RX1 W/Bender Can't Diagnose problem - Can anyone Help

[LANEO]

Have Rx1 with problem. It runs ok till around 6000RPM then breaks up badly and won't go over 6000 to 7000 RPMs. Doesn't get enough RPM to develope boost. Ran good for first 15 minutes out then turned bad. No warning, indication or event to indicate cause of problem (was not runnig it hard prior to problem).

So far have:

1) checked compression all 4 at 145lbs (is set up to run at 9.4 to 1)
2) replace plugs (2x)
3) cleaned carbs (2x sure they are clean)
4) verified TOS was operating then bypassed
5) checked all vac lines and fule lines - are good
6) sealed carb Tees and all intake boots sealed good
7) swapped out all 4 coils
8) swapped out clutches - definately not clutching
9) verified aux fuel pump is running
10) checked boost pipe - no leaks, no obstrustions
11) inspected exhaust for leaks/obstuctions (what I can see from underneath and near turbo
12) Checked most electrical connections resealed with Die Electric grease including to CDI
13) disconnected intercooler and tried to run without turbo - Runs same p bad
14) No evidence of oil in coolant
15) added Sea Foam to fuel
16 Inpected turbo and wastegate for obstruction and verified turbo freely spinnig freely (also disconnected turbo system and still runn same so don't think it is turbo rel;ate)
17) inspected carb intake boots - good shape.
and more.

Next: am going to
1) install fule pressure guage to check fuel pressure (does anyone know what fuel pressure should be?)
2) inspect exhaust manifold joints (but does not seem to be loud)
3) Inspect Oil to make sure not milky (but seems to have good compression)
4) Swapout CDI box
5) Swap out Ignition
6) bypass kill switch (think I already did but will again)

At his point feel I have rulled out carboration and vacume lines. (except fuel pressure)

Any Ideas That I havn't tried or other things to test to determine problem ????????

I'm running out of ideas. Need Help!!!!!!!

Does anyone have any ideas that I haven't tried to diagnose problem.


Thanks,
Perplexed and frustrated

 

[spray25]

Check all lines with the airbox installed to make sure nothing is kinked specifically fuel lines.

Are your tees plastic/rubber ones or alluminum? If plastic/rubber they are probably leaking.

Check fuel pressure.

 

[rxrider]

How is your fuel regulator pressurized? It is possible to mix up the lines that goes to the fuel pressure regulator with the one that pressurizes the carb float bowl.

 

[LANEO]

I checked all fuel and vacum lines and am sure there are no leaks or kinks. Tees are rubber, but are sealed well and have zip ties holding tight. Not as good as the aluminum but i dont beleive they are leaking.

I checked fuel pressure and have just under 5 lbs while off and at idle. When i rev (won't rev over 6000 rpm and won't develope boost) fuel pressure drops to 3 1/2 to 4 lbs. Does anyone know what fuel pressure should be????

 

[rxrider]

.02 cents wort a bet on that's the T's that goes in between the carbs to the float bowls are leaking.

Do as spray25 says, he has many years of experience with the Bender system.

Get the billet ones from MPI - www.mauntainperformance.com or other that sells them, and get it fixed once and for all.

What did u use to seal those T's?

 

[FAMILYMAN]

The 4 nipples on the top of the carb boots will cause backfiring and problems running completely if leaking.

One of the lines under the intercooler goes to the fuel pump. One goes to the rubber tees on the engine side of the carbs. The tees that should be replaced are the ones on the intercooler side of carbs and they get tied into the charge tube.

If there is boost going to the carbs the intercooler vacum line changes the carbs to prepare for the boost that is about to reach them. If they are leaking it will not convert the carbs in time before the boost gets there. If this happends the pressure builds in the charge tube and causes the engine to not want to rev.

This is my understanding of the bender2 turbo...hope this helps.

 

[KnappAttack]

It either your T's leaking, or the exhaust going to the turbo. I just had one in that warped the "Y" pipe so bad going to turbo that it ran the same way. I warped enough that it came off at the Y with 2-clamps and the donut sleeves in it towards the front.

 

[spray25]

I'm not convinced that your tees are sealed. To many people have thought they were sealed (including me) and later found they were not. Even they are sealed one day they will start leaking. Trust me get the alluminum ones.

5 lbs at idle is fine. 3.5 to 4 at 6000 is not. This would lead me to beleive that either that the regulator is either broken or you are building vacuum that is preventing the regulator from doing what you want it to. Either way for now don't worry about the regulator. You should be able to support about 3-3.5 lbs of boos twith that fuel pressure.

When you inspected the carbs did you check each needle and CV slide? I saw a needle dislodge once and it ran like yours.

If I am understanding correctly you are saying that the sled ran fine for 15 minutes then all of a sudden it stopped running correctly. Is that correct? If this is correct then you need to look for something that has suddenly started leaking or broke. Have you ruled out engine failure?

Some more things that might help....
Ellevation?
Mains?
Needle position?
Pitot jet?
Amount of boost when it was running?
Fuel?

 

[LANEO]

I will definately order the aluminum tees. I had them leak last year and been meaning to get them. I will re-seal tees in the mean time till I receive aluminum tees. I will check needles for dislodgement. CV slide freely. all lift evenly. I have an digital Air fuel guage whic reads 12 in the to 13 rang. Runs kind of like on full choke. HAve checked and claened chokes allseem to be functioning correctly.

Yes correct it ran fine for 15 minutes. Built boost, no issues. Then gave throttle and it just wouldn't co over 6000 rpm and won't build any boost. No indication, no long runs , no hard driving. I have not ruled engine out problem but have 145 to 150 compression in all four cyls. (I am running 9.4 to 1 compression). I was running at 5/10 lbs boost depending on switch position. I have no blow through of oil through breather. No indication of oil in coolant no indication of coolant or coolant in oil. Did wonder about head gasket failure. Am sure I did not run it hard enough to to cause turbo related engigne damage. Head gasket I know could happen whenever. Any way to test for head gasket other than compression ? Any electrical related tests or ideas?

I even pilled off intercoolr t see if would run better, but same problem exists with intercooler off.

 

[spray25]

Any updates?

 

[LANEO]

Ran the sled inside and saw exhaust was a little blackish. Figured either rich (which air fuel guage does not indicate) or turbo problem. Inspected turbo closer and determined turbo has gone bad (still spins freely but a lot of side to side play in turbine and can see that turbine hit housing. Its a ballbearing turbo so its not rebuidable ( im told. I think it is but not worth the cost vs getting new one). sled has less than a thousand miles so doesn't make sense that it would go bad. However, determined that oil pump failed or got debris in it (people say a minute peice of debris will do it). Anyway pump failled yet sensor light never went on.

I am going to replace the turbo (with the bigger GT28 versus the GT25 of course) as It is defeinately bad. Just hoping that is the only problem. It seems to explain the no boost issue and I think that even khnow the turbine spun freely it would spin fast enough to generate any boost and probably resulted in a vacume condition in the intercoler. That may explain the drop in fuel pressur. What I am not sure about is why it ran just as bad with the intercoller disconnected. Maybe cause the jetting would be so bad or all the other stuff that is done to pressurize the carbs?

Allso am ordering the aluminun tees. Will probably be mid or late in the week before I get my hands on a new turbo. Bender split off thier turbo business and I cant get them to sell me one. Not in any reasonble time frame anyway. I did all the reasearch and have one lined up though. Bit of an expensive fix though.