Banzai rebuild, original irons/bearings, new-to-me used "very good condition" housings, new rotors and seals.

- Seems to be flooding as the plugs are always wet.
- Got it started with starting fluid once and kept it running for 2-3 minutes at ~4.5K RPM with throttle at 50-75%. Could not re-start.
- Tried many variations of the de-flood routine, many times.
- Several sets of new plugs.
- Mystery oil in plug holes.
- Verified strong spark with IGN-1A.
- Fuel pressure is good at 38psi with no leaks (see attached PFC log).
- Drained tank and replaced with 10 gallons new fuel + 2/3 bottle of Heet.
- Stock primaries, RP 2200 secondaries.
- Primary and secondary injectors were just cleaned and tested by RX Injectors.
- 95.6% sure everything is installed correctly.
- Airbox <-> tailpipe holds air pressure well (no large vacuum leaks).
- Smoke machine test also verified no vacuum leaks (except @ turbo -> DP and DP -> Cat gaskets)
- Brand new wiring harness + removed fan recall harnesses @ fan relays and @ ECU (see pic of ECU-side harness -- I thought it only intercepted 1 connector, not 2?)
- Tested with all intake ducting installed but no airbox, also tested with elbow removed.
- Tested with PFC and stock ECU.
- Played with idle air screw.
- All sensor readings look fine to me in FC Edit (see attached log/screen shot for a start attempt -- note WB is not presently installed).
- Stock DP and Cat have been sitting in the basement for the past two years and are now installed for the smog man.
- No compression test yet.

 

looks like a map sensor issue to me. your pim voltage looks high and it also says -99 with a max of -78. doesnt seem right even for just cranking. which btw your cranking speed is super impressive

whats the story on this map? have you tried using the stock pfc settings to start it? with the stock primaries youll be good to start on that. use the dwell settings from sakebomb with those coils. either way, i would try a different map sensor or check the calibration on that map. seems like a good place to start considering what youve done so far

 

Good catch!!! PIM 8981 is ~ -1.9 psi relative to sea level pressure. I actually checked that and thought to myself, at my elevation ambient pressure should be about -1.5psi below sea level pressure so that sounds right -- but not while cranking! Will plug in the GM sensor and update the PFC for it.

That map is the map that came originally on my PFC, modified with 2200 secondary injector settings, then run through FC Tweak (which should also modify the dwell settings for the IGN-1As).

Back to the map sensor... I was actually looking at the gas filter on the map vacuum line last night scratching my head as to which way it should be oriented. One end of the filter has a lip of larger diameter than the other end, and there is an arrow marked on the side. The vacuum diagram illustration shows both the lip and the arrow, but the arrow in the diagram is facing the opposite direction from real life. So which way should the filter face??

 

Just tried with the GM 3-bar sensor, updated PFC settings for that sensor, and removed gas filter and now am seeing ~9200 PIM / -1.6 PSI while cranking... What should I be seeing?

Edit: I see what you mean by VOLTAGE. Seems like ~1.6V is about normal for ignition on, not running of cranking (at least that's what one of my old logs says). So why is it currently 2.5V...

 

I checked the MAP sensor connector on the harness side with a multimeter. I was expecting that the +V and sensor signal wire were shorted, and both would read +2.5V. However, when using the middle pin as a common ground, one of the other pins showed +5.01V, and the other +4.79V. So they are not shorted... But why is the sensor signal wire showing positive voltage when the sensor isn't connected to it...

 

First off, for the purposes of getting that first start and letting it idle, use the stock MAP sensor and the stock MAP sensor settings in the PFC. I'd almost do a full reset on the PFC and start with the PFC's base map. You don't want something that may have some weirdness that could affect things.

I'm also suspicious of the cleaned injectors. I've seen MANY MANY people get injectors cleaned and have them lock up, stuck open, etc. Possible you have an injector that's dumping fuel or something in there.

I think your compression is most likely fine, Banzai is a solid shop and they wouldn't send you a lemon.

The ignition coil setup - did the car have this before the rebuild process or did you install it with the new engine? I'd also be suspicious of that. A lot of those kits are SUPER finicky with wiring and grounds. If possible I'd get the car running with some stock coils to rule all that out.

Dale

 

Thanks Dale, responses below...

Roger, I'll throw it back on. Regardless, something weird seems to be happening with the MAP connection. Shouldn't 2 of the three wires be GND and +5, and the 3rd is the signal wire which the sensor supplies voltage in [0, 5] back to the ECU? So why is the signal wire showing +5/+4.8 when nothing is connected...? Going to have to do some more hunting there...

What you say "reset PFC to default" do you mean use the "re-initialize" menu?

Well that sucks. Hopefully that is not the case... Any pattern in who did the cleaning vs. borked injectors?

