1986 rx7 died while driving
07-07-17, 04:54 PM
#1
Junior Member
Thread Starter
1986 rx7 died while driving
Hello everyone, this is my first rx7, I traded a clapped out $500 miata for this 1986 rx7 with an 88 motor swapped in, motor has around 120k (Borrowed time, I know). The car was in non-running state since 2014. I began by going over the basics since I know little about rotaries. I pulled look at the fuel after realizing that it had no gas cap, it was more water than gas, luckily there wasn't much in the tank so I put in fresh 93, the car still wouldn't run for more than a few seconds. I looked over the wires and plugs, they all looked fresh and the plugs were used but still looked like they were changed recently. Then after reading on here for a while I realized that the car would only run when the secondary injectors were on, IE: at warm up for a few seconds and above 3k. I swapped the primary and secondary injectors around and the car would actually idle, so I ordered a new set of injectors which made the car actually driveable.
So from that point on, I'd say maybe a week to a week and a half I was driving the car almost everyday, until a few days ago. I was driving home and then the car just went "Click" and shut off, no bucking, no stuttering, just like I turned the key. I pulled over and tried to roadside diag the issue but ended up needing a tow. The next day my friend tapped the tank and noticed it was empty, I felt relieved that the car probably just ran out of gas, I put fresh 93 in it but to my surprise the car wouldn't start. I then proceed to check the fuel pump which looked fine, thinking maybe it sucked some dirt up or something. I checked the filter and made sure that it was getting to the rail. I then tried to deflood the car, I pulled the plugs and all, they were wet with gas but the car still wouldn't run after I deflooded it. I don't think the engine is blown because of how the car just died, it seemed like an electrical cut more than mechanical.
I put a plug in a spark plug wire and held it up to the block while some one turned it over, it wouldn't spark, which makes me think its a spark issue. The main relay click and I don't think the car would blow out both leading and trailing coil packs at the same time. Any one have any ideas? Maybe the CAS died?
So from that point on, I'd say maybe a week to a week and a half I was driving the car almost everyday, until a few days ago. I was driving home and then the car just went "Click" and shut off, no bucking, no stuttering, just like I turned the key. I pulled over and tried to roadside diag the issue but ended up needing a tow. The next day my friend tapped the tank and noticed it was empty, I felt relieved that the car probably just ran out of gas, I put fresh 93 in it but to my surprise the car wouldn't start. I then proceed to check the fuel pump which looked fine, thinking maybe it sucked some dirt up or something. I checked the filter and made sure that it was getting to the rail. I then tried to deflood the car, I pulled the plugs and all, they were wet with gas but the car still wouldn't run after I deflooded it. I don't think the engine is blown because of how the car just died, it seemed like an electrical cut more than mechanical.
I put a plug in a spark plug wire and held it up to the block while some one turned it over, it wouldn't spark, which makes me think its a spark issue. The main relay click and I don't think the car would blow out both leading and trailing coil packs at the same time. Any one have any ideas? Maybe the CAS died?
07-08-17, 06:58 PM
#5
Junior Member
Thread Starter
Ok, So I spend a half a day on trying to diag this thing with no luck. I started by checking all the ground, the one from the battery to the lower shock tower, the two near the trailing coil pack on the shock tower and I even checked the one under the manifold with no luck. I then began to read up almost every thread on the issue. I checked to make sure I had 12v going to both coils, which I did. I tried a different CAS, I also pulled the cas and cranked it over by hand to check for spark, still no dice. I then check the engine fuse in the foot well, and replaced the egi fuses with known good ones. I checked the CAS plug that leads under the trailing pack. I then began to look at the ecu, I believe this is an ecu related problem because the tach doesn't move when the car is cranking. The car was running with a n327 ecu, it came with another n326 ecu and I bought another n326 because I was told it came from a 1987, and that 86-87 use the same ecu.
