Details on the car:
-87 Turbo
-emissions removed
-custom TID
-Racingbeat turboback exhaust
-350 miles on the rebuild
-128k on the drivetrain

So now that i have put a couple hundred miles on the car, I figured it was time to start addressing some of the issues that I am having with the car... The two first and foremost problems are my gas mileage and how hot my turbo appears to get.

MPG problem - I'm working on getting an actual mileage estimate with the tank of gas I just put in yesterday, but a quarter of a tank gets me about 30 miles, so im looking at about 7 miles to the gallon right now. Now I am aware of the nature of the rotary and that i wont be pushing over 25, but 7 just seems downright ridiculous.

Turbo problem - This problem seems to scare me more, any time i drive it and it gets up to operating temperature, the turbo will be glowing red hot when I stop. I am still in the break in stage, so i do my best to stay out of boost, and I am in no way "flogging" the car around town. Hell, i get dirty looks from the 70 year old drivers who pass me. So why is my turbo getting so hot? Could it be related to the MPG's being bad in that possibly I am running overly rich, therefore having the extra fuel burning off in the turbo? The coolant line that runs through the LIM and and through the turbo appears to be working, as coolant comes out of the turbo when I took it off last.


Suggestions? Things I can test?

 

cat is probably clogged..look under the car at nite after a hard driving session and see if its glowing

 

i don't think he has a cat anymore,

I would check timing.

 

the turbo glowing is from way to much unburnt fuel in the turbo igniting in the turbo itself

 

Right no cat, Timing should be spot on, but it wont hurt to give it a shot

That's what I was thinking...pretty much just the turbo glows, the glowing stops pretty much 2-3 inches down the downpipe.

How would I go about adjusting that unburnt fuel?
I've already got the variable resistor pretty much all the way over to "L" Aka "Lean" I would assume.
Does this mean the next reasonable step would be installing aftermarket fuel control?
If so, whats a good recommended setup? I'm not looking to be doing a standalone...maybe one of these options? Or is there something else better?
-Stock ECU with SAFC
-Rtek 1.7 with SAFC
-Rtek 2.1 with a Palm to adjust it

Thoughts?

 

what kind of fuel pump do you have?

If the timing is retarded it will cause the fuel to be burned late in the turbo.

 

what other modifications have you made?

 

Did you clean the injectors with the rebuild?

Mine only glows after a hard drive, and wont idle all the way on "L". Sounds like a fuel delivery promlem for sure. For the MPG I can only get 17 with cruise and no boost.

 

Stock fuel pump, should still be wired factory, stock fuel injectors too.

I don't think I've got any other mods, I do have an Autometer boost gauge, but that shouldnt do anything.

The coolant hoses that go to my heater core are disconnected b/c my heater core has a leak. Thermowax lines are also disconnected.

No A/C, Air Pump. Running a yohoo belt.

 

Yes, had it done by injector-rehab, highly recommend them, did a great job.

 

have you adjusted the TPS, you may want to take a look at that.

 

I would say Timing... Fo sho

 

What about fuel pressure? Maybe the injectors are getting too much, try checking it after the FPR.

Side note: Does anybody know if the boost pressure sensor would deliver extra fuel if it had failed? If it was reading atmospheric pressure.

 

Looks like I've got some work cut out for me tomorrow...

 

check the easy stuff first. Timing should be first on the list.

 

Fuel pressure should be checked on the feed side (w/ the filter). The FPR regulates the pressure throughout both rails, but it is actually located directly before the return line. If the FPR fails, then I guess it'd be possible to see huge increases in fuel pressure, which would mean a severely rich mixture at all times. Stock will be ~30psi at idle, ~40 psi at 0 manifold pressure, and then +1 psi per lb. of boost.

To the OP, does it idle rough at all? I've experienced a poor idle with a walbro that jacked my fuel pressure up to 46psi at idle, so if you're having a pressure issue, it should show up as roughness or even black smoke out the exhaust.

