HoustonMS3

I posted a while ago about my 90' TII that has sat in a garage for about 10 years..

First problem was no fuel:
I have replaced the tank, installed a walbro pump, replaced the resistor relay, new fuel filter, drained fuel line, replaced plugs.

Now the car will turn over, but unless I keep my foot on the throttle about 2-3K+ rpm it will sputter and die. I was hoping that this is caused by some residual bad fuel in the mix, so I let the motor run at about 3k for two intervals of five minutes. No change.

Thoughts on what my next few steps should be? (besides change oil and coolant).

Aaron Cake

iTrader: (1)

http://www.aaroncake.net/rx-7/unstore.htm

Check compression first to make sure you aren't chasing your tail.

Then look for large vacuum leaks, test for spark, and have the injectors professionally cleaned (they stick after sitting)

diabolical1

iTrader: (3)

soak the engine seals in some Seafoam or MMO overnight, periodically rotating it. get on it early in the morning. if it still does what you describe, then looks for vacuum leaks.

HoustonMS3

If I didn't have compression , I wouldn't be able to keep the engine running as well as it does (or at all) one would think. Tell me if I'm wrong here.

Tomorrow after work I'll start in again. I can check for spark on each cable by disconnecting it from the plug and putting it against a ground, right?

And thanks for the website, I had read quite a bit of it when this project got started.

diabolical1

iTrader: (3)

some engines with low compression can run. surprisingly, some can even hold a somewhat decent idle. they just runs like crap.

HoustonMS3

Alright, advice taken. Leaks and easy audible compression test first. Then ill go ahead and get a compression gauge from amazon.

HoustonMS3

No major leaks evident. But its a little difficult getting a thorough inspection when working by myself and the car wont stay running. I still think a large leak is possible due to the hoses sitting for almost a decade. The AFM is testing at the right Ω. And I have a feeling the TPS will too.

I found this video on you tube:
http://www.youtube.com/watch?v=XzsSV4PsM5Q

It is very similar to my problem, but I can over 4k rpm.

Anyone seen this behavior before?

HoustonMS3

Would a crack in the turbo inlet hose of this size cause such a irregular idle?

JoshDC2

wow i would say youve got a pretty good project ahead of you. time to do a rebuild id say

HoustonMS3

I have fixed the turbo inlet pipe and the car will now idle, but terribly.



As you can see in the video, the car idles and pours smoke. The smoke is white/gray and has a lot of fuel. It is not coolant. I am also getting a CEL that I will attempt to check later tonight.

Some one suggested the Walbro pump could be over flooding the stock fuel pump regulator and/or a fuel injector could be stuck open. Due to time an location restraints I would like to keep removing injectors as my last option. Anyone think an aftermarket FPR is a good bet (if so, what brand: SARD, SX, Aerofoce, etc.)? Simple method to try to fix or evaluate a stuck injector considering my situation? Or should I be examining other possibilities?

To recap: all plugs are firing (tested, new plugs), new Walbro pump, new plugs, new fuel filter, new fuel pump resistor relay, new gas tank and fuel, vacuum leaks appear to be fixed (tested to the best of my ability), compression check done 65-70psi all around (rubber hosed standard compression gauge so itmight not be totally accurate.), MAF sensor tested good, TPS sensor good.

Funny to think last month I never knew how to test compression, use an ohm meter, or seen an in tank fuel pump...

HoustonMS3

It has been brought to my attention that the FPR is welded to the fuel rail.. so I guess I'm screwed there. It looks like I need a stock volume FP to test with.

Anyone bought a http://www.genesisautoparts.com/fuel...a-rx7-1990.htm ? or any other suggestions?

Aaron Cake

iTrader: (1)

That leak certainly would have caused idle issues.

The Walbro will raise fuel pressure, without a doubt. S5 rails have an integrated FPR. You can cut it off and weld on a fitting to run an aftermarket unit.

I have the volume cranked but can still hardly hear the video so I don't quite know what you are referring to. However, cleaning the injectors, assuming the engine has good compression, would be my first step. Far too many times I have run round and round on a car that has been sitting before coming back to the injectors. Injectors do not like to sit around. They stick, clog and freeze up.

HoustonMS3

Thanks for the reply.

I think my only two options at this point are testing with a stock FP, and cleaning the injectors as you said.

