TwinTurbo_SE7EN

I just did a compression test with a piston tester. I held the check valve open like youre supposed to. I saw even pulses of 90-95 psi on all 6 faces. however both times when I let go of the check valve I saw 125 psi. how is it possible to see 125 psi if all 3 faces are putting out 90-95? is it that the bounces are just too fast to register fully on a piston tester and thats why I only see 90 - 95?

Thanks.

Turborx7s

I'm not sure about "holding the check valve" open...

I just actually remove the valve from the gauge, and watch the needle pulses.

yodaddy

if they valve is closed it will show much higher pressure as with every pulse the pressure in he guage will rise. go by the nymbers you got while holding the valve open.

TwinTurbo_SE7EN

I took the car out this morning and everything was great. I havent had a problem with it since I replaced the FPR. I got back from picking up some pizza and when I parked it there was nothing wrong with it. then about an hour later I go back out and start the car up. It starts right up but it idles and revs like a blown engine.

BTW: it hasnt been past 6k rpms and no more than 11 psi...ever. it is set up to run 14 psi. the motor has ~ 6,000 miles on it. thats reliability for ya.

sferrett

? How's that supposed to be true? If the pressure in the chamber never exceeds the pressure in the gauge, the valve wont open.

When the valve is open you probably dont see the peak reading because it's going by to fast, flow restrictions in the gauge, etc. With valve closed you'd see the max pressure of the three faces, but you wouldn't see more.

If you want to test the theory, get a tire pressure gauge with a check valve - checking your tire more than once without letting the valve out does not increase the pressure shown on the gauge.

Simon

TwinTurbo_SE7EN

That is exactly how I thought of it.

cooljerk187

If you hold the needle valve down... it will read subtantially less than normal, on mine holding it down i am truely feeling for even pulses, thats it, the guage itself will read only like 35 PSI.... If you dont hold the valve down it is going to stay at the highest compression rate per rotor, not face (125 and will slightly move by 3 or 4 psi per pulse)
What you want to do is take the whole valve system out of the assembly, then you will see your true compression per pulse... assuming the motor is warm

TwinTurbo_SE7EN

ok, with the valve removed I got ~115 psi on all 6 faces.

now I just need to find the cause of this problem. any suggestions?

EDIT: water temp for these numbers was 46*C. it had cooled off a bit since earlier and was only slightly warm to the touch.

dgeesaman

iTrader: (7)

Sometime when you expect to have trouble starting it, remove the lower (leading) plugs and see what they're wetted with. If it's fuel, it's probably a leaking injector.

Dave

TwinTurbo_SE7EN

Thanks Dave.

My injectors have been cleaned and flow tested 6 days ago. I have no trouble starting it, it starts right up and runs without me touching the gas. it just idles like a blown engine. I am thinking coil, CAS, TPS, or map sensor. TPS voltages check out and the map sensor is ok. I have yet to check the CAS and coils...it might even be a short somewhere in the engine harness. Fuel pressure regulator is brand spanking new and thats all I can think of right now.

Sean

dgeesaman

iTrader: (7)

Damn. That's exactly what I've been dealing with. Did this trouble begin/change when you had the injectors cleaned?

Dave

nopistons94

bro by not going past 6k RPMs, your building up carbon in your motor in excess amounts. I'd highly suggest bringing it up to redline in 3rd gear a few times to clean the motor up a little bit. Theres a reason mazda put the redline at 8k not 6k ..

TwinTurbo_SE7EN

actually no, I installed the injectors 6 days ago and went to the tail of the dragon this weekend without a problem. I drove it this morning with no issues at all. then an hour after I parked it, I went back out and started the car. it started right up and just idles like ****.

FDNewbie

iTrader: (10)

What ya mean? I thought a blown engine won't hold idle? Is it holding an idle or is it not?

TwinTurbo_SE7EN

my last blown engine would hold an idle. of course it wasnt very pretty varying from 300 - 1000 rpms and pulling 6-8 inHG...but it wouldnt die. lol.

vacuum is about 10-11 inHG while my engine is running. However, my compression is great at ~115 on all faces. if the engine was fully warmed up when I did the comp test I would say maybe 120 psi on all faces. They were all very even.

I am going to look at my wideband today when I start it up and maybe its not getting enough fuel...stuck primary or something.

yuichiror

iTrader: (1)

Actually, I once had an FC that had a missing apex seal and 2 bad seals on the back rotor. The car idled fine, when I drove, it had no power, but she idled great.....

TwinTurbo_SE7EN

well, I started her up and it was still the same for a little bit. then all of a sudden it cleared right up. This sounds like a leaky injector. puddles of fuel in the chambers eventually clearing up...right. Well, this was like that except for one thing...it was extremely quick to clear up. It went from shitty to perfect in 1 second. My experience has been that the clearing of fuel from a leaky injector is more of a gradual thing. I have delt with that since january until I replaced my FPR a week ago. So my conclusion is a short somewhere in the wiring. Im having another wiring quirk that just magically appeared today as well. it could be part of the problem.

charliegt

What other symptoms are you having? What do you mean by idles and revs like it is blown?

