TheWonder

Hello all,

I own a 1988 FC GXL that has treated me great up until now. The car has around 48k miles on it. My issue is the car will crank as it would normally but never 'catch' and start.
I began my troubleshooting by making sure 3 things were good to go. The car was running great and then it sat for a week and then it would not start.

1. Power
   1. I had the battery recharged and readings look good on the dash gauge when under load (starting) and the battery reads what it should when just hooking up a multimeter. I also have tried starting the car while its being jumped and no change.
2. Fuel
   1. I did a rudimentary test where I unplugged the fuel line from the bottom of the fuel filter and put it into an empty milk jug to see that fuel was flowing. It was. What I have not done is test the fuel pressure. I am not super sure how to do this to be honest.
   2. I replaced the fuel filter and no change.
   3. I did the deflooding procedure that is stickied and no change. When I cranked it with the plugs out no fuel sprayed out what so ever (Does this suggest a fuel issue?)
   4. The fuel pump does not make any noise when i turn the ignition on. (It is supposed to correct? Another indicator of bad fuel pump?)
3. Spark
   1. I replaced the spark plugs and made sure all was positioned correctly. No change.
   2. I actually brought the car to my trusted auto shop and they initially though it was the ignition coil. I bought a good one off ebay but no change.

I am a novice at this kind of stuff but this is increasingly frustrating not being able to get it running. I am open to try anything at this point. Does any of this potentially point to a fuel pump issue? I will try to find a how to guide on testing it if there is one. Any help is appreciated.

ATTACHMENT REMOVED AT OP'S REQUEST.

j9fd3s

iTrader: (3)

nope, the pump runs with the key in the start position or when the ECU sees an RPM signal

so if you have a timing light, you might want to put the timing light on it, and see if you have spark.

usually the default with these cars is if the ECU is seeing RPM, its flooded. if the ECU does not see RPM, it won't spark, or fire the injectors, etc.

arghx

iTrader: (3)

any codes? it's pretty rudimentary on the series 4 but worth a check. FC3S Pro v2.0:&nbsp How-To - Zenki FC3S Error Codes

ATC529R

pdf says no spark....but has new coils etc.

can he check the ECU?

TheWonder

Just talked with them and they said fuel pressure was great and they are convinced it has something to do with the ignition. I do not have a timing light and have no idea how to use one. I will have to research this. How can I check the ECU is seeing RPM?

TheWonder

This is interesting. Of the issues this could suggest, could any of them cause the car to not start? Obviously the coil failure but any idea on the others?
Do the numbers in the pdf seem normal? Unfortunately the car was towed back to my house so its up to me. Is there any helpful links on how to check the ECU?

ATC529R

I’d see if you can borrow someone’s ecru and just plug it in. Pretty easy to get to.

if it has no spark all the timing lights in the world won’t help

Pete_89T2

iTrader: (4)

At this point I would get a timing light or one of those inline spark plug tester lights just to verify that you have consistent spark at all plugs while cranking. For a timing light, you can get one from the tool loaner program from just about any major auto parts retailer (Advance, AutoZone, etc.); pay a deposit and get it refunded when you return the tool. The inline spark plug tester is a cheap tool available everywhere, here's an example of one Harbor Freight sells: https://www.harborfreight.com/in-lin...ker-63590.html

Which ever tool you choose to use, just follow the instructions that come with it to check each plug. If you get consistent blinking lights while an assistant cranks over the engine, you have good spark and can rule that problem out.

If you find you don't have spark at all or the lights are firing inconsistently, then most likely the ECU is not receiving a good signal from the crank angle sensor (CAS), which usually turns out to be a failing wiring harness issue. At this point, you'll need to consult the FSM/wiring diagrams and do the electrical troubleshooting.

j9fd3s

iTrader: (3)

the easy way is to put a timing light on it and crank the engine; no flash, no spark, no rpm signal.

plan B if you can borrow or have an extra crank angle sensor (CAS), you can plug it in and spin it by hand you should hear all the clicks from the injectors and the spark plugs.

btw i'm looking more at the crank angle sensor than the ecu, although you might want to make sure all the fuses are good

DR_Knight

iTrader: (23)

If you have the factory logicon and I’m assuming oem ecu and the car has a CEL function on the logicon, the CEL should light up for a few seconds when ignition is turned on. This should indicate the ecu is on.

there is a fuse under the dash for the ecu, called Engine.

you should have 12v to most connectors on the engine harness when ignition is on. Check the FSM.

Correct me if I’m wrong and please just read through my posts on other threads on this exact same issue, but the fuel pump primes when key goes to ignition on then fuel pump turns off. Then when cranking, air entering the afm triggers the afm which turns the fuel pump back on. I always forget how s4 vs s5 functions, so check on this.

there may be a fuel pump jumper connector under the hood, I forget s4 vs s5, so read up on this too.

but it does sound like no spark, worry about fuel later. Look into the CAS as suggested by others.

check the fsm wiring manuals for how power is routed. There are other relays under the hood which may be in question.

looks like a multimeter will become your best friend.

TheWonder

Picked up an inline spark plug tester. Will this read accurate if I have a bad battery? It seems the battery may be junk now. Even when its connected to my other car it is like 6v when cranking. Just fyi it was not always like this.

carsebuco

I just dealt with a very similar issue as yours a few weeks ago, only we did less troubleshooting, and it turned out to be a simple fix.

For the car to start, the battery had to be at 100%, charged with an outside battery charger (hooking up a charger/jump starter would not help). If this happened, the car would start. If the car sat for a day, I wouldn't be able to start the car back up (it cranked and everything). It would only start if the battery was at 100%, but the car would never die on its own. Naturally, each time I got no start, I had to make sure to unflood the car.

