rmauser

Hello, all.

I'm having a problem with my '85 GSL-SE. Sometimes it won't start, sometimes it dies on me when slowing down to a stop, either going forward or backing up, once when accelerating from a stop it stalled, etc.

Since I could not always hear the fuel pump kicking on, I thought it was a fuel pump problem, so I changed the fuel pump and filter, and also the spark plugs, wires, cap & rotor. Still had the problem (when it didn't work, I couldn't hear the pump, and tested the circuit using a 12V bulb at the connector under the driver's junk compartment (no power).

The COR relay looks to be in 'pristine' condition, so I don't think that is a problem.

Since the fuel pump circuit is controlled by the trailing igniter (or something like that), I pulled the J-109 igniters and tested them using the "checking igniter" setup shown in the manual, and when I applied a current to them, the light will stay on as long as the switch is on, for both units (not 'flashing' like the manual says - but their wording is a little ambiguous to me). Is that a problem?

I pulled both coils and tested their resistance with a multimeter (indoors, 68 deg F). I get primary readings of 1.1 ohms or sometimes 2.0 ohms (I'm not sure I trust the meter....) The manual says the primary resistance should be 0.9 +/- 0.09 ohms at that temperature. The manual also says to test the coils after they are heated up, and should be 1.35 +/-10% ohms (???!!)
I get secondary resistance at 8.35 K ohms. I can't find a requirement in the manual for that. Does anyone know?

I didn't see much corrosion on the coil terminals, but I cleaned them off and applied electrolytic grease. Let's see if that eliminates the problem.

Meanwhile, I'm driving it around, and I really don't trust it to run.

I followed kyle_84rx7 thread for "Please Help-rough idle-backfire and more"
https://www.rx7club.com/1st-generation-specific-1979-1985-18/please-help-rough-idle-backfire-more-831992/, so I'm looking for more info.
Does anyone know of anything else that might be causing the problem? Any advice would be greatly appreciated.

rmauser

A correction, and an update:

I corresponded with a manufacturer of coils, who said that "when you use an ohm meter to test a very low reading you need to factor in the built in resistance of the meter. With the meter on, touch the two test leads together, record that value. Now, when you perform the primary resistance check you will need to subtract the initial value from the recorded value from the primary winding test. This will give you the true resistance value of the primary winding." Doing that, I found the primary resistance to be .85Ω or 1.75Ω (.85Ω is in the ball park)

He went on to say: "the specs that are provided both by us and the OE are guides to statically check an ignition coil, but just because the coil passes the static test doesn't mean it will function dynamically. Coil manufacturing has changed through the years. Engineers have found that by changing the turns between the primary and secondary winding the coil will function the same, only the heat produced will be less. What destroys any electrical device, on your car or in your home, is heat and vibration. A little change in design or manufacturing may solve a life cycle issue. Nothing in this world will last forever. If these are the original ignition coils then they have 25 years of service life, doesn't mean they're faulty, only that they've had 25 years of service life."

So, although he suggested tracking down the circuit with a volt meter before and after it gets funky again to see whether the pump is getting some or no voltage, I figured I'd throw in two new coils for $75. Borg Warner (Beru) unless somebody tells me it is no good. The other options I see out there are Std Motor Products, Accel, Airtex, Beck/Arnley.

rmauser

Update (I guess this is my private blog!):
I tested the coils I bought with a multimeter, and the reading pretty much matched my existing coils.
Since I've garaged the RX for the winter I didn't change out the coils, but decided to return them to the store, and if I need them in the spring, I'll buy them again, and the warranty will run from then on, when I'm driving the car.
The clerk at the store suggested that next spring when I get it running, to tap on the coils with the butt end of a screw driver, and to wiggle wires etc to see if I can get the engine to quit, as a way to track down the problem. Sounds like a method that is cheaper than replacing everything, so I guess I'll do that. Anyone have a better idea? Anyone? Anyone? Hellooooo out there? ;-)

10aebuild

Very nice blog you've got going

I have never really understood how to test coils so I prefer to test the spark directly instead with spark testers. I figure if the spark is good, so should the coil.

