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Engine runs, no boost.

6K views 53 replies 13 participants last post by  kittyboy 
#1 · (Edited)
I'm trying to find out why my car is not showing any boost on the gauge or on hptunners. I don't know if it's actually boosting or not.

I've tried tightening and checking everything like vacuum lines, sc torqued, lid torqued, bypass adjustment, but I can't figure out what's going on.

In park the car will rev up naturally everything seems fine "minus no boost"
"The car used to boost if I revd it over 3k in park no load. Before the swap"

Engine trans computer was pulled from my wrecked coupe. Also added a lot of bolt ons.
11coupe -> 09sedan

Driving the car had no power, and acts worse the more I try to go 30+.
The car will do a kinda fuel cut, and if I get around 40 the car cuts all power and start to surge.
 
#5 ·
I just did a log of everything im not seeing the map on there tho
 
#3 ·
I just tried to drive it up to the store. The car does not like to go over 30 at all it starts fuel cutting and surging.

If I barely touch the gas it'll cruise at 20 anything over that and it starts acting up.
 
#7 · (Edited)
11Coupe "modified a bit upper injectors airaid e85 catch can hx" - wrecked - engine trans computer pulled. Dropped into a 09sedan.

The car is also now full bolt ons, lower, 1300cc injectors, full exhaust, chiller, oil cooler, trans cooler, ext...

There was no codes till after driving it, and it was the same codes that came up when the battery was low. I just bought this battery and it almost died from just having the car settings for a few minutes key turned on
, iat2, iat1, cam sensor, 5 driver,
Personal computer Computer Font Material property Software
 
#6 ·
engine wont run well if at all without the map sensor, is it plugged in still or become disconnected ? may be your issue if its not reading it then u wont be running well and boost wont read n such might have to check the sensor
 
#8 ·
It's plugged in. The car idles and runs fine.
Until you drive it, then it runs like shit.

It idles like shit when map is unplugged.
I left it unplugged one time after like the 5th time taking my lid off to try and fix the bypass placement, and make sure everything is done right.
 
#9 ·
that comms issue will be causing problems, also the ect and camshaft will cause engine to run bad, unless they are just because of the lost comms issue id prob think to fix that and it will all turn good again
 
#10 · (Edited)
codes I believe are coming from low battery.
I cleaned all the grounds and bought a new battery, codes went away.

I had the ignition on for a few minutes with all my extra things hooked up. chiller, o2 gauge, hpt, hx pump, oil cooler fan. all running. headlights might have even been on.
New battery got low and the codes came back. Except it was crank last time not cam.

my tuner said it looked like a bad battery. on here everyone recomened cleaning the grounds. so I sanded all of them down cleaned them and put back tight.
 
#11 ·
Check cam sensor, as well as MAF (could be bad ?)
Is "new" TCM from the same year V ?
Try to do TPS learn as well.
Who did the tune ? If you added ported blower + TB, your fueling will be all messed up and it won't rev/drive obviously, not trying to insult your intelligence or anything.
 
#12 · (Edited)
tuned by Justinwhite, Everything is in my signature. Ported sc is ordered not installed yet.
 
#13 · (Edited)
The computer is out of the 11. The tcm and fscm are from the 09. I did a relearn on the car after swapping out the computer.

The tcm relearned the new vin. The fscm I had to buy a credit for.
 
#15 ·
How should I check those sensors?
 
#16 ·
Basics first.
What is your battery voltage when checked with a DVM at the battery and also at the fuse box area?
Hook up the DVM near the fuse box and place the DVM on the windshield or hood so that you can see it and see what it reads when you try to drive the car.
Drain some fuel at the fuel rail (rig up a hose, use the fuel pump to run a cup or so into a jug) and make sure you didn't get a tank of water at some point.
Log the fuel pressure when you 'drive' it.
 
#18 · (Edited)
Ya I'll post the log. when I started the car today it was 13.2v on the dash

there was old e85 in there 3/4 tank. I pumped most of it out with my aux pump. there was little less then a 1/4 tank in there when the aux would no longer pump it out any more.
i got about 12gallons out. then I added 10 gallons of 91-93 im not sure which it was. then pumped out another gallon.

Ethanol reading is 28.2% so maybe 18% of the tank is still old e85? Should I drain more?
 
#19 ·
Cant figure out how to attach the log file on here. I can email it to you ?
 
#21 ·
I would unplug your 3 sensors on the driver side of the blower and make sure they snap in really good.

You're also getting current codes for your Cam Position Sensor (P0340, P0341) that could also cause weird engine performance.

Automotive tire Motor vehicle Hood Vehicle Auto part
 
#22 ·
I unplugged the dsx aux pump jumper and swapped map sensor from another lid. The car is now reading some boost on hptuners like 3lbs.

The car still fuel cuts around 3k and the gauge cluster still reads no boost.

My tuner added a bit more fuel but still having issues.
 
#23 ·
All those lost coms point to a wiring issue. I would check the harness by the ECM, check the ECM connector pins and make sure something has not come loose. What is your fuel pressure whe the car hits fuel cut?
 
#24 · (Edited)
I cleared those codes and they have not come back since the battery charged back up
 
#25 ·
dos yours have two map sensors ? one for manifold pressure and another just for baro reading ? if its reading 100kpa all the time it may be blocked as u should see lower under vacuum and higher on boost, if u can get the scanner going and use an air compressor on like 20psi and take the map sensor out and watch the scanner with the pressure into it and see if its showing correctly and moving
 
#26 · (Edited)
There is 2 maps on the lid yes.

Swapped the 3 bar map out and I removed the dsx aux pump jumper wire and started getting vacuum readings in hpt.

The Kpa was 20~ idle.
After this I got the dsx jumper working but the average Kpa went up to 46~ .

The car won't go over 38mph.
some times it'll boost a small amount I've seen 3-5lbs. At 38 mph the traction control light starts flashing and it'll cut all power. As the speed drops the traction control will turn off.
 
#38 ·
There is 2 maps on the lid yes.

Swapped the 3 bar map out and I removed the dsx aux pump jumper wire and started getting vacuum readings in hpt.

The Kpa was 20~ idle.
After this I got the dsx jumper working but the average Kpa went up to 46~ .

The car won't go over 38mph.
some times it'll boost a small amount I've seen 3-5lbs. At 38 mph the traction control light starts flashing and it'll cut all power. As the speed drops the traction control will turn off.
Sounds like you've got a bad ground if connecting the aux fuel pump jumper makes the kPa change
 
#28 · (Edited)
I can email you the log
tuner told me to mess with the map. That's the only thing I changed. The map wasn't reading before that.

Fuel pressure was around 53psi
Voltage on dash is 13.7
I'll have to check at the battery still w. Voltmeter tonight.
 
#29 · (Edited)
Update With stabilitrak off the car seems to drive normally.

Also discovered one of my -an fittings is leaking oil 🤦 gonna be a fun fix. pinned right behind the headers.
 
#30 ·
Ok. So my car was reading no codes in hpt. "Engine light on"
Went to the store and they read the codes po340, po341

So I tried to take the cam position sensor out.
However it's stuck in there. It'll rotate but I can not pull it out.
"after putting it back together the engine light went off. But now hpt reads code po340

Anyone ever have this issue? I need some help figuring out how to get the sensor out.
 
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