From what I've read the only differences in the n327 and n326 is mapping and that they should swap fine. I checked to make sure that the ecu was getting 12v and I even believe that it was pushing out 5 or 12v, I can't remember, I can recheck later. So that leaves me with the question what else could there be? I believe both coils packs wouldn't blow out at the exact same time right? Please help, it's got me very confused
From what I've read the only differences in the n327 and n326 is mapping and that they should swap fine. I checked to make sure that the ecu was getting 12v and I even believe that it was pushing out 5 or 12v, I can't remember, I can recheck later. So that leaves me with the question what else could there be? I believe both coils packs wouldn't blow out at the exact same time right? Please help, it's got me very confused
07-10-17, 02:01 PM
#6
Penis Healthy
iTrader: (5)
Join Date: Jul 2013
Location: █▬█ █▄█ █▬█ █▄██▬█ █▄█ █▬█ █▄█
Posts: 2,595
Received 779 Likes
on
446 Posts
Ok, So I spend a half a day on trying to diag this thing with no luck. I started by checking all the ground, the one from the battery to the lower shock tower, the two near the trailing coil pack on the shock tower and I even checked the one under the manifold with no luck. I then began to read up almost every thread on the issue. I checked to make sure I had 12v going to both coils, which I did. I tried a different CAS, I also pulled the cas and cranked it over by hand to check for spark, still no dice. I then check the engine fuse in the foot well, and replaced the egi fuses with known good ones. I checked the CAS plug that leads under the trailing pack. I then began to look at the ecu, I believe this is an ecu related problem because the tach doesn't move when the car is cranking. The car was running with a n327 ecu, it came with another n326 ecu and I bought another n326 because I was told it came from a 1987, and that 86-87 use the same ecu.
From what I've read the only differences in the n327 and n326 is mapping and that they should swap fine. I checked to make sure that the ecu was getting 12v and I even believe that it was pushing out 5 or 12v, I can't remember, I can recheck later. So that leaves me with the question what else could there be? I believe both coils packs wouldn't blow out at the exact same time right? Please help, it's got me very confused
From what I've read the only differences in the n327 and n326 is mapping and that they should swap fine. I checked to make sure that the ecu was getting 12v and I even believe that it was pushing out 5 or 12v, I can't remember, I can recheck later. So that leaves me with the question what else could there be? I believe both coils packs wouldn't blow out at the exact same time right? Please help, it's got me very confused
12v at coils means its a trigger issue.
Your tach runs off of the trailing coil signal so it makes sense it doesnt work.
The way youre checking compression wont really tell you if the engine is blown. If your using a standard piston compression tester, youll need to remove the schrader valve from the bottom of the hose. Connect it and watch for 3 even bounces on each rotor.
You said you used a spark wire to check spark. Have you tried using a spark plug and holding it to the block?
I say double check your spark with a spark plug to the block. If you have spark im gonna say the engine is flooded and you didnt deflood it good enough.
Also, what injectors did you replace the old ones with? Are they the correct impedance?
Last edited by FührerTüner; 07-10-17 at 02:08 PM.
Trending Topics
07-12-17, 06:55 PM
#8
Junior Member
Thread Starter
Ok so I made some progress, still puzzled.
About me not deflooding enough, I pull each spark plug and cranked the engine over with both fuses removed for at least 30 seconds.
I replaced the injectors with the same impendance 86-87 460cc injectors, 88 uses a high or low, I forget, 460cc injector. The car ran for a few hundred miles before this issue on the new injectors, so I'm not suspecting an issue there.
I don't know whether it was coincidence or not but I removed the AFM plug, because I know on miata's you can pull the maf plug and the car will run for a few seconds (I was trying to rule out a bad AFM), and the tach started to work again
I pulled the intake manifold to replace the gasket and fix a fuel leak. I also tried a known working maf, and now the car runs. It starts up, revs to about 3k and then dies, sometimes even back fire. I can keep the car running by reving it out to around 3-5k, the car will backfire and bounce. I'm still puzzled. I will recheck compression
About me not deflooding enough, I pull each spark plug and cranked the engine over with both fuses removed for at least 30 seconds.
I replaced the injectors with the same impendance 86-87 460cc injectors, 88 uses a high or low, I forget, 460cc injector. The car ran for a few hundred miles before this issue on the new injectors, so I'm not suspecting an issue there.
I don't know whether it was coincidence or not but I removed the AFM plug, because I know on miata's you can pull the maf plug and the car will run for a few seconds (I was trying to rule out a bad AFM), and the tach started to work again
I pulled the intake manifold to replace the gasket and fix a fuel leak. I also tried a known working maf, and now the car runs. It starts up, revs to about 3k and then dies, sometimes even back fire. I can keep the car running by reving it out to around 3-5k, the car will backfire and bounce. I'm still puzzled. I will recheck compression
07-13-17, 05:47 PM
#10
Junior Member
Thread Starter
Im 90% sure the fuel pump on this car was wired to be always on, it never shuts off when the key is in the acc 2 position
07-18-17, 08:58 PM
#11
Junior Member
Thread Starter
anybody have any ideas?
