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3SGTE can`t rev above 6800-7000

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3SGTE

PS500

New spark plugs, spark plug wires, distributor cap, distributor rotor, ignition coil

Injectors are ID1000

Trigger type is Motronic 36-2+1 home. Miss counter remains 1 after start up.

Any ideas?

Attached Files

From the log file and how smoothly the engine holds rpm, I'd swear it's simply sitting on a limiter. The fact that your AFR is stable and reasonable though would tend to throw this theory out the window. Can you have a look at fuel and ignition cut % during this type of event? That may shine some light on what is happening.

Also does the rpm change at all with tuning changes? What happens if you go 10% richer? 10% leaner. Add or subtract 10 degrees timing (obviously be careful of knock).

Hey, Andre, thanks for the answer. Too bad I have no such a channel logged as % of ignition cut or % of fuel cut. But the rev limiter setup is hard ignition cut on 7500 RPM. I can`t imagine that the ECU cuts earlier. Making it leaner/richier, more advanced/retarded seems to be no matter.

Why do you have such big injectors??... what kind of turbo are you running??

Your problem has to be rev-limiter. What else could it be?

Big injectors are ID2000, these are only a half of big ones and less then 2 times bigger than stock ones)))

I have only 4 cylinders, so the injectors should be 1.5 times bigger then on 6 cylinder engine and 2 times bigger then on 8 cylinder with the same power gain)))

The turbo is diesel truck T04E.

Again, rev limiter set is 7500 RPM. I could set it to 6800 and look if some changes occuring.

Can you post your tune file?

The Rev limiter may be set to 7500 but if you goto Setup -> Main Setup (or just press F4) Then click "Advanced" then "Rev Limiter" If the "cut type" is set to "soft" then it gives you a option for "cut span" if this is set to say 1000 rpm then even tho your revlimit in the tuning menu is set to 7500 it will actually start cutting at 6500.

Sure I have a Hard cut enabled, I`m really familiar with Haltech since the Platinum series was released. The problem is not as easy as someone thinks.

Just throwing ideas out there. I got no idea how much you do or do not know.

Can you post the tune file?

Sure. The ignition table is not optimised yet

Attached Files

I don't know... you're maxing out at 40% duty-cycle at 8psi. How much boost are you planning on running?

23 - 25 psi of boost if everything would be fine and I would like to have a safe margin of 10-15% DC

Marek

questionig the post opener about oversized injectors is totally irrelevant.

Graf

What was Haltech's reponse ?

Any chance the dyno is set to hold the speed. It's like you hit the load wall.

Dynodom

Haltech staff keeps silence

David Ferguson

The car hasn`t seen the dyno yet) That log was on the road

I guess that something gone wrong with camshaft timing, should I check it up?

If your valve/cam timing was abruptly changing... to such a degree that the car stopped accelerating... your AFR's would go insanely rich. This is not the case.

The problem was: both camshafts were 2 teeth advanced

Thats insane... you're lucky you didn't destroy your valve-train.

I second that, you just got away with being so far off. At least now you know that this is not an interfierence engine, but finding this out in an empirial approach will, more often than not, result in catastrophic failure of not only the valvetrain.

You lucky man, one engine for free!

Cam timing can cause all sorts of ugly problems and it can often be difficult to diagnose. This is why one of the very early steps in our 10 step process is to make sure you can achieve good idle quality with the engine before beginning the tuning process.

In my experience a cam timing issue will almost always show up at idle. Either you won't be able to achieve a reasonable idle speed (won't idle below 1500 rpm when it should idle at 800 for example), or alternatively you have little to no vacuum at idle in an engine that doesn't have aggressive cam design. For a cam around stock duration/lift I would expect to see the vacuum at idle somewhere in the -60-70 kPa region.

The camshafts are GSC 274/274 of duration and 9.9/9.9 valve lift.

In that particular case the idle speed seems to be ok, the vacuum is a little bit low at about -40 kPa.

The main thing I am thinking about how the hell the engine works on that angles. The cam gear has 45 teeth, it means 8 degrees per 1 tooth. 2 teeth is 16 degrees of cam rotation and 32 degrees of crankshaft rotation so that that intake valve opens far beyond TDC, something about 25 degrees ATDC o_O

Now approaching the horisontal part of the torque curve likes a huge kick from the back). But before that point the engine is totally dead even if the boost pressure has been risen.

274/274 should make the 3SGTE an interference engine though. From what I know 264's are still non-interference.

One of our customer's had the same problem on his 3SGTE, in our case we ended up ditching the factory VR sensors and going with hall effect sensors.

Also we just redid the whole engine wiring harness, as it was a total mess.

Well yes, it seems more like an electronic problem but sometimes the symptom confuse a lot.

Once I rebuild a small block Ford with all new components and it can t rev above 3800-4000 RPM

an with always a rattle and misfire at those RPM. (it seems like a rpm hard cut at 4000rpm)

I change all the ignition components and the fault persist , check all the fuel line , pump pressure, carb, etc.

and nothing.

The problem was that I assambled the cylinder head with taller valve stems without know it and obvoiusly the valve

springs have far less assambled and open pressure so the valves float at 3800-4000 rpm and produce that rattle

and misfire . I put the correct springs height for those valve lenght and the problem disappear , it rev clean

to 5500-5800 rpm that was the camshaft rpm range.

I dont say that is something like this but you know your engine or ask the engine builder if he interchange some internal

parts with other dimensions.

Stock 3SGTE valve springs dont have float problems at 7000 rpm but all other dimensions and parts are stock?

Only something to rethink or recheck.

I had the same issue with my mr2, it would not rev pass 6000 rpm... engine would sound as if it died at that rpm... bet behaved like a limiter with a steady afr... tried all manner of things checked timing disabled limiters.... it was a total nightmare almost tore the engine and electronics apart!!... i got fedup and ignored it... after tuning the ignition table i started adding timing then realized i started to actually hit limiter which at the time was set to 7500rpm... so i figured the ignition timing was just too retarded my problem was solved :v

3sgte 4th gen head 3rd gen block

hks 264 cams (no cam trigger)

haltech PS1000

bws366 turbo