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General Lean and no boost on gauge

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Steve92talon

Proven Member
156
21
Jul 3, 2019
Fernie, BC_Canada
So I got my wide band working correctly, did a test run and I know why my motor is choking and dies when the boost comes on. It goes off the chart lean and starved of fuel.

Is this connected to the stock boost gauge only reading vacuum and stays at 0 when boost comes on?

I can see the fuel pressure regulator is hooked to a vacuum line on the intake and runs to the firewall to a round sensor with 3 wires on it. Is this the differential pressure sensor the ECU needs to read boost?

Cruising along it's at 13 to 14:1 soon as I boost it the gauge stays at 0 and I go off the gauge lean. Am I mistakenly running a NA computer that does not register boost?

It's making 10psi easy, verified with a external gauge.

I'm new to all of this stuff. At least twice it had enough fuel to pull hard and it's very surprising how quick it can be.
 
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Take a picture of your ecu,
What color Injectors are yours?pink,blue,grey?

And a few questions

Waste gate works properly?
Any shaft play on the turbo?
seems like your running out out of fuel and cant spool up.
Any mods? (Afpr,SAfc,dsmlink ect...)?
Spark plug gap?
Cracked exhaust manifold?
Boost leak test?
Any unrelated issues?
Any knock?
Are you able to do any logs?


Few things off the top of my head to help ya
 
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It has a pretty long list of stuff the previous owner did already.
Just bought a 92 talon AWD turbo over the weekend has some goodies on it I have no idea how to use. .020 oversized forged pistons, scat h beam rods, ARP head and main studs with a MLS headgasket, EGR delete, Counter balance shaft removed. ACT stage 3 clutch and lightweight flywheel, HKS fuel cut defender, HKS ss bov, Apexi AVCR digital boost controller. Injectors I will have to look tomorrow.

Race head is blown up but the 400 plus lift cams are in the trunk of the car.

Just put new plugs in it, NGK stock ones everyone uses that I read. The pacesetter manifold is cracked for sure gotta put some weld on it.

Has the coil on plug conversion but a stock ecu set up no tuning capability.

it's like the fuel shuts off or runs out. Really hard to check fuel pressure without a Schrader valve since it's a 92. Possibly the fuel defender is suspect shutting my fuel off? I have it turned all the way left. When its turned up u cant rev it past 4500 at a stop like its rev limited? I turned it all the way counter clock and then it will rev like normal no limiter.

I'm new to tuning and all this computer controller stuff. No idea how to use the AVCR thing it's set however the previous guy used it.

It spools up good makes 10psi easy but after 7psi fuel goes lean and it breaks up and dies. Plus why dose the stock boost gauge only read vacuum and stays at 0 into boost?
 
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Stock booat gauge may be reprogrammed. Does the car run an eprom ecu? Possible chip change.
No the item that goes to fuel pressure regulator does not measure boost.
 
It's a stock ecu no socket. What dose the sensor do that the fuel pressure regulator is tied into
 
It's a stock ecu no socket. What dose the sensor do that the fuel pressure regulator is tied into

There’s a diaphragm inside and for every 1lb of boost it sees, it increases fuel pressure by 1lb. There’s no sensor.
 
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Do you have a stock coil and plug wires you can throw in? have heard alot of people having issues with cheap cop setups. And usually most people can get away the stock coils depending on there setup.

Have you checked and set base timing ?

That cracked exhaust manifold will affect spool.

Wonder if your wastegate arm is cracked where the flap seals If it's an internal wastegate that your running.

Are you trying to run the car with the bad head ? (What's wrong with it?)


The factory boost gauge is trash imo .
Do you have a aftermarket boost gauge?

+1 on checking out the fpr

I wish I could help you with the hks controller but dont have experience working with those.

You should do a build thread with all your mods so people can more easily help you out. Pictures help also
 
So how dose the ECU read boost pressure? My factory gauge only works in vacuum stays at 0 when boost builds.

You should do a build thread with all your mods so people can more easily help you out. Pictures help also

I didn't build anything LOL bought the car as is. It's on a stock head and cams right now.
 
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looks to be the correct ecu for your car . I'd like to mention if the caps on that ECU havent been replaced I'd atleast look inside it or send it to someone who does cap replacment (pretty easy depending on the extent of damage ) .
 
So how dose the ECU read boost pressure? My factory gauge only works in vacuum stays at 0 when boost builds.
Its just calculated and not accurate the maf has somthing to do with it I think its the 7th wire on the maf plug. I would not even try and use the stock gauge for reading boost levels.
 
I swapped ecu to this one and now I have a working boost gauge and all the fuel it needs!!! Too much right now its pig rich in boost instead of cutting out lean. Super fun test drive I'm excited
 

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That's an ECU for an 1G Turbo Automatic. It's not going to have the right tuning due to the injector, base fuel pressure and turbo differences but it suggests that the other ECU is damaged. You could adjust (retune) with the AVCR but write down all the settings before you change anything.

I'd remove the HKS fuel cut defender. Think about changing to a recirculated BOV rather than the HKS. Every time that BOV opens it will release measured air causing the fuel to go rich for a moment.

You have a stock FPR and it looks like stock blue top 450cc injectors.
 
Go back to the stock 1g dsm bov and recirculate it back to the stock intake.

Check to see what fuel pump you have. If it's aftermarket, grab yourself a fuel pressure regulator and make sure you have stock pressure.
 
Is the fuel defender not required anymore for stock boost levels? I have one more ecu but it dose not have the knock board on it. I'm waiting to hear on getting a chip put in one of my ecu. But there is no stock currently to get a chip :( bummer on the bov to atmosphere being no good it sounds so fun ha ha
 
That's an ECU for an 1G Turbo Automatic. It's not going to have the right tuning due to the injector, base fuel pressure and turbo differences but it suggests that the other ECU is damaged. You could adjust (retune) with the AVCR but write down all the settings before you change anything.

I'd remove the HKS fuel cut defender. Think about changing to a recirculated BOV rather than the HKS. Every time that BOV opens it will release measured air causing the fuel to go rich for a moment.

You have a stock FPR and it looks like stock blue top 450cc injectors.
Do u know more about the avcr module. I'm still learning about all this tuning stuff
 
Do u know more about the avcr module. I'm still learning about all this tuning stuff
Virtually nobody uses those fuel-cut defenders and acvr anymore. If you're running stock boost then the car is completely stock going off your pics and what you've said. You shouldn't need anything to run a stock car.
 
Yes far as I can tell besides the header and some engine internals being upgraded and its bored 20 over its stock. I do have some racing cams for it but not sure the stock head has enough lift to use a high lift set of cams
 
Do u know more about the avcr module. I'm still learning about all this tuning stuff

Senior moment for me. I thought at the time that the AVCR was the upgraded SAFC but I see it's only a boost controller. I've attached the manuals.
 

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