A friend of mine and his n/a 86 Rx7 shared similar symptoms as yours. It failed the spark test and my next move at that time was to spray the entire ignition system with Windex. Lucky for us we quickly found that one of the coils was arcing like crazy. Everything was back to normal after a straightforward coil replacement. You may use water like I used to, but Windex seems to work even better for some reason.

Hope you find the gremlin and when you do, please fill us in

rmauser

10aebuild,
Thanks for your thoughts. I'll give it a try.

Anyway, to pick up my blog where I left off.... I garaged the car for the winter, and this spring I got it going - it popped right off as if nothing ever happened.... until last Friday, when the engine quit on me as I was approaching a friend's house. Died, just like that. I coasted and pushed it into a parallel parking spot, tried starting it, and didn't hear the fuel pump, so I knew it was the same old problem, whatever that is!

I left it there overnight and to get it home I ended up jumpering the fuel pump by using a lamp chord, extension chord and assortment of alligator clips and spring clamps to hot wire it - and it worked![1] Actually, I got the polarity wrong first, so it worked after I switched the wires, which is pretty much how everything seems to go....

I drove it home, reviewed what I copied from the posts, and figured it HAD to be the IGNITER! (As one poster on this site said, "when it works, it works, and when it doesn't, it doesn't) So I buy a new igniter (not cheap, but hey, I'm on my way to getting my car back, right? How can you put a price tag on that?), and it arrived today, so I switched it out and .... NUTTIN! NUTTIN! Nuts.[2]

Next, I figured it had to be the coil[3] so I swapped the two. NUTTIN again![4]

I'll try spraying the coils as you suggest, after I hotwire the fuel pump again some night, but I'm thinking that swapping them should have allowed the fuel pump to run, if that was the issue.... because the lead coil and igniter worked fine when I hotwired the fuel pump.

I'm open to more ideas, anyone.... Anyone.... HELLooooo?

For other neophytes:
[1] The snap connector for the fuel pump is hidden under the driver's side compartment, accessed by removing the compartment.
[2] The igniters are little boxes attached to the side of the distributor, and the trailing igniter is the one facing the engine. The leading igniter faces the radiator.
[3] The trailing coil is the one closest to the headlight.
[4] If the definition of insanity is doing the same thing over and over, expecting to get a different result, then what is defined by doing a different thing every time and getting the same result? How about 'being driven to insanity'?

rmauser

Okay,
Tonight I hot-wired the fuel pump again to be able to run the engine, and then sprayed the coils with windex. I didn't see any blue arcs. I pulled the spark plug wires from both of the top (trailing) plugs, one at a time, and saw sparks arcing across as I pulled and reinstalled them, so both trailing plugs are working. (wish I had done that before buying a new igniter...)

What's left to look at? In some other thread they talked about checking the AFM.
WTF is the AFM? Air Flow Meter? Where is it located? How would that affect the fuel pump? Where is the fuse for the fuel pump? I'd hate to think it was that simple, but I'm grabbing for straws here......

Kentetsu

1. The fuel pump will only run if two conditions are met:
a. The engine is actually being craked over.
b. The trailing ignition system is working.

2. Having said that, there is also a relay located under the steering wheel, which is known to cause problems for some. You can jump two of the three contacts to bypass it, and eliminate that as a possibility. When this is done, the fuel pump will run when the key is on, regardless of the trailing ignition system.

That's about all I know in regards to the FI first gens. Best of luck to you...




.

OK13B

iTrader: (3)

yes air flow meter. it is located under your air filter. it's the silverish box under air filter box. it has a little flap inside of it, if you turn your key to the "on" position and push the flap open your fuel pump will turn on. not sure if that will help you at all. but that's where it's at

rmauser

OK13B,

Thanks. I'm getting desperate! My air filter is located off to the side, I popped the filter out, and can feel the flap. It's worth a try.