I am having a very similar problem, (car seems like its flooded when I first start it up, and its running rich). I replaced the FPR as well, and had the injectors cleaned and rebuilt - no dice.

Keep me posted on your progress, it sounds like we may be having the same problem.

Thanks,
-Charlie

TwinTurbo_SE7EN

EDIT: idles like a blown engine: pulling 10 inHG of vacuum...sounds like its running on one rotor. shakes a LOT.

no other symptoms. I started it this morning again and it started right up. This morning there was only 2-3 seconds of shitty idle before it cleared right up. Then I let it sit for ~20 minutes and started it up again...this time it was perfect.

I am thinking it could be an intermittent problem with the coils or my injectors. Im thinking that if it were my injectors, it is either my primaries leaking from the unit itself or from an o-ring. it is possible that the secondaries are leaking from an o-ring as well. it has now been 10 days since they were cleaned. I installed them within an hour of receiving them. They all popped right in without really forcing them. if you have to force them, most likely you pinched an o-ring. I DO NOT smell fuel anywhere...tested for leaks and saw/heard/smelled none.

I did fix a short in the front relay box. the one with the fog light relay and the fuel pump relay...the short was on the 'TNS' relay. What the hell is the TNS relay?



Thanks all for your help so far. Let me know if what I said seems possible or if I am just flat out crazy.

charliegt

I'm having/was having what sounds like the EXACT same problem. Have you checked for engine codes since you re-installed the fuel rails? Did you run the fuel pump by grounding the f/p in the diagnostics box before re-installing the rats nest to ensure there were no leaks? If you did there should be stored trouble codes 9, 11, 13, 17, 18, 23 (all of the sensors that you had unhooked). Reset your ECU by disconnecting the negative battery terminal and holding the brake for 20 seconds. Then start it up.

I just finished putting in my freshly cleaned and rebuilt injectors and it was still running rich with low vac at idle, then I remembered that it stores the codes from when I was running the pump when the UIM was off, so I reset the ECU. Wala, no more rich idle and seems to run fine.

At one point while idleing when the idle dropped from 1,100 to 900 the vac quickly dipped to 10 and the car ran rich for a second - then vac returned to 15 and the a/f went back to fluttering around like it should.

I am still not sure if the problem is fixed, or just taking a break - but I have my fingers crossed. Try resetting your ECU if you haven't already and let me know what your results are.

By the way - have you replaced the plugs since you were having flooding problems? It wouldn't be a bad idea to replace those while you're at it to ensure that a fouled plug isn't causing your problems.

-Charlie

TwinTurbo_SE7EN

I have a PFC and run non-sequential. no rats nest... it actually turned out to be extremely lean in the idle cells. This was because I had taken out lots o fuel before I replaced my FPR to try to get a decent idle. I was never able to get it leaner than 9.9:1. once I replaced the FPR I added fuel to a couple cells and completely forgot about the cells where it should idle. I forgot about them because I have been having sticking issues with the throttle plates (or something) and it wont drop below ~1400 rpm on its own. I have to shut the TB by hand to get it to drop below 1400. I have cleaned the TB extremely well...I think.

long story short...very lean idle = barely running and sounds like a blown engine. I wasnt flooding at all. it makes sense now that I think about it cause it didnt smoke at all like it used to when the FPR was bad or like it did when my last motor blew. It runs great now and I just have to work out some issues with my idle cells vs. TB air screws.

TwinTurbo_SE7EN

OKAY...maybe I didnt fix it. it starts up fine when hot and starts up fine when cold. the 3 times it has acted up on me are when it sits for long enough to get down to ~50 - 60*C. Does anyone have any idea as to why it acts like this when its "warm" and not when its hot or cold?

Fero313

iTrader: (1)

3 words....

talk to garfinkle.

come to the M'boro car show on fri. and talk to him... this sounds like a sensor/solenoid problem, obviously your engine isn't blown, and with clean injectors they shouldn't be leaking/flooding...

if you cant make it PM him.

GarfinkleMotorworks (i believe)

BoOsTin FD

Was this problem ever fixed? I'm having same sympthoms of blown engine, but compression seems to be fine.

Thanks

TwinTurbo_SE7EN

I think it was a stuck seal or two. I havent had it act up since I took it to redline a couple times. I also changed the offset for PIM voltage so that my map sensor read 0 when the engine is off. it was reading -0.43 mmHG. I dont know if the offset change helped my issue or not...it did change the way it ran a little bit...I had to re-tune drivability.

I havent tried atf or anything because Im afraid I would mess something up. I think it got this way because I didnt boost it much from 0-5000 miles. plus it was running very rich for a good bit of those miles until I replaced my FPR.