I ordered a new set of coil packs and spark plug wires because sometimes the leading coil would not give off a spark on L2. I pulled the plugs and the car sparked on the trailing coil set but not the leading set
I ordered a new set of coil packs and spark plug wires because sometimes the leading coil would not give off a spark on L2. I pulled the plugs and the car sparked on the trailing coil set but not the leading set
07-20-17, 12:27 AM
#13
Retired Moderator, RIP
iTrader: (142)
Join Date: Sep 2005
Location: Smiths Falls.(near Ottawa!.Mapquest IT!)
Posts: 25,581
Likes: 0
Received 131 Likes
on
114 Posts
Just pulling the plugs is not an effective way to deflood,as it still gets fuel.
If you pull the EGI Fuse(engine bay) that will cut fuel and spark to the engine so you can deflood it.
You may have to go further and add a shot of oil into the plug holes and roll the engine over like 5 seconds with plugs OUT and EGI Fuse OUT to get the engine to regain it's sealability(Compression) back.
*sealability..New word by Styx..patenting pending!
If you pull the EGI Fuse(engine bay) that will cut fuel and spark to the engine so you can deflood it.
You may have to go further and add a shot of oil into the plug holes and roll the engine over like 5 seconds with plugs OUT and EGI Fuse OUT to get the engine to regain it's sealability(Compression) back.
*sealability..New word by Styx..patenting pending!
07-20-17, 02:16 PM
#14
Just pulling the plugs is not an effective way to deflood,as it still gets fuel.
If you pull the EGI Fuse(engine bay) that will cut fuel and spark to the engine so you can deflood it.
You may have to go further and add a shot of oil into the plug holes and roll the engine over like 5 seconds with plugs OUT and EGI Fuse OUT to get the engine to regain it's sealability(Compression) back.
*sealability..New word by Styx..patenting pending!
If you pull the EGI Fuse(engine bay) that will cut fuel and spark to the engine so you can deflood it.
You may have to go further and add a shot of oil into the plug holes and roll the engine over like 5 seconds with plugs OUT and EGI Fuse OUT to get the engine to regain it's sealability(Compression) back.
*sealability..New word by Styx..patenting pending!
07-22-17, 08:10 AM
#15
Junior Member
Thread Starter
Ok so I replaced the plugs, I used ngk plugs and the ones I pulled out of the motor were a way different design. Replace the plugs did fix the issue of the car acting like it had no spark sometimes. I pulled apart to the intake manifold to check and see if the injectors had seated correctly. When I put it back together and the car ran a little better, it would actually somewhat run if I kept it at 2k. So I believe it is a really large vacuum leak? But from where?
Also shouldn't the fuel pump be either on or off? Is there a way to test? I'll look at the wiring again, it's mostly twisted and taped on this car from shitty previous owners
Also shouldn't the fuel pump be either on or off? Is there a way to test? I'll look at the wiring again, it's mostly twisted and taped on this car from shitty previous owners
07-22-17, 03:35 PM
#16
Junior Member
Thread Starter
this car is so fucked
looked further at the fuel pump wiring, it was getting power from the ignition switch, ran back through 6 different scraps of wire twisted and taped together and spliced into the pump...
So this is the best that I can describe the problem.
with everything plugged in, the car starts, revs to 3k for 2 seconds, then dies unless you give it gas in which case it will back fire and not hold a steady throttle position
with the afm and tps unplugged the car starts, idles somewhat at around 1500 rpm, tachs up to 4-5k over a 10 second period, then tachs down slowly, hunts for idle around 1-2k for 5 seconds, back fires and dies.
Also because of the fuel pump wiring I think the relay under the dash by the sterring colum is useless. Makes no difference whether or not it's plugged in
looked further at the fuel pump wiring, it was getting power from the ignition switch, ran back through 6 different scraps of wire twisted and taped together and spliced into the pump...
So this is the best that I can describe the problem.
with everything plugged in, the car starts, revs to 3k for 2 seconds, then dies unless you give it gas in which case it will back fire and not hold a steady throttle position
with the afm and tps unplugged the car starts, idles somewhat at around 1500 rpm, tachs up to 4-5k over a 10 second period, then tachs down slowly, hunts for idle around 1-2k for 5 seconds, back fires and dies.
Also because of the fuel pump wiring I think the relay under the dash by the sterring colum is useless. Makes no difference whether or not it's plugged in
07-24-17, 01:41 PM
#17
Penis Healthy
iTrader: (5)
Join Date: Jul 2013
Location: █▬█ █▄█ █▬█ █▄██▬█ █▄█ █▬█ █▄█
Posts: 2,595
Received 779 Likes
on
446 Posts
this car is so fucked
looked further at the fuel pump wiring, it was getting power from the ignition switch, ran back through 6 different scraps of wire twisted and taped together and spliced into the pump...
