xcannibalx

Ok, so I'm buying an FD in the next few days, and i need some help diagnosing it. I admit i've got very little knowledge about rotaries, but a LOT with piston engines, so i hope to get learning
I've searched and searched, and I'm trying to decide whats going on. Heres the story:

The current owner bought this car about 2 years ago. The prior owner tore off all the emissions stuff. It ran great, according to current owner. The current owner needed to do emissions testing, so he proceeded to install the factory vacuum stuff. He said he was able to get it running, but it failed the emissions testing 3 times. He said it also didnt run right, thought it might have been a little rich. He said the next day after failing the test, it wouldn't fire over. And that was about 2 years, and it sat for a long time while he tried to figure it out.

In August he said he got it to fire over, and run, but it ran crappy, and the turbos weren't turning on when they should.
Now, again, it doesnt run.

Here's what we found:
Diagnostic codes
5 (Knock sensor)
9 (Water thermosensor) - we found this sensor to be broken from the base, so ill be replacing it soon. (this wouldn't prevent the motor from running, right?)
46 Charge relief solenoid - we troubleshooted the solenoid, and it seems to be working, but i dont know if maybe its not plumbed correctly?

Motor sounds like it has good compression, and altho the test wasn't accurate (not warmed up, etc), it hit 90's psi's across the board. It also smells like gas out the tail, so i know fuels getting in there.
We DIDN'T check the spark (he claims he did, but i didn't) So i dunno if its TRYING to light it off or not.

So....Any suggestions? The first thing im going to do is try and remove all the emissions garbage. Apparently he kept all the block off plates when he reinstalled the air pump, egr, rats nest, etc.

Help me get this car back on the road fellas, i'd really appreciate it.

Mahjik

iTrader: (1)

The emissions stuff won't stop the car from starting. Some of those codes will cause the car to run in limp mode, but they won't stop the car from starting. I would start by trying to get the car to fire up. Here's what I would do first:

1. Remove current spark plugs
2. Remove EGI fuse
3. Crank motor for 10-15 seconds
4. Clean area around spark plug holes
5. Squirt a little ATF in the lower spark plug holes
6. Install new spark plugs
7. Re-install EGI fuse
8. Start the car

See if it fires after that. Make sure the battery is completely charged. Even with a good battery, trying the crank the car a few times will put a significant drain on it.

Also, make sure you have some decent gas in it. If the gas has been sitting in it for a while, jack up the car, undo the drain bolt on the bottom of the gas tank to drain it, put 2-4 gallons of fresh fuel in with a bottle of fuel system/injector cleaner.

Let us know what happens!

the_saint

I did the above EXACT steps today to get my car fired up. I flooded it trying to get it going after storage.

It fired up INSTANTLY after following the steps outlined above. Previous to that I spent wasted time trying to get it to turn over with no progress.

Thankfully this was the first time I flooded it after 9 years of owning the car. And the first time it didn't start up after storage.

xcannibalx

Wow...Thanks for the response. Whats the ATF for? I'll have to try this out when i get ahold of the car. Thanks!

Mahjik

iTrader: (1)

The ATF will help add a little extra sealing and lubrication to temporarily (and artificially) build a little extra compression to help the motor kick over.

xcannibalx

Good deal. The exhaust smells like gas that might be bad too. So i'll be draining that first thing too. I'll let you know what i find out

the_saint

I wasn't sure I needed to do this, but I still did.

Drove it today, and fired up 'instantly'

Good luck Mr. Cannibal

xcannibalx

Wow. Thanks a ton guys!
So i found that a water temp sensor was broken. After replacing that, draining the tank, putting in a few fuel filter and some gas (with FI cleaner), it fired right up!

So I took it around the block, but above 7psi, it cuts out. If i slowly creep up in the rpm's, staying out of boost, its fine.

Any suggestions? I know that the ECU was reporting an issue with the knock sensor. Also, with the uglyness of the emissions, i really should hack all that out. I've searched, and even contacted bonzai but they never got back to me (i have all the blockoff plates from the prior owner), but i don't know where everything goes for sure, and whats blocked off.

I'm hoping i can get all the kinks worked out.

Mahjik

iTrader: (1)

If the ECU is reporting the Knock Sensor code, that can limit your performance as a protective mechanism.

xcannibalx

well i guess thats the first step then. more updates to come.
Thanks

xcannibalx

OK, so i decided to do some simplification of the emissions setup. I followed the non-sequential diagram found here : https://www.rx7club.com/showthread.p...ight=emissions

The car runs still, but now wont even make 2 psi of boost. Under heavy tip-in of the throttle, it "pop-pop-pop-pop" and just stutters and doesn't go. If you SLOWLY dip in the throttle, not allowing any boost, it slowly climbs the RPM's.
I still have a check engine light, would the knock sensor really kill it that bad?

xcannibalx

Alright, so i had some time to work on the car today :

Diagnostic shows knock sensor is still throwing a code, few of the emissions codes too (no surprise, i didnt have enough wire-loops to delete all the plugs.

Also traced down a few vacuum leaks by making a boost tester. I was thinking my problems were solved when i got them all plugged off, but it still does what was mentioned above. Just "pop-pop-pop-pop" when giving it throttle. Anyone else have issues like this?

Mahjik

iTrader: (1)

If you are still throwing the knock sensor code, then the car is most likely still in limp mode. You need to fix that first before doing anything else.

7dust

iTrader: (14)

Reset the ecu. Even when you fix the offending problem that puts you in limp mode, the ecu requires a manual reset. Take off the ground wire to the battery and hold the brake pedal down for 10 seconds.

xcannibalx

Update :

Guys, i need help. This car is really starting to **** me off.

Got a knock sensor, (they looked the same, but had different numbers on the side, dont think thats an issue)

Reset the ECU.

Now i have no check engine light lit. So i thought "sweet!", problem solved. It can't be in limp mode now, right?

The car is still doing the same thing! I can hear the turbo's spooling and trying to make the boost, but then the car just pops and pops, and surges, and WON'T go above vacuum.
Whats going on here?

I did do the turbo simplification, but i checked it twice and i think its right.
Also, can i bypass the solenoid for the FPR, and just plumb the FPR directly into the intake vacuum source? Will that work?
I'm needing suggestions guys!

THanks

xcannibalx

Bump, its my day off. Hoping for any other suggestions

Mahjik

iTrader: (1)

For starters, you need to work on one thing at a time. i.e. instead of only fixing the Knock Sensor, you also did the turbo simplification. So now you have no idea if you fixed your original problem or just created a new problem with the simplification.

As for the FPR:
https://www.rx7club.com/showpost.php...10&postcount=2

xcannibalx

Granted, you're correct. Fixing the knock sensor did not take care of the issue, so now i am trying to figure out what there is left to diagnose?

I'm going to straight plumb the FPR, as per the post. Thanks for the info.

xcannibalx

Ok, another update.
After struggling to figure out what else is wrong, i worked on finding a better diagram/instructions for the non-sequential.
I followed the original diagram i found here : https://www.rx7club.com/showthread.p...vacuum+diagram

This is not very helpful, and found something MUCH better after searching around here:http://www.blackgto.com/RX7/nshoses.jpg
This one actually gives instructions beyond "it should look like this".

Well i didn't fully accomplish the welding open of the flaps until today. After it was all pulled apart, i was feeling confident that maybe the turbo's were closed shut and not able to bring boost into the intake. After accomplishing all this, it's still doing the same thing.

Any other suggestions guys? Seriously, I'm ready to sell this motor, and go LS1 at this point.