ok... Try solving this one. I have a 10ae with a s5 Turbo engine i just rebuilt and ported running premix. So the problem is, when I give it more than about 1/3 throttle it completely cuts the fuel.
I have replaced the fuel filter, fuel pump, re-wired the pump, and completely ruled out the TPS. Before I rebuilt the engine I didnt have a FCD on it so I dont think that is the problem, but i ordered one from racingbeat and it should be here tomorrow (just in case). But i had this engine in for 4 months and never had this issue, then it blew, sat for a total of about 10 months (since March 20 last year) and after breaking the new engine in (exactly how Rotary Aviation told me to do with their Super Seals), I now have found I have this problem.
I had a friend at a smog shop put my car on his dyno and he said that I am running rich at idle. I then got it to second gear and got on it hard, he said his readings showed it went completely lean. So he then pumped propane directly into the intake and the car took off hard like it should. But I can't figure out why it is doing this!
I think I covered everything... any suggestions?
Here is a link to a video of what I am experiencing. As you can see, it doesnt matter the RPM but as soon as I give it over 1/3 throttle it cuts out.
http://www.youtube.com/watch?v=5ZEX5p6p9Kk

 

IF someone has been playing around with the guts of the afm (spring tension) they might have misrigged the afm and that could cause a problem similar to what your seeing.

If the afm has not been messed with...........ignore this reply.

 

How did you rule out the TPS? Did you test the full range of the TPS? When you ported it, did you increase injector size at all? Rtek? I'm assuming you aren't running a WB since you took it to a smog shop to see how it was running?

 

Secondaries not kicking on, might wanna check that

 

if it happens only above 3.5k rpm then yes the secondaries might not be working.

Normally when a engine cuts out like that with certain throttle positions, its a TPS issue, did you check for continuity on all range of the tps?

 

Btw why did the original engine blow? Could be a something to address with this motor.

 

yes we checked the full range of the TPS and it is working properly. I am not running WB and did not increase injectors, but is that something I need to do? I dont think that would make it go completely lean and I would still be getting some fuel pushed in. So i'm thinking it's electronic or ECU or something. It happens even before 3500 rpm so i'm not thinking it's secondaries. and I have messed with the AFM but I checked that, but I will look again just to be sure. And I have checked the timing and it is in spec too.
any other theories? I'm at work so i'll try all this tonight.
Thanks everyone.

 

And yes this is the motor that blew, I think the oil injectors got clogged or something, so I just took that off when i did the rebuild and am now running premix. The engine ran great up til then tho

 

So you don't know for sure? And for the record most motors run good b4 they blow, doesn't mean it didn't have problems

 

where is the fuel pressure regulator vacuum line hooked up? the n00b move is to just use any of the 3 vacuum lines in the rear of the intake, but only one of those sees boost AND vacuum.

i've done it and seen it a couple more times, same symptom. runs fine in vacuum, hit boost, and it falls flat, cause the fuel pressure regulator only sees 0psi

 

Not saying it IS the AFM, but if it were there's no way to check it out. It will ohm out just like a factory afm right out of the factory.

Saying there's no way to check the right spring tension in a backyard atmosphere.

 

For that vacuum line for the fuel pressure, is it one of the 3 coming off the backside of the UIM you are talking about? I'm pretty sure those are all in the right spot but its one more thing to check on

 

could be a vacuum/boost leak.

 

2 step fuel pump relay is bad or wired incorrectly after the swap.

put a voltmeter on your black/white wire on top of the fuel pump and take the car for a drive, almost positive you'll notice your voltage drops to nothing once to get anywhere near boost.

my advice though is try to keep it out of more than a few psi of boost/under 5k RPMs if you are pushing it that hard, otherwise another new motor will be in the near future.

you can mail me a cookie.

 

karack: i read another thread where you told the guy the same thing, this is why i rewired the fuel pump to begin with. I wired it directly to the battery with a relay in between and jumped it off an ignition wire. so it shouldn't have anything to do with the factory wiring right?

 

On a series FOUR turbo car, only one of the nipples on the rear is vacuum.

On a stk turbo car the FPR is fed thru the FPR solenoid which is fed from a nipple on the front of the throttle body.

ON a series four turbo car the bottom nipple is the one that has vacuum. I'm sure it's the same on a series five turbo car.

 

I guess I'll check those lines now that I know what they are. And I'll check the readings on a volt meter to make sure my fuel pump is doing work.

