Loss of power on canyon run.
 

Symptoms: Cruising down the highway I have a sudden loss of power with boost dropping to zero and RPMs dropping steadily. I attempt to downshift and give it gas with no luck. I pull off to the side of the road and let the car sit for a few minutes. I attempt to start the engine and it starts, revs to about 2000 rpm, studders/shudders and then dies. I do this a couple of times, while holding down the gas and it won't hold an idle and just slowly drops until it dies. Car basically can't start and if it does, will not hold an idle for more than a quarter of a second and dies.

Troubleshooting: Upon initial inspection, no lines or hoses were blown off. We don't suspect a vacuum issue because it won't even hardly start to hold an idle. The engine should start and rev fine, just not build boost. I don't think it's an electrical issue because all the lights and displays were working with no issue. Car turns over fine and I don't think spark is an issue. We're thinking the TPS has gone bad or is mis-adjusted. Another thought would be the manifold absolute pressure sensor (with paper diaphragm). Those will be the first two checked and evaluated. Vacuum lines and hoses will also be inspected with the UIM off. Plugs will be replaced and engine will be de-flooded.

Any suggestions while we attack this is greatly appreciated.

check engine codes first. then compression, igniton and fuel delivery

Before you do anything, I would suggest scanning for any CEL codes.

Also, how old are your injectors?

Can I just use a wally world code puller from Kragen, or do I need a Mazda unit? I've never pulled codes on my FD, but I'm glad you guys mentioned that.

Injectors are about 1.5 years old.

Edit: CEL never kicked on either (not that that means much...)

First thing, get it towed somewhere and have a compression test done on it. You basically only need three things for the car to start and run:

1. Compression
2. Fuel
3. Ignition

Driving is something else, but if you car won't idle you have a problem with one of those three. Typically with those symptoms, it's #1 but that is at least the easiest to check. Just buy or borrow a cheap piston compression tester and use that:

http://www.rotaryresurrection.com/3r...ion_check.html

It won't give you "exact" compression numbers, but it will give you the general health of your engine.

im pretty sure thats a map sensor, I forgot to plug back in the electrical connector to it one day and I got the exact starting symptoms you are describing. Also some times the vacuum line pops off when boosting so that would explain it dying when you were boosting it.

good luck,
Jason

Thanks Mahjik. I had a flatbed come out before CHP tried to take it off my hands. We'll do the compression test and see what comes about.

Mahjik and Archie----- first I have quested the ignition issue as well---he has great spark next i have questioned the fuel delivery issue by checking the system. I have the compression test issue as my last suggestion to Archie!!!!
I am thinking is a very minor issue but who the hell knows

Compression test done using a regular piston compression tester utilizing Kevin Lander's method:

106 on the front peak with pulse bounces 38-40
93 on the rear peak with pulse bounces around 39-41

Compression is not great but not absolutely terrible. At any rate, It should still start and idle with that compression correct?

I attempted to pull the codes using this method:
http://rx7city.com/ecucodes.htm

I didn't see any flashing off any of the lights on the gauge display. Maybe I'm not understanding what "MIL" is? Insight?

Just to add:

I utilized pg. 215 in the FSM (Fuel) and used the jumper wire to ground-out the F/P in the diagnosis box. The car cranked harder, but no turnover. I'm guessing I should check the voltage on the fuel pump at this point.

compression is on the limit i guess. you better save for rebuild.
if your car is not USDM, it wont have CEL light on the dash. for Euro and JDM FDs you need a led and 680ohm resistor to connect it to + side of battery and FEN (or MEN i dont remember exactly) terminal. search for it.

Dont go crazy.

Check fuses and relays before anything.

Kinda strange how just out of the blue the car dies and just doesnt start.

Start from the obvious yet neglected factors, then work your way to the most thought of yet expensive factors.

It's USDM. What I wondered was if my PFC was preventing it from throwing a CEL.

:icon_tup:Yeah, that's what I've been up to at this point. I want to know the true issue, before considering rebuilding. A rebuilt engine with blown fuses or bad connections wouldn't do me any good.