So this is the best that I can describe the problem.
with everything plugged in, the car starts, revs to 3k for 2 seconds, then dies unless you give it gas in which case it will back fire and not hold a steady throttle position
with the afm and tps unplugged the car starts, idles somewhat at around 1500 rpm, tachs up to 4-5k over a 10 second period, then tachs down slowly, hunts for idle around 1-2k for 5 seconds, back fires and dies.
Also because of the fuel pump wiring I think the relay under the dash by the sterring colum is useless. Makes no difference whether or not it's plugged in
looked further at the fuel pump wiring, it was getting power from the ignition switch, ran back through 6 different scraps of wire twisted and taped together and spliced into the pump...
So this is the best that I can describe the problem.
with everything plugged in, the car starts, revs to 3k for 2 seconds, then dies unless you give it gas in which case it will back fire and not hold a steady throttle position
with the afm and tps unplugged the car starts, idles somewhat at around 1500 rpm, tachs up to 4-5k over a 10 second period, then tachs down slowly, hunts for idle around 1-2k for 5 seconds, back fires and dies.
Also because of the fuel pump wiring I think the relay under the dash by the sterring colum is useless. Makes no difference whether or not it's plugged in
The car is going to run like **** without the AFM and TPS.
Fix your fuel pump wiring.
If I thought i had a vacuum leak, what I would do is:
Pressure test the whole intake system to find the leak or;
Change LIM to Block gasket
Change LIM to UIM gasket.
Change injector grommets, Primary and secondary.
Replace all vacuum hosesand clamp or zip tie them on.
Check all emissions gaskets on the UIM.
07-25-17, 07:09 PM
#18
Junior Member
Thread Starter
Car is an 86' so if I'm wrong let me know but I don't think codes can be pulled, it's an n237 ecu
the car is back firing often when running, it makes me believe that the timing is retarded. But I have replaced the cas and retimed the car multiple times, all the same way I did when the car was running fine
i have checked for vac leaks with carb cleaner, the injector gromets all seem fine and show no signs of cracking
i don't understand how I go from losing an Ecu crank signal when running to randomly regaining it and then the car running like ****
the car is back firing often when running, it makes me believe that the timing is retarded. But I have replaced the cas and retimed the car multiple times, all the same way I did when the car was running fine
i have checked for vac leaks with carb cleaner, the injector gromets all seem fine and show no signs of cracking
i don't understand how I go from losing an Ecu crank signal when running to randomly regaining it and then the car running like ****
Last edited by Forrest95m; 07-25-17 at 07:11 PM.
07-26-17, 08:22 AM
#19
Penis Healthy
iTrader: (5)
Join Date: Jul 2013
Location: █▬█ █▄█ █▬█ █▄██▬█ █▄█ █▬█ █▄█
Posts: 2,595
Received 779 Likes
on
446 Posts
Car is an 86' so if I'm wrong let me know but I don't think codes can be pulled, it's an n237 ecu
the car is back firing often when running, it makes me believe that the timing is retarded. But I have replaced the cas and retimed the car multiple times, all the same way I did when the car was running fine
i have checked for vac leaks with carb cleaner, the injector gromets all seem fine and show no signs of cracking
i don't understand how I go from losing an Ecu crank signal when running to randomly regaining it and then the car running like ****
the car is back firing often when running, it makes me believe that the timing is retarded. But I have replaced the cas and retimed the car multiple times, all the same way I did when the car was running fine
i have checked for vac leaks with carb cleaner, the injector gromets all seem fine and show no signs of cracking
i don't understand how I go from losing an Ecu crank signal when running to randomly regaining it and then the car running like ****
07-28-17, 06:02 PM
#20
Junior Member
Thread Starter
When the car would turn over and the tachometer would not move, I assume it means the Ecu lost a signal somewhere because it was supposed to move while cranking
07-31-17, 07:16 AM
#21
Penis Healthy
iTrader: (5)
Join Date: Jul 2013
Location: █▬█ █▄█ █▬█ █▄██▬█ █▄█ █▬█ █▄█
Posts: 2,595
Received 779 Likes
on
446 Posts
Thats an assumption. Theres a few different things that could make the tach stop working. Im not sure how you checked for vacuum leaks with carb cleaner when the engine wont even idle.
Did you ever pull the plugs again and see whats going on with them? That can tell us a lot.
Did you ever pull the plugs again and see whats going on with them? That can tell us a lot.