Turbos spool but no boost and limited rpms
 

Hey guys, hoping to get some insight on an issue with my turbos that started happening a few days ago. Scoured through the 3rd gen FAQ and queried multiple turbo related searches that resulted in nothing that has me convinced is my issue, so here it goes..

I have a 93 R1 with 70k miles and a remaned engine at 35k with stock non-seq turbos, 3' downpipe, apexi ecu, and greddy pulleys.

My issue is I am hearing what sounds like the turbos spooling (compared to what a boost leak would sound like) but with absolutely no boost or acceleration at all and no sounds from the BOV. I previously had a small boost leak after the y pipe, due to a loose hose clamp, and in this case the turbos would spool and the blow off valve would would activate but much quieter than normal. This time the BOV isn't activating at all so I assumed the leak would be pre turbo. I removed the rubber hose connected to the UIM and inter cooler and it seemed to be in great condition, no excess wear or cracks but noticed the hose clamp was stripped, so I replaced that.

WOT in neutral only got the rpms to 6000 this morning, although it now seems to only hit 5500... is this related to the turbos not providing enough boost to reach redline? or does the ecu limit this based on its air and fuel readings?

I then noticed one of the hoses was completely disconnected from the y-pipe, thinking I had found my issue, I snapped it back on and secured with a zip tie, but to no avail.

Ran out of day light today so I had to button her back up. Anyone have similar issues to what I am experiencing? Would like some suggestions to try when the sun comes up tomorrow morning.

Will driving the car like this hurt the engine or turbos? The thought of having to keep the rpms low until it is fixed makes me cringe but the FD is my daily so if necessary I might have to get a rental until I can figure it out....or buy a scooter :lol:

Any info is greatly appreciated :icon_tup:

Took a quick video for sound reference. Once I start accelerating I'm almost WOT...

Check all of your hoses to make sure they are all clamped tight. A zip tie is not a proper hose clamp.

Even if you completely disconnect the intercooler pipes from your throttle body you should still be able to rev all the way to the rev limiter. If in neutral you can't rev past 6000 rpm there is something more than a boost leak around the intercooler going on.
Check the line to your MAP sensor, look for leaks on other lines and sensors around the intake manifold.

Appreciate all the feed back, quick update:

Car ran the same as it did last night when I left for work this morning but a couple miles later there is more power loss and the rpms are now capping at 3k..scared to drive it at all at this point.

Ran out to look at the MAP sensor and it seems fine and the hoses are in good condition. However, looking at this diagram

https://cimg9.ibsrv.net/gimg/www.rx7...ca85d4d8ac.png

there are 4 nipples to be capped on the left side of the LIM which are not capped on mine, the top L shaped nipple looks clean like it may have been capped before. Could this be an issue?

https://cimg6.ibsrv.net/gimg/www.rx7...d18f74d375.jpg

Just ran out and turned the car over, getting a small gas odor from the left side of the engine bay in the UIM area....after searching I found many posts around gas smell from a bad FPD. Do these symptoms sound like a bad FPD?

After a few more searches I am thinking bad injector..

not sure if the injector is your issue or not but the 4 vac ports on the LIM don't have to be capped off. They are just passed through ports for the seq stuff.

there should be a troubleshooting guide on how to test your injectors.

I would remove the FPD or replace it with a new one soon. While your at it might as well change the fuel hose if you haven't already.

Looks like I'll be leaving my car at work overnight..plan on removing the UIM tomorrow morning to see what I can find.

I agree with Johnny

Search for the fuel line recall kit and order one from Mazda (Ray at Malloy is unavailable) it's got new injector diffusers, new fuel lines, and even the banjo line in it. The FPD doesn't really have symptoms of being bad other than leaking.

Matt

What happened to Ray?

When I tried to place an order with him about a week ago, I was informed that he was locked out from getting Mazda parts or something along those lines. Think there is a topic in the 2nd gen forum regarding this too.

Matt

ok, so, firstly, you wont build boost in neutral..that's normal.

secondly, if that nipple you circled that is not capped off goes right through to the runners, then yes that's a big problem and would contribute a massive vacuum & boost leak.
Also thats really close to where fuel is getting injected, so would make sense it would smell like fuel there with that nipple open. (i have a late model FD which has no nipples there so not sure if its a dummy nipple or actually goes somewhere).

I notice you have no hose clamps on the hoses/ capped nipple on the UIM. Put hose clamps on EVERYTHING :)

Some misinformation here:

On a stock ECU, and possibly a PFC (don't own one), you should build 4 psi revving in neutral.

Those nipples identified on the LIM are pass through and are for the EGR valve and sequential control components. Being you have none of those, they were left open.

A fuel smell from the UIM area is NOT something to drive the vehicle with. These cars are known for engine fires stemming from exactly this.

Sounds like a boost leak. And a big one. What's up with the blue pipe to the intercooler? Check your couplings for splits, and put some clamps on your y pipe coupler. Looks like you have none unless they were just off in the second picture...

Matt

I had a buddy come sniff around the UIM and he thinks it is more of an exhaust smell rather than fuel. The Y pipe coupler does have 2 clamps which are kind of hard to see in that picture. The blue pipe was on the car when I bought it, going to remove and inspect it and its coupler tomorrow morning.

I also noticed that the o2 sensor is completely disconnected...the wire is broke off but I couldn't find the other end hanging anywhere by the UIM

https://cimg9.ibsrv.net/gimg/www.rx7...9fc0dd835c.jpg

Unless a new o2 sensor could solve these problems, I plan on removing the UIM and checking every vac hose and all the pipping for cracks and wear. The vac hoses were all replaced not even 2 years ago.

So turns out it was a clogged cat, perfect time for a resonated mid pipe I suppose

Yep. Not being able to rev is a restriction problem - intake restriction, exhaust restriction, or throttle body not fully opening.

Glad you found the culprit!

Dale

Nice, how did you find that out?

Have fun removing that cat, i hate removing old exhaust stuff.

Couldn't get time off of work and couldn't wait till the weekend to look at it myself so I had it towed to a local rotary shop. They are going to unclog it and bolt it back on while I wait for my DP MP combo from rx7store to arrive :icon_tup:

So excited, I feel like a kid on Christmas. Appreciate the feed back guys, cheers!

Non sequential and full exhaust is going to give you issues controlling boost. I would install a high-flow cat or at least a 2.5" restrictor plate in the midpipe.

I will be closely watching my boost and plan on getting a few different size restrictor plates to test if need be, really want to port the wastegate as well