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I'm still trying to figure out why you're reading higher pressure when running -there is vacuum present which should drop your pressure pound per pound. If you are running 37lbs when running that puts you almost 10lbs over your mark which is pretty rich.
If your FPR is working properly then, while idling, you should see the pressure increase but 8 or so lbs(iirc) when the vac line is disconnected from FPR(use thumb on vac line to prevent vac leak and confirm that you actually have vacuum present at that line). However, even with your line not working you should still only read what you read when it's not running which in your case would be 25psi. Strange.
Or you have a clogged/kinked line. I can't see anything else causing this issue. Unless you have a setting that is incorrect in which case I can't help you :/.
Last edited by Rotary Alkymist; 06-24-19 at 09:14 PM.
I'm still trying to figure out why you're reading higher pressure when running -there is vacuum present which should drop your pressure pound per pound. If you are running 37lbs when running that puts you almost 10lbs over your mark which is pretty rich.
If your FPR is working properly then, while idling, you should see the pressure increase but 8 or so lbs(iirc) when the vac line is disconnected from FPR(use thumb on vac line to prevent vac leak and confirm that you actually have vacuum present at that line). However, even with your line not working you should still only read what you read when it's not running which in your case would be 25psi. Strange.
Or you have a clogged/kinked line. I can't see anything else causing this issue. Unless you have a setting that is incorrect in which case I can't help you :/.
Hmmm the vacuum port im using certainly could be clogged. I'll have to pull the UIM and try and clean it. Im using a nipple on the LIM for my vacuum source for the fpr. I'll also make sure the vacuum hose isn't getting kinked or crushed.
Though I don't think this is a vacuum thing. When I set the static pressure it shouldn't go up unless I'm on boost right? It could and should go down with vacuum but the only way it should go up is with boost or at least that's how I understand it. Think something like a primary not injecting could cause the higher fuel pressure?
Anyway, I guess I have a little list of things to do over the week.
Thinking on it more, the SAFC cannot control pressure, at least I don't imagine that it can, so it's not the issue but disabling it could still prove useful.
Honestly, it has to be one of these things: bad gauge, clogged line, bad FPR. A bad gauge is probably the most annoying of these so hopefully it's good.
Logically these are your problems/solutions:
Problem
You test your "line pressure" and you get 25psi. It should be at 36-37. This is a problem which can only be fixed by adjusting FPR.
Solution
Adjust FPR to 36-37.
Problem
When you start the car your fuel pressure rises to 37psi. It should be at 30ish. This is caused by two things. A bad FPR or a clogged return line.
Solution
Replace FPR or clean/replace clogged return.
Is there any chance that you may have purchased a fuel regulator that is too small? Hmm, unlikely. Maybe your return is too small? This would explain the fuel pressure issue. I don't know the specs on your pump.
Last edited by Rotary Alkymist; 06-25-19 at 11:01 AM.
Thinking on it more, the SAFC cannot control pressure, at least I don't imagine that it can, so it's not the issue but disabling it could still prove useful.
Honestly, it has to be one of these things: bad gauge, clogged line, bad FPR. A bad gauge is probably the most annoying of these so hopefully it's good.
Logically these are your problems/solutions:
Problem
You test your "line pressure" and you get 25psi. It should be at 36-37. This is a problem which can only be fixed by adjusting FPR.
Solution
Adjust FPR to 36-37.
Problem
When you start the car your fuel pressure rises to 37psi. It should be at 30ish. This is caused by two things. A bad FPR or a clogged return line.
Solution
Replace FPR or clean/replace clogged return.
Is there any chance that you may have purchased a fuel regulator that is too small? Hmm, unlikely. Maybe your return is too small? This would explain the fuel pressure issue. I don't know the specs on your pump.
I was actually thinking that the return line could be too small for this pump. I've read of other fc with this pump though in the 200 and 300 hp ranges. I'd be surprised if they all replaced their metal return line for modest hp setups. I checked the flow from both the fpr and the return line at the tank and the flow seemed great.
