kb58

I'm the builder of the mid-engine Mini in my sig. Today was Test Drive #3, which included slightly faster driving than in earlier drives (I'll get the video up soon.)

The engine is a H22A1 with 12K miles (yes, 12K), never rebuilt. It has no EGR, has a custom header, no cat, an aluminum flywheel and Quaife LSD. The idle coolant circuit is disconnected, but is otherwise stock, including the stock P13 ECU. There is one error code, "20", which is the Electrical Load Detector (disconnected), but I don't think that's the issue here.

During moderate acceleration, right around 5000rpm, the engine cuts out. It feels like either ignition or fuel is being cut off; I have no idea what's going on. For that reason I back out of it as soon as it happens so I don't know if it would persist.

As far as I can tell all vacuum lines are properly connected. If I rev the engine in neutral, it has no problem going to 6000. With this happing around 5000rpm it makes me wonder if it's VTEC related. Like I said, the engine feels like it gets kicked in the nuts. There's a loud popping out the exhaust or intake (hard to tell which) but when it happens the engine just goes flat.

Any ideas would be greatly appreciated, and thanks for your continued support.



Modified by kb58 at 4:39 PM 6/26/2005

DarkBB4

cel causing limp mode?

Shakes

is the dizzy new as well?

how is your oil pressure looking?

fix the electrical load detector and then if that doesnt work swap ecu's or vise versa.

kb58

I can't fix the ELD - I don't have one... All it does is tell the alternator to charge at a higher or lower current so I can't see how that would do anything.

No the alternator has never been changed. Keep in mind the engine only has 12K miles on it... it's essentially factory new.



Modified by kb58 at 4:12 AM 6/20/2005

PirateMcFred

You can check the VTEC solenoid screen for grime/debris and see if that helps. But AFAIK the P13 is pretty temperamental about not having everything hooked up.

If you cannot figure it out after a while send me a PM And I will loan you my socketed P28 ECU with an H22 basemap to see if you can eliminate the ECU as a problem.

Except for the above problem I hope that the test drive renewed your interest in finishing your project.

Pirate

kb58

It has, though it would have been a lot better if this hadn't happened! I'm afraid it could be a tough problem to debug since it doesn't show itself when in neutral. If the screen is clogged could it really cause this symptom? The popping is pretty loud, though on the video you can can't really hear it due to the audio limiting. As said before, during that moment the engine loses power and I didn't want to keep my foot down. I might hook up an LED to the VTEC oil solenoid to see if the problem really is at the crossover point.

[Edit] BTW, once VTEC is working, it's going to be really fast.


Modified by kb58 at 3:35 PM 6/20/2005

red92s

Maybe try a new fuel filter (?) I know a lot of people, myself included, have had problems with uneven acceleration and a new fuel filter has helped out.

Well, now that I think back, I'm pretty sure you are not running a factory filter, so I guess that blows my theory.

machine4321

id say its almost timing related...or lack of fuel under load ..reving in nuetral wouldnt really show the the hesitation due to not having any load on the motor

im sure youve gone over all this stuff...and your car kicks ***..for real

kb58

Fuel filter is new, a generic high pressure GM part.

It's a bit embarrasing to say I've never checked the timing... guess that's next. Thanks for the help.

machine4321

np..i could only imagine how much i would forget to do on a project like that haha

94vtecmn

Are you sure it was warmed up enough? I mean you only drove it for a couple blocks, slowly. The engine temperature may not have been high enough for the computer to let VTEC engage.

Also, I thought it was kind of funny how you were concerned about that last stop sign, without proper light markers anyway......

kb58

All the cables and hoses pass very close under the exhaust. Approaching the stopsign, some smoke started coming out and I thought a hose was melting through - maybe a fuel line... so I made a bee-line for home.

After my buddy's Lotus Esprit burned to the ground I was a bit paranoid. Thinking back though, pulling into the garage in a car that may have been burning wasn't real bright

Anyhow it was only the header wrap "cooking in."

