

iTrader: (1)

Jumpering the Black/Blue wire to one of the B/G wires at the Starter Cut Relay will bypass this relay so if there is an alarm issue it will not interfere in your car cranking over. Now there should be two B/G wires at this relay where one has voltage w/key to on while the other B/G wire will not have voltage w/key to on and it is this B/G wire that does not have voltage w/key to on is the wire you jumper to the Black/Blue wire. Do this then try to crank the car.

The B/G wire powered by the Antenna's 10 amp fuse is for the alarm aspect of the relay. The other B/G wire is what receives voltage from the Black/Blue wire when things are in working order.

salex

I think I found the problem, corroded connectors on the starter cut relay. I've found several posts on the cut relay and there are server different version of the wire colors. Guess it has to do with version. Mine is also different. I have Black/Green and Black/Blue with heavy gauge wire and two smaller wires, black with white does and yellow green with dots. The only one had voltage with connector disconnected was the small B/W wire. I connected it back together and was going to do some more research and the engine fired up.

I thing that is one of the things on the list of todo's for a car that has set a long time, clean all the connectors you can.

I won't have a chance to fully test my theory until later today, but it seems like a reasonable candidate for the problem and the fix.

satch

iTrader: (1)

The two smaller wires are associated w/the alarm as they are only used to trigger the relay to start the car or prevent the trigger from occuring so as to prevent the car from starting. Of these two wires if the Black/White wire has voltage w/key to on then the Y/G wire comes from the alarm and its role is to provide a ground for the coil relay that allows the relay contact to close thus allowing voltage to pass from the B/L wire to the B/G wire which then takes the voltage to the starter solenoid and the car cranks over. If the Y/G wire does not have a ground when trying to start the car it is either because the alarm is telling it not to in an effort to prevent the car from being started or the alarm is malfunctioning and not grounding the Y/G wire properly. When this occurs the coil in the relay is not excited which causes the relay contact to stay in the open position, which prevents the voltage from the Black/Blue wire from passing onto the B/G wire, which prevents the starter solenoid from receiving voltage and the end result is the starter doesn't crank.

salex

Looks like cleaning contacts on Starter Cut Relay was not enough. Not as bad, but key to start back to intermittently not cranking.

I wiggled and tapped the relay and it would then crank. Kind of put in on the back burner and went on repairing my clutch problem. Removed the clutch slave cylinder (both master and slave were frozen) and noticed what looked like a ground tap on the cylinder.

It would not start with the tap off. Bolted in on with a nut spacer and back to intermittent.

Have not cleaned all the connections and have temporarily jumped the B/L and B/G wire on the relay connector to take it out of the picture. Has not failed in about 10 tries today.

I'm attaching a picture of the ground tap. There is a small square black piece that I'm not sure what it is (diode?). It is just stuck in between a few hoses by the oil filter. Also including picture of my vert in current state.

Steve

satch

iTrader: (1)

The pic of what looks like a computer chip is a condenser which eliminates noise for a particular circuit. There are two of these, one for the coils and one for the oil pressure gauge. This is not related to your starting problem.

Since your car cranks w/the two wires jumpered only reinforces the notion that one of the two smaller gauge wires in the relay are problematic. As previously stated, the Y/G wire comes from the alarm control unit and is supposed to supply a ground signal to the relay. The B/W wire supplies voltage to the relay w/key to on. If the alarm is not grounding the Y/G wire properly then in a normal situation the car is not going to crank over, and it is as simple as that. If you jumpered a ground to the Y/G wire, and the other jumper were pulled, and the car has no problem cranking time after time then the alarm is the problem.

salex

Time to get back on the vert.

It seems that a lot of my problems are related to the theft deterrent system. Jumping the starter cut relay band-aided my intermittent no crank. Another post dealing with oil pressure experienced a warning buzzer with no lights - again intermittent.

Since this is a 91 vert, I assume that it is a FC S5. Still not used to the shorthand used at rx7club.

There are not a lot of posts on the theft deterrent system, but I've learned (I think!) that it is controlled by the body cpu. Many of the problems with the system are related to the different door/hood/trunk switches and key switches. I'm trying to parse the section on the system in the body electrical section of what I believe is an 89 SM. There is a little trouble shooting but I want to ask basic question. Does the Security idiot light come on when you turn the key on and the other lights come on in the test mode?

Mine does not come on. Not even sure where it is since I can't find a idiot cluster picture/diagram for a S5. I remember it blinking when armed - years ago. It does not arm. I've found a few corroded connections (right door switch) but several posts point out that the S5 cpu is a piece of crap.

I took out what I think is the cpu, opened it up and looked for damage, I see none.

Before I take out my idiot light console to check the bulb (which I have not figured out how to do yet), I though I'd ask my basic question.

Enclosed picture of what I think the cpu is.

salex

Opps. Not sure what that is but not cpu. Found the blue cpu behide the kick panel

Wouldn't mind knowing what I did take off.

satch

iTrader: (1)

That's not the CPU. The CPU is Black and made of plastic and would have a few plugs connected to it. The alarm circuit board has 20 wires connected to it.

The number of wires the unit has plus the color of the wires would help. If you know this then by looking at the wiring diagram it would be easy to figure out.

salex

Well it looked blue until I took it out, it is black.

Following some post on rx7 cpu around the net, cold solder joints seems to be an issue, maybe a fact of life. After taking mine apart I found a few suspect joints - mainly 1c and 1d on the 20 pin connector (r/b and b/y wire). 1c goes through a 7.5 amp fuse and is labeled IG (guessing ignition). 1d goes through a 15amp fuse and is labeled TNS, which I have no idea what that is. Could not find those wires (other than the connector) in my wiring diagram. Not part of Theft Deterrent circuits, but they do not have connectivity to there components (a diode and a transistor).

I tried to desolder it but, I can do a lot of things, some good - some half ***. Soldering and plumbing are two areas I try to avoid. Could not even get the grey looking joints to melt, others that looked ok would melt almost immediately. I decided to try to find help and found an old radio/tv shop that will give it a try. He said he did some cold solder joints on another Mazda part (think ECU) and the customer was just tickled pink. It is too bad that those basic skills, like soldering, are being lost in todays world.

Anyhow he'll give it a try next week. Not sure what it will fix (or break!).

Still looking for answer on whether the security lamp comes on with the key to test lamp. Also looks like my SM says the lamp in on the console, though my vert was on the idiot cluster.

Thanks for the help so far.