MyE28.com DEV

As the title states. My afr is not solid but respectable 14.3-14.9 @ stoich. Begi when clamped pegs past 60psi(inline gauge(stock fpr-pressure gauge-BEGI RRFPR). Pulled plugs, indications of running rich, but no electrode damag/gaps checked-plugs are 2 deg colder/new 30# injs seem ok.(pulled indiv. harnesses and listened to changes) Replaced fuel filter/checked 15A fuse for pump(255 walbro fed to stocker) Replaced CTS last night after checking for proper ohms. It was within range but decided to do it anyway as I'm baffled here. checked wires to cts/vacuum leaks/AFM wires and holddown screw/BEGI@ idle is 10 psi, at mani atmosphere 48psi, and needle screwed all the way out on the proportional boost control. Car was running great until left work yesterday and it started bucking like a bronco under load. As a side note, I decided to goose it a couple of times, and under WOT it bucks like crazy, plays catchup for a few seconds(pig rich 10.0 and bucking) and then accelerates under boost like normal. The TIAL38mm WG is to atmos and I hear it opening. I even manipulated the AEM Tru boost spring settings from 1.0 to 12.0 (10PSI spring in WG currently- normally @ 7.0 setting on AEM Tru boost controller). Checked for loose wires. Blah blah blah. There is something staring me right in the face, I can feel it, but I'm just out of ideas at this point. Is the stock Fuel pump shot? Wastegate stuck open. I guess those pull and play tests are next. This is getting VERY old.
TIA-

Dash Pod :
AEM TruBoost on the left showing manifold vac/partial boost
AEM Wideband on right AFR showing rich condition

Have you pressure tested the piping system for a boost leak?

Brad D. wrote:Have you pressure tested the piping system for a boost leak?

I have not. After your post, I did a search and came up w/one guy w/a vacuum cleaner and another w/a wooden plug etc... I don't have a smoker, besides a visual insp of all the silicone couplers, is there a diy besides the aforementioned. Thanks

Just pressurize with shop air. Get a pvc cap, drill a hole, install valve stem, clamp into either turbo inlet or compressor discharge pipe and, using a pressure regulator, charge the system and use soapy water to check for leaks.

Brad D. wrote:Just pressurize with shop air. Get a pvc cap, drill a hole, install valve stem, clamp into either turbo inlet or compressor discharge pipe and, using a pressure regulator, charge the system and use soapy water to check for leaks.

Got it. Thanks Brad. Will post with results after I rodeo home and cobble my pressure tested together.

Bucking usually is lean in my car,also timing can cause bigger bucking issues than afr if fluctuating.
what's a cts?
marc

marc79euro645 wrote:Bucking usually is lean in my car,also timing can cause bigger bucking issues than afr if fluctuating.
what's a cts?
marc

Hey Marc
CTS Coolant temperature sensor. From what I understand, the readings from this sensor are fed back to ECU. This data from the sensor is then used to adjust the fuel injection and posibbly ignition timing(?) someone can chime in if I've misunderstood this. But either way, I can see how it might be leaning out too, even if the wideband is reading pig rich. There's no air to come the dance and well-ah. I didn't have time or interest to rig the tester yet for the boost thing-ey, but this weekend will free up a couple hours(read 8) Thanks for the input.

Made up the pressure rig w/ regulated shop air @ 5 psi from the charge air exit@Turbo. Solid. No leaks. Pulled all silicone connectors and inspected. Soapy water test also. Checked the underside of the intake manifold/vacuum lines.
Replaced the sketchy looking ground strap that connects the hood to the front pass. side fwd rail. I guess tomorrow I'll pop the distributor to check out the points. I can drive it just fine. But even @ the mention of boost,(getting into throttle) the car misfires(?)/bogs down(pig rich)/shutters is the best I can describe it.(BEGI ?) Its definitely an under load condition. Scratching my head, but I'm not giving up yet. What am I missing guys? Thanks!

What are your plugs gapped at?

I run NGK BPR7ES, just like you recommended in the FAQ, @ .028. Will check the TPS today as well as the dizzy as my weekend slowly melts into nothingness.... BTW I believe my wife now officially hates this car.

I'm gonna hate to see her go...

mpowertech wrote:I run NGK BPR7ES, just like you recommended in the FAQ, @ .028. Will check the TPS today as well as the dizzy as my weekend slowly melts into nothingness.... BTW I believe my wife now officially hates this car.

I'm gonna hate to see her go...

They always hate the other woman.....

So the issue has been resolved. I decided to break down the BEGI and low and behold the antiseize/molykote they use during the assembly process had turned to a hardened clay-like consistency. I cleaned the entire unit and all pieces w/Simple green aircraft precision cleaner. Checked the diaphragm for tears/exercised the adjustment screw/tightened signal and check fittings /tested check valve and reassembled. To note: I also back seated prop. band needle valve. I was futzing around with it at some point and the needle valve was turn in about 1/2 the throw of the adjustment point. Also...Very important, I did not have a restrictor in the signal line. I remember putting one in-line to the original hard-line signal I had originally installed but when I c/o to a newly purchase vacuum line i neglected to reinstall it. Either way I just grabbed another one from the 10 pack I bought @ HDepot. (I used a replacement tip from a Lincoln MIG welder (.025) they run about 8 bucks for a half dozen or so. Not sure if this is undersized , but I will order the proper one from Mr. Bell today. The car runs strong now, but still burps a cloud of fuel when I go WOT. I'd certainly like to address that, but another post/another time.
Thank you for all who freely took time to help me with this problem. I am extremely grateful..

Glad you got that figured out. I definitely didn't have that cause on the radar.