Good point about it not being warmed up. I just can't believe that's normal operation to limit rpm in such a heavy-handed way, cold or not.


Modified by kb58 at 5:16 PM 6/20/2005

94vtecmn

Well, that's a fact with the P13 and an H22, engine temp has to be near normal operating range for VTEC.

xludexgenx5

If you're running the p13 wouldnt that throw CELS for the EGR? but I dont think it'll put the car into limp mode..

kb58

From what I've read, nothing in the P13 really puts the car in "limp mode". Abut the EGR, it's hooked up but is blanked off (I think... geez it's been a while, I need to go look.)

You are right about the VTEC not working with a cold engine. My question is, what happens when you go above the VTEC rpm with a cold engine? What does the engine do? I suppose it simply won't engage the cam, but that shouldn't cause the popping out the exhaust.

pentaq

The ECU will not allow to switch to the high cam and your rev limit will be ca. 6500.

94vtecmn

I just came back from lunch and I see pentaq already posted what I was going to edit. The rev limiter should be closer to 6500 if VTEC does not engage. So, why was it popping and losing power right at the VTEC crossover of ~5000rpm? Not sure, it should rev to 6500 without being warmed up. Not advisable, but that's what it does.

Perhaps your fuel pressure is low, thus when it switched to the VTEC cam, it was starving for fuel?

Shakes

the lobes wont switch over to VTEC when there is no load, i.e. in neutral.

timing and ECU swapping should be first on the list after warming kimini up and taking her for a run.

kb58

The external fuel pump is from a Nissan 280ZX Turbo; it "should" have enough delivery. I'm using a stock Prelude fuel pressure regulator. You're right that I need to know for certain what the pressure is. Unfortunately just screwing a cheap gauge into the fuel rail does me no good since I can't see it when driving! I hate to spend the money on a real gauge since I don't want want one permanently.

Something else I need to check is that the tach is accurate. The factory setting is a four-cylinder, but if it's something else that can throw everything off. But it idles fine, showing 8-900rpm which is what it sounds like, so I don't think that's it.

Too many variables... and obviously one of the things I assume is fine, isn't...

Shakes

add the gauge onto the rail. then to check the WOT pressure you remove the vacuum line to the regulator. that simulates WOT.

kb58

Really, it's that simple? I'd think since under load the engine is consuming a lot more fuel, so no matter what test I try at idle won't give an accurate result.

skunked

you may want to take a quick look at your cap and rotor too.

machine4321

fuel pressure isnt directly related to flow ......so it will atleast give you a good idea of what fuel pressure youll be runnign at WOT

again id start with timming ignition as well as cam

and a quick look at the plugs will help detemin if its runnig very lean

Shakes

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kb58 &raquo;</TD></TR><TR><TD CLASS="quote">Really, it's that simple? I'd think since under load the engine is consuming a lot more fuel, so no matter what test I try at idle won't give an accurate result.</TD></TR></TABLE>

yes its that simple.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by machine4321 &raquo;</TD></TR><TR><TD CLASS="quote">fuel pressure isnt directly related to flow ......so it will atleast give you a good idea of what fuel pressure youll be runnign at WOT</TD></TR></TABLE>

it is the same as WOT.

While at WOT there is a lack of or near lack of vacuum in the intake manifold. removing the vacuum line from the regulator is the same as having zero vacuum in the manifold as far as fuel pressure is concerned.

so in essence yes you are correct. just adding to it.

mgags7

that crackling and the sudden pop out of the exhaust are reminiscent of the time i played a little too much with my VAFC and the map sensor cut out.....

i think whats happening is that physically the engine goes into vtec, and the fuel isnt sufficient, so the suddenly extremely lean mixture as soon as the lobes switch cuts it due to mixture probs....maybe....

figure out the fuel deal and get back to us....