Ok so a friend of mine asked me to come over and tune his car but i would have to get it running first in order to do so. I said ok and gave it a shot.

to start off, i have worked on this car before and the wiring that was done on the car is not "the best" and i had to clean up alot of the wiring when i removed the afc.
Prior to his problem, he made a trip out of town and beat on the motor real hard for a good 45 minutes. Then he said that the car starting running as it is now and has been sitting in the garage for the last 6 weeks.

To start off, when you start the car, it sounds like it is running off 3 cylinders. He's not running a dumptube on the wastegate and it smokes like a bitch upon startup. The throttle does not have the normal response, it is delayed and unpowerful. Reading off the AVCR, the map signal is bouncing a good bit (between 30mmhg to 250mmhg) and idle is irratic, especially when holding the throttle in attempt to keep the engine running. This lead me to believe there was a vacuum leak.
AFR bounces from 11 to 13.5 is correlation with the bouncing idle. its just everywhere.

He's running a 3bar MSD map sensor that has been spliced into the stock map. I took the voltage from the stock map sensor and got the required 5volts.
I then tested the TPS sensor and got a rather weird reading....
.28v at closed
2.01v at WOT
~2v at the 5v pin (#3)
However, the AVCR still reads the TPS perfectly. shows 0% to 100%.

I pulled the plugs out, cleaned them and regapped the plugs. He was running .028 gap and i made the gap bigger to .035. (originally he was running too much gap at 16psi and the turbo would blow out the spark). Just from trying to get the car to idle, the plugs are filthy black, but all of them have been tested and are getting spark.

The motor is running a stock FPR with 550cc injectors / Crome. Pressure with the vac line connected is 40psi so thats over 50psi with the line off. Pretty high, imo.

He has had an oil leak for a "long time". I took a look around the bay and found that the hose coming from the bottom of the PCV, leading to the black box was not attached to the box and was just kinda chillin. I put that back and im sure that will fix his oil leak considering its just spitting oil out of that line.

I do not know how long the engine has been running like that so i performed a compression test. This is a 9:1 compression motor and it pumped out 160psi across the board. Lower than i expected it to be, however, they were all consistent.

any advice or help would be greatly appreciated.

 

anyone?

 

try forced induction forum

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1sickEJ &raquo;</TD></TR><TR><TD CLASS="quote">try forced induction forum</TD></TR></TABLE>

its not a boost problem, thanks.

 

where are all the smart b series folk?

 

bump

 

Hahahaha.....Blake, seeing how the other side works......

 

Silly idea, and not electronicly related at all, but have you thought about a compression test?

Maybe it sounds like it's running on 3 cylinders because it actually is.

I'm sure you might be dealing with some wiring issues too, but it'd be a ton of wasted time fixing sensors/wiring on an engine that has low compression on any cylinders.

 

yea...sorry. Forgot to add that we already performed a compression test. Although the engine was not at normal operating temp (cold) it still put out 160psi at each cylinder.

 

Long shot, but what kind of plug wires?

Does this car have an aftermarket ignition/coil system like MSD?

 

stock ignition. I thought about his plug wires as well as the source to his problem considering he has some 10mm off brand ones.

I took each plug out and grounded it to the motor and each spark plug fired so i dunno......

 

sounds really silly, but how is the o2 sensor reading:?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B16B_coupe &raquo;</TD></TR><TR><TD CLASS="quote">sounds really silly, but how is the o2 sensor reading:?</TD></TR></TABLE>

i have it running in open loop

 

i say check all the wiring againg make sure everthing is good and see ... or put stock injetor and stock ecu and see how it idle's

 

Hey, fellow Floridian! Try borrowing a friends' distributor just for testing. For it can be as simple as changing the rotor inside the distributor. It happened to me before but managed to fix it just by replacing the rotor. Please update me if it worked..

 

well i knew it had to be something with the map sensor because his boost controller wasnt reading the map signal correctly. He followed the map wires to the ecu and found that the pin was loose. Plugged it back in and secured it and now it runs good.