The fpr is an aeromotive 13129. In their description it says it handles pumps capable of 1000 hp so it should be able to handle my pump. Here's what's interesting though, aeromotive says it's a 40 to 70 psi regulator, everywhere else says it's a 30 to 70 psi regulator, and my gauge currently says it's adjusted to 23 psi static. So something isn't adding up and im betting it's the gauge. Im going to hook the gauge directly to the regulator next time im under the hood to see exactly what the pressure is at.
However even if the numbers aren't exactly accurate the pressure is still going up instead of down. I'll buy a cheap mechanical gauge just to be sure it isn't the gauge being completely messed up.
Fuel system has been sorted i think. I disconnected the SAFC, swapped primary and secondaries, and scrubbed the return line. Static psi is set to 37ish and when the car starts it drops down to 28. However it still wont start without unplugging the fuel pump and once i do get it started it still wont idle. Whats happening now is once i get it started and the pump turned back on i have to keep the rpms above 2.5k or it will die. With the maf propped all the way open this drops down to 2kish before it dies
I triple checked for vacuum leaks while i had the UIM off and everything was good so i dont think this is a vacuum thing.
Still looking for help on this. I've done a few more things since last post in attempt to see if i can get it to stay alive on its own. I've adjusted the idle set screw and reset the TPS. I also went back through the vaccum system and everything seems to be in place. The car will now stay alive as long as I keep it above 2k rpm, but as soon as it drops below that it literally just shuts off.
Is it still back firing? Compression and timing should be checked again.
Also, your engine is ported. Who did the porting? What was ported? I have no experience with porting but I do know it can lead to the need for a high idle if done incorrectly.
What I can say for sure is that if your fuel system, ignition system, timing settings and compression are OK, you have zero vacuum leaks and your car can't idle below like, 1500, then you might have a build issue.
Have you ran it for any amount of time? It may need to just run. If you aren't overheating or leaking and pressures are ok then run it for some time. You might surprise yourself.
TPS would not cause your issue.
If you haven't I would be absolutely certain that all injectors are working as they should.
Re-check the timing. So many times people think they have it timed and it isn't.
Above all: CHECK COMPRESSION.
If you read enough threads on here you will see a pattern of people doing loads and loads of work, throwing money into the engine bay, just to realize that their compression just wasn't good enough. I can't imagine how many good TPS end up in a dirt pile -it hurts the soul. It's the first test that should be done to avoid the grief. If it checks out then you can sigh in relief and move on.
Last edited by Rotary Alkymist; 07-06-19 at 05:00 PM.
It doesn't backfire at all anymore while I have it above 2k rpm. It sounds good even.
I've checked timing 4 times now but I think it's time to invest in a timing light just so I can be 100% sure that's straight.
I did the street port myself using a mazdatrix intake template and a pineapple racing exhaust template. Im sure they aren't perfect but I took my time and tried my best. I felt like they came out well enough but it was my first attempt so as I said, I'm sure it wasn't the best port job ever.
I really doubted it had anything to do with tps or idle settings. Was just kinda grasping at straws. I guess I can't be 100% on the vacuum either. Everything is certainly hooked up but it could still have a leak somewhere. Problem is I can't get it to idle so I can't spray starter fluid around the hoses or manifolds.
I'll start with timing and compression though since those will be fairly easy to do.
Could you perhaps take a photo of your CAS(with the blind cap off) with yellow mark lined up with timing pin?
Try to take a photo straight on with zero shadows and take a close shot. I'm interested to see your settings just to cross it off the list.
Could you perhaps take a photo of your CAS(with the blind cap off) with yellow mark lined up with timing pin?
Try to take a photo straight on with zero shadows and take a close shot. I'm interested to see your settings just to cross it off the list.
Post back with a photo and compression readings.
I ordered a compression tester and timing light online. Should be here Friday it says. In the mean time here is the photos of the timing. Note that I don't have the red and yellow paint anymore. I set my tdc to the first(right) timing mark.
Also something I forgot to mention last time. My boost gauge was showing that the car was pulling like 15 inhg of vacuum while it was running. Not sure if that's indicative of it being vacuum leak free or not. That seems to be in the ball park of other rx7s from what I've read.
Finally got to the car today. To start, the car started on its own without having to mess with the pump for the first time which was nice. Not only that but it "idled" on its own at 2.5k for about 20 seconds before dying which was also a first. Aside from that it was business as usual. Falls on its face immediately after it drops below 2k rpm.
