No power when hit 7 psi
 

On Tuesday my FD wouldn't start...tried several times and it just cranked and cranked, but woudn't fire. Battery was fully charged a couple weeks ago, and it cranked hard so it wasn't a battery issue. One one last attempt I pressed the gas (shoulda known better). Got it towed to shop, where they found it flooded and dried the fuel and reinstalled plugs. It started up so they couldn't say why it didn't work for me.

I figured it was either fuel or fire, so I had them change plugs since they were due (quite black) so it's possible that was the cause of not starting. However, they said when they test drove it afterwards it wanted to fall flat on its face when hitting 7 psi (This had not been happening beforehand). They commented they saw buildup of soot by the turbo (actuator?) and thought maybe that was the cause. But it had not been occurring before coming to the shop.

It was closing time so I took it home and found it consistently cannot accelerate when hitting 7 psi. Anything under that, regardless of RPM is fine.

I looked for a hose that maybe had come off or something unplugged...can't see anything odd. If I drive it I can put some boost, but once it's enough to hit 7 psi the car seriously hesitates.

Anyone have any idea what might be causing this, or perhaps what they might have done at the shop to cause it? Help!

Thanks,
Sebastian

Hello,

Not going to be much use, but in order for people to help you out, post more info about your car, like mileage on the motor, condition of the solenoids, anything you have done to the rats nest and components.

the condition of the rats nest in our cars are constantly causing problems, we need to know more to help out :)

it's a 93 with 35k original miles including motor (I bought it with 9k). I haven't done anything to the rats nest, battery is in original location.

When I lived in Tucson, I had Jay at Rx for your 7 install a PFS intercooler w/ cold air box & K&N filter, Racing Beat catback, 185k thermostat, boost gauge, oil temp gauge, and some minor electrical with HID lights and radar detector. Still has original cat & precat.

I have no idea about condition of solenoids.

What other info can help?

Thanks

Check for clogged cat? I don't know how relevant that is since it's 7psi specific though. You might wanna replace the pre-cat for a downpipe soon though. The pre cat causes a lot more heat.

along with that, RX7 CITY.COM - Tech Connect _Help Section, Manuals, How To's, FSM <--- try seeing if your ecu is storing any codes.

really low mileage car! sucks having these kinds of problems. If the ECU is storing something thatll definitely let you know where to start. Other wise there are several things it could be from a simple clogged fuel filter, to secondary injector failure. Most likely with such few miles you can hope fuel is the problem, otherwise time to dig into the vacuum system, do you hear any unusual hissing or anything that could constitute a vacuum leak.

a really helpful site for turbo/vacuum issues ---> Troubleshooting

keep us posted!

Never heard of rx7city before, that's a helpful site, thanks. I was thinking fuel might be the problem, will need to check that too. Once before I had a hose slip off and I think the symptoms were very similar if not identical. I couldn't find any hoses that were off, but still thinking that is very possible culprit...especially after seeing the diagram of where they all are.

Most likely they put the spark plug wires on wrong when they changed the plugs. I've worked on cars that have had them mixed up, that's exactly what will happen.

Also, make sure they used the right plugs - NGK BUR7EQ leading, BUR9EQ trailing. That's the stock setup, if you have some mods on the car you can run all 9's.

If the plug wires are on wrong, the timing gets all screwed up. Worst case you can blow an engine with them on wrong, I'd check that pronto.

Dale

yeah I thought about the plugs, so I immediately called and asked and they said they replaced by the book (ngk plats - 2 7's and 2 9's) and all this shop works on just about is sports cars...rx7s Z's etc. There's one mechanic that knows FD's well and they always have him work on it. I really doubt he put the new plugs in the wrong spots.

BUT something happened. My thought is something didn't get connected back together right, or perhaps one of the vacuum hoses got separated. I looked up the diagram and am thinking it could easily be one of the ones in the throttle body area and I wouldn't know.

Check the charge control vacuum line. Mine popped off one day at the track as they little oem clamp got hot and lost tension

charge control line...does that come off the Y-pipe?

I would take 5 minutes and verify the plug wires are on properly before delving further. It's VERY easy to cross plug wires, even for an experienced mechanic - hell, I've done it before. With plug wires on wrong, you can have a lot of boost and no power.

Typically if the car was working fine then suddenly is not, it's the thing that was most recently touched.

Dale

Very true, I bought my fd in a "non running" condition for super cheap, got it in my garage, plugs wires were mixed up, fired right up after

Yes. It's the actuator on the Y pipe, just to the rear of the duct to the intercooler.

Also check the two short hoses (wastegate and turbo precontrol) on the front turbo running to the 2 actuators.

See the diagram for locations: https://www.rx7club.com/3rd-generati...-turbo-749702/