jrd-90rx7

Hi all. I'm getting my 1990 Rx7 convertible out of storage, and it's acting wierd. When I go to start it, it catches right away, then immediately quits. It's as if the ignition has cut off. After repeating several times, I can get it to stay running. But when I shut it off and let it cool a few minutes, it'll do it again.

I *think* I hear a sound like a relay clicking when it shuts off, but it's hard to tell over the engine noise.

My best guess is there's some safety system which is stuck. Something that's supposed to detect that the engine is running and leave the ignition on even after I disengage the starter. That's just a guess.

Anybody got hints on what to look for? I have the shop manual set, that'll be my next stop. I'm hoping somebody can tell me where to look.

Thanks in advance.

Rotary Alkymist

You might have some corrosion in the starter relay if you have one. Here's a recent post you should check out.

​​​​​​https://www.rx7club.com/2nd-generati...ypass-1141583/

You should also check the condition of the the clutch switch. Sometimes bending the tab out a bit will remedy this. The tab of metal that comes into contact with the switch bends over time(30 some years).

jrd-90rx7

Interesting. I'll look into the relay issue.

It doesn't sound like quite the same symptoms; mine cranks immediately, and catches immediately, every time. It's about 1/2-1 seconds later that it quits again. But it gives me a place to start looking.

The clutch switch would prevent it from cranking at all, correct? So that's not it.

Thanks!

Rotary Alkymist

You could be experiencing an intermittent issue. Sometimes it works sometimes it doesn't... until it just doesn't.

I didn't mention starter connections and battery -things to check.

jrd-90rx7

I'm confused. I don't see how starter has anything to do with this.

When I turn the key, it always cranks great, never any issue there. It turns over, catches within a fraction of a second, starts to rev up a bit, then quits, as if the ignition has been cut off. Turning the key again causes it to crank perfectly, and again catch right away, and then quit within a second or two. How could that be a starter issue, whether the starter itself or a bad connection to it?

The battery is several years old, that's not unreasonable to check. But since it cranks so well, it's hard for me to see how the battery could be too terrible. Are you suggesting that there's something in the system which is voltage sensitive? There's enough battery to turn it over really well, but somehow not enough to keep some relay energized, causing the ignition to cut off?

I'll get out my voltmeter tomorrow and see what I'm getting out of the battery idle and under load.

Rotary Alkymist

I read this on my phone initially, sorry for the confusion, I'm not sure where my head was last night.

jrd-90rx7

Cranking: Engine turning over
Catch: Starts to fire and run on its own

The issue is not that the starter stops. It's that the starter works perfectly, the engine starts, runs for 1/2-1 sec, then stops running, sounding exactly as if the ignition was cut off. You could describe that as stalling.

The car is bone stock, original ECU.

Perhaps the ECU is getting confused. I assume given the rest of the tech in the car that it's partly electronic partly mechanical, like relays. What's the parts situation like for an ECU for this car?

Rotary Alkymist

How long has it been in storage? How old is your gas?

If it was running good before you parked it just do the regular maintenance.

Drain gas, change oil, oil filter, fuel filter, etc.. I'm sure if you do all of that stuff it'll run a lot better. It could be cranky too. Have you tried putting your foot on the gas to keep it going in during the event?

I think a couple of real world heat cycles will help too.

jrd-90rx7

It's my daily driver in good weather. Took it off the road in november. It's been running perfectly up until I got it out yesterday. And even now, after a number of tries, it runs great once it will stay running.

Yes, tried putting foot on gas, a little or a lot. Makes no difference. If I start it with a bit of throttle, it'll rev right up, just like always, then quit, even if I hold the throttle on It takes anywhere from 3-4 tries to about a dozen tries before it will stay running.

It's about due for plugs and air filter, and of course oil change. I'll do that stuff anyway. But this is the first year it's done this wierd quit-after-a-couple-of-seconds thing. I'm not really anxious to take it anyplace if I can't get it started reliably.

I expect you're right about the heat cycles too; cars want to be driven. This car is a bit of a creampuff; I bought it new, and have put only 60K miles on it. I expect more problems due to lack of use than due to being beat up.

Rotary Alkymist

It does seem to point to a fuel issue. If this problem persists after changing filters/fluids/fuel then it could be a clogged sock in the tank. It's common to find a clogged sock in these cars.
I would save that one for last since it's not that fun to do. The condition of your sender will dictate how much of PITA it'll be haha.

The AFM could also cause this but your car eventually stays on. I'm assuming your AFM is good. Hard to diagnose over the internet.

The fuel would be over three months old too... definitely something to consider.

jrd-90rx7

Ok, I hear you . . . but it still doesn't make sense to me.

I've never seen a fuel problem that behaves like this. If it were a pump issue, or the pickup was plugged up, or something like that, I see how that would let it run a bit then die. But in that case, when I crank it again, I'd expect to get nothing out of it for many seconds, or even longer, while it tried to get enough fuel out of the tank to run on. It doesn't do that, when I crank it a second time, it lights right up immediately.

I don't know enough about the AFM to know whether to suspect it. I suppose it could be in the same category as the ECU; old and behaving intermittently.

Old fuel: Yep, agreed. If I can't get it running well enough to get to a gas station with reasonable odds of restarting, I'll go get a couple cans and refill it that way.

I'll dig out a camera and get a video with audio of the problem.

Rotary Alkymist

I wouldn't even worry really it until you get all that stuff done. You would have to do all this stuff anyway if you wanted to diagnose the issue. Im gonna be bold and say that your problem will most likely disappear.

Good luck man! I'm pulling my car out next month -can't wait! Im jealous.

jrd-90rx7

Got a video. Of course, this time, it only failed once, and then worked after that. That's what I get for doing a demo

I'll keep playing with it, and run it around some. Here's hoping you're right, and a few cycles will stop it being difficult

http:/www.jrd.org/name/03-07-20/MVI_0243.AVI

Thanks!

RXSpeed16

iTrader: (41)

Sorry I can't see the video. I've had similar symptoms due to fuel delivery. It dies without stumbling, no hiccup, just stops running like you turned off the ignition. Once because the car was out of gas. The other was due to a leak in the hose between the fuel pump and the tank mount. Fuel pressure checked good with the pump running, but pressure would drop to zero right after turning it off.
I assume it was supplying just enough fuel to pressurize the system and work with the rich starting map. After that, it can't keep up and it's too lean to run.

If it's the AFM, it'll run for like 10 seconds before cutting out. You can jumper the fuel check connector on the passenger strut tower to bypass it for diagnosis.

jrd-90rx7

Oops.

http:/www.jrd.org/nate/03-07-20/MVI_0243.AVI

Rotary Alkymist

See? it's already getting better haha. Bad gas.

jrd-90rx7

. . . . but how does that explain how it runs perfectly once it gets going?

Rotary Alkymist

When your car is started the return line is mixing your gas up. Couldve had air in your line too. Like I said -asking "why" is futile. Too many variables.

RXSpeed16

iTrader: (41)

My symptoms were the same. It was intermittent and got progressively worse until it just did it continuously. Check the dead head fuel pressure and if it hold pressure after turning off the pump power.

MartyMoore

Did you get to the end of this? I have the exact same problem with start up but mine wont fire at all.

A few mentioned the AFM to me but I didnt have too much time to did around at it