To clarify on the flooding part, when I pull the plugs (and EGI) and crank, I never see/smell fuel coming out the holes, so it's not THAT flooded. But the plug tips are a little wet.

Same thoughts here...

I started with the OEM coils, verified spark, then switched to the IGN-1As (and verified spark) with a homemade harness that worked fine in the past.

 

Where do you have the vacuum line connected on the UIM for the MAP sensor? I have seen people connect it to the post for the double throttle, that is not a vacuum nipple. BTW the filter has an arrow on it, should be pointing away from the sensor.

 

It is connected to the lower vacuum nipple in your image above, the one with the white paint mark under it, not the post on the block-off plate above.

Edit: I used a Mityvac and verified the sensor is working correctly. Apparently that signal wire will show ~+4.8 volts when the sensor is not connected... So MAP is not my issue.

 

To get the base map back, I think its ETC then RESET TO DEFAULT - then YES.

..on the commander menu.

Good luck!

 

Turns out compression is very low. Like 55, 60, 55 front and 50, 50, 45 rear.

I pulled the rat's nest to check the injector grommets and o-rings. The primaries look fine to me, but I'm not quite sure on the secondaries (RP rail with the Bosch 2200's that came with it). I know the 2200's don't use the diffusers, but I can't recall if the grommets are supposed to stay in -- the injectors fit nicely without the grommets, but seem a little squished with the grommets in. Can't seem to find the instructions.

Primary:




Secondary:





Will missing grommets/o-rings on the injectors cause low compression...?

 

^Interesting question. I'm not 100% sure, but I suspect this could be a factor. Reason is the FI grommets/seals are located on the keg where the intake/suction stroke happens; I suppose if they are missing/leaking, less air will get sucked into the chamber, so there's a less dense volume of air to compress on the compression stroke, which might result in lower numbers. Kind of like what would happen when you do a compression test with the throttle closed.

Assuming you used a good rotary compression tester (e.g., RCT 5.x), did you do the test with the throttle wide open? If not, that could bugger up your readings. Similarly, you should hook up the tester to the trailing plug hole, with the leading plug still installed - obviously if both plugs are out, the readings will be buggered.

 

Since you want the throttle open doing a compression test, leakage around injectors will only aid that, not lower compression readings. So, IMO, that's not a factor in low readings.

 

compression numbers are extremely influenced by cranking rpm. (as you probably know)... your numbers are fairly even so whatever is going on is global. was your cranking rpm adjusted to 250?

 

Now that I think about it, you're right - leakage around the FI's would be the same as cracking the throttle open a bit.

FWIW, out of curiosity, after buying my RCT 5.2 rotary compression tester years ago, I did compression tests of my FC's 13BT engine the correct way at wide open throttle, and then re-tested with the throttle closed just to see what kind of difference it would make. I forget the exact #'s I got but it was very substantial - great/passing compression #'s when tested at WOT, poor/failing #'s when tested at closed throttle.

 

Yes, using a RCT.com v5.2 unit. By the way, these units do not like high cranking RPMs like you get with a lithium ion battery. It will fail to normalize the readings and show all zeros for the corrected values. I spoke with Mr. Miracle about this, and he even replaced my unit, but I still have to throw in a lead acid battery when I do a compression test (which hopefully there will not be many more of). I know at one point he had some college students working on a project, I wonder if college students also wrote the firmware for the RCT. I would guess that they fitted a curve to data collected by testing a Mazda tester, and perhaps extrapolated a bit, but apparently not far enough to get to 380 RPM. Who knows.

Well then, you already know what I'm going to say, don't you?

Halfway through pulling the UIM on the way to the injectors I realized that, hmm, I'm not so sure I floored it when doing the compression tests. The tester was actually still screwed into the L2 hole so I just hopped in and did another test, this time with the pedal down. Same results, oh well...

A couple hours later after inspecting the injectors, I realized that, when I did that second compression test I had already removed the throttle cable from the UIM... So there is STILL hope that I have simply failed to properly complete a compression test.

Now for the next problem.. I inspected the primary diffusers and they were both intact. I then proceeded to stick an endoscope down the intake runners to check that were was nothing stuck in there, like a shop rag I had forget to remove before installing the UIM or something. Ended up breaking a diffuser with the endoscope. So now the turbos and LIM need to come off to remove that piece of broken diffuser...

At this point I was 10 days into a 2-week vacation from work, everyday working on the car in the sun, and I was pretty tired. I unfortunately don't have space to work on the car where I live, so it is presently sitting on jack stands at my folk's place 200 miles away. That adds a lot of overhead to this project, including dragging my sick old cat along with me. I'm back home now, enjoying one actual day of vacation. I will have to go back another weekend to replace that busted diffuser and do another compression test.