The only reason I have no removed the injectors is because I am working outside in low or no light and I think it might get ugly while removing that intake manifold and associated gaskets/hardware.

But it looks like I will have a lit garage with air tools in the next week or two. So I am confident it will be running soon.

And yeah, sorry the video from my phone isn't top notch quality. What I was trying to illustrate were the sound and smoke pulses. It is hard to explain with text but its a 1,2,3,1,2,3 with the motor rocking a fair bit. The smoke has a very distinct pause between puffs. In my inexperienced assessment, its seems like one rotor isn't firing at all.

irishpilot

iTrader: (4)

My 12a had no compression on rotor 2 and it idled but would run like your describing, especially with a load (trying to move/drive the car)

if your seals are stuck, the seafoam or marvel mystery oil can SOMETIMES free them if they are in tact and not broken.

Goodluck

HoustonMS3

If a seal was stuck or broken would it of consistently pinged 65-70ish psi on the compression gauge? I thought it would be something like 65, 30, 30, repeat.

I read that "Using a normal compression tester with valve removed/held open will typically result in readings about 20% under spec.", which translates into a little under 80psi across all 3 faces on both rotors. That gave me hope that the seals should be sound.

I just picked up an brand new Borg Warner pump with assembly for $100, so by tomorrow I should know whether its injector removal time or not.

HoustonMS3

Well, for anyone who cares..

I replaced the Walbro with a OEM replacement, nada.

But!

I pulled (deciphered) the code from the new CEL. It lead me to a damaged wire on the MAF. Now I have have a much more solid idle, but it surges up and down and has an intermittent miss. I'm thinking TPS or smaller vacuum leak.

Now that idle the car without smoking out the neighborhood, I will revisit the TPS tomorrow while the car is at operating temp.

At least there seems to be a light at the end of the tunnel for this part of the work.

fc3si

man, sounds like alot of work, at least yours will start.

making progress, GL man.

HoustonMS3

Sorry for the older thread bump, but the car is now drivable,

Update:
Changed clutch master and slave cylinder.
Changed brake fluid, engine oil, trans oil, rear diff oil.
Removed the 20 year old purple tint.
Changed fuel tank, filter, pump, relay.
Changed plugs, checked compression.
Repaired MAF, adjusted TPS (incorrectly I think).
Worked a miracle with Meguiar's 105 and 205 polish + Porter Cable DA buffer.


Three new questions:

The brakes still are not at 100%. I have very limited knowledge of brake boosters and such. Why at hard stops cause the engine want to die?


Could the turbo's main seal leak so bad as to make a 2 inch puddle within an hour of driving the car? I know that oil was leaking from the turbo area, but I wanted to get some experienced opinions. Is it more likely to be a line or something that is specifically problematic on these cars?. That whole side of the engine is saturated with old oil for years of leaking, and I can smell it burning after the car warms up.

The car runs super rich! Very very noticeable gas smell all the time coupled with the occasional "putt" every few seconds. Not loud like a backfire, but a random miss sound. I have changed the plugs and tested the spark. Could leaking pressure after the turbo causing it to run rich? Would an old O2 sensor do anything similar? Injector stuck open (I assume this would be a more rhythmic and less random sound, but what do I know.)?

Aaron Cake

iTrader: (1)

Turbo seals leaking like that would cause a smoke screen out the exhaust, so check for external leaks first.

Rich running is usually just a tuneup issue. The TPS needs to be set right. Also, what does a "repaired" AFM mean?

If the injectors have never been cleaned, having that done will help a lot.

HoustonMS3

Cables in the connector at the AFM (I usually say mass air flow) where not connected properly, giving me a check engine light. I fixed it, checked the the AFM
resistance against the FSM.. all within spec and the CEL is gone.

I thought that the TPS was correctly set. I set it manually with a multimeter per the resistance I read on the FSM. The reason why I think its incorrect is because once the care gets to operating temp it has the surging idle that I have seen in videos. After a little bit of throttle or driving it stops fairly quickly.

And yes, now that I can work indoors the injectors will be addressed. I'll start looking into what it takes today. I remember reading a little about it in the FSM, seemed at the time like the pretty complex endeavour, at least for my experience level.

Also, I took one of the plugs out and its quite oily already. Thoughts? At first I assumed it was the turbo seal dripping into the intake.