 

I wasn't too clear on my reply. On a series four and on the rear of the throttle body, the bottom nipple is vacuum.

On the front of a series four turbo throttle body, the top nipple is vacuum. See jpg for that one. The rear isn't shown too clearly but it does show the bottom rear nipple going to the water therovalve. Vacuum.

EDIT: Even thought that decal came off my 87 turboii car..........I think the FPR feed is wrong on that decal. It shows the source from a nipple located near the air supply valve. Ain't no nipple there though.

 

thank you for this diagram it will be helpful to make sure all my lines are correct.
Also, I was wondering if the lines that are for the oil injectors are vacuum? do I need to cap them off now that i don't have them connected?

And I am still wondering if I have eliminated the problem of the 2 stage fuel pump by just hardwiring my fuel pump directly from the battery? I imagine it wouldn't be an issue now and it should be at a constant reading, but I haven't checked yet to be sure. I will tomorrow after work if nobody replies.

 

I read this as you not using the oil injectors. If so........then at the back of the throttle body there are three nipples one above the other. One is LARGER than the other two. Remove the hose going to it and cap the Nipple off.

IF the injectors are in place on the engine...cap off the top nipple and the side nipple that fed oil to it. Some remvove the oil injectors and install a bolt in it's place. Some don't

IF you hard wired the fuel pump off a relay then you no longer have a two stage fuel pump and its running full power all the time.

FYI; Oil injectors top nipple on a stk car gets fed metered air from the large nipple on the back of the throttle body. Not a source of vacuum at all. There is vacuum on the oil injectors though. That vacuum is from the bottom of the injectors and comes from the intake stroke of the rotor. So if not using the oil metering pump.......make sure to cap off the nipple on the injector that fed oil to the injectors.

 

yeah I did remove the injectors. Bolts came in the Pineapple Racing kit. But I didn't know about the vacuum lines, I didn't think that far into it at the time. And I figured that I didn't have to worry about the 2 stage fuel pump now but wanted to make sure.
I still need to check all these vacuum lines to see if it changes my fuel pressure and maybe that'll solve the problem. I'll keep you posted.

 

Idle the engine. While it's idling reach around the back and pull the vac line off the FPR. Feel for vacuum on it. IF it's there then that's good. No vacuum......not good.

Or heres a better idea now that I re read you first post. Saftey wire the outter set of throttle plates full closed. Then go for a ride and see if the power changes or not. What that would do is cut off the air source to the secondary runners so you only have the primary runners in play.

It still has traits of a mis rigged afm. Been there and done that to myself in the past. I do not recommend playing with the afm spring tension. Ever.

Just throwing ideas out there.

 

I did have to wire my AFM for the S4 plug to the S5 harness... so maybe something came loose inside my connection since? Although, that has happened once, and my car wouldn't even idle and was poppin flames out and backfiring and stuff. I'll perform the other tests you suggested also. And i went out on my break (i work at a parts store) and put a vacuum cap over the oil injectors vacuum line and switched those two other hoses on the rear of the manifold to see if maybe one was backwards, but it didn't change anything. So onto the next test.

 

why are you running a s5 harness in a factory T2? could be limp mode kicking on. get rid of the s5 trash.

 

Series five harness??????

I've been looking at this as a series four car with a series five engine and assumed a series four EM harness all the way.

How much series five harness are we talking? What ECU? I guess I should go reread the whole thread if that is there up above.


Here's an idea although I think the prolem is afm related................if you have a fuel pressure gauge here's something one could do. Install the fuel pressure gauge (a test gauge will do fine , it does not have to be a permanent fuel pressure gauge. So with gauge installed turn the pump on and see what the fuel rail pressure is (engine off). Should be approx 37-39 psi. Now by hook or crook (I use a MITTYVAC pump) apply pressure to the FPR (remove the stk vac hose and install the pumps hose on the FPR). As you apply pressure the fuel pressure should rise. About the highest the pressure will rise in the rail is approx 50 psi. IF it does rise up then all is ok with the FPR itself. I've even done this on a non turbo car and seen 50psi in the rail although the non turbo will never see that high a pressure with no boost/turbo.

I still think its afm related. One way to tell is to monitor the signal from the AFM to the ECU using a digital meter. With key ON engine off or even with engine at idle the figure should match the FSM (fuel and emission section {control unit pages}. I know that's what I'd do.

Remember the afm is the primary tool for fuel delivery/amount of delivery ( I read that somewhere or other, Henrik I think).