So if I assume the compression actually is fine, why the hell won't it start? Everything looks fine.

When I did get it running that one time, using starting fluid, I had the PFC setup for the 2200 secondaries, and I had to hold the throttle open >50%, and the RPMs at around 4.5k to keep it running (engaging the secondaries...?). The second I let off the throttle the car would very quickly want to die (going back to primary-only?). Subsequent attempts to start I had re-initialized the PFC to default values (for 850 secondary injectors) and it showed no interested in staying running now. Maybe that's because the primary injectors are fucked off from being cleaned by RX Injectors, and pushing the throttle/RPMs high to try to keep it running is engaging the secondary injectors, which are configured as 850's in the PFC, massively flooding the engine so it wants to die.

So I'm tempted to, after re-compression testing, put it back together with brand new primaries. But that's an awfully expensive hunch to go on.

 

First off, I'd try the shop vac trick for that broken diffuser. You can put something like a fine piece of women's hose over the shop vac and suck the broken part up - many people have had luck with that. The hose is so you can see that you got it and don't have to try and find it in the junk that's in the vacuum.

It really sounds like you aren't getting fuel to start with and I'm really thinking it's stuck primaries. Hit them with 12v and ground and you should have them click open. If they don't click or move at all, get some PB Blaster on the tip of the injector and try again, click it on and off multiple times to get the tip of the injector moving.

Secondaries don't come online at all for idle/low load.

I wouldn't keep trying to mess with a compression test, if it was a used engine or an engine that you rebuilt yourself and you weren't sure about, maybe. An engine from a reputable shop that has done this thousands of times, it's not going to be the problem. You should also be able to hear the compression pulses as you crank the engine - if you near nice, strong "chug-chug-chug" it's fine. May be worth getting some engine oil into the engine to get a good layer of oil in there, it may be washed out now from trying to start it. That will help the initial startup. Also sounds like you have a good battery and starter and that makes a world of difference.

Dale

 

Maybe a little late but you sure your fuel lines aren't backwards? I see you have good fuel pressure but where are you measuring it from?

 

It's the whole bottom of the diffuser that's broken off so might be hard to get it that way but worth a shot.



That's good to know.

I don't have a trained ear but it certainly sounds like it's sucking and compressing air when I turn it over without plugs. I think I will test it again anyway before bothering to put the rats nest and UIM back on -- done that enough to know it's not a fun afternoon.

I did check and they looked correct. But that begs the question, if the pressure is fine does it even matter? The sensor is installed in the hose between the hardlines on the firewall and the hardlines at the base of the rats nest bracket, by the oil filter pedestal (on the feed line).

 

If you hook up the fuel lines backwards you'll have a world of weirdness. Ran into that a long time ago on an FC.

Fuel pump feed should go to the primary rail, then secondary rail, then FPR, then back to tank. If it's backwards, it hits a wall at the FPR and SOME fuel gets through but not enough. If you are reading pressure on a gauge on an aftermarket FPR that could be showing the pressure in the FPR, I'm not sure there. It's worth spending a few minutes to triple check. That's an easy one to cross off the list.

On the shop vac thing -

https://www.rx7club.com/3rd-generati...ngine-1140725/

It's worked for many people many times. Worth spending a few minutes that could mean you don't have to pull every damn thing apart.

Dale

 

Just spoke with Chris @ RP. He was very adamant that, if you don't put cleaned injectors into use immediately, they almost always stick, and if you let them sit long enough it can be very hard to get them working again at all.

Fingers crossed (and $$$ later) this is the issue.

Is it okay to turn the motor over for a compression test without the turbos, LIM/UIM, or engine oil in it?

Edit: I let my injectors sit on a shelf for several months after cleaning and before installing.

 

Don't compression test it without oil in the sump - even though it's only spinning at cranking RPMs, zero oil pressure would not be good for the bearings or any rotating bits. OK to compression test w/o the turbo, but I would at least put the LIM/UIM back on, just to avoid the risk of any debris getting sucked into the intake ports while testing.

 

Again, stop wasting time with a compression test. That's not getting you anywhere.

That said, you have to have oil in the system or you will be cranking dry which will cause damage. If you have the turbos off, the oil feed line will be disconnected and you'll spray oil everywhere during the process.

Besides that, the engine doesn't care. It's an air pump. A compression test means you crank it over and see how much air the air pump compresses.

Get the broken piece out, get your injectors working, and I bet you will have progress.

Dale

 

I'm doing it primarily out of curiosity.

 

Stoked that you seem to be on the right track. I've never heard that about injectors, but I guess it makes sense since they're designed to spray volatile chemicals for years at a time.

Let me know if I can help at all, brother!