Come to find out, the alternator was going out, even though all the lights would work and nothing was flickering. Since replacing the alternator, we haven't had this issue again.

Hopefully it's as simple as that, but looks like there are many other threads like this with similar issues.

djSL

iTrader: (5)

I hate to be that guy, but my first suggestion is to always test compression when you have a no start situation. While the vehicle has low miles, it is old and it's very possible for something to let go; a quick compression test can save you tons of unnecessary troubleshooting later on. I learned that the hard way.

If you don't want to spend money, you can check for spark by removing the plugs from the engine, grounding them on the block, and have someone visually check for spark while you crank the engine. If spark is confirmed, I'd shoot some starting fluid down the intake. If the engine catches and starts, that would indicate you have a fuel delivery problem.

Another possibility is failed coolant seals leaking coolant into the combustion chamber. If the leak is bad enough, no amount of fuel or spark will ignite a large amount of coolant. Do the plugs smell like coolant? Or just fuel?

Cardinell

Do you have verified 12v to the coils? There is a small black connector at the leading coil. Turn the ignition on, then use your multimeter to see if there's voltage to the coil. If you replaced it with a known good spare, I would suspect they're not getting power.

cereal

When cranking does your tachometer move at all? even just a tiny bit up and down or is there nothing?

rlynchster

If I was confident with the compression, I would change the water temp sensor behind the water pump flange. ($25 amazon) Removing the alternator helps you get to it. You'll need a tiny pick to get the connector retaining ring off. I had a really really hard time getting my car started, and once I replaced that, everything changed.

I might also get a rebuilt mass air meter for $99.

I would set the Throttle Position Sensor voltage per the Field Service Manual on foxed.ca

The FSM on Foxed.ca gives you a lot of trouble shooting procedures. . . .Get out the volt meter and follow the directions. . .. The Field Service Manual is gonna be your best friend.

The Double Throttle Valve and EGR probably leak. Best to plug leaky items and convert hose to silicon. Always twist the hose when removing it from a plastic barb stub.

TheWonder

How do I test the alternator if the car doesnt run? Never done it that way before.

Thanks everyone for the suggestions. I bought a brand new battery cause the old one was absolute trash. No change, which I wasn't expecting it to start but now the car sounds even worse when turning over. I will pull the spark plugs and inspect next. I can now try the inline spark tester but I'll need a buddy to help. No movement on the tach.

For checking the coil where do i put the multimeter +/- ends? I am not very inclined when it comes to this stuff. Any pictures to reference? The auto shop had tested coils and confirmed 12v to both trailing and leading.

Cardinell

If the tach doesn't bounce when cranking, I would suspect a fault with the ECU. Whether just a blown circuit on the board, or the entire unit itself, I'm not sure, but try swapping it out to see if that makes a difference

As for testing the coils, there's a procedure in the FSM. Check page 5-32. Wright-here.net has an entire pdf dedicated to the engine Elictrical system. You'll find it there
have you pulled the plugs and turned the engine over by hand to listen for compression on all 3 faces of the rotor? Although this won't give you exact compression numbers, it will at least tell you if you have a dead face, or two

TheWonder

Finally got a buddy to help me with the inline spark plug tester. The light literally didnt come on when pluggin into any of the spark plug cables. 0/4. I was going to try a spare coil / ignition pack I had laying around but I have a feeling it wont make a difference.
bigger issue?

j9fd3s

iTrader: (3)

next step is to see if the coil has power when the key is on, its easy just unplug the coil by the battery. if no, then the main relay is the next stop, if yes, then you need to look at the Crank Ange Sensor (CAS)

its like this, CAS generates an RPM signal -> ECU -> Coils
the power side is like Battery -> Main Relay -> Main Fuse -> Coil

rlynchster

Might be helpful .. . . . Page 33

http://www.foxed.ca/rx7manual/manual...CAL_SYSTEM.pdf

DaBrkddy

Quickest way to tell without any tools if the crank angle sensor is sending a signal out in an S4 is to watch for the tachometer needle bouncing off zero during cranking. This assumes your tach worked before the issue arose. If there's no CAS signal getting to the ECU, that's also an easy test by back probing the wires at the ECU. This should be step one if there truly is no spark and your spark tester is working correctly. Don't throw parts at the problem until you know what is bad.

Just an unrelated aside for anybody who no-start issues: on a stock S4 N/A, there is no fuel pump prime signal from the ECU or otherwise at initial ignition key on.

To my knowlege, the fuel pump relay does not recieve ANY signal related to the CAS either.

There is a small switch in the AFM that triggers the fuel pump relay to turn on the pump as the flap inside the AFM comes off it's resting position.

TheWonder

Ok so I tried this again and the tach DOES move when I first start cranking but does not after the first second or two. The needle moves very little but it does move.

I think the auto shop tested the CAS and said it was 165ohms? In the diagnosis paper I have attached to this thread that seems to be the case.

Akaviri

iTrader: (1)

Pop out one trailing plug at a time and turn the engine over manually. Listen for three even swooshes.

If it sounds off, you probably flooded it and washed out the oil residue. Get a plastic syringe and squirt some two stroke oil in each hole. Then crank the engine over without the spark plugs. It will help restore compression. Put clean plugs back in and make sure they are correct (BUR7 leading, BUR9 trailing).

Also whenever in doubt about anything, calibrate that gotdang TPS sensor.

Good luck

kzoomatt

This issue is not compression related. I had him check all the plugs and he is getting zero spark. I sent him today with my N326 NA S4 ecu and crank angle sensor. He is swapping the ecu first and seeing if that corrects the issue. From the documentation he has from the shopping the crank angle sensor is sending good signal but the coils don't seam to be getting it. Wilmington the last month has gotten pretty hot so it's possible the ecu overheated and fried a board.