I tried turning the CAS as suggested. The car does sound smoother now. Before it would pop constantly. Still does pop a decent amount but not nearly as much, as you can hear in the videos I linked.
I tried checking timing with a light, but at 2k rpm its just impossible to see the timing marks. It should be close enough to run at this point so I think we can rule out timing.
I also checked compression. It was hard to tell individual face readings, but they were all consistent with no sudden drops in compression from one face to another.
Front compression: 60 psi
Rear compression: 65 psi
I know those numbers are not great, but its a fresh rebuild with new apex seals and used housings. From what i read that's normal to have low compression for awhile.
That's good. These videos are unavailable to me for some reason. You're timing is close enough that is should be able to drop below 2k.
Is the brake booster line hooked up on the intake? Just an idea, it's happened to me.
Another idea... have you set your throttle body? Maybe you're choking yourself out? Just brainstorming.
After it dies does the car start easily afterward? If it does that is a good sign. I'm running out of ideas.
Oops videos were set to private. Should be able to view them now.
Yeah brake booster is hooked up. I don't know what setting the throttle body is. Like the idle set screw?
Historically it hasn't started on its own ever lol. This was ther first time I turned the key and it fired up. I ran it up to operating temp for the compression check so I didn't get to try a second cold start. It does not start up without messing with the fuel pump while it's hot though. That's probably just the low compression while warm though I assume.
It's kind of a pain in the *** to set but it's very critical that the throttle body is set properly. Butterfly clearances mainly. If you consult the FSM you'll find the info.
Question: Does the car start on it's own and hold 2000rpm and THEN it dies after it warms up? If so then maybe your throttle isn't set properly and after the high idle cam rolls off you choke yourself out. Hard to say over the net lol.
That last video did sound a bit smoother. Keep it there until you get a light on it. Even if you were off by 5 degrees you should still get lower than 2000rpm. I wouldn't worry just yet. You still have a few things to look over.
Are you positive you don't have a post-AFM leak? When I first bought my TII I had a leak in the TID which showed a similar symptom. Car would stay running as long as I held the throttle.
It's kind of a pain in the *** to set but it's very critical that the throttle body is set properly. Butterfly clearances mainly. If you consult the FSM you'll find the info.
Question: Does the car start on it's own and hold 2000rpm and THEN it dies after it warms up? If so then maybe your throttle isn't set properly and after the high idle cam rolls off you choke yourself out. Hard to say over the net lol.
That last video did sound a bit smoother. Keep it there until you get a light on it. Even if you were off by 5 degrees you should still get lower than 2000rpm. I wouldn't worry just yet. You still have a few things to look over.
Cool I'll definitely look into setting the throttle body tomorrow. I did the throttle body mod so do I still have the high idle cam? Today was the first day it held idle at all so its hard to say if that's the habit it's going to have.
Checked the throttle body today. The bottom two plates were within spec. Top plate was over double the spec so that got adjusted. Idk if that could be the issue though. Wouldn't that make it idle high if the plate was open more?
However what did happen was this.
I don't know how or when the hell that happened but it must have been cracked the whole time to suddenly just snap. So maybe I have been battling a hidden vacuum leak all along?
Anyway I guess I can't really go further until I get a new UIM.
It runs! Looks like the manifold was the main issue all along. It "idles" at about 400 rpm right now though. Timing is way off. Looks like its pretty well advanced. Which is odd because it's been set just like the fsm specified so im not sure why it's so off.
Anyone know which direction I have to turn the cas to retard timing?
have you tested your BAC? also, what do you know about the port work done to it? basically, i'm curious just how much more overlap was introduced.
if you're referring to the "ticking" noise i heard in the video, it sounds suspiciously like an exhaust leak.
No bac. Previous owner deleted it.
I ported it myself. Ported with mazdatrix street port intake template and pineapple racing ep2 exhaust template. So a pretty average port job in terms of size.
I think the ticking is an exhaust leak as well actually. I had custom exhaust work done and never double checked if the guys tightened everything down well.
As of right now im thinking I may still have a vacuum leak just because of how the vacuum fluctuates at low rpm. Might be time to start spraying carb cleaner around the engine bay.
06-24-19, 09:12 PM