Can You tell me exactly where the fuel pump relay is, and what it looks like, what color the wires are? Sorry to get so specific, but I've been trying to locate it under the dash, and if the thread https://www.rx7club.com/1st-gen-archive-71/fuel-84-85-fuel-pump-relay-trick-597949/ is correct, I don't have any relay there, over the gas pedal under the dash. This, I think, is the next thing I should check.

rmauser

I found the COR and it is working. I jumped the blue-with-black-dot wire from the COR connector to the fuel pump, which did nothing to change things, so that wire is good.

There is a brown-with-black -dot wire that becomes a brown-with-yellow stripe-&-black-dot wire to the Air Flow MEter (AFM). Supposedly if you ground that wire, the fuel pump could work. I pulled the air filter and pushed on the flapper of the AFM in a WTF fashion. I was able to start the car. So maybe that flap was stuck? With the car idling, if I push on the flap to open it up more, the idling gets real rough, not unlike what I see after a cold start, after the engine heats up. When I accelerate quickly, that flapper has to open up fast, right? So if it doesn't, stalling could be likely, maybe? Could this AFM be the culprit? If so, what could be the diagnostics? The fix? Can they be cleaned?

From Discount Auto Parts website:
urpose: The Mass Air Flow sensor is used to measure (actually weight) the amount of air entering the engine. This measurement is used by the engine computer or ECM to calculate proper amount of fuel injected into the cylinders in order to provide optimum combustion and low emissions.

Maintenance Tips/Suggestions: MAZDA RX7 Mass air flow sensor requires no regular maintenance. On mass air flow sensors with a sense wire, this wire can become contaminated with dust particles. These particles can be removed with automotive solvents that are safe for the use on mass air flow sensors. MAZDA RX7 mass air flow sensors are commonly misdiagnosed. Before replacing the mass air flow sensor check for air leaks in the connecting air ducts and intake manifold. These leaks can cause similar symptoms as a malfunctioning mass air flow sensor.

Failure symptoms: Problems with Mass Air Flow sensors are common. Bad or contaminated MAZDA RX7 Mass Air Flow sensor can possibly cause a wide range of various vehicle drivability problems such as stalling, especially when the engine is cold, misfiring, poor acceleration, etc. In addition, a problem with the Mass Air Flow sensor often causes the "check engine" or "service engine soon" light in the vehicle instrument panel to illuminate.

rmauser

I'm now thru another season (I'm in Rochester NY, so I garage it in the winter). Last spring, I cleaned out the AFM, but I did not buy new coils. The car started off fine and I drove it all summer. About a week ago, during some cold wet weather, it wouldn't start, even jumpering the fuel pump using the jumper at the AFM. I just succeeded in flooding the engine. However, today, after several dry sunny but not all that warm days, I gave it another try before having to push it into the garage, and it started (a bit rough, and in a HUGE streaming puff of white smoke - probably because I had flooded it the prior week). So, does anyone care to suggest what I might want to check / replace next? (I'm thinking next spring, but maybe it would be better to do it now, in lousier weather, even if the product warranty expires while the car is stored....)

rmauser

Hi all,

My '85 GSL-SE ran fine all summer, and now in late October it wouldn't start. (I'm sensing a pattern here -- seems to be an upstate NY late autumn issue, as this is how I ended the season in the past few years....)

I think I did something dumb, thought I'd fish for more than just a confirming "yes you did".

I cranked it a little, then thought "maybe its flooded" so I pulled the wire harness off of both injectors, cranked it a little, hoping it would clear out any flooding. I was looking for a 'put-put gasp', but nothing happened. I reconnected the injectors and there is no firing going on. The starter engages the flywheel (tested that by trying the starter in reverse - good? bad? very bad?) and the tank is full. Any ideas other than garage it now, take it out in the spring?

BTW, I did not replace the coils in the spring, as it started right up, no problemo.

rmauser

Okay.....
Its the next morning and I try to start it again and it still won't start. So I've had it - I give up.
Time to have it towed to Tony, my mechanic. Let him deal with it.
I call him. He tells me to pull the spark plugs and bring them to him. The top two plugs ('trailing' or 'top'?) are wet, soaked in gas. The bottom two ('leading' or 'lower'?) are dry. (the distributor cap has 'T' and 'L' on the cables connecting to them) The spark ends are encrusted brown, but not worn - showing some carbon build-up?

