So specs on the car:

- Rebuilt about 4500 miles ago (in July '11)
- Streetport, TB port
- Lucky 7 V-Mount
- Dual Oil Coolers (running Castol GTX 20w-50 with about 1.5k miles on the oil, was JUST going to switch to 10w30 because of the colder weather [was on the fence though, cuz I'm in CA, hardly 'cold'])
- '99 Spec Turbos with a tune by Nelson at R3 Tuning @ 13psi (put down 290whp)
- Bonez High-flow cat (probably reason for lower whp @13psi)
- Power FC
- Idle control valve is stuck open (car won't idle well with AC on)

Was on the freeway at night (11pm), air temp on PFC was around 30C, water temp on PFC was around 81-83C. water temp gauge that was separately installed showed around 180-185F.

Hadn't gone WOT for a few days so I decided to do it to clear up some of the carbon, pulled from 2nd at around 45mph to the top of 3rd. Did that, let it cruise at around 65-70mph in 4th for a minute or so and did it again.

Did those runs a total of 3 times, the water temp was 86C just before the third run, and was 89C (maximum temp during my whole drive as recorded by the PFC). The separate water temp never showed above 195F to around ~200F after all 3 runs.

I get to my destination, pull up to a parking spot and it stalls out on me. I turn it back on, and the idle is super lumpy. I quickly pull into my spot and I turn it off (turbo-timer was set to 1.5 minutes). I turn the car back on without starting the engine and turn on the AC to turn on the fans to cool the engine.

Tried to find out the problem this morning by starting it. First thing I noticed was vacuum is at 11 (it's supposed to be above 16 isn't it?), and the idle is still very lumpy. Please tell me this could MAYBE just be a vacuum leak? The engine only has 4.5k miles on it and I just spent a majority of my savings fixing it (screw rotaries and how it makes me justify spending all my money)...

To make matters worse, my hood release latch in the car has no pressure (tried pulling the wire itself, still no bueno) so I can't pop the hood...

Obviously I'm going to take the car in sometime soon to have them check it out, but what are your opinions? Blown engine?

 

Similar things like this has happen to me quite a few times and it's always something stupid ( good luck so far)... But U have to pop that hood open and take comp- right away..

 

check the map sensor, the hose may have just popped off and will give similar symptoms as a blown motor including low vacuum. you can double check the map sensor with the PFC by reading the boost level, if it doesn't change then you found your problem.

if the map sensor is ok, pray and break out the compression tester.

 

Double whammy between the hood release cable and the other problems.

Are you running water injection? What does the PFC commander say for vacuum at idle? -250ish?

 

PFC vacuum says just under 400, around 370-390. If I recall correctly, it used to say above 400 on idle.

Also, no water injection.

 

then i think you may be out of luck. the PFC would read about -25 to 0 if the map sensor was disconnected.

 

Damnit...

 

On a lighter note I got dibs on ur V mount

 

Well, if the idle dropped vacuum will get higher/worse.

on a stock port motor that isn't great but not necessarily indicative of a blown motor..... that converts to around 15 inches Hg.

Do you have a boost gauge? does the needle 'tick' back and forth at idle?

 

Yeah, what does the boost gauge needle do while idling? Does it flicker around and jump? Or is it holding steady at a particular vacuum?

 

Yeah, the boost gauge reading is the one giving me the 11 vacuum reading. It's pretty steady at 11 vacuum.

I do hear sorta a lumpy exhaust sound. I don't want to say it but it sounds like every 3rd 'rotation' the exhaust gives out a sound that sounds like its running too rich.

 

compression test then go from there...

 

open hood then go from there

 

Do you have a wideband? Did you see what the af's were during your pulls? It was pretty cold last night, temps were about 3-9°C just about everywhere in SOCAL.. colder in the valley. If the PFC read 30°C and the tune was aggressive, you might have ran a bit lean and damaged a side seal from pinging.

But like mentioned before, compression testing would be the first thing to do to confirm or rule out a blown engine.

 

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/better-way-open-hood-w-broken-latch-cable-557418/

 

Don't have a wideband, so I didn't get to see the A/F Ratio. The intake temp did get close to mid 40's after those runs. To my knowledge though, the tune is not aggressive at all. It runs rich and backfires quite often (I know this is common but I feel like just from rolling up in Sevenstock, I was backfiring more than people that had far more mods than me).


Thanks for the link. I'll try it out as soon as I can.

 

On a slightly better note, I managed to get the hood opened. Will get a compression test done as soon as I can...

 

First thing I would do is a compression test & do a visual check. Why don't you have a EGT or wideband? It's a simple safety instrument that will save your motor. Invest in it next time.

 

Before doing a compression test. Do a thorough inspection of your vacuum hoses and solenoid connections. Your problem could be as simple as a hose coming off of its fitting.

 

hope you didnt bro. Your car actually stalled out on you? did you overboost with the cool weather?

 

Maximum boost it hit on the PFC and on my boost gauge is 0.91kg/cm2 and about 12.9-13 psi, which is normal.

Got the compression test done today and the fronts have 120+ on all 3 (great), but the rears have 93 on 2 sides and much lower on the 3rd (bad news...)

Definitely a chipped apex seal...

Looks like I'll be babying this for a while and saving up to get another rebuild...

 

this is not very comforting as the same happened to me yesterday on the way to work. In the QC IL

 

This.

Every year around this time there are a lot of these threads. Modifying your tune a bit when it gets cold (thank you Mr. Wideband) can save you a lot of time and money.

 

this is not very comforting as the same happened to me yesterday on the way to work. In the QC IL
I do believe I over boosted hitting the on ramp in cold temp like 15-17 psi in 30 degree weather. I shifted into third car ran fine at 80 until i backed off of the throttle a bit to accomidate slower traffic. Thats when the feeling of only running on one rotor kicked in and boost gauge was all over the place. oddly enough you get the same symptoms for a blown coil. so ordered one for 40 bucks and will throw it in when it gets here. I havent driven it home from work yet and its the first time this car has ever seen snow having to stay in the lot overnight "i wanna cry"
sence the car is still in the parking lot at work and I havent had a chance to do compression check. it runs the same way whether I pull the top plug wire from the front coil or leave it plugged in, It does not even start when I pull the bottom plug wire and leave the top one on though. but this could also be a cause from no compression.
I fear the worst after reading nothing but the worst out of all the threads that cover this same issue.
note: it does turn over and run but sounds like a wrx and rough idol still makes boost but not smooth or steady map sensor is new and plugged in. will be doing comp test hopefully by thursday or poor mans test tomorrow
mods are
pfc
single turbo/custom dp and exhuast
3500 miles on rebuild and tune from RP
50mm adj. preload wastegate no bov
greddy pully kit
greddy elbow
stock ic (I know I know havent gotten around to putting in hmic in yet)

 

That's true... but it was about 10-13 degrees C (around 50-55F) outside and my air temps were around 30 degrees C (I had driven for about 40 miles straight prior to doing my runs).

Air intake temp - 30C (I have the faster IAT sensor, if that means anything)
Water temp - 81-85C (smack in the middle of optimal driving temps)

No vented hood so the engine bay was pretty warm.

The wideband definitely could have saved me but to be honest, I've pushed the car at colder temperatures before. The night that the Los Angeles area had crazy gusty winds, the temps were definitely colder and I was pushing it a bit to get home quick.

Anyways... none of this matters at this point. Chipped apex seal, no money because I just did the rebuild 5 months ago. Probably just gonna baby it around (pretty much my daily driver) and keep saving up...