29 replies to this topic

[WJM]

5 seconds after boost comes on (posi mani pres) i get a fuel/ignition cut that lasts about 1/4 of a second. Then 5 secs later it does it again. This happens at 2/3 throttle or more. Does it in every gear now.

I dont like it. Any ideas on the problem?

BIG NOTE: I am running STOCK BOOST, on an otherwise STOCK engine.

[JWX]

switch cars with me so you can run this one into the ground, instead of a nice near mint RX. I think thats a good idea you can keep your engine and tranny too.

[WJM]

Ha. Ha. Ha. No.

I may need that extra ECU in the 89 RX.... :-\

[JWX]

dang man you be taking all me parts. I kid I kid

[northguy]

Is there a possibility of a partially clogged fuel filter or a leak in the seal on the filler cap that would be causing a void in pressure?

[All_talk]

Yep, I'd check fuel pressure first. I think 36psi over manifold pressure is the stock number.

Gary

[WJM]

Well...the stock boost controller is going crazy...so at one instance it was boosting 30 PSI....big fuel coud...so I dont think its fuel pres issue...

the ECU finally threw a code. 31: TPS sensor circuit open/shorted. So...ive got an TPS laying around...so I'll swap it.

I am also going to isntall the header/DP on this car tonight...and swap out shift linkages as the ones in it are JUNK! And...idk what else. :-p

Oh, clean the MAF as well. It might be sending funky signals...as well as fix t3h boost controller.

[WJM]

Cleaned MAF. Installed TWE Header/DP...and GReddy EBC...cleaned TPS connections...

STILL CUTS OUT AT 5 SECONDS!!!!!!!!



I guess I will replace the MAF tomorrow...

this pre 87...yet 87+ RX has a strange TPS. TWO wire...with a separate TWO wire connector that has 3 leads comming out of the female end going to the main harness...?!??!?!?!

[WJM]

Change MAF this morning.

Still does it.

Played with boost...now i hit REAL boost cut.

But...after a few sessions of the 5 second on boost 1/4 sec cut...its now going 12+ secs before the 1/4 cut...or doing it at odd intervals...but no longer after the usual 5 seconds.

[JWX]

ECU borked?

[WJM]

ECU borked?

I dont think so...but its something to try.

Still ahve not found a TPS...i am really thingking thats the problem...but since I dont ahve one, i am trying to see if any ofthe other items that could be it are it that I do have an can replace...i may have to get a NEW TPS fromdealer...and thats a $h!t load of cash...

[JWX]

then get the job there and have one come up "missing"

[WJM]

then get the job there and have one come up "missing"

No....i'll just call Randy in atlanta...

[WJM]

Swapped out coils....still does it.

[JWX]

does the check engine light come on? (like when you turn the ign switch on but don't start it) maybe theres a code and its not tripping the light on the dash or maybe the light is out?

[WJM]

its the TPS. I still dont have a replacement for it.

[JWX]

well then better get on that then

[WJM]

well then better get on that then

Kinda hard to do that when NONE exist and I have not looked at the part number... :-p

[WJM]

Ok, so I got unlazy and got the TPS out to test it. WOT switch works, and there is a smooth arc or ohms on the TPS part...looks like its just out of adjustment. I'll re install it now.

Also broke every single PCV plastic peice and hose on the system. Time to put my custom breather on now.

[stngllhm]

if the tps turns out to be bad i may have an extra one comeing into my hands that i could let you have

[WJM]

Is it the wierd one with the connector on top as well as on the side?

[WJM]

Ok, TPS fixed. ECU not throwing code for that anymore.

its just giving me the 'model designation' flash on the ECU now.

BUT ITS STILL CUTTING OUT!

Also...it will boost creep to 13 psi or so, and NOT fuel cut. BUT...when i use the EBC to control boost, it will fuel cut.

[operose]

I know nothing about turbos except what you and the other people talk about, but my powers of deduction would lead me to find the problem with the electronic boost controller.... as that seems to be what's causing your fuel cut if it's only happening when you use it.... (master of the obvious = me!)

Ok, TPS fixed. ECU not throwing code for that anymore.

its just giving me the 'model designation' flash on the ECU now.

BUT ITS STILL CUTTING OUT!

Also...it will boost creep to 13 psi or so, and NOT fuel cut. BUT...when i use the EBC to control boost, it will fuel cut.

[WJM]

I know nothing about turbos except what you and the other people talk about, but my powers of deduction would lead me to find the problem with the electronic boost controller.... as that seems to be what's causing your fuel cut if it's only happening when you use it.... (master of the obvious = me!)

Um....duh....but even at stock levels and before the EBC was installed, it has done its little 1/4 sec burps.

I adjusted the timing and the low end bog dissapeared...but came back.

[jazzician]

Hey there. I have an 89 Subaru GL10 Turbo and we may be experiencing the same thing. Pretty much right after the turbo kicks in, I start experiencing quick hesitation (cutting out) about every 1/2 second or so and we've been chasing it for sometime now. Tried 94 octane, new coil, relay for abetter spark, K&N filter, TPS change, new plugs/line, fuel filter, added muffler as it was straight pipe before, changed the ECU. I think we're still thinking Knock Sensor as the engine is quite noisy and could be setting it off when the Turbo kicks in or some fuel injection issue. The pressure is good on idle but may change during Boost. So, in short, maybe Knock Sensor, Fuel injector? If anyone figures this out, let me know. My engine's getting near the end of it's life so I think I'm going to drive it till it dies, then put another engine in. We have a "dying, noisy engine"/knock sensor theory.

Simon