Anyway, Tony bead blasts them and now they are nice and shiny. He tells me that autumn is colder and wetter than spring, so even though the car sits all winter, when I pull it from the cold garage and start it in April, it is actually warmer and dryer than now. Maybe.

I reinstall the plugs and crank the car. It doesn't sound good (i.e. not firing), but I keep cranking, and then it catches, and one mother******* long stream of white smoke comes blowing out the exhaust like yew-wooden-be-leave, and every so often I swear I see tinges of blue blue/green in the smoke. Shezzam! (The plugs were out for about 5 hours on a damp day - could all that smoke be from water vapor getting in through the spark plug holes??? Whats with the blue tinges? Tony put some never-seize on the spark plug threads. That has copper in it. I hope it's not the wiper seals at the edge of the drums crapping out on me due to the gas watering down the oil .....)

About a week later, it is still running fine. I put it in the garage at the start of lousy weather, took it out a couple of times when the weather was good and .... even on a cold, clear day it's running like an 'Eveready Bunny'!

This leaves me wondering:
1) since the plugs were encrusted in brown, not black, is there a problem with the gas/air ratio (or is it the other way around) that is crapping them up way too quickly? Are they in fact getting crapped up too quickly?
2) has everything I've done in the past been a complete waste of time (other than keeping me entertained), and all I really had to do was clean or replace the spark plugs every year, regardless of mileage? (sort of a 'Wizard of Oz ruby shoes' moment?)
3) should I change my meditation mantra to "owe wa tagoo siam"?

I bought a set of spare plugs to keep on hand. A friend recommended I keep a good brass wire brush handy, too. I can afford that tool.

Stay tuned (or tuned up, or whatever) ...

rmauser

It is March now, and after a mild winter, my baby fired right up, no problem not even much of a puff of water vapor. Life is sweet! But I'm wondering what will go wrong next.......

AJfc3s

I have one question I when my engine light comes on it feels like im losing compression my rps usally stop where ever they are at. Just wondering if the MAF would cause this?? I don't have the money at the moment to rebuild the engine soo I just wanna be sure.

rmauser

Hi AJfc3s,

I'm not sure about your issue. My engine would die sometimes when accelerating from stop, sometimes when slowing down to stop.

FYI, I had my same problem a week ago. Got to my destination and later it wouldn't start. I left the car for a couple of hours, tried again later and it fired up. After I got home, I changed out the plugs, and all is fine.... for now.

Makes me wonder whether I should check for vacuum leaks, i.e. if that is messing up things, causing the engine to run too rich and fowling up the plugs....

How should I check for leaks? Use a can of spray ether? Or will that make me a Darwin Award candidate?

AJfc3s

Well I found out my problem is both rotars are spinng at the same pace instead of offset, thank you very much for the advice. the way I have checked for vacuum leaks in the past was just by ear. Good luck and keep me up to date its a really nice thread you have going

rmauser

Well, its November 2016, and the engine died again, about a month ago, but I haven't had the time to work on it. Here's the synopsis:
The engine started for a split second, and then nothing. The engine would crank, but it acted like it wasn't getting any fuel. So I bypassed the wires to check if the fuel pump was good (yes) and checked to hear the relay under the passenger floorboard working (yes) and then went to check on the MAF sensor under the air filter, where I saw the tag I left on the MAF sensor jumper years ago, so I jumped that and the fuel pump worked, the engine started. I popped the cover off the air filter, and it was pretty dirty. So here is my checklist, in case I forget what to do in the future.
(This is for a 13B engine)

1) Check to make sure the spark plugs are good, the battery is good and the air filter is clean,
2) Listen for the fuel pump when turning the ignition switch. If I can't hear that, then
3) Jump the MAF sensor to test if the fuel pump is getting electric. If not,
4) Pull up the passenger carpet to get to the computer & relay under the passenger floorboard, remove its cover and listen for the relay to click on. If it doesn't
5) Curse, screw around with the igniters, coils, whatever, then
6) Tow the car to Tony's.