4age 20v blacktop bogging ( good link, sorry for that lol )

[joe86]

Hi everyone !

I recently swap my 1980 liftback Te72 with a 20v blacktop ! The 20v now starts and idling good, but i'm having some issues when i open the throttle

All is connected, wiring have been checked twice, i run 70mm stacks with mesh, at the moment i have no exhaust ( straight to downpipe ), i'm converted to coils on plugs, i run SQ water kit and a inline walbro 255 fuel pump on stock regulator and my fuel pump is connected with a open relay controlled with the ecu, front booster vacuum banjo bolts was swap to the rear and the front one was block off

My tps have been tested and should work fine, my MAP when its disconected it run like crap and when its connected its fine, so i guest its good too !

I got 2 checks engine code, 21 and 41 ( o2 sensor and tps ) only few minutes running, no test drive at all.

The problem :

Randomly when i open the throttle the engine want to bogged,
If i rev fastly and gradually it can reach redline but if i try to reach the redline gently it will bogged and sometimes stop running completly
If i reach around 4k rpm or so and stay there for couple second, the rpm will varied by itself between 3,2k and 4k

here is a quick vid :


My thought;

I dont think the o2 can cause this trouble ( i've tried unplug it and it wont change anything )
Can it be the the ecu who detected bad ignition due to the cop and send fuel cut ?
Maybe bad timing ?

** note that the engine was running fine last year when it was in an other car ( fwd ae101 ) ! I've modified NOTHING excepted the cop conversion, naturally the wiring to adapt my te72, the inline pump and the banjo bolt for the booster **


Thanks for helping me guys !!

[jondee86]

IIRC someone else had these same codes in a thread not so long ago. Had
a quick look but couldn't find the thread... will take another look later

Cheers... jondee86

[jondee86]

OK... couldn't find it... must have been halucinating again

First you should unhook the battery and press the brake pedal a few times
to reset the ECU and clear any latched codes. Then start the car and let it run
without disconnecting any plugs, to see if the codes come back.

The BT ECU has some "learning" ability. Disconnecting the battery not only will
clear the codes, but also clears the learned behavior from the ECU memory. It
is then necessary for the ECU to relearn fuel and ignition settings for correct
operation. This usually requires 2 or 3 days of driving under a full range of
engine loads and speeds. It won't learn anything worth a damn in your garage.

Also, the BT is very sensitive to small changes. You have made changes to the
factory intake system, ignition system and you are running the engine without
an exhaust. The ECU can most likely adapt to these changes (even if your
neighbours can't), but you will need to get the car on the road and learning.

Cheers... jondee86

[joe86]

Damm you really thinks it only need a learning sessions with a load ( driving it ) ?

I'm wondering if I'll be able to drive it in those circumstances because it really get his rpm roughly sometimes !
Anyway i'm having issues bleeding the brakes at the moment, so i can't test drive it right now

Like i need to replace the vvt pulley i'll try to re-time it and between that i'll try to verified a things or two in the wiring/sensor/vacuum !

Thanks a lot for replying me fastly !!

[joe86]

Damm it was the map who's getting faulty reading, i've removed the little check valve and it runs like a champion !

[jondee86]

HA You wouldn't be the first person to put a check valve in the map sensor
hose instead of a pulsation damper !! But easy fix, and you got it solved.

Cheers... jondee86

[joe86]

Funny fact : I've google search my trouble to find information about the tps and i've seen an old thread with you telling a guy that he dont need this check valve and to try removed it haha

So you saved my summer haha thanks !

[v33sonata]

Just went thru this. STA wire... check it. I thought there was no way one wire could make my car run this bad. Sure enough...... Tonight she is alive!!!


Edit guess I should have finished reading! haha glad she is up and running!