To answer your question RXJIM, I don't know that boost sensors fail all that commonly. But if it did default to always reading atmospheric pressure, it would mean the engine would be getting less fuel. The stock map is much leaner in the areas not under boost.

I'd start checking the major fuel control components (TPS, AFM, boost sensor, ECU, intake air temp sensor). Checking for codes would be very helpful, and the FSM has tests for each. Here's a link on how to pull codes: http://www.teamfc3s.org/info/article...odes/main.html. Also, the variable resistor only adjusts mixture at idle, so it's not going to affect any other driving condition at all.

 

Guess I'll have to work on finding a way to read fuel pressure...

As for rough idle, i would say it does idle a little rough. Thing is idle changes constantly, and I cant seem to place the conditions that makes it idle in different ways, it seems to do a variety of things, even when the engine has fully warmed up, it can idle at like 1700, 1500, 1100, 750, or sometimes as low as 550. It idles quite smoothly at 1100, but anything below that it gets much rougher, when its at 550 it sounds like it is right about to stall at any point, although given it shouldn't idle that low anyway, so that could be the reason. Maybe could have something to do with the Lean setting of the variable resistor then.

P.S. - Rotary Rocket - finally got around to building the Air Box that you gave me the plans for, thing fits like a champ, and looks good to boot!

 

I had the exact problem after my rebuild. The turbo glowed red hot. It was the timing that was the problem. Once I fixed that the turbo stopped glowing and mpg got much better..Timing

 

check the oil lines to the turbo and make sure that they are flowing properly. also do the same with the coolant lines. they both can cause it to overheat. i had the same problem

 

If you're running lean it would cause the same thing. Get a wideband and see where your AFR's are at, or get an EGT gauge. Either one will tell you what's going on.

 

Good point. Rereading my post it makes no sense.

The return line has no effect on pressure unless it's kinked. Sad part is I know that and still posted nonsense.

 

Jesus man.. did you check the timing YET!!!?

FRIST THING TO CHECK = TIMING!!!!!!!!!!!! GOHGOGOGGOGGOGOGOO

 

+1

also I once had the vacuum line come off my turbo and it made the turbo glow real hot like that.

 

check to make sure that there is nothing clogging the exhaust. and are you using coolant 50/50 or just water? water heats up very fast through the turbo if your just using water for summertime.

 

Yes, 50/50 mix of Peak "Lifetime" or something like that.


Sorry on the wait I advanced the timing a bit yesterday, and it seemed to even out the idle a little bit, also I noticed that the car doesnt boost when I'm not in gear anymore. Like i used to just be able to rev the engine in neutral and it would build 1-2 psi of boost. With the timing advanced, my boost gauge goes right to 0 psi and wont go above, I also cant hear the BOV going off either, so I'm assuming that there really isn't any boost being created, which is good (I think?).

But after I did that I decided that while I'm at it i better do as the saying goes "Do a job, big or small, do it right or not at all." and went ahead and attempted to adjust the TPS, Lo and behold, its proving to be nearly impossible, as now i cant get the car to idle and I've adjusted it way outside of where I started from and cant get it back to where it was working. I let off the throttle and the engine just instantly dies.

I have the TPS test lamps, and I cant make the TPS adjustment screw come close enough to close the plunger enough to get it to make the one light come on, as it is now, neither of the lights are on but if i finger the plunger around I can get both or just one to come on.

After giving up on it yesterday I revisited it now, and went through with my multimeter and ohm'd it out, to see if I could find anything amiss, however I dont really fully understand the readings that I am getting from the ohm meter, so I will post them and let you guys help me out with the diagnosis. I referenced this article for the Plugs: http://howto.globalvicinity.com/gv_w...i=58&co=1&vi=1

Multimeter was set to 20K ohms, as that was the only setting that allowed the meter to read the resistance through the entire range of the TPS.

A To C
Plunger Extended: .56
Plunger Closed: 5.61
A To B
Plunger Extended: 5